[Show abstract][Hide abstract] ABSTRACT: Mitral isthmus (MI) ablation is an effective option in patients undergoing ablation for persistent atrial fibrillation (AF). Achieving bidirectional conduction block across the MI is challenging, and predictors of MI ablation success remain incompletely understood. We sought to determine the impact of anatomical location of the ablation line on the efficacy of MI ablation.
A total of 40 consecutive patients (87% Male; 54 ± 10 years) undergoing stepwise AF ablation were included. MI ablation was performed in sinus rhythm. MI ablation was performed from the left inferior PV to either the posterior (Group 1) or the anterolateral (Group 2) mitral annulus depending on randomization. The length of the MI line (measured with the 3D mapping system) and the amplitude of the EGMs at 3 positions on the MI were measured in each patient. MI block was achieved in 14/19 (74%) patients in group 1 and 15/21 (71%) patients in group 2 (p = NS). Total MI radiofrequency time (18 ± 7 min vs. 17 ± 8 min; p = NS) was similar between groups. Patients with incomplete MI block had a longer MI length (34 ± 6 mm vs. 24 ± 5 mm; p < 0.001), a higher bipolar voltage along the MI (1.75 ± 0.74 mV vs. 1.05 ± 0.69mV; p < 0.01), and a longer history of continuous AF (19 ± 17 months vs. 10 ± 10 months; p < 0.05). In multivariate analysis, decreased length of the MI was an independent predictor of successful MI block (OR 1.5; 95% CI 1.1-2.1; p < 0.05).
Increased length but not anatomical location of the MI predicts failure to achieve bidirectional MI block during ablation of persistent AF. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Catheter ablation has emerged as an effective treatment strategy for atrial fibrillation (AF) in recent years. During AF, complex fractionated atrial electrograms (CFAE) can be recorded and are known to be a potential target for ablation. Automatic algorithms have been developed to simplify CFAE detection, but they are often based on a single descriptor or a set of descriptors in combination with sharp decision classifiers. However, these methods do not reflect the progressive transition between CFAE classes. The aim of this study was to develop an automatic classification algorithm, which combines the information of a complete set of descriptors and allows for progressive and transparent decisions. We designed a method to automatically analyze CFAE based on a set of descriptors representing various aspects, such as shape, amplitude and temporal characteristics. A fuzzy decision tree (FDT) was trained and evaluated on 429 predefined electrograms. CFAE were classified into four subgroups with a correct rate of 81±3%. Electrograms with continuous activity were detected with a correct rate of 100%. In addition, a percentage of certainty is given for each electrogram to enable a comprehensive and transparent decision. The proposed FDT is able to classify CFAE with respect to their progressive transition and may allow objective and reproducible CFAE interpretation for clinical use.
[Show abstract][Hide abstract] ABSTRACT: Catheter ablation is an established treatment option for patients with atrial fibrillation (AF). In paroxysmal AF ablation, pulmonary vein isolation alone is a well-defined procedural endpoint, leading to success rates of up to 80% with multiple procedures over 5 years of follow-up. The success rate in persistent AF ablation is significantly more limited. This is partly due to the rudimentary understanding of the substrate maintaining persistent AF. Three main pathophysiological concepts for this arrhythmia exist: the multiple wavelet hypothesis, the concept of focal triggers, mainly located in the pulmonary veins and the rotor hypothesis. However, the targets and endpoints of persistent AF ablation are ill-defined and there is no consensus on the optimal ablation strategy in these patients. Based on these concepts, several ablation approaches for persistent AF have emerged: pulmonary vein isolation, the stepwise approach (i.e. pulmonary vein isolation, ablation of fractionated electrograms and linear ablation), magnetic resonance imaging (MRI) and rotor-based approaches. Currently, persistent AF ablation is a second-line therapy option to restore and maintain sinus rhythm. Several factors, such as the presence of structural heart disease, duration of persistent AF and dilatation and possibly also the degree of fibrosis of the left atrium should influence the decision to perform persistent AF ablation.
[Show abstract][Hide abstract] ABSTRACT: -This study aimed to determine five-year efficacy of catheter ablation for persistent atrial fibrillation (PsAF) using AF termination as a procedural endpoint.
