Noninducibility Of Ventricular Tachycardia Research Articles

Fast nonclinical ventricular tachycardia inducible after ablation in patients with structural heart disease: Definition and clinical implications

Noninducibility of ventricular tachycardia (VT) with an equal or longer cycle length (CL) than that of the clinical VT is considered the minimum ablation endpoint in patients with structural heart disease. Because their clinical relevance remains unclear, fast nonclinical VTs are often not targeted. However, an accepted definition for fast VT is lacking. The shortest possible CL of a monomorphic reentrant VT is determined by the ventricular refractory period (VRP). The purpose of this study was to propose a patient-specific definition for fast VT based on the individual VRP (fVTVRP) and assess the prognostic significance of persistent inducibility after ablation of fVTVRP for VT recurrence. Of 191 patients with previous myocardial infarction or with nonischemic cardiomyopathy undergoing VT ablation, 70 (age 63 ± 13 years; 64% ischemic) remained inducible for a nonclinical VT and composed the study population. FVTVRP was defined as any VT with CL ≤VRP400 + 30 ms. Patients were followed for VT recurrence. After ablation, 30 patients (43%) remained inducible exclusively for fVTVRP and 40 (57%) for any slower VT. Patients with only fVTVRP had 3-year VT-free survival of 64% (95% confidence interval [CI] 46%-82%) compared to 27% (95% CI 14%-48%) for patients with any slower remaining VT (P = .013). Inducibility of only fVTVRP was independently associated with lower VT recurrence (hazard ratio 0.38; 95% CI 0.19-0.86; P = .019). Among 36 patients inducible for any fVTVRP, only 1 had recurrence with fVTVRP. In patients with structural heart disease, inducibility of exclusively fVTVRP after ablation is associated with low VT recurrence.

Catheter ablation of repetitive ventricular tachycardia in patients with ischemic heart disease – our experience

Ventricular tachycardia (VT) poses a significant risk for sudden death and heart failure exacerbation in patients with ischemic heart disease. Catheter-based radiofrequency ablation is the last treatment option for patients with frequent VT recurrences despite antiarrhythmic drugs. The aim was to present our retrospective catheter ablation data in this group of patients. The majority of 34 patients, who underwent percutaneous endocardial radiofrequency catheter ablation, were male, median age 67.5 years, who presented with electrical storm, had underlying cardiomyopathy after remote inferior wall myocardial infarction and preceding myocardial revascularization procedure, and had been implanted with cardioverter-defibrillator (ICD). Two ablation methods were used: linear ablation and/or scar homogenization. Acute ablation success (non-inducibility of any VT) was achieved in 59 % of procedures. VT could not be interrupted in 2 (6 %) patients. Pericardial tamponade that needed surgical intervention occurred in one procedure (2 %), and was related to inadvertent perforation of the right ventricular apex with a diagnostic catheter. Seven (20 %) patients died and additional 3 were lost from the median of 31 (6–151, rank) months of follow-up. No late VT recurrences were demonstrated in 20 (59 %) patients, and rare in 4 (12 %). Overall, the ablation procedure was successful in 71 % of patients. Catheter ablation gave very good long-term clinical result in about two-thirds of our patients with ischaemic cardiomyopathy and frequent VT recurrences. Catheter ablation, preferably with scar homogenization approach, should be considered early to reduce the number of VT episodes and ICD discharges.

Substrate characterization and catheter ablation in patients with scar-related ventricular tachycardia using ultra high-density 3-D mapping.

Ablation of scar-related ventricular tachycardia (VT), especially in noninducible VT or hemodynamically unstable patients, can be challenging. Thus, we evaluated feasibility of an ultra high-density 3-D mapping approach to characterize the ventricular substrate and, if possible, to map VT. Twenty-two patients (67 ± 2 years, mean LV-EF 36 ± 3%) with both ischemic and nonischemic cardiomyopathy and documented VT underwent mapping and catheter ablation using a 64-electrode mini-basket catheter. Substrate characterization included ultra high-density voltage maps, identification of areas of slow conduction and late potentials. Whenever VT was inducible activation mapping was performed. In 13 of 22 patients, the presumed clinical VT (in 16 of 22 any VT) was inducible. A total of 50 maps were generated (22 substrate maps, 28 during VT), mapping time was 33 ± 4 minutes, number of points was 10,937 ± 1,923. Low voltage areas were related with the site of origin in all mapped VT. Isochronal maps indicated areas of slow conduction in 14 of 22 patients, all in border zone scar. In 95% of patients, late potentials were found. Mapping time during VT was 9 ± 2 minutes, number of points 6,740 ± 1,140. Covered cycle length was 82 ± 5% (16 re-entry, 10 focal, and two undetermined). During 4 months follow-up, 90% remained free from VT recurrence. Ultra high-density mapping in patients with scar-related VT is feasible, safe and enables detailed insight into tachycardia mechanisms. Critical sites can be identified (1) by precise substrate characterization when VT is not inducible or hemodynamically not tolerated and (2) during short lasting episodes of VT in order to guide catheter ablation.

