The following protocol complies with the guidelines of the human research ethics committee of the department for internal medicine/cardiology of the Hietzing Hospital in Vienna.
1. Preliminary Measures
<ol>
	<li>Administer the patient for whom VT ablation is planned at the ward at least 2 days prior to the procedure.</li>
	<li>Acquire blood sampling, X-ray of the chest and transthoracic echo-cardiography. In case of known atrial fibrillation (persistent or paroxysmal), perform a transesophageal echocardiography one day prior to the procedure.</li>
	<li>On the day of VT ablation, discontinue oral anticoagulants (in case the patient takes some for atrial fibrillation or other co-morbidities requiring the use of oral anticoagulants) and administer i.v. antibiotics.</li>
</ol>
2. Patient Preparation During the Procedure
<ol>
	<li>Apply self-adhesive ECG electrodes for 12-lead ECG (on the front chest - see Supplementary Figure 1 - and extremities in a standard position) as well as surface patches, neutral electrode and a system reference electrode compatible with the designated 3D mapping system (see Table of Materials) and a neutral electrode for the ablation catheter in a standard position to the patient&#180;s skin (see also Supplementary Figure 2).</li>
	<li>Apply self-adhesive defibrillator patches to the patient&#180;s skin in the advised position (below the right clavicle and at the left ventricular apex) and switch on the defibrillator.</li>
	<li>Deactivate the tachycardia therapies of the ICD with the appropriate programmer, optionally deactivate all device functions that might interfere with the ablation current. 
	NOTE: Tachycardia therapies of the ICD will stay deactivated throughout the procedure. Guarantee close monitoring and consistent readiness of the external defibrillator.</li>
	<li>Use a pulse oximeter to monitor the oxygen saturation.</li>
	<li>Introduce a sheath via the left radial artery for invasive blood pressure monitoring, either via Seldinger technique6 or with an arterial puncture system with an integrated cannula (see Table of Materials).</li>
	<li>Disinfect patient&#180;s skin in both groins with 75% propanol (see Table of Materials) and cover the patient&#180;s body with a sterile cloth, sparing the groins. 
	NOTE: At this point, all persons entering the catheter laboratory and working in close proximity to the patient have to wear hoods and masks.</li>
</ol>
3. Groin Puncture and Catheter Positioning
<ol>
	<li>Apply local anesthesia (xylocaine) in both groins by subcutaneous injection and introduce a central venous catheter via the left femoral vein and 3 sheaths (5, 6 and 12 Fr) via the right femoral vein with Seldinger technique6.</li>
	<li>Place a quadripolar catheter in the right ventricular apex and an 8-polar steerable catheter in the coronary sinus by means of fluoroscopy (beam positions: AP, RAO 30&#176;, and LAO 60&#176;). 
	NOTE: As soon as the x-ray equipment is activated, all persons entering the catheter laboratory have to wear lead protection.</li>
	<li>Connect diagnostic catheters to the electrophysiology system and stimulator (see table of materials).</li>
	<li>Verify that the quadripolar catheter in the right ventricle has sufficient capture by stimulating with a cycle length of 600 ms (or less, if the patient is tachycardic) and look for the adequate response.</li>
	<li>Administer 5000 IU heparin via a venous sheath in the groin. Perform activated clotting time (ACT) measurements every half hour with an appropriate device (see Table of Materials, ACT goal: above 300 s).</li>
	<li>Introduce a long steerable sheath (see Table of Materials) via the right femoral vein into the right atrium of the heart and perform trans-septal puncture using an appropriate needle connected to a pressure sensor line (beam positions AP and LAO 90&#176; or RAO 20&#176; and LAO 50&#176; depending on the investigator). After puncturing the inter-atrial septum of the heart, disconnect the pressure sensor line and apply contrast agent via the needle to check the correct position inside the left atrium. Then advance the sheath over the dilator under fluoroscopy control and place the distal end of the long steerable sheath in the left atrium pointing towards the left ventricle.</li>
	<li>Initiate general anesthesia by administration of propofol and remifentanil.</li>
</ol>
4. Electro-anatomical Reconstruction of the Left Ventricle
<ol>
	<li>Introduce a multipolar mapping catheter (steerable 16 pole catheter, electrode spacing 3-3-3, electrode length 1 mm, see Table of Materials) in the left ventricle via the steerable sheath and collect anatomical and electrical data of the endocardial left ventricle using the 3D mapping system (see Table of Materials) and the multipolar catheter.</li>
	<li>Define voltage of ventricular signals as follows: scar area under 0.5 mV, low voltage area between 0.5 and 1.5 mV and normal voltage area above 1.5 mV. Be careful to take into consideration only ventricular beats of the same type: either intrinsic ventricular activation in sinus rhythm or stimulated ventricular beats if the patient is pacemaker-dependent. Do not use premature ventricular complexes. Use the morphology matching feature to sort out unwanted ventricular complexes (see Figure 1).</li>
	<li>Optionally, turn down the lower voltage limit to 0.2 mV to identify viable conducting tissue inside the scar (see&#160;Figure 2&#160;and&#160;3).</li>
	<li>Pay close attention to fractionated (ventricular activation with more than one component) and late (second ventricular activation clearly separated from the first ventricular activation on a given electrode) potentials and annotate them separately (e.g. with special tags, see Figure 4A).</li>
	<li>Optionally, pace from the right ventricle to clearly separate the late potential from the first ventricular activation (see Figure 4B).</li>
	<li>Remove the multipolar&#160;mapping catheter and introduce an irrigated tip ablation catheter with sensor (electrode spacing 2-2-2, see Table of Materials) connected to a cooling pump into the left ventricle. Complete the electroanatomical map with the ablation catheter by adding missing anatomy (collect electroanatomical points at places where the multipoloar catheter could not be placed) and verifying zones of high interest (i.e. zones with very fractionated and late potentials &#8212; tag those zones separately, see Figures 1-2).</li>
</ol>
5. Programmed Ventricular Stimulation (PVS)
<ol>
	<li>Perform PVS7 via the catheter in the right ventricular apex and the EP stimulator (see Table of Materials) using a predefined protocol of up to 9 steps or until a sustained VT is induced:
	<ol>
		<li>Begin with a 6-beat drive train (10 V over 2 ms) with 500 ms cycle length and add an extra-stimulus of 350 ms coupling interval after the last stimulus of the drive train. Then, after a pause of at least 5 s, repeat this maneuver by decrementing the coupling interval of the extra-stimulus every cycle by 10 ms until the refractory time of the right ventricle is reached.</li>
		<li>Then, add a second extra-stimulus (beginning with 350 ms coupling interval) and repeat the above-mentioned protocol until ventricular refractory time. Couple the first extra-stimulus with the following interval: refractory time plus 20-30 ms, as appropriate (make sure the first&#160;extra-stimulus captures the right ventricle).</li>
		<li>Reduce the drive train to 430 ms, then 370 ms and at last 330 ms and repeat the above-mentioned steps.</li>
		<li>At last, add a 3rd extra-stimulus to the drive train of 500 ms and repeat the above-mentioned protocol.</li>
		<li>Repeat the protocol in the right ventricular outflow tact (RVOT) if no sustained VT can be induced.</li>
		<li>Make sure that the external defibrillator is ready to deliver a shock at any time during the whole procedure, and re-check it before PVS.</li>
	</ol>
	</li>
	<li>In case a sustained monomorphic VT can be induced (the following also applies if VT occurs during mapping or ablation):
	<ol>
		<li>Create an activation map of the left ventricle using the 3 D mapping system (LAT-map: local activation time) if the VT is hemodynamically stable. Optionally, perform entrainment mapping.</li>
		<li>Stop the VT by overdrive stimulation via the catheter in the right ventricular apex or, if that fails, by external cardioversion/defibrillation, if the VT is hemodynamically unstable.</li>
		<li>Mark and annotate every VT that can be induced and compare them to spontaneously occurring VTs or use it for pace mapping.</li>
		<li>If no sustained VT can be induced, continue with substrate modification (point 6) in case of a well-defined scar in ischemic cardiomyopathy. However, without inducible VT at the beginning of the procedure, there is no clear endpoint and control of success of the ablation therapy.</li>
	</ol>
	</li>
</ol>
6. Catheter Ablation
<ol>
	<li>Start irrigated radio frequency ablation with 35 to 45 W using the ablation catheter. Optionally, use a contact force catheter that provides information on tissue contact. Apply energy per lesion until a force-time-integral of 450 gs. Encircle scar areas by ablation lesions. Then, ablate all previously mapped abnormal potentials (substrate modification). Match pace mapping in electrically interesting regions to previously marked VTs.</li>
	<li>Pay close attention to ablation catheter impedance (usually between 90 and 150 Ohm), catheter temperature (max. 43 &#176;C) and patient&#180;s blood pressure (compared to the initial value). Immediately stop ablation if impedance drops or rises substantially compared to the initial value.</li>
</ol>
7. Post Ablation
<ol>
	<li>After ablation, repeat PVS.
	<ol>
		<li>If ventricular arrhythmias can be induced, re-evaluate the substrate and continue ablation (see points 5 and&#160;6).</li>
		<li>If no arrhythmia can be induced, stop the procedure.</li>
	</ol>
	</li>
	<li>Stop general anesthesia (optionally an anesthesiologist takes care of general anesthesia and gradually discontinues all sedative agents at the end of the procedure).</li>
	<li>Remove all catheters and sheaths from the heart.</li>
	<li>Re-activate the tachycardia therapies of the ICD and restore all formerly de-activated functions.</li>
	<li>Perform transthoracic echocardiography to exclude pericardial effusion.</li>
	<li>Take a final ACT measurement and administer protamine, if appropriate.</li>
	<li>Remove the sheaths of the right groin and apply a compression bandage. The central venous catheter in the left groin remains.</li>
	<li>As soon as the patient is awake and extubated, bring him to the intensive care unit for further surveillance.</li>
</ol>