-150 patients (57±10 years) underwent PsAF ablation using a stepwise ablation approach (pulmonary vein isolation, electrogram-guided and linear ablation) with the desired procedural endpoint being AF termination. Repeat ablation was performed for recurrent AF or atrial tachycardia (AT). AF was terminated by ablation in 120 patients (80%). Arrhythmia-free survival rates after a single procedure were 35.3±3.9%, 28.0±3.7%, and 16.8±3.2% at 1, 2, and 5 years, respectively. Arrhythmia-free survival rates after the last procedure (mean 2.1±1.0 procedures) were 89.7±2.5%, 79.8±3.4%, and 62.9±4.5%, at 1, 2, and 5 years, respectively. During a median follow-up of 58 (IQR 43-73) months following the last ablation procedure, 97 of 150 (64.7%) patients remained in sinus rhythm without antiarrhythmic drugs (AADs). Another 14 (9.3%) patients maintained sinus rhythm after re-initiation of AADs, and an additional 15 (10.0%) patients regressed to paroxysmal recurrences only. Failure to terminate AF during the index procedure (HR 3.831; 95%CI: 2.070-7.143; p<0.001), left atrial diameter ≥50mm (HR 2.083; 95%CI: 1.078-4.016; p=0.03), continuous AF duration ≥18 months (HR 1.984; 95%CI: 1.024-3.846; p<0.04) and structural heart disease (HR 1.874; 95% CI: 1.037-3.388; p=0.04) predicted arrhythmia recurrence.
-In patients with PsAF, an ablation strategy aiming at AF termination is associated with freedom from arrhythmia recurrence in the majority of patients over a 5-year follow up period.Procedural AF non-termination and specific baseline factors predict long-term outcome after ablation.
[Show abstract][Hide abstract] ABSTRACT: -Rapid pulmonary vein (PV) activity has been shown to maintain paroxysmal AF. We evaluated in persistent AF (PsAF) the cycle length (CL) gradient between PVs and the left atrium (LA) in an attempt to identify the subset of patients where PVs play an important role.
-97 consecutive patients undergoing first ablation for PsAF were studied. For each PV, the CL of the fastest activation was assessed over 1 min (PVfast) using Lasso recordings. The PV to LA CL gradient was quantified by the ratio of PVfast to LA appendage (LAA) AFCL. Stepwise ablation terminated AF in 73 patients (75%). In the AF Termination group, the PVfast CL was much shorter than the LAA CL resulting in lower PVfast/LAA ratios compared to the Non-termination group (71±10% vs 92±7%, p<0.001). Within the Termination group, PVfast/LAA ratios were notably lower if AF terminated after PVI or limited adjunctive substrate ablation compared to patients who required moderate or extensive ablation (63±6% vs 75±8%, p<0.001). PVfast/LAA ratio <69% predicted AF termination after PVI or limited substrate ablation with 74% positive predictive value and 95% negative predictive value. After a mean follow-up of 29±17 months, freedom from arrhythmia recurrence off-antiarrhythmic drugs was achieved in most patients with PVfast/LAA ratios <69% as opposed to the remaining population (80% vs 43%, p<0.001).
-The PV to LA CL gradient may identify the subset of patients in whom PsAF is likely to terminate after PVI or limited substrate ablation and better long-term outcomes are achieved.
[Show abstract][Hide abstract] ABSTRACT: Introduction:
The atrial outcome after extensive ablation is unknown. We sought to quantify atrial structure and function years after successful ablation for persistent atrial fibrillation (PsAF).
Methods and results:
We studied after 80 ± 15 months 26 patients (54 ± 8 years, 1 woman) with PsAF successfully treated by ablation (2.2 ± 0.7 stepwise approach procedures, cumulative RF duration 126 ± 37 minutes). At follow-up atrial scar burden and atrial outflows were quantified using delayed-enhanced and velocity-encoded MRI, respectively. Cine imaging was used to quantify atrial conduit function (CF), active emptying fraction (AEF), expansion index (EI), and the inter-appendage mechanical activation delay. Patients underwent exercise testing at baseline and follow-up. LA and RA scar extent were 29 ± 6 and 4.3 ± 2.8%, respectively. LA and RA AEF were 10.0 ± 5.3 and 30 ± 8%. Mean inter-appendage delay was 83 ± 47 ms [42-217]. Complete LAA isolation was found in 3 patients. A wave was absent in 9/26 patients. LA scar extent related to the number of procedures (R = 0.58, P = 0.002) and total RF duration (R = 0.56, P = 0.003). Among follow-up characteristics, LA scar extent related to LAAEF (R = -0.73, P < 0.0001), LAEI (R = -0.64, P = 0.0003), A-wave peak (R = -0.72, P < 0.0001), and inter-appendage mechanical delay (R = 0.47, P = 0.02). At multivariable analysis, LA scar extent was independently related to LAAEF and LAEI. LAAEF and LA scar extent correlated with exercise capacity at follow-up (R = 0.44, P = 0.02, and R = -0.40; P = 0.04).