Scar characteristics derived from two- and three-dimensional reconstructions of cardiac contrast-enhanced magnetic resonance images: Relationship to ventricular tachycardia inducibility and ablation success

BackgroundThe relationship between cardiac contrast-enhanced magnetic resonance imaging (CE-MRI)-derived scar characteristics and substrate for ventricular tachycardia (VT) in patients with structural heart disease (SHD) has not been fully investigated. MethodsThis study included 51 patients (mean age, 63.3±15.1 years) who underwent CE-MRI with SHD and VT induction testing before ablation. Late gadolinium-enhanced (LGE) regions on MRI slices were quantified by thresholding techniques. Signal intensities (SIs) 2–6 SDs above the mean SI of the remote left ventricular (LV) myocardium were considered as scar border zones, and SI>6 SDs, as scar zone, and the scar characteristics related to VT inducibility and successful ablation via endocardial approaches were evaluated. ResultsThe proportion of the total CE-MRI-derived scar border zone in the inducible VT group was significantly greater than that in the non-inducible VT group (26.3±9.9% vs. 19.2±7.8%, respectively, P=0.0323). The LV endocardial scar zone to total LV myocardial scar zone ratio in patients whose ablation was successful was significantly greater than that in those whose ablation was unsuccessful (0.61±0.11 vs. 0.48±0.12, respectively, P=0.0042). Most successful ablation sites were located adjacent to CE-MRI-derived scar border zones. ConclusionsBy CE-MRI, we were able to characterize not only the scar, but also its location and heterogeneity, and those features seemed to be related to VT inducibility and successful ablation from an endocardial site.

Extracorporeal Membrane Oxygenation for Hemodynamic Support of Ventricular Tachycardia Ablation.

We report the experience in a cohort of consecutive patients receiving extracorporeal membrane oxygenation during catheter ablation of unstable ventricular tachycardia (VT) at our center. From 2010 to 2015, extracorporeal membrane oxygenation was initiated in 64 patients (average age: 63±15 years; left ventricular ejection fraction in 27±9%; cardiogenic shock in 23%, and electrical storm in 62% of patients) undergoing 74 unstable VT catheter ablation procedures. At least one VT was terminated in 81% of procedures with baseline inducible VT, and VT noninducibility was achieved in 69%. Acute heart failure occurred in 5 patients: 3 underwent emergency heart transplantation, 1 had left ventricular assist device (LVAD) implantation, and 1 patient eventually died because of subsequent mesenteric ischemia. All other patients were discharged alive. After a median follow-up of 21 months (13-28 months), VT recurrence was 33%; overall survival was 56 out of 64 patients (88%). Extracorporeal membrane oxygenation-supported ablation was the bridge to LVAD in 6.9% and to heart transplantation in 3.5% of patients. VT recurrence was related to ablation success (after 180 days of follow up: 19% when VT was noninducible, 42% if nonclinical VT was inducible, 75% when clinical VT was inducible, and 75% in untested patients, P<0.001). Incidence of all-cause death, heart transplantation, and LVAD was independently related to ablation outcome (at 180 days of follow-up: 9% when noninducibility was achieved, 50% in case of inducible VT, and 75% in untested patients, P<0.001). At multivariable analyses, noninducibility (hazard ratio 0.198; P=0.001) and left ventricular ejection fraction (hazard ratio 0.916; P=0.008) correlated with all-cause death, LVAD, and heart transplantation. Ablation of unstable VTs can be safely supported by extracorporeal membrane oxygenation, which allows rhythm stabilization with low procedure mortality, bridging decompensated patients to permanent LVAD or heart transplantation. Successful ablation is associated with better outcomes than unsuccessful ablation.