<ol>
	<li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+top+10+causes+of+death.">The top 10 causes of death.</a> Health Organization Organization. , (2007).</li><li>Poole, J. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prognostic+importance+of+defibrillator+shocks+in+patients+with+heart+failure.">Prognostic importance of defibrillator shocks in patients with heart failure.</a> N. Engl. J. Med. 359 (10), 1009-1017 (2008).</li><li>Kamphuis, H. C., de Leeuw, J. R., Derksen, R., Hauer, R. N., Winnubst, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Implantable+cardioverter+defibrillator+recipients:+quality+of+life+in+recipients+with+and+without+ICD+shock+delivery:+a+prospective+study.">Implantable cardioverter defibrillator recipients: quality of life in recipients with and without ICD shock delivery: a prospective study.</a> Europace. 5 (4), 381-389 (2003).</li><li>Stevenson, W. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Irrigated+radiofrequency+catheter+ablation+guided+by+electroanatomic+mapping+for+recurrent+ventricular+tachycardia+after+myocardial+infarction:+the+multicenter+thermocool+ventricular+tachycardia+ablation+trial.">Irrigated radiofrequency catheter ablation guided by electroanatomic mapping for recurrent ventricular tachycardia after myocardial infarction: the multicenter thermocool ventricular tachycardia ablation trial.</a> Circulation. 118 (25), 2773-2782 (2008).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Task+Force+for+the+Management+of+Patients+with+Ventricular+Arrhythmias+and+the+Prevention+of+Sudden+Cardiac+Death+of+the+European+Society+of+Cardiology+(ESC).+2015+ESC+Guidelines+for+the+management+of+patients+with+ventricular+arrhythmias+and+the+prevention+of+sudden+cardiac+death.">The Task Force for the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death of the European Society of Cardiology (ESC). 2015 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death.</a> Eur Heart. 36 (41), 2793-2867 (2015).</li><li>Seldinger, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Catheter+replacement+of+the+needle+in+percutaneous+arteriography;+a+new+technique.">Catheter replacement of the needle in percutaneous arteriography; a new technique.</a> Acta radiol. 39 (5), 368-376 (1953).</li><li>Kossaify, A., Refaat, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Programmed+ventricular+stimulation+-+indications+and+limitations:+a+comprehensive+update+and+review.">Programmed ventricular stimulation - indications and limitations: a comprehensive update and review.</a> Hellenic J Cardiol. 54, 39-46 (2013).</li><li>. Figures taken and modified from the user handbook of the EnSite Precision Cardiac Mapping System Available from: <a target="_blank" href="https://manuals.sjm.com">https://manuals.sjm.com</a> (2017)</li><li>Tsuchiya, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+mapping+of+cardiac+arrhythmias+-+string+of+pearls.">Three-dimensional mapping of cardiac arrhythmias - string of pearls.</a> Circ J. 76 (3), 572-581 (2012).</li><li>Cano, O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Utility+of+high+density+multielectrode+mapping+during+ablation+of+scar-related+ventricular+tachycardia.">Utility of high density multielectrode mapping during ablation of scar-related ventricular tachycardia.</a> J Cardiovasc Electrophysiol. 28 (11), 1306-1315 (2017).</li><li>Schaeffer, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization,+mapping+and+ablation+of+complex+atrial+tachycardia:+initial+experience+with+a+novel+method+of+ultra-high-density+3D+mapping.">Characterization, mapping and ablation of complex atrial tachycardia: initial experience with a novel method of ultra-high-density 3D mapping.</a> J Cardiovasc Electrophysiol. 27 (10), 1139-1150 (2016).</li><li>Latcu, D. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selection+of+critical+isthmus+in+scar-related+atrial+tachycardia+using+a+new+automated+ultrahigh+resolution+mapping+system.">Selection of critical isthmus in scar-related atrial tachycardia using a new automated ultrahigh resolution mapping system.</a> Circ Arrhythm Electrophysiol. 10 (1), (2017).</li></ol>