LA contractility and compliance are markedly impaired years after successful PsAF ablation. LA dysfunction is closely related to scar burden.
[Show abstract][Hide abstract] ABSTRACT: Objectives
We evaluated the feasibility and safety of epicardial substrate elimination using endocardial radiofrequency (RF) delivery in patients with scar-related ventricular tachycardia (VT).
Epicardial RF delivery is limited by fat or associated with bleeding, extra-cardiac damages, coronary vessels and phrenic nerve injury. Alternative ablation approaches may be desirable.
Forty-six patients (18 ischemic cardiomyopathy [ICM], 13 non-ischemic dilated cardiomyopathy [NICM], 15 arrhythmogenic right ventricular cardiomyopathy [ARVC]) with sustained VT underwent combined endo- and epicardial mapping. All patients received endocardial ablation targeting local abnormal ventricular activities in the endocardium (Endo-LAVA) and epicardium (Epi-LAVA), followed by epicardial ablation if needed.
From a total of 173 endocardial ablations targeting Epi-LAVA at the facing site, 48 (28%) applications (ICM: 20/71 [28%], NICM: 3/39 [8%], ARVC: 25/63 [40%]) successfully eliminated the Epi-LAVA. Presence of Endo-LAVA, most delayed and low bipolar amplitude of Epi-LAVA, low unipolar amplitude in the facing endocardium, and Epi-LAVA within a wall thinning area at CT scan were associated with successful ablation. Endocardial ablation could abolish all Epi-LAVA in 4 ICM and 2 ARVC patients, whereas all patients with NICM required epicardial ablation. Endocardial ablation was able to eliminate Epi-LAVA at least partially in 15 (83%) ICM, 2 (13%) NICM, and 11 (73%) ARVC patients, contributing to a potential reduction in epicardial RF applications. Pericardial bleeding occurred in 4 patients with epicardial ablation.
Elimination of Epi-LAVA using endocardial RF delivery is feasible and may be used first to reduce the risk of epicardial ablation.
Journal of the American College of Cardiology 04/2014; 63(14). DOI:10.1016/j.jacc.2013.10.087 · 16.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Local abnormal ventricular activities (LAVA) in patients with scar-related ventricular tachycardia (VT) may appear at any time during or after the far-field electrogram. While they may be separated from the far-field signal by an isoelectric line and extend beyond the end of surface QRS, they may also appear fused or buried within the QRS.
To characterize LAVA in post-infarction VT patients with respect to their anatomical locations.
Thirty-one patients with post-infarction VT underwent mapping/ablation during sinus rhythm with 3-dimensional electroanatomic mapping system. From a total of 18,270 electrograms reviewed in all study subjects, 1,104 LAVA (endocardium: 839, epicardium: 265) were identified and analyzed.
The interval from the onset of QRS-complex to the ventricular electrogram (EGM-onset) on the endocardium was significantly shorter than the epicardium (p<0.001). EGM-onset was shortest in the septal endocardium and longest in the inferior and lateral epicardium. There was a significant positive correlation between EGM-onset and LAVA lateness as estimated by the interval from surface QRS-onset to LAVA (r=0.52, p<0.001). LAVA were more frequently detected after the QRS-complex in the epicardium (241/265 [91%]) than in the endocardium (551/839 [66%])(p<0.001). Only 43% of endocardial septal LAVA were detected after the QRS-complex.
Lateness of LAVA is affected to a large extent by their locations. The chance of detecting late LAVA increases when the electrogram onset is later. Substrate-based approach targeting delayed signals relative to the QRS-complex may miss critical arrhythmogenic substrate, particularly in the septum and other early-to-activate regions.