Can ventricular tachycardia non-inducibility after ablation predict reduced ventricular tachycardia recurrence and mortality in patients with non-ischemic cardiomyopathy? A meta-analysis of twenty-four observational studies

BackgroundAt present, the role of ventricular tachycardia (VT) non-inducibility after ablation in patients with non-ischemic cardiomyopathy (NICM) remains controversial. We conducted a meta-analysis of the published literature to assess whether VT non-inducibility after ablation could predict reduced VT recurrence and mortality in patients with NICM. MethodsPubMed, ScienceDirect, and the Cochrane library were searched for studies evaluating the effects of VT non-inducibility after catheter ablation on the long-term outcome in NICM patients with sustained VT. Results were analyzed using a fixed-effect model, and the data were pooled using RevMan 5.3 software. ResultsTwenty-four observational studies were identified (736 participants, mean follow-up time: 22months). NICM patients with VT inducibility after ablation had a higher risk of VT recurrence (odds ratio [OR]=5.83, 95% confidence interval [CI] 4.07–8.37; P<0.00001) and all-cause mortality (OR=3.55, 95% CI 1.62–7.78; P=0.002) compared with VT non-inducibility. Similarly in the subgroup analysis, patients with VT inducibility showed a higher risk of VT recurrence from non-ischemic dilated cardiomyopathy (OR=3.92, 95% CI 2.36–6.50; P<0.00001) and arrhythmogenic right ventricular dysplasia/cardiomyopathy (OR=5.37, 95% CI 2.20–13.10; P=0.0002). Additionally, meta-analysis also showed that combined endo–epicardial ablation significantly reduced the risk of VT recurrence compared with endocardial-only ablation (OR=2.02, 95% CI 1.19–3.44; P=0.009; mean follow-up time: 22months). ConclusionRecent evidence has shown that VT non-inducibility after ablation is a predictor for reduced VT recurrence and mortality compared with VT inducibility in NICM patients with sustained VT. In addition, endocardial plus adjuvant epicardial ablation provides better long-term arrhythmia-free survival than endocardial ablation alone.

Impact of New Technologies and Approaches for Post-Myocardial Infarction Ventricular Tachycardia Ablation During Long-Term Follow-Up.

During the past years, many innovations have been introduced to facilitate catheter ablation of post-myocardial infarction ventricular tachycardia. However, the predictors of outcome after ablation were not thoroughly studied. From 2009 to 2013, consecutive patients referred for post-myocardial infarction ventricular tachycardia ablation were included. The end point of the procedure was complete elimination of local abnormal ventricular activities (LAVA) and ventricular tachycardia (VT) noninducibility. The predictors of outcome with primary end point of VT recurrence were assessed. A total of 125 patients were included (age: 64±11 years; 7 women) for 142 procedures. The left ventricle was accessed via transseptal, retrograde aortic, and epicardial approaches in 87%, 33%, and 37% of patients, respectively. Three-dimensional electroanatomical mapping system was used in 70%, multipolar catheter in 51%, and real-time image integration in 38% (from magnetic resonance imaging in 39% and multidetector computed tomography in 93%) of patients. Before ablation, VT was inducible in 75%, and endocardial/epicardial LAVA were present in 88%/75%. After ablation, complete LAVA elimination was achieved in 60%, and VT noninducibility in 83%. During a median follow-up of 850 days (interquartile range, 439-1707), VT recurrence was observed in 36%. Multivariable analysis identified 3 independent outcome predictors: the ability to achieve complete LAVA elimination (R(2)=0.29; P<0.0001; risk ratio=0.52 [0.38-0.70]), the use of real-time image integration (R(2)=0.21; P=0.0006; risk ratio=0.49 [0.33-0.74]), and the use of multipolar catheters (R(2)=0.08; P=0.05; risk ratio=0.75 [0.56-1.00]). Achievement of complete LAVA elimination and use of scar integration from imaging and multipolar catheters to focus high-density mapping are independent predictors of VT-free survival after catheter ablation for post-myocardial infarction ventricular tachycardia.