The use of 3D mapping systems in complex electrophysiological procedures is a well-established method to acquire detailed and precise anatomical information and reduce radiation time and enables the creation of substrate and activation maps9. However, data acquisition can be challenging due to difficult catheter movement, especially in the left ventricle. Furthermore, point by point map acquisition takes a lot of time and thus prolongates the electrophysiological procedure. Wide electrode spacing at the tip of the mapping catheter reduces resolution and quality of the created map, critical signals may be overlooked. The use of a multipolar catheter for mapping of the ventricle solves the above-mentioned issues: several mapping points can be taken simultaneously; procedure time decreases. The narrow-spaced electrodes guarantee a very high resolution of the map, important signals are not so easily missed anymore.
Currently, there are 3 different 3D mapping systems available, all of them allowing the use of multipolar mapping catheters.
So far, one of them using a magnetic field is widely used, especially in VT ablation, due to its user-friendly handling and highly accurate electroanatomical reconstruction. A suitable mapping catheter, a 20-pole steerable catheter with narrow electrode spacing, can access even difficult anatomies due to its special configuration (star shape) and provides precise high density maps10.
A relatively new 3D mapping system also allows a very quick and precise acquisition of multiple mapping points by means of a 64-electrode mapping catheter with a basket shape11,12.
The 3D mapping system used in the protocol (see Table of Materials) combines impedance and magnetic field technology and thus allows precise navigation and accurate tracking of mapping and ablation catheters, either conventional or sensor enabled. The created electro-anatomical maps are highly accurate and don&#180;t need further post-processing compared with former versions of the mapping system. A huge advantage for accurate mapping is the morphology matching feature, which allows continuous comparison of QRS morphologies during map acquisition. The suitable 16-pole mapping catheter (see Table of Materials) allows the acquisition of multiple points simultaneously and makes possible high resolution and the detection of even small critical signals due to its narrow electrode spacing (3-3-3).
To further improve the quality of the map and identify critical potentials, we changed the low voltage range from 0.5-1.5 mV to 0.2-1.5 mV (to identify viable and conducting tissue inside the scar). Interestingly, most late potentials were detected in viable zones within the scar (see Figure&#160;1 and Figure 2).
By pacing from the catheter in the right ventricle, late potentials could clearly be separated from the first ventricular activation (see Figure 4B).
Despite the steerability of the 16-pole mapping catheter, we could not access all regions of the left ventricle. Those sites had to be addressed with the ablation catheter, which also has close electrode spacing (2-2-2), as well as a pressor sensor to guarantee adequate wall contact.
Despite all the above-mentioned advantages, the more sophisticated a method gets, the more prone it is to disturbances. Catheter noise can occur and make the interpretation of signals very difficult. Artifacts can simulate electrically interesting potentials and misguide the investigator. Multipolar catheters require more cables that can be damaged, the connection can be disturbed, troubleshooting costs time. 
Despite those disadvantages, multipolar catheters, if used correctly and by experienced investigators, are very useful for complex electrophysiological procedures and have a large potential in the future. Reduction of procedure time helps to prevent adverse events in these often very ill patients. The additional electrical information provided has to be interpreted carefully and along with other parameters available

Coronary artery disease and myocardial infarction remain major causes for morbidity and mortality in the industrialized world1. Myocardial scars after transmural infarction represent low voltage areas and thus zones of slow electrical conduction and facilitate the appearance and maintenance of macro-reentrant circuits. Ventricular tachycardias (VT) are responsible for repeat hospitalizations, painful shocks of implantable cardioverter defibrillators (ICD) and thus lessen quality of life and cause poor outcome2,3. Catheter ablation can reduce the occurrence of VT, especially in ischemic heart disease4, and should be considered in patients with ventricular arrhythmias and underlying structural heart disease in the presence of an ICD (class IIa B recommendation)5. In patients with structural heart disease with ventricular arrhythmias already suffering from ICD shocks, catheter ablation is recommended (class I B recommendation)5. However, catheter ablation is still a high-risk procedure, considering the often-poor state of health of concerned patients with mostly reduced left ventricular ejection fraction and multiple co-morbidities. Furthermore, the precise localization of scars and abnormal potential can be challenging but are critical for ablation success. The use of 3D mapping systems and multipolar catheters allow electro-anatomical high-density mapping and can considerably facilitate the acquisition of electrical information and thus improve the quality and validity of the 3D model and consequently enhance ablation success and patient outcome. So far, there are 3 different 3D mapping systems available, whereof one is commonly used for VT ablation. The following protocol describes an approach to endocardial ischemic VT ablation using a less common 3 D mapping system in the field of VT ablation and a multipolar catheter (see Table of Materials) for high-density electro-anatomical reconstruction.