Heart rhythm: the official journal of the Heart Rhythm Society 08/2013; 10(11). DOI:10.1016/j.hrthm.2013.08.031 · 5.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVES: We prospectively evaluated the role of a novel three-dimensional(3D), non-invasive, beat by beat mapping system, Electrocardiographic Mapping(ECM), in facilitating the diagnosis of atrial tachycardias(AT). BACKGROUND: Conventional 12-lead electrocardiogram, a widely used non-invasive tool in clinical arrhythmia practice, has diagnostic limitations. METHODS: Various ATs (de novo and post atrial fibrillation(AF) ablation) were mapped using ECM followed by standard of care electrophysiological(EP) mapping and ablation in 52 patients. The ECM consisted of recording body surface electrograms from a 252-electrode-vest placed on the torso combined with CT-scan-based biatrial anatomy (CardioInsight Inc., USA). We evaluated the feasibility of this system in defining 1) the mechanism of AT: macroreentrant (perimitral, cavotricuspid isthmus-dependent and roof-dependent circuits) vs. centrifugal (focal-source) activation and 2) the location of arrhythmia in centrifugal ATs. The accuracy of the non-invasive diagnosis and detection of ablation targets was evaluated vis-a-vis subsequent invasive mapping and successful ablation. RESULTS: Comparison between ECM and EP diagnosis could be accomplished in 48 patients (48 ATs) but was not possible in 4 patients where the AT mechanism changed to another AT (1), AF (1) or sinus rhythm (2) during the EP procedure. ECM correctly diagnosed AT mechanisms in 44/48 (92%) ATs; macroreentry: 23/27, focal-onset with centrifugal activation: 21/21. The region of interest for focal ATs perfectly matched in 21/21 (100%) ATs. The 2:1 ventricular conduction and low-amplitude P waves challenged the diagnosis of 4/27 macroreentrant (perimitral) ATs that can be overcome by injecting atrioventricular node blockers and signal averaging, respectively. CONCLUSIONS: This prospective multicenter series shows high success rate of ECM in accurately diagnosing the mechanism of AT and the location of focal arrhythmia. Intraprocedural use of the system and its application to AF mapping is underway.
Journal of the American College of Cardiology 05/2013; 62(10). DOI:10.1016/j.jacc.2013.03.082 · 16.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVES: We evaluated the relationship between fibrosis imaged by delayed enhancement (DE) MRI and atrial electrograms in persistent atrial fibrillation. BACKGROUND: Atrial fractionated electrograms (CFAE) are strongly related to slow anisotropic conduction. Their relationship to atrial fibrosis has not yet been investigated. METHODS: Atrial high resolution MRI of 18 patients with persistent AF (11 long-persistent) was registered with the mapping geometry (NavX). DE areas were categorized as dense or patchy, depending on their DE content. Left atrial electrograms (Egm) during AF were acquired using a high-density 20-pole catheter (514+/-77 sites/map). Fractionation, organisation/regularity, local mean cycle length, and voltage were analysed with reference to DE. RESULTS: Patients with long-persistent vs persistent AF had larger LA surface area (134+/-38cm2 vs 98+/-9cm2, p=0.02), higher amount of atrial DE (70+/-16cm2 vs 49+/-10cm2, p=0.01), more CFAE extent (54+/-16cm2 vs 28+/-15cm2, p=0.02) and a shorter baseline AF cycle length (147+/-10ms vs 182+/-14ms, p=0.01). Continuous CFAE (CFEmean<80ms) occupied 38+/-19% of total LA surface area. Dense DE was detected at the left posterior LA. In contrast, the right posterior LA contained predominantly patchy DE. Most CFAE (48+/-14%) occurred at non-DE LA sites, followed by 41+/-12% CFAE at patchy DE and 11+/-6% at dense DE regions (p=0.005 and p=0.008 respectively). 19+/-6% CFAE sites occurred at border zones of dense DE. Egms were less fractionated, with longer cycle length and lower voltage at dense DE vs non-DE regions: CFEmean: 97ms vs 76ms, p<0.0001; local cycle length: 153ms vs 143ms, p<0.0001; mean voltage: 0.63mV vs 0.86mV, p<0.0001. CONCLUSIONS: Atrial fibrosis as defined by DE MRI is associated with slower and more organized electrical activity but with lower voltage than healthy atrial areas. Ninety percent of continuous CFAE sites occur at non-DE and patchy DE left atrial sites. These findings are of importance for the choice of ablation strategy in persistent AF.