Image Integration to Guide Catheter Ablation in Scar‐Related Ventricular Tachycardia

Although multi-detector computed tomography (MDCT) and cardiac magnetic resonance (CMR) can assess the structural substrate of ventricular tachycardia (VT) in ischemic cardiomyopathy (ICM), non-ICM (NICM), and arrhythmogenic right ventricular cardiomyopathy (ARVC), the usefulness of systematic image integration during VT ablation remains undetermined. A total of 116 consecutive patients (67 ICM; 30 NICM; 19 ARVC) underwent VT ablation with image integration (MDCT 91%; CMR 30%; both 22%). Substrate was defined as wall thinning on MDCT and late gadolinium-enhancement on CMR in ICM/NICM, and as myocardial hypo-attenuation on MDCT in ARVC. This substrate was compared to mapping and ablation results with the endpoint of complete elimination of local abnormal ventricular activity (LAVA), and the impact of image integration on procedural management was analyzed. Imaging-derived substrate identified 89% of critical VT isthmuses and 85% of LAVA, and was more efficient in identifying LAVA in ICM and ARVC than in NICM (90% and 90% vs. 72%, P < 0.0001), and when defined from CMR than MDCT (ICM: 92% vs. 88%, P = 0.026, NICM: 88% vs. 72%, P < 0.001). Image integration motivated additional mapping and epicardial access in 57% and 33% of patients. Coronary and phrenic nerve integration modified epicardial ablation strategy in 43% of patients. The impact of image integration on procedural management was higher in ARVC/NICM than in ICM (P < 0.01), and higher in case of epicardial approach (P < 0.0001). Image integration is feasible in large series of patients, provides information on VT substrate, and impacts procedural management, particularly in ARVC/NICM, and in case of epicardial approach.

Catheter Ablation of Ischemic Ventricular Tachycardia With Remote Magnetic Navigation: STOP-VT Multicenter Trial.

Catheter ablation is an effective treatment of scar-related ventricular tachycardia (VT), but the overall complexity of the procedure has precluded its widespread use. Remote magnetic navigation (RMN) has been shown to facilitate cardiac mapping and ablation of VT in a retrospective series. STOP-VT is the first multicenter, prospective, single-arm and single-procedure study evaluating RMN-based mapping and ablation of post-infarction VT. Patients with documented VT and prior MI, in whom an ICD was implanted either for primary or secondary prevention, were recruited from four EU and US centers. Either a transseptal (48 patients) or transaortic (5 patients) approach was employed to gain access for ventricular endocardial mapping/ablation during VT (entrainment mapping, activation mapping) and/or substrate mapping in sinus rhythm (elimination of fractionated/late potentials, variable extent of substrate modification) with RMN and irrigated RF ablation. The primary endpoints were as follows: (i) non-inducibility of the target VT or any other sustained VT; (ii) elimination of sustained VT/VF during ICD follow-up of up to 12 months. The cohort included 53 consecutive patients (median age 67 years, 49 men, median LVEF 31%). One hemodynamically unstable patient was excluded at the onset of mapping. Inducibility of sustained VT was achieved an average of 2.2 times per patient (1-8), with mean tachycardia cycle length (TCL) 374 milliseconds (179-510). Mean total procedure and fluoroscopy times were 223 minutes and 8.7 minutes, respectively; mean cumulative fluoroscopy time during mapping and ablation was 0.95 minutes; maximum power averaged 42.3 W with nominal saline 30 cc/min irrigation; mean cumulative RF time was 38 minutes. Non-inducibility of the target VT was achieved in 49/52 patients (94.2%) and non-inducibility of any VT was achieved in 38/52 patients (73.1%). A combination of RMN and manual ablation was performed in two patients, rendering one non-inducible. During the 12-month ICD follow-up period, freedom from any sustained VT/VF was observed in 30 patients (62%), of which 19 (63%) were off antiarrhythmic medications. Five patients expired during follow-up: one presented with a VT storm, but for the others, death was not related to VT/VF (MI-cardiogenic shock, pulmonary embolism, bronchogenic carcinoma, end stage heart failure). No procedural complications were reported. This first prospective, single-procedure, multicenter study indicates that remote magnetic navigation is a safe and effective method for catheter ablation of post-infarction VT.

Fast rate (≥ 250 beats/min) right ventricular burst stimulation is useful for ventricular tachycardia induction in arrhythmogenic right ventricular cardiomyopathy.

BackgroundOne of the major challenges in arrhythmogenic right ventricular cardiomyopathy (ARVC) ablation is ventricular tachycardia (VT) non-inducibility. The study aimed to assess whether fast rate (≥ 250 beats/min) right ventricular burst stimulation was useful for VT induction in patients with ARVC.MethodsNinety-one consecutive ARVC patients with clinical sustained VT that underwent electrophysiological study were enrolled. The stimulation protocol was implemented at both right ventricular apex and outflow tract as follows: Step A, up to double extra-stimuli; Step B, incremental stimulation with low rate (< 250 beats/min); Step C, burst stimulation with fast rate (≥ 250 beats/min); Step D, repeated all steps above with intravenous infusion of isoproterenol.ResultsA total of 76 patients had inducible VT (83.5%), among which 49 were induced by Step C, 15 were induced by Step B, 8 and 4 by Step A and D, respectively. Clinical VTs were induced in 60 patients (65.9%). Only two spontaneously ceased ventricular fibrillations were induced by Step C. Multivariate analysis showed that a narrower baseline QRS duration under sinus rhythm was independently associated with VT non-inducibility (OR: 1.1; 95% CI: 1.0–1.1; P = 0.019).ConclusionFast rate (≥ 250 beats/min) right ventricular burst stimulation provides a useful supplemental method for VT induction in ARVC patients.