<table border="0" cellpadding="0" cellspacing="0" style="width:1280px;" width="1279">
	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:411px;">NaVX EnSite Precision 3 D mapping system</td>
			<td style="width:201px;">Saint Jude Medical</td>
			<td style="width:353px;"></td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">EnSite Precision Surface Electrode Kit</td>
			<td>St. Jude Medical</td>
			<td>EN0020-P</td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Ampere RF Ablation generator&#160;</td>
			<td>St. Jude Medical</td>
			<td>H700494</td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">EP-4, Cardiac Stimulator</td>
			<td>St. Jude Medical</td>
			<td>EP-4I-4-110</td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">LabSystem PRO EP recording system, v2.4a&#160;</td>
			<td>Boston Scientific</td>
			<td></td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">octapolar diagnostic catheter, EP-XT</td>
			<td>Bard</td>
			<td align="right">200797</td>
			<td style="width:315px;">electrode spacing 2-10-2</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">supreme quadripolar diagnostic catheter</td>
			<td>St. Jude Medical</td>
			<td align="right">401441</td>
			<td style="width:315px;">electrode spacing 5-5-5</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Agilis NxT 8.5F, 71/91 cm steerable sheath, large curl</td>
			<td>St. Jude Medical</td>
			<td>G408324</td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">BRK transseptal needle, 98 cm</td>
			<td>St. Jude Medical</td>
			<td align="right">407206</td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Advisor HD Grid mapping catheter, sensor enabled</td>
			<td>St. Jude Medical</td>
			<td>D-AVHD-DF16</td>
			<td style="width:315px;">electrode spacing 3-3-3</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">quadripolar irrigated tip ablation catheter, TactiCath SE</td>
			<td>St. Jude Medical</td>
			<td>A-TCSE-F</td>
			<td style="width:315px;">electrode spacing 2-2-2 with pressure sensor</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Cool Point pump for irrigated ablation</td>
			<td>St. Jude Medical</td>
			<td>IBI-89003</td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Cool Point tubing set</td>
			<td>St. Jude Medical</td>
			<td align="right">85785</td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">GEM PCL Plus Instrumentation laboratory</td>
			<td>IL Werfen India Pvt. Ltd.</td>
			<td></td>
			<td style="width:315px;">&#160;activated clotting time measurement device</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">X-ray equipment</td>
			<td>Philips</td>
			<td></td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Heartstart XL defibrillator and associated patches</td>
			<td>Philips</td>
			<td></td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">12 F Fast-Cath sheath</td>
			<td>St. Jude Medical</td>
			<td align="right">406128</td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">6 F sheath</td>
			<td>Johnson-Johnson</td>
			<td></td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">5 F sheath</td>
			<td>Johnson-Johnson</td>
			<td></td>
			<td style="width:315px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">BD Floswitch&#8482;</td>
			<td>Becton Dickinson</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Isozid&#174;-H gef&#228;rbt</td>
			<td>Novartis</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

ablation of ischemic ventricular tachycardia using a multipolar catheter and 3-dimensional mapping system for high-density electro-anatomical reconstruction

Ventricular tachycardia (VT) in patients with ischemic cardiomyopathy mainly results from endocardial scars after myocardial infarction; those scars represent zones of slow conduction that allow the occurrence and maintenance of reentrant circuits. Catheter ablation enables substrate modification of those low voltage areas and thus can help to alter the scar tissue in such a way that arrhythmias cannot appear anymore. Hospitalizations of concerned patients decrease, quality of life and outcome rise. Consequently, VT ablation represents a growing field in electrophysiology, especially for patients with endocardial scars in ischemic heart disease after myocardial infarction. However, ablation of ventricular tachycardia remains one of the most challenging procedures in the electrophysiology lab. Precise scar definition and localization of abnormal potentials are critical for ablation success. The following manuscript describes the use of a multipolar mapping catheter and 3-dimensional (3D) mapping system to create a high density electro-anatomical map of the left ventricle including a precise scar representation as well as mapping of fractionated and late potentials in order to allow a highly accurate substrate modification.