Journal of the American College of Cardiology 05/2013; 62(9). DOI:10.1016/j.jacc.2013.03.081 · 16.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background:
Atrial tachycardias (AT) during or after ablation of atrial fibrillation frequently pose a diagnostic challenge. We hypothesized that both the patterns and the timing of coronary sinus (CS) activation could facilitate AT mapping.
Methods and results:
A total of 140 consecutive postpersistent atrial fibrillation ablation patients with sustained AT were investigated by conventional mapping. CS activation pattern was defined as chevron or reverse chevron when the activations recorded on both the proximal and the distal CS dipoles were latest or earliest, respectively. The local activation of mid-CS was timed with reference to Ppeak-Ppeak (P-P) interval in lead V1. A ratio, mid-CS activation time to AT cycle length, was computed. Of 223 diagnosed ATs, 124 were macroreentrant (56%) and 99 were centrifugal (44%). When CS activation was chevron/reverse chevron (n=44; 20%), macroreentries were mostly roof dependent. With reference to P-P interval, mid-CS activation timing showed specific consistency for peritricuspid and perimitral AT. Proximal to distal CS activation pattern and mid-CS activation at 50% to 70% of the P-P interval (n=30; 13%) diagnosed peritricuspid AT with 81% sensitivity and 89% specificity. Distal to proximal CS activation and mid-CS activation at 10% to 40% of the P-P interval (n=44; 20%) diagnosed perimitral AT with 88% sensitivity and 75% specificity.
The analysis of the patterns and timing of CS activation provides a rapid stratification of most likely macroreentrant ATs and points toward the likely origin of centrifugal ATs. It can be included in a stepwise diagnostic approach to rapidly select the most critical mapping maneuvers.
[Show abstract][Hide abstract] ABSTRACT: The Effect of Antiarrhythmic Drugs Ablation Outcomes Background
Patients commonly present for atrial fibrillation (AF) ablation while taking antiarrhythmic (AA) medications. It is unknown if AA use at the time of ablation affects procedural outcome. This study compares the AF ablation outcomes of patients who underwent ablation while on AA medications to those who were not on AA medications. Methods and ResultsA total of 180 consecutive patients who underwent their first catheter ablation of AF were identified from the Johns Hopkins Hospital AF registry and divided into 2 cohorts: those On AA at the time of ablation (127patients, mean follow-up 24.6months) and those Off AA at the time of ablation (53patients, mean follow-up 20.3months). Follow-up was performed to identify recurrent AF. There was no statistically significant difference in the percentage of patients without a recurrence of symptomatic AF (single procedure success rate) in the On and Off AA groups at 6months postablation (53.5% vs 50.1%, P= 0.75), or by the end of follow-up (37.8% vs 41.5%, P= 0.64). For those patients who had symptomatic AF recurrence, the average time to recurrence was 6.2 9.0months in the On AA group and 4.2 +/- 7.2months in the Off AA group (P= 0.27). Conclusions
There was no statistically significant difference in the rate of symptomatic AF recurrence between the On AA and Off AA groups in this study. The use of AA medications at the time of ablation does not appear to affect procedural outcomes in this population.
[Show abstract][Hide abstract] ABSTRACT: Background:
A majority of patients undergoing ablation of ventricular tachycardia have implanted devices precluding substrate imaging with delayed-enhancement MRI. Contrast-enhanced multidetector computed tomography (MDCT) can depict myocardial wall thickness with submillimetric resolution. We evaluated the relationship between regional myocardial wall thinning (WT) imaged by MDCT and arrhythmogenic substrate in postinfarction ventricular tachycardia.
Methods and results:
We studied 13 consecutive postinfarction patients undergoing MDCT before ablation. MDCT data were integrated with high-density 3-dimensional electroanatomic maps acquired during sinus rhythm (endocardium, 509±291 points/map; epicardium, 716±323 points/map). Low-voltage areas (<1.5 mV) and local abnormal ventricular activities (LAVA) during sinus rhythm were assessed with regard to the WT. A significant correlation was found between the areas of WT <5 mm and endocardial low voltage (correlation-R=0.82; P=0.001), but no such correlation was found in the epicardium. The WT <5 mm area was smaller than the endocardial low-voltage area (54 cm(2) [Q1-Q3, 46-92] versus 71 cm(2) [Q1-Q3, 59-124]; P=0.001). Among a total of 13 060 electrograms reviewed in the whole study population, 538 LAVA were detected and analyzed. LAVA were located within the WT <5 mm (469/538 [87%]) or at its border (100% within 23 mm). Very late LAVA (>100 ms after QRS complex) were almost exclusively detected within the thinnest area (93% in the WT<3 mm).