Impact of Substrate-Based Ablation of Ventricular Tachycardia on Cardiac Mortality in Patients With Implantable Cardioverter-Defibrillators.

This study sought to determine if the acute procedural outcome of ventricular tachycardia (VT) substrate ablation is associated with a mortality benefit in patients with implantable cardioverter-defibrillators (ICD). A total of 195 ICD recipients (65 ± 11years) with ischemic or nonischemic dilated cardiomyopathy underwent substrate-based ablation targeting elimination of local abnormal ventricular activities (LAVA). Acute procedural success, which was defined as elimination of all identified LAVA in addition to the lack of VT inducibility, was achieved in 95 (49%) patients. During a median follow-up of 23 months, patients with acute procedure success had a significantly lower incidence of ICD shocks compared to those with ablation failure (8% vs. 30%, P < 0.001). In multivariate analysis, acute procedural success was associated with a lower risk of VT recurrence (hazard ratio [HR] 0.30, 95% confidence interval [CI] 0.18-0.49, P < 0.001) and all-cause mortality (HR 0.32, 95% CI 0.17-0.60, P < 0.001). While the impact of ablation success on mortality was not statistically significant in patients with LVEF > 35% (HR 0.45, 95% CI 0.15-1.34, P = 0.15) and those with NYHA class I/II (HR 0.63, 95% CI 0.29-1.40, P = 0.26), it was marked in patients with LVEF ≤ 35% (HR 0.30, 95% CI 0.14-0.62, P = 0.001) and NYHA class III/IV (HR 0.17, 95% CI 0.05-0.57, P = 0.004). LAVA elimination in addition to VT noninducibility as a procedural outcome for substrate-based ablation is associated with reduced mortality and better VT-free survival during follow-up. This prognostic benefit may be most pronounced in patients with severe heart failure as indicated by severely depressed LV function and NYHA class III/IV symptoms.

Procedural Outcomes and Survival After Catheter Ablation of Ventricular Tachycardia in Relation to Electroanatomical Substrate in Patients With Nonischemic-Dilated Cardiomyopathy: The Role of Unipolar Voltage Mapping.

In patients with ischemic cardiomyopathy the size of bipolar low-voltage areas (LVA) in electroanatomical maps (EAM) was associated with poorer outcomes after catheter ablation (CA) of ventricular tachycardia (VT). However, the effect of LVA size on the survival after VT ablation in patients with nonischemic dilated cardiomyopathy (NIDCM) has not been studied. In 55 patients with NIDCM (48 male, age 61 ± 16 years, ejection fraction 32 ± 13%) an EAM to delineate the bipolar and unipolar LVAs was performed in 52 (94.5%) patients endocardially, in 24 (43.6%) patients epicardially, and in 21 (38.2%) patients on both surfaces. Additionally, activation mapping of the VT was possible in 22 (40%) patients. CA with lines transecting the scar and targeting late potentials was performed in all patients. Complete VT noninducibility at the end was achieved in 40 (72.7%) patients. During the median follow-up of 22 (interquartile range IQR 6, 34) months, VT recurrences were observed in 30 (54.5%) and cardiac death in 14 (25.5%) patients. The ROC analysis revealed that the size of endocardial unipolar LVA (<8.3 mV) was associated with cardiac death (AUC 0.89, 95% CI 0.79-0.98, P <0.0001). UVA = 145 cm2 discriminates for cardiac death with 83% sensitivity and 78% specificity. Endocardial UVA > 145 cm2 was a predictor for cardiac death (adjusted HR = 6.9; P = 0.014) and UVA ≥ 54% (of total endocardial LV surface) for VT recurrence (adjusted HR = 3.5; P = 0.016). The size of endocardial unipolar LVA (<8.3 mV) was a strong and independent predictor for cardiac mortality and VT recurrence in patients with NIDCM.