The protocol describes in detail catheter ablation of monomorphic ventricular tachycardia in a patient with ischemic heart disease after anterior myocardial infarction with occlusion of the proximal left anterior descendant artery. The patient suffered from multiple ICD shock deliveries. Transthoracic echocardiography showed a severely reduced systolic left ventricular function (ejection fraction 30%) with a large apex aneurysm. VT ablation was performed using a 3D mapping system (see Table of Materials) and a multipolar (16 pole) steerable mapping catheter (see Table of Materials, electrode size 1 mm, electrode spacing 3-3-3). Simultaneous acquisition of numerous mapping points allowed a rapid and precise electroanatomical reconstruction of the left ventricle (see Figures 1, 2 and 3). The close electrode spacing of the multipolar catheter made possible the detection of critical signals such as fragmented and late potentials. Additional pacing from the right ventricle clearly separated the late potential from the first ventricular activation and thus identified the mapped area as a zone of slow conduction and therefore of high importance regarding the occurrence and maintenance of ventricular arrhythmias (see Figure 4). Areas that could not be reached with the multipolar catheter where addressed with the ablation catheter (see Table of Materials), which also has a close electrode spacing of 2-2-2.
By means of all the above-mentioned mapping strategies, a very precise map could be generated, showing a scar area at the left ventricular apex and adjacent areas (see Figures 1, 2 and 3, scar area 54 cm2). However, mapping time could be limited to 27 min.
During programmed ventricular stimulation and ablation, a total of 4 VTs could be induced. One of them (see Supplementary&#160;Figure 3) could be entrained and successfully ablated at the lateral border zone of the scar. Additionally, substrate modification was performed by encircling the scar, ablating all late abnormal potentials and ablating sites of pace maps matching the induced VTs.
At the end of the procedure, no VT could be induced with the stimulation sequences that enhanced the VTs at the beginning of the procedure. Only a VT with presumably epicardial origin could be induced with very aggressive stimulation. We decided to stop the procedure at that point.
The described method helps to improve ablation success and patient outcome.
<img alt="Supplementary Figure 1" src="/files/ftp_upload/57234/57234supfig1.jpg" /> 
Supplementary Figure 1: ECG electrode position. The position of the surface ECG electrodes on the front chest (taken and adapted from the user handbook of the 3D mapping system8). <a href="/files/ftp_upload/57234/57234supfig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Supplementary Figure 2" src="/files/ftp_upload/57234/57234supfig2.jpg" /> 
Supplementary Figure 2: 3D mapping system patch position. The position of the EnSite Precision&#8482; patches on the body (taken and modified from the user handbook of the 3D mapping system8). <a href="/files/ftp_upload/57234/57234supfig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Supplementary Figure 3" src="/files/ftp_upload/57234/57234supfig3.jpg" /> 
Supplementary Figure 3: Clinical tachycardia. One of four induced ventricular tachycardias during the procedure, written with 50 mm/s, cycle length 440 ms. <a href="/files/ftp_upload/57234/57234supfig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57234/57234fig1.jpg" /> 
Figure 1: Voltage map range 0.5 to 1.5 mV. RAO (left side) and LAO (right side) projections of a voltage map of the endocardial left ventricle. Small yellow dots represent electro-anatomical mapping points. The voltage of ventricular signals is defined as scar below 0.5 mV (grey), the low voltage between 0.5 and 1.5 mV (from red to blue) and the normal voltage above 1.5 mV (purple, see the scale on the left side of the figure). Large green dots represent late potentials. <a href="/files/ftp_upload/57234/57234fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57234/57234fig2.jpg" /> 
Figure 2: Voltage map range 0.2 to 1.5 mV. RAO (left side) and LAO (right side) projections of the same voltage map, this time with a low voltage range between 0.2 and 1.5 mV. Note the now patchy still viable and thus conducting tissue inside the scar. Late potentials (green dots) are located those areas that presumably represent zones of slow conduction. <a href="/files/ftp_upload/57234/57234fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57234/57234fig3.jpg" /> 
Figure 3: Voltage map with ablation lesions. RAO (left side) and LAO (right side) projections of the voltage map of the endocardial left ventricle (low voltage range between 0.2 and 1.5 mV) including ablation lesions (large red dots). <a href="/files/ftp_upload/57234/57234fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57234/57234fig4v2.jpg" /> 
Figure 4: Intracardiac electrogram with late potentials. Intracardiac electrogram at a site where late potentials could be recorded. 12-lead ECG on top of the screen; RVAd: catheter in the right ventricular apex; Grid: multipolar catheter (16 poles); CS: 8-pole catheter in the coronary sinus. (A) in sinus rhythm. The late potential visible on the multipolar catheter (marked with the red arrow) is located directly after the first ventricular activation. (B) during RVA-stimulation at the same site. The late potential visible on the multipolar catheter (red arrow) is now clearly separated from the first ventricular activation.&#160;<a href="/files/ftp_upload/57234/57234fig4v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Ablation of Ischemic Ventricular Tachycardia Using a Multipolar Catheter and 3-dimensional Mapping System for High-density Electro-anatomical Reconstruction a

Ablation of Ischemic Ventricular Tachycardia Using a Multipolar Catheter and 3-dimensional Mapping System for High-density Electro-anatomical Reconstruction

With the following protocol, we provide an approach to Ventricular Tachycardia (VT) ablation using high density mapping with a multipolar catheter and 3D mapping system enhancing the success of the procedure.

Ventricular tachycardia (VT) in patients with ischemic cardiomyopathy mainly results from endocardial scars after myocardial infarction; those scars ...

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14.4K Views.  Hietzing Hospital. With the following protocol, we provide an approach to Ventricular Tachycardia (VT) ablation using high density mapping with a multipolar catheter and 3D mapping system enhancing the success of the procedure.

Video: Ablation of Ischemic Ventricular Tachycardia Using a Multipolar Catheter and 3-dimensional Mapping System for High-density Electro-anatomical Reconstruction

Modeling and Imaging 3-Dimensional Collective Cell Invasion

A defining characteristic of cancer malignancy is invasion and metastasis 1. In some cancers (e.g. glioma 2), local invasion into surrounding healthy tissue is the root cause of disease and death. For other cancers (e.g. breast, lung, etc.), it is the process of metastasis, in which tumor cells move from a primary tumor mass, colonize distal sites and ultimately contribute to organ failure, that eventually leads to morbidity and mortality 3. It has been estimated that invasion and metastasis are responsible for 90&#37; of cancer deaths 4. As a result, there has been intense interest in identifying the molecular processes and critical protein mediators of invasion and metastasis for the purposes of improving diagnosis and treatment 5.
A challenge for cancer scientists is to develop invasion assays that sufficiently resemble the in vivo situation to enable accurate disease modeling 6. Two-dimensional cell motility assays are only informative about one aspect of invasion and do not take into account extracellular matrix (ECM) protein remodeling which is also a critical element. Recently, research has refined our understanding of tumor cell invasion and revealed that individual cells may move by elongated or rounded modes 7. In addition, there has been greater appreciation of the contribution of collective invasion, in which cells invade in strands, sheets and clusters, particularly in highly differentiated tumors that maintain epithelial characteristics, to the spread of cancer 8.
We present a refined method 9 for examining the contributions of candidate proteins to collective invasion 10. In particular, by engineering separate pools of cells to express different fluorescent proteins, it is possible to molecularly dissect the activities and proteins required in leading cells versus those required in following cells. The use of RNAi provides the molecular tool to experimentally disassemble the processes involved in individual cell invasion as well as in different positions of collective invasion. In this procedure, mixtures of fluorescently-labeled cells are plated on the bottom of a Transwell insert previously filled with Matrigel ECM protein, then allowed to invade "upwards" through the filter and into the Matrigel. Reconstruction of z-series image stacks, obtained by confocal imaging, into three-dimensional representations allows for visualization of collectively invading strands and analysis of the representation of fluorescently-labeled cells in leading versus following positions.