Regional myocardial WT correlates to low-voltage regions and distribution of LAVA critical for the generation and maintenance of postinfarction ventricular tachycardia. The integration of MDCT WT with 3-dimensional electroanatomic maps can help focus mapping and ablation on the culprit regions, even when MRI is precluded by the presence of implanted devices.
[Show abstract][Hide abstract] ABSTRACT: Introduction:
Entrainment criteria for the diagnosis of reentrant atrial tachycardia can be difficult to apply and cannot detect double-loop reentry. We sought to develop and clinically test a new criterion for the diagnosis of single- and double-loop reentry.
Methods and results:
(1) Proposed criterion: after sequential overdrive pacing at 2 different locations and assessing the first ensuing beats of tachycardia, the difference in activation time recorded between 2 appropriate stationary positions changes by 1 or 2 tachycardia cycle lengths; a change of 2 tachycardia cycle lengths usually indicates double-loop reentry rather than only a single-loop. (2) Clinical testing: multiple overdrive pacing maneuvers were undertaken and analyzed in 5 patients with common flutter (single-loop reentry). In total, 23 pairs of overdrive pacing maneuvers were performed using electrodes in the coronary sinus and a distribution of positions in the right atrium. In 22/23 pairs of maneuvers, the change in Activation Difference was within 2.6 ± 12.4 milliseconds of the tachycardia cycle length, confirming single loop reentry. For double-loop reentry, the literature was reviewed and 3 cases of double-loop reentry were identified with sufficient data. In all of these cases, double-loop reentry was detected and also the zone containing the common isthmus was identified.
The proposed criterion can diagnose single- and double-loop reentry atrial tachycardia using intracardiac recordings from any pair of well separated positions. The criterion does not require precise electrode placement or extensive activation mapping.
[Show abstract][Hide abstract] ABSTRACT: MDCT/MRI Fusion for the Guidance of VT Ablation. Background: Delayed enhancement (DE) MRI can assess the fibrotic substrate of scar-related VT. MDCT has the advantage of inframillimetric spatial resolution and better 3D reconstructions. We sought to evaluate the feasibility and usefulness of integrating merged MDCT/MRI data in 3D-mapping systems for structure–function assessment and multimodal guidance of VT mapping and ablation.
Methods: Nine patients, including 3 ischemic cardiomyopathy (ICM), 3 nonischemic cardiomyopathy (NICM), 2 myocarditis, and 1 redo procedure for idiopathic VT, underwent MRI and MDCT before VT ablation. Merged MRI/MDCT data were integrated in 3D-mapping systems and registered to high-density endocardial and epicardial maps. Low-voltage areas (<1.5 mV) and local abnormal ventricular activities (LAVA) during sinus rhythm were correlated to DE at MRI, and wall-thinning (WT) at MDCT.
Results: Endocardium and epicardium were mapped with 391 ± 388 and 1098 ± 734 points per map, respectively. Registration of MDCT allowed visualization of coronary arteries during epicardial mapping/ablation. In the idiopathic patient, integration of MRI data identified previously ablated regions. In ICM patients, both DE at MRI and WT at MDCT matched areas of low voltage (overlap 94 ± 6% and 79 ± 5%, respectively). In NICM patients, wall-thinning areas matched areas of low voltage (overlap 63 ± 21%). In patients with myocarditis, subepicardial DE matched areas of epicardial low voltage (overlap 92 ± 12%). A total number of 266 LAVA sites were found in 7/9 patients. All LAVA sites were associated to structural substrate at imaging (90% inside, 100% within 18 mm).
Conclusion: The integration of merged MDCT and DEMRI data is feasible and allows combining substrate assessment with high-spatial resolution to better define structure–function relationship in scar-related VT. (J Cardiovasc Electrophysiol, Vol. 24, pp. 419-426, April 2013)