Predictive Value of Programmed Ventricular Stimulation After Catheter Ablation of Post-Infarction Ventricular Tachycardia

BackgroundA recent meta-analysis demonstrated a survival benefit in post-infarction patients whose ventricular tachycardia (VT) was rendered noninducible by catheter ablation. Furthermore, patients with noninducible VT had a lower VT recurrence rate than did patients whose VT remained inducible after ablation. ObjectivesThe purpose of this multicenter cohort study was to assess whether noninducibility after VT ablation is independently associated with improved survival. MethodsData from 1,064 patients who underwent VT ablation for post-infarction VT at seven international centers were analyzed. The ablation procedure was considered successful if no VT was inducible at the end of the procedure and unsuccessful if VT remained inducible or if programmed stimulation was not performed at the end of the ablation. ResultsMedian follow-up time was 633 days. Noninducibility was independently associated with lower mortality (adjusted hazard ratio: 0.65; 95% confidence interval: 0.53 to 0.79; p < 0.001). Atrial fibrillation, diabetes, and age were other independent predictors of higher mortality. Ablation of only the clinical VT in patients who also had inducible, nonclinical VTs was not associated with improved survival. ConclusionsNoninducibility after VT ablation in patients with post-infarction VT is independently associated with lower mortality during long-term follow-up.

Catheter ablation of ventricular tachycardia and mortality in patients with nonischemic dilated cardiomyopathy: can noninducibility after ablation be a predictor for reduced mortality?

Data on outcomes after catheter ablation of ventricular tachycardia (VT) in patients with nonischemic dilated cardiomyopathy (NIDCM) are insufficient. We aimed to investigate the effects of successful catheter ablation of VT on cardiac mortality in patients with NIDCM. One hundred two patients with NIDCM (86 men; mean age, 58.8±15.2 years; mean ejection fraction, 33.3±11.9%) underwent VT ablation. After catheter ablation, a programmed ventricular stimulation to test for success was performed. Complete VT noninducibility was achieved in 62 (61%) patients and partial success or failure in 32 (31%) patients. During 2 years of follow-up, VT recurrence was observed in 33 patients (53%) without inducible VTs and in 24 patients (75%) with inducible VT inducible (P=0.041). VT inducibility was associated with higher VT recurrence (adjusted hazard ratio, 1.84; 95% confidence interval, 1.08-3.13; P=0.025). The primary end point of all-cause mortality was reached in 9 patients (15%) with noninducible VTs versus 11 patients (34%) with inducible sustained VTs (P=0.026). VT inducibility was associated with all-cause mortality (adjusted hazard ratio, 2.73; 95% confidence interval, 1.003-7.43; P=0.049). In patients with NIDCM and recurrent sustained VTs, a complete ablation of all inducible VTs may be achieved in 60% of the cases. The complete noninducibility may be a preferable end point of ablation because it was associated with better long-term success. Importantly, if possible to achieve through ablation, a complete VT noninducibility was associated with reduction of the likelihood for all-cause mortality in patients with NIDCM.

Clinical impact of mapping strategies for treatment of ventricular tachycardias in patients with structural heart disease.

Substrate-based catheter ablation (CA) can be applied to more complicated cases such as hemodynamically unstable ventricular tachycardia (VT). We aimed to compare the efficacy between substrate-based and activation/entrainment-based ablation. We investigated 85 consecutive patients (62 male, 53 ± 16 years) who underwent CA of VT to analyze the relationship between the ablation strategy and clinical outcome. The patients included 34 individuals with arrhythmogenic right ventricular cardiomyopathy, 16 with ischemic heart disease, 14 with dilated cardiomyopathy, 11 with sarcoidosis, and 10 with other heart diseases. The primary strategy was activation/entrainment mapping (Group-AE, N = 35); otherwise, substrate-based strategy was adopted (Group-S, N = 50) because of non-inducibility of VT or hemodynamic instability. Successful CA was defined as the non-inducibility of any VT at the end of the procedure in those with inducible clinical VT before ablation, and substrate elimination in those without. There were no significant differences in the left ventricular function, percentage of implantable cardioverter-defibrillator implantations, results of CA, and number of radiofrequency applications between Group-S and Group-AE. During 5 years of follow-up, there were no significant differences in sustained VT recurrences (15/50 vs. 15/35, P = 0.22), and cardiac death (2/50 vs. 3/35, P = 0.38). In patients with inducible VT before ablation, the elimination of the VT inducibility was associated with a lower recurrence rate (12/47 vs. 16/26, P = 0.003). The substrate-based strategy adopted as an alternative option when the activation/entrainment-based strategy was unable to be performed resulted in a comparable VT recurrence rate. The extinction of VT inducibility achieved a favorable prognosis in structural heart disease patients.