Models of tumor cell invasion into three-dimensional extracellular matrix better reflect the in vivo situation than two-dimensional motility assays. Using matrix invasion assays combined with confocal imaging of fluorescently-labeled cells, detailed information on invasion modes and the distinct contributions of leading versus following cells can be obtained.

A defining characteristic of cancer malignancy is invasion and metastasis 1. In some cancers (e.g. glioma 2), local invasion into surrounding healthy ...

Remote Magnetic Navigation for Accurate, Real-time Catheter Positioning and Ablation in Cardiac Electrophysiology Procedures

New remote navigation systems have been developed to improve current limitations of conventional manually guided catheter ablation in complex cardiac substrates such as left atrial flutter. This protocol describes all the clinical and invasive interventional steps performed during a human electrophysiological study and ablation to assess the accuracy, safety and real-time navigation of the Catheter Guidance, Control and Imaging (CGCI) system. Patients who underwent ablation of a right or left atrium flutter substrate were included. Specifically, data from three left atrial flutter and two counterclockwise right atrial flutter procedures are shown in this report. One representative left atrial flutter procedure is shown in the movie. This system is based on eight coil-core electromagnets, which generate a dynamic magnetic field focused on the heart. Remote navigation by rapid changes (msec) in the magnetic field magnitude and a very flexible magnetized catheter allow real-time closed-loop integration and accurate, stable positioning and ablation of the arrhythmogenic substrate.

This report provides a detailed description of a new remote navigation system based on magnetic driven forces, which has been recently introduced as a new robotic tool for human cardiac electrophysiology procedures.

New remote navigation systems have been developed to improve current limitations of conventional manually guided catheter ablation in complex cardiac ...

Catheter Ablation in Combination With Left Atrial Appendage Closure for Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting millions of individuals worldwide 1-3. The rapid, irregular, and disordered electrical activity in the atria gives rise to palpitations, fatigue, dyspnea, chest pain and dizziness with or without syncope 4, 5. Patients with AF have a five-fold higher risk of stroke 6.
Oral anticoagulation (OAC) with warfarin is commonly used for stroke prevention in patients with AF and has been shown to reduce the risk of stroke by 64% 7. Warfarin therapy has several major disadvantages, however, including bleeding, non-tolerance, interactions with other medications and foods, non-compliance and a narrow therapeutic range 8-11. These issues, together with poor appreciation of the risk-benefit ratio, unawareness of guidelines, or absence of an OAC monitoring outpatient clinic may explain why only 30-60% of patients with AF are prescribed this drug 8.
The problems associated with warfarin, combined with the limited efficacy and/or serious side effects associated with other medications used for AF 12,13, highlight the need for effective non-pharmacological approaches to treatment. One such approach is catheter ablation (CA), a procedure in which a radiofrequency electrical current is applied to regions of the heart to create small ablation lesions that electrically isolate potential AF triggers 4. CA is a well-established treatment for AF symptoms 14, 15, that may also decrease the risk of stroke. Recent data showed a significant decrease in the relative risk of stroke and transient ischemic attack events among patients who underwent ablation compared with those undergoing antiarrhythmic drug therapy 16.
Since the left atrial appendage (LAA) is the source of thrombi in more than 90% of patients with non-valvular atrial fibrillation 17, another approach to stroke prevention is to physically block clots from exiting the LAA. One method for occluding the LAA is via percutaneous placement of the WATCHMAN LAA closure device. The WATCHMAN device resembles a small parachute. It consists of a nitinol frame covered by fabric polyethyl terephthalate that prevents emboli, but not blood, from exiting during the healing process. Fixation anchors around the perimeter secure the device in the LAA (Figure 1). To date, the WATCHMAN is the only implanted percutaneous device for which a randomized clinical trial has been reported. In this study, implantation of the WATCHMAN was found to be at least as effective as warfarin in preventing stroke (all-causes) and death (all-causes) 18. This device received the Conformit&eacute; Europ&eacute;enne (CE) mark for use in the European Union for warfarin eligible patients and in those who have a contraindication to anticoagulation therapy 19.
Given the proven effectiveness of CA to alleviate AF symptoms and the promising data with regard to reduction of thromboembolic events with both CA and WATCHMAN implantation, combining the two procedures is hoped to further reduce the incidence of stroke in high-risk patients while simultaneously relieving symptoms. The combined procedure may eventually enable patients to undergo implantation of the WATCHMAN device without subsequent warfarin treatment, since the CA procedure itself reduces thromboembolic events. This would present an avenue of treatment previously unavailable to patients ineligible for warfarin treatment because of recurrent bleeding 20 or other warfarin-associated problems.
The combined procedure is performed under general anesthesia with biplane fluoroscopy and TEE guidance. Catheter ablation is followed by implantation of the WATCHMAN LAA closure device. Data from a non-randomized trial with 10 patients demonstrates that this procedure can be safely performed in patients with a CHADS2 score of greater than 1 21. Further studies to examine the effectiveness of the combined procedure in reducing symptoms from AF and associated stroke are therefore warranted.

Catheter ablation is combined with placement of the WATCHMAN Left Atrial Appendage Closure Device to prevent ischemic stroke in a patient with non-valvular atrial fibrillation.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting millions of individuals worldwide 1-3. The rapid, irregular, and ...

