Characterization of the arrhythmogenic substrate in patients with arrhythmogenic right ventricular cardiomyopathy undergoing ventricular tachycardia ablation.

AIMS: Arrhythmogenic right ventricular (RV) cardiomyopathy (ARVC) is associated with ventricular arrhythmias, even without RV structural disease. We aimed to characterize the RV substrate using electroanatomical mapping and to define outcomes following ventricular tachycardia (VT) ablation in patients with and without RV structural abnormalities. METHODS AND RESULTS: Twenty-nine patients with definite or suspected ARVC undergoing VT ablation were classified as 'electrical' and 'structural' cardiomyopathy based on the absence or presence of major structural criteria. Right ventricular (RV) endocardial and epicardial mapping with assessment of bipolar and unipolar voltages, distribution of late potentials (LPs), and inducible VT morphologies were performed. The endpoints for VT ablation were VT non-inducibility and LP abolition. Fourteen patients were categorized as electrical RV cardiomyopathy and 15 were categorized as structural RV cardiomyopathy. In patients with electrical cardiomyopathy, scar was limited to the epicardial surface (epicardium 13 cm2vs. endocardium 1 cm2, P < 0.05), primarily in the outflow tract, whereas patients with structural disease had greater involvement of the endocardium. During a mean follow-up of 22 ± 11 months, the VT recurrence rate was 27%, with LP abolition being a predictor of VT-free survival (HR 0.075 (0.008-0.661), P = 0.020). There was a trend towards higher recurrence rates in structural RV cardiomyopathy (40%) compared with the electrical cardiomyopathy (15%, P = 0.17). CONCLUSION: The development of RV structural disease in patients with ARVC is associated with extensive epicardial and endocardial scar. Conversely those patients without RV structural disease have identifiable epicardial scar limited to the RV outflow tract. Ventricular tachycardia (VT) ablation in both groups targeting LP abolition is effective in preventing VT recurrence.

Third- versus Second-Generation Stent Graft for Endovascular Aneurysm Repair: A Device-Specific Analysis.

PURPOSE: Our purpose is to analyze the outcomes of endovascular aneurysm repair (EVAR) in patients treated with Excluder endograft (W.L. Gore and Associate, Flagstaff, AZ), comparing second generation, featuring SIM-PULL delivery system (ExSP) and third generation, featuring C3 (ExC3), concerning intraprocedural data and long-term outcomes. METHODS: In our single-center, comparative study, we retrospectively analyzed all patients undergoing elective EVAR with Excluder from May 2008 to December 2015. This cohort was firstly divided according to the design of the endograft used, and then, two subgroups of complex procedures were identified according to International Standards. Preliminary end points were early- and mid-term outcomes. Primary end point was procedural data (i.e., procedural and fluoroscopy time, radiation dose (DAP), and contrast medium amount). RESULTS: The study included 64 patients (24 ExSP and 40 ExC3) with a mean follow-up of 31.6 ± 22.9 months. Patients in ExC3 group had significantly more risk factors (past or present history of smoking, P = 0.019), comorbidities (chronic heart failure and chronic kidney disease, both P = 0.032), as well as a more unfavorable anatomy (neck angulation, P = 0.035). Concerning preliminary outcome, no significant between-group difference was noted. As for intraoperative data, procedure duration was significantly shorter: 120 vs. 151 min (P = 0.002) in the overall population and 129 vs. 173 min (P = 0.004) in complex cases. A significant reduction was also found in fluoroscopy time and radiation exposure: 24,084 vs. 32,548 cGy/cm2 (P = 0.020) in the overall population and 26,770 vs. 41,104 cGy/cm2 (P = 0.003) in complex cases. No significant difference was found for contrast volume. CONCLUSIONS: The study shows that new C3 excluder enables to reduce radiation exposure and procedural time compared to the previous device. C3 excluder results are comparable to those of the previous device in spite of more comorbidities and complex anatomy of the treated patients. Further studies are needed to assess device performance on longer-term follow-up.