Abstract 12571: Successful Catheter Ablation of Ventricular Tachycardia is Associated With Reduction of Mortality in Patients With Ventricular Tachycardia and Nonischemic Dilated Cardiomyopathy

Introduction: Recent publications reported on higher recurrence rates and lack of survival benefit after catheter ablation (CA) of ventricular tachycardia (VT) in nonischemic dilated cardiomyopathy (NIDCM). Methods: We aimed to investigate the VT recurrence and cardiac mortality in patients with NIDCM ablated for VT. The studied cohort was divided in 2 groups depending on procedure success: complete success (group 1), and failure or incomplete success (group 2). Success definition was based on the VT inducibility after CA. The patients were prospectively followed for cardiac mortality and VT recurrence. Results: 104 patients with NIDCM (87 males, mean age 59.65 ± 14.69 years, mean ejection fraction 33.42 ± 11.42 %) underwent VT ablation. Ventricular stimulation after CA was not attempted in 13 (12.5%) patients. Out of the rest 91, complete success was achieved in 62 (68.1%) patients (group1), and incomplete success or failure in 29 (31.9%) patients (group 2). During 2-years follow-up, VT recurrence was observed in 56.5% in group 1 vs. 82.8% in group 2. Incomplete success was associated with higher VT recurrence (HR 1.91; 95% CI 1.13-3.22; p=0.015). The 2-years mortality was 14.5% in group 1 vs 34.5% in group 2. The probability for death was 3-times higher in group 2 (adjusted HR 3.18; 95% CI 1.18-8.56; p=0.022). The primary and secondary endpoints were comparable between patients with idiopathic, post-myocarditis and secondary NIDCM. Conclusion: Procedure success, defined as complete VT noninducibility after CA of VT, was associated with reduced VT recurrence and improved survival in patients with nonischemic dilated cardiomyopathy.

Noninducibility in postinfarction ventricular tachycardia as an end point for ventricular tachycardia ablation and its effects on outcomes: a meta-analysis.

Although ventricular tachycardia (VT) ablation is a widely used therapy for patients with VT, the ideal end points for this procedure are not well defined. We performed a meta-analysis of the published literature to assess the predictive value of noninducibility of postinfarction VT for long-term outcomes after VT ablation. We performed a systematic review of MEDLINE (1950-2013), EMBASE (1988-2013), the Cochrane Controlled Trials Register (Fourth Quarter, 2012), and reports presented at scientific meetings (1994-2013). Randomized controlled trials, case-control, and cohort studies of VT ablation were included. Outcomes reported in eligible studies were freedom from VT/ventricular fibrillation and all-cause mortality. Of the 3895 studies evaluated, we identified 8 cohort studies enrolling 928 patients for the meta-analysis. Noninducibility after VT ablation was associated with a significant increase in arrhythmia-free survival compared with partial success (odds ratio, 0.49; 95% confidence interval, 0.29-0.84; P=0.009) or failed ablation procedure (odds ratio, 0.10; 95% confidence interval, 0.06-0.18; P<0.001). There was also a significant reduction in all-cause mortality if patients were noninducible after VT ablation compared with patients with partial success (odds ratio, 0.59; 95% confidence interval, 0.36-0.98; P=0.04) or failed ablation (odds ratio, 0.32; 95% confidence interval, 0.10-0.99; P=0.049). Noninducibility of VT after VT ablation is associated with improved arrhythmia-free survival and all-cause mortality.

Noninducibility and late potential abolition: a novel combined prognostic procedural end point for catheter ablation of postinfarction ventricular tachycardia.