3-Dimensional Resin Casting and Imaging of Mouse Portal Vein or Intrahepatic Bile Duct System

In organs, the correct architecture of vascular and ductal structures is indispensable for proper physiological function, and the formation and maintenance of these structures is a highly regulated process. The analysis of these complex, 3-dimensional structures has greatly depended on either 2-dimensional examination in section or on dye injection studies. These techniques, however, are not able to provide a complete and quantifiable representation of the ductal or vascular structures they are intended to elucidate. Alternatively, the nature of 3-dimensional plastic resin casts generates a permanent snapshot of the system and is a novel and widely useful technique for visualizing and quantifying 3-dimensional structures and networks.
A crucial advantage of the resin casting system is the ability to determine the intact and connected, or communicating, structure of a blood vessel or duct. The structure of vascular and ductal networks are crucial for organ function, and this technique has the potential to aid study of vascular and ductal networks in several ways. Resin casting may be used to analyze normal morphology and functional architecture of a luminal structure, identify developmental morphogenetic changes, and uncover morphological differences in tissue architecture between normal and disease states. Previous work has utilized resin casting to study, for example, architectural and functional defects within the mouse intrahepatic bile duct system that were not reflected in 2-dimensional analysis of the structure1,2, alterations in brain vasculature of a Alzheimer's disease mouse model3, portal vein abnormalities in portal hypertensive and cirrhotic mice4, developmental steps in rat lymphatic maturation between immature and adult lungs5, immediate microvascular changes in the rat liver, pancreas, and kidney in response in to chemical injury6.
Here we present a method of generating a 3-dimensional resin cast of a mouse vascular or ductal network, focusing specifically on the portal vein and intrahepatic bile duct. These casts can be visualized by clearing or macerating the tissue and can then be analyzed. This technique can be applied to virtually any vascular or ductal system and would be directly applicable to any study inquiring into the development, function, maintenance, or injury of a 3-dimensional ductal or vascular structure.

A method of visualizing and quantifying the 3-dimensional structure of mouse hepatic portal vein or intrahepatic bile duct is described. This resin cast technique can also be applied to other ductal or vascular systems and allows for in situ visualization or quantification of a system's intact communicating architecture.

In  organs, the correct architecture of vascular and ductal structures is  indispensable for proper physiological function, and the formation and  ...

Intraoperative Detection of Subtle Endometriosis: A Novel Paradigm for Detection and Treatment of Pelvic Pain Associated with the Loss of Peritoneal Integrity

Endometriosis is a common disease affecting 40 to 70% of reproductive-aged women with chronic pelvic pain (CPP) and/or infertility. The purpose of this study was to demonstrate the use of a blue dye (methylene blue) to stain peritoneal surfaces during laparoscopy (L/S) to detect the loss of peritoneal integrity in patients with pelvic pain and suspected endometriosis. Forty women with CPP and 5 women without pain were evaluated in this pilot study. During L/S, concentrated dye was sprayed onto peritoneal surfaces, then aspirated and rinsed with Lactated Ringers solution. Areas of localized dye uptake were evaluated for the presence of visible endometriotic lesions. Areas of intense peritoneal staining were resected and some fixed in 2.5% buffered gluteraldehyde and examined by scanning (SEM) electron microscopy. Blue dye uptake was more common in women with endometriosis and chronic pelvic pain than controls (85% vs. 40%). Resection of the blue stained areas revealed endometriosis by SEM and loss of peritoneal cell-cell contact compared to normal, non-staining peritoneum. Affected peritoneum was associated with visible endometriotic implants in most but not all patients. Subjective pain relief was reported in 80% of subjects. Based on scanning electron microscopy, we conclude that endometrial cells extend well beyond visible implants of endometriosis and appear to disrupt the underlying mesothelium. Subtle lesions of endometriosis could therefore cause pelvic pain by disruption of peritoneal integrity, allowing menstrual or ovulatory blood and associated pain factors access to underlying sensory nerves. Complete resection of affected peritoneum may provide a better long-term treatment for endometriosis and CPP. This simple technique appears to improve detection of subtle or near invisible endometriosis in women with CPP and minimal visual findings at L/S and may serve to elevate diagnostic accuracy for endometriosis at laparoscopy.

Loss of peritoneal integrity provides a new paradigm to understand and treat chronic pelvic pain in women with mild forms of endometriosis and can be easily detected using intraoperative instillation of dye at the time of laparoscopy.

Endometriosis is a  common disease affecting 40 to 70% of reproductive-aged women with chronic  pelvic pain (CPP) and/or infertility. The purpose of this ...

Generation and 3-Dimensional Quantitation of Arterial Lesions in Mice Using Optical Projection Tomography

The generation and analysis of vascular lesions in appropriate animal models is a cornerstone of research into cardiovascular disease, generating important information on the pathogenesis of lesion formation and the action of novel therapies. Use of atherosclerosis-prone mice, surgical methods of lesion induction, and dietary modification has dramatically improved understanding of the mechanisms that contribute to disease development and the potential of new treatments.
Classically, analysis of lesions is performed ex vivo using 2-dimensional histological techniques. This article describes application of optical projection tomography (OPT) to 3-dimensional quantitation of arterial lesions. As this technique is non-destructive, it can be used as an adjunct to standard histological and immunohistochemical analyses.
Neointimal lesions were induced by wire-insertion or ligation of the mouse femoral artery whilst atherosclerotic lesions were generated by administration of an atherogenic diet to apoE-deficient mice.
Lesions were examined using OPT imaging of autofluorescent emission followed by complementary histological and immunohistochemical analysis. OPT clearly distinguished lesions from the underlying vascular wall. Lesion size was calculated in 2-dimensional sections using planimetry, enabling calculation of lesion volume and maximal cross-sectional area. Data generated using OPT were consistent with measurements obtained using histology, confirming the accuracy of the technique and its potential as a complement (rather than alternative) to traditional methods of analysis.
This work demonstrates the potential of OPT for imaging atherosclerotic and neointimal lesions. It provides a rapid, much needed ex vivo technique for the routine 3-dimensional quantification of vascular remodelling.

Ex vivo analysis of arterial lesions from animal models of cardiovascular disease classically relies on histological and immunohistochemical techniques. These provide 2-dimensional measurements in 3-dimensional lesions. This manuscript describes the generation of arterial lesions for quantitative analysis in 3-dimensions using optical projection tomography.

The generation and analysis of vascular lesions in appropriate animal models is a cornerstone of research into cardiovascular disease, generating ...