The value of the 12-lead electrocardiogram in localizing the scar in non-ischaemic cardiomyopathy.

AIMS: Patients with non-ischaemic cardiomyopathy (NICM) and ventricular tachycardia can be categorized as anteroseptal (AS) or inferolateral (IL) scar sub-types based on imaging and voltage mapping studies. The aim of this study was to correlate the baseline electrocardiogram (ECG) with endo-epicardial voltage maps created during ablation procedures and identify the ECG characteristics that may help to distinguish the scar as AS or IL. METHODS AND RESULTS: We assessed 108 baseline ECGs; 72 patients fulfilled criteria for dilated cardiomyopathy whereas 36 showed minimal structural abnormalities. Based on the unipolar low-voltage distribution, the scar pattern was classified as predominantly AS (n = 59) or IL (n = 49). Three ECG criteria (PR interval < 170 ms or QRS voltage in inferior leads <0.6 mV or a lateral q wave) resulted in 92% sensitivity and 90% specificity for predicting an IL pattern in patients with preserved ejection fraction (EF). The four-step algorithm for dilated cardiomyopathy included a paced ventricular rhythm or PR > 230 ms or QRS > 170 ms or an r ≤ 0.3 mV in V3 having 92 and 81% of sensitivity and specificity, respectively, in predicting AS scar pattern. A significant negative correlation was found between the extension of the endocardial unipolar low voltage area and left ventricular EF (rs = -0.719, P < 0.001). The extent of endocardial AS unipolar low voltage was correlated with PR interval and QRS duration (rs = 0.583 and rs = 0.680, P < 0.001, respectively) and the IL epicardial unipolar low voltage with the mean voltage of the limb leads (rs = -0.639, P < 0.001). CONCLUSION: Baseline ECG features are well correlated with the distribution of unipolar voltage abnormalities in NICM and may help to predict the location of scar in this population.

Catheter ablation of ventricular arrhythmia in nonischemic cardiomyopathy: anteroseptal versus inferolateral scar sub-types.

BACKGROUND: The aim was to relate distinct scar distributions found in nonischemic cardiomyopathy with ventricular tachycardia (VT) morphology, late potential distribution, ablation strategy, and outcome. METHODS AND RESULTS: Eighty-seven patients underwent catheter ablation for drug-refractory VT. Based on endocardial unipolar voltage, 44 were classified as predominantly anteroseptal and 43 as inferolateral. Anteroseptal patients more frequently fulfilled diagnostic criteria for dilated cardiomyopathy (64% versus 36%), associated with more extensive endocardial unipolar scar (41 [22-83] versus 9 [1-29] cm(2); P<0.001). Left inferior VT axis was predictive of anteroseptal scar (positive predictive value, 100%) and right superior axis for inferolateral (positive predictive value, 89%). Late potentials were infrequent in the anteroseptal group (11% versus 74%; P<0.001). Epicardial late potentials were common in the inferolateral group (81% versus 4%; P<0.001) and correlated with VT termination sites (κ=0.667; P=0.014), whereas no anteroseptal patient had an epicardial VT termination (P<0.001). VT recurred in 44 patients (51%) during a median follow-up of 1.5 years. Anteroseptal scar was associated with higher VT recurrence (74% versus 25%; log-rank P<0.001) and redo procedure rates (59% versus 7%; log-rank P<0.001). After multivariable analysis, clinical predictors of VT recurrence were electrical storm (hazard ratio, 3.211; P=0.001) and New York Heart Association class (hazard ratio, 1.608; P=0.018); the only procedural predictor of VT recurrence was anteroseptal scar pattern (hazard ratio, 5.547; P<0.001). CONCLUSIONS: Unipolar low-voltage distribution in nonischemic cardiomyopathy allows categorization of scar pattern as inferolateral, often requiring epicardial ablation mainly based on late potentials, and anteroseptal, which frequently involves an intramural septal substrate, leading to a higher VT recurrence.