Successful late potential (LP) abolition and postprocedural ventricular tachycardia (VT) noninducibility constitute significant end points after catheter ablation for VT. We investigated the prognostic impact of a combined procedural end point of VT noninducibility and LP abolition in a large series of post-myocardial infarction patients with VT. A total of 160 (154 men, 94% with implantable cardioverter defibrillators) consecutive post-myocardial infarction patients undergoing first-time ablation procedures from 2010 to 2012 were included. Of the 159 patients surviving the procedure, 137 (86%) were either inducible or in VT at baseline and 103 (65%) had baseline LP presence, of which 79 (77%) underwent successful LP abolition. The combined end point was assessable in 155 (97%) patients. There were 50 (32%) patients with VT recurrences and 17 (11%) cardiac deaths during follow-up. Patients who fulfilled the combined end point of VT noninducibility and LP abolition compared with inducible patients exhibited a significantly lower incidence of VT recurrence (16.4% versus 47.4%; log-rank P<0.001) and cardiac death (4.1% versus 42.1%; log-rank P<0.001). Among noninducible patients, those with additional LP abolition also had a lower incidence of VT recurrence (16.4% versus 46.0%; log-rank P<0.001). After multivariate analysis, the combined end point of VT noninducibility and LP abolition (hazard ratio, 0.205, P<0.001) was independently associated with VT recurrence and cardiac death (hazard ratio, 0.106; P=0.001). Achieving a combined catheter ablation procedural end point of VT noninducibility and LP abolition reduces VT recurrence rates to low levels (16%). The overall strategy was associated with a significant impact on cardiac survival.

Imaging and epicardial substrate ablation of ventricular tachycardia in patients late after myocarditis

We present clinical, electroanatomical mapping (EAM), imaging, and catheter ablation (CA) strategies in patients with myocarditis-related ventricular tachycardia (VT). Between January 2010 and July 2012, 26 consecutive patients underwent imaging-guided CA of myocarditis-related ventricular arrhythmias, 23 of 26 using a combined endo-epicardial approach. Segment per segment correspondence of late enhanced (LE) scar localization with EAM scar was assessed in all patients with available uni/bipolar maps (n = 19). Induced VTs were targeted prior to substrate modification. Late potentials (LPs) abolition constituted a procedural endpoint independently from VT inducibility. Clinical monomorphic VT was induced in 15 of 26 patients (57.7%) and was associated with epicardial LPs in 10 of 15, completely abolished in 7 of 10 patients. Of the 10 patients rendered non-inducible VTs were ablated epicardially in 7. Late potentials were also detected in 7 of 11 initially non-inducible patients and completely abolished in 4. After a median follow-up of 23 (15-31) months, 20 of 26 patients (76.9%) remained free from VT recurrence. Bipolar mapping revealed low-voltage scar (<1.5 mV) in 1 patient endocardially and in 14 of 19 epicardially. Unipolar mapping revealed low-voltage scar (<8 mV) in 12 of 19 patients endocardially and in 18 of 19 epicardially. Correspondence of LE scar localization with endocardial bipolar scar was 1%, with endocardial unipolar scar 23.7%, with epicardial bipolar scar 39.8%, and with epicardial unipolar scar 66.2%. Pre-procedural scar imaging and EAM findings support the necessity of an epicardial approach in patients with prior myocarditis. Epicardial unipolar mapping (<8 mV) is superior in scar identification and CA based on substrate modification is safe and effective in this setting.

Outcomes in Catheter Ablation of Ventricular Tachycardia in Dilated Nonischemic Cardiomyopathy Compared With Ischemic Cardiomyopathy

Data on the outcomes of ventricular tachycardia (VT) ablation in nonischemic dilated cardiomyopathy (NIDCM) are insufficient. The Heart Center of Leipzig VT (HELP-VT) study was conducted prospectively to compare outcomes after radiofrequency catheter ablation of VT in patients with NIDCM compared with ischemic cardiomyopathy (ICM). Two hundred twenty-seven patients, 63 with NIDCM and 164 with ICM, presenting with sustained VT were ablated with radiofrequency catheter ablation. Noninducibility of any clinical and nonclinical VT was achieved in 66.7% of NIDCM and in 77.4% of ICM patients. Ablation of the clinical VT only was achieved in 18.3% of ICM and in 22.2% of NIDCM patients. There was no statistically significant difference in short-term outcomes between the 2 groups. At the 1-year follow-up, VT-free survival in NIDCM was 40.5% compared with 57% in ICM. In univariate analysis, the hazard ratio for VT recurrence was significantly higher for NIDCM (1.62; 95% confidence interval, 1.12- 2.34; P=0.01). In both the ICM and NIDCM subgroups, procedure failure and incomplete procedural success were independent predictors of VT recurrence. Although the short-term success rates after VT ablation in NIDCM and ICM patients were similar, the long-term outcomes in NIDCM patients were significantly worse. Complete VT noninducibility at the end of the ablation is associated with beneficial long-term outcome in NIDCM. Pursuing compete elimination of all inducible VTs is desirable and may improve the long-term success in NIDCM.