Porcine As a Training Module for Head and Neck Microvascular Reconstruction

Live models that resemble surgical conditions of humans are needed for training free-flap harvesting and anastomosis. Animal models for training purposes have been available for years in many surgical fields. We used the female (because they are easy to handle for the procedure) Yorkshire pigs for the head and neck reconstruction by harvesting the deep inferior epigastric artery perforator or the superior epigastric artery perforator flap. The anastomosis site (neck skin defect or tracheal wall defect) was prepared via the dissection of the common carotid artery and the internal jugular vein, in which 3.5&#215; loupe magnification was used for anastomosis as we use on human cases in real life. This procedure demonstrates a new training method using a reliable learning model and provides a detailed anatomy in a live scenario. We focused on the ischemia time, harvesting, vessel anastomosis, and designing the flap to fit the defect site. This model improves tissue handling and with the use of proper instruments can be repeated many times so that the surgeon is fully confident before starting the surgery on humans.

Here we present a protocol for the use of the pig superior epigastric artery perforator flap as a learning module for head and neck microvascular reconstruction.

Live models that resemble surgical conditions of humans are needed for training free-flap harvesting and anastomosis. Animal models for training purposes ...

High-Throughput Analysis of Optical Mapping Data Using ElectroMap

Optical mapping is an established technique for high spatio-temporal resolution study of cardiac electrophysiology in multi-cellular preparations. Here we present, in a step-by-step guide, the use of ElectroMap for analysis, quantification, and mapping of high-resolution voltage and calcium datasets acquired by optical mapping. ElectroMap analysis options cover a wide variety of key electrophysiological parameters, and the graphical user interface allows straightforward modification of pre-processing and parameter definitions, making ElectroMap applicable to a wide range of experimental models. We show how built-in pacing frequency detection and signal segmentation allows high-throughput analysis of entire experimental recordings, acute responses, and single beat-to-beat variability. Additionally, ElectroMap incorporates automated multi-beat averaging to improve signal quality of noisy datasets, and here we demonstrate how this feature can help elucidate electrophysiological changes that might otherwise go undetected when using single beat analysis. Custom modules are included within the software for detailed investigation of conduction, single file analysis, and alternans, as demonstrated here. This software platform can be used to enable and accelerate the processing, analysis, and mapping of complex cardiac electrophysiology.

This protocol describes the setup and use of ElectroMap, a MATLAB-based open-source software platform for analysis of cardiac optical mapping data. ElectroMap provides a versatile high-throughput tool for analysis of optical mapping voltage and calcium datasets across a wide range of cardiac experimental models.

Optical mapping is an established technique for high spatio-temporal resolution study of cardiac electrophysiology in multi-cellular preparations. Here we ...

A Training and Testing System for Performing Vascular Reconstruction In Vitro

Manual vascular reconstruction training is essential for a beginner surgeon. However, an optimal training system for vascular reconstruction in vitro has yet to be developed. In this study, we introduce an in vitro training and testing system using a magnetic anchoring technique with which a trainee can practice manual vascular reconstruction individually. Additionally, this system can also be used to test the quality of the reconstruction. The described system includes a vascular reconstruction training machine, magnetic tractors, and a magnetic suture puller. In this manuscript, we detail an end-to-end vein anastomosis using porcine right and left iliac veins. To identify the potential damage caused by a magnetic suture puller on the suture, we created three groups with six segments of 4-0 polypropylene sutures each: a control group with no intervention on the polypropylene suture, a group in which the polypropylene suture is manually pulled with sterile gloves 20x, and a magnetic puller group in which the magnetic puller pulled the polypropylene suture 20x. These groups were tested by light microscopy and breaking strength tests, and the effect of reconstruction was assessed. In the light microscopy test, the control group was less likely to be damaged (p &#60; 0.05) and the number of damaged points of the manual group and magnetic puller group were similar (p &#62; 0.05). The results of the breaking strength test were compared across groups and no significant difference was observed (p &#62; 0.05). The end-to-end anastomosis of the porcine iliac veins was successfully performed using this training system, and the reconstructed veins could undergo 2.0 kPa perfusion pressure. Using this training and testing system the trainee can practice manual vascular reconstruction in vitro individually with the aid of magnetic tractors and a magnetic suture puller, and the quality of the reconstruction can be tested.

Here we present a training and testing system where a trainee can complete manual vascular reconstruction in vitro individually using a magnetic anchoring technique. The system can also be used to test the quality of reconstruction.

Manual vascular reconstruction training is essential for a beginner surgeon. However, an optimal training system for vascular reconstruction in vitro has ...

A Postoperative Evaluation Guideline for Computer-Assisted Reconstruction of the Mandible

Valid comparisons of postoperative accuracy results in computer-assisted reconstruction of the mandible are difficult due to heterogeneity in imaging modalities, mandibular defect classification, and evaluation methodologies between studies. This guideline uses a step-by-step approach guiding the process of imaging, classification of mandibular defects and volume assessment of three-dimensional (3D) models, after which a legitimized quantitative accuracy evaluation method can be performed between the postoperative clinical situation and the preoperative virtual plan. The condyles and the vertical and horizontal corners of the mandible are used as bony landmarks to define virtual lines in the computer-assisted surgery (CAS) software. Between these lines the axial, coronal, and both sagittal mandibular angles are calculated on both pre- and postoperative 3D models of the (neo)mandible and subsequently the deviations are calculated. By superimposing the postoperative 3D model to the preoperative virtually planned 3D model, which is fixed to the XYZ axis, the deviation between pre- and postoperative virtually planned dental implant positions can be calculated. This protocol continues and specifies an earlier publication of this evaluation guideline.

Here, we propose a practical, feasible and reproducible evaluation guideline for computer-assisted reconstruction of the mandible in order to create uniformity between studies regarding postoperative accuracy evaluation. This protocol continues and specifies an earlier publication of this evaluation guideline.

Valid comparisons of postoperative accuracy results in computer-assisted reconstruction of the mandible are difficult due to heterogeneity in imaging ...