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Background: In dilated cardiomyopathy (DCM), outcome after catheter ablation of ventricular tachycardia (VT) is modest, compared with ischemic heart disease (IHD). Pleomorphic VT (PL-VT) has been associated with fibrotic remodeling and end-stage heart failure in IHD. The prognostic role of PL-VT in DCM is unknown., Methods: Consecutive IHD (2009-2016) or DCM (2008-2018) patients undergoing ablation for monomorphic VT were included. PL-VT was defined as ≥1 spontaneous change of the 12-lead VT-morphology during the same induced VT episode. Patients were followed for VT recurrence and mortality., Results: A total of 247 patients (86% men; 63±13 years; IHD n=152; DCM n=95) underwent ablation for monomorphic VT. PL-VT was observed in 22 and 29 patients with IHD and DCM, respectively (14% versus 31%, P =0.003). In IHD, PL-VT was associated with lower LVEF (28±9% versus 34±12%, P =0.02) and only observed in those with LVEF<40%. In contrast, in DCM, PL-VT was not related to LVEF and induced in 27% of patients with LVEF>40%. During a median follow-up of 30 months, 79 (32%) patients died (IHD 48; DCM 31; P =0.88) and 120 (49%) had VT recurrence (IHD 59; DCM 61; P <0.001). PL-VT was associated with mortality in IHD but not in DCM. In IHD, VT recurrence was independently associated with LVEF, number of induced VTs, and procedural noncomplete success. Of note, in DCM, PL-VT (HR, 2.62 [95% CI, 1.47-4.69]), pathogenic mutation (HR, 2.13 [95% CI, 1.16-3.91]), and anteroseptal VT substrate (HR, 1.75 [95% CI, 1.00-3.07]) independently predicted VT recurrence., Conclusions: In IHD, PL-VT was associated with low LVEF and mortality. In DCM, PL-VT was not associated with mortality but a predictor of VT recurrence independent from LVEF. PL-VT in DCM may indicate a specific arrhythmic substrate difficult to control by current ablation techniques.

Background: Noninducibility is frequently used as procedural end point of ventricular tachycardia (VT) ablation after myocardial infarction. We investigated the influence of left ventricular (LV) function on the predictive value of noninducibility for VT recurrence and cardiac mortality., Methods and Results: Ninety-one patients (82 men, 67±10 years) with post-myocardial infarction VT underwent ablation between 2009 and 2012. Fifty-nine (65%) had an LV ejection fraction (EF) >30% (mean 41±7) and 32 (35%) an LVEF≤30% (mean 20±5). Thirty patients (51%) with EF>30% and 13 (41%) with EF≤30% were noninducible after ablation (P=0.386). During a median follow-up of 23 (Q1-Q3 16-36) months, 35 patients (38%) experienced VT recurrences and 17 (18%) cardiac death. At 1 year follow-up, survival free from VT recurrence and cardiac death for patients with LVEF>30% was 80% (95% confidence interval [CI], 70-90) compared with 42% (95% CI, 33-51) for those with LVEF≤30% (P=0.001). Noninducible patients with LVEF>30% had a recurrence-free survival from cardiac death of 90% (95% CI, 71-100) compared with 65% (95% CI, 47-83) for inducible patients (P=0.015). In the subgroup of patients with LVEF≤30%, the survival free from VT recurrence and cardiac death was 31% (95% CI, 0%-60%) for noninducible compared with 39% (95% CI, 27-52) for those who remained inducible (P=0.842)., Conclusions: Noninducible patients with moderately depressed LV function have a favorable outcome compared with patients who remained inducible after ablation. On the contrary, patients with severely depressed LV function have a poor prognosis independent of the acute procedural outcome., (© 2015 American Heart Association, Inc.)

Background: Ablation failure and recurrence rates after ventricular tachycardia (VT) ablation in nonischemic cardiomyopathy are high and the optimal procedural end point is not well defined. This study assessed the outcome after ablation, the impact of noninducibility, and other potential predictors of VT recurrence., Methods and Results: Forty-five patients with nonischemic cardiomyopathy (60±16 years; left ventricular ejection fraction, 44±14%) accepted for VT ablation were included. Epicardial mapping was performed in 29 (64%). A median of 2 (first-to-third quartile, 2-4) VTs (cycle length, 342±77 ms) were induced per patient. After ablation, the complete programmed electric stimulation protocol (3 drive cycle length, 3 extrastimuli ≥200 ms, and burst≥2 sites) was repeated. Complete success (noninducibility of any monomorphic VT) was achieved in 17 patients (38%), partial success (elimination of clinical VT, persistent inducibility of nonclinical VT) in 17 patients (38%), and failure (persistent inducibility of clinical VT) in 11 patients (24%). During 25±15 months of follow-up, VT occurred in 24 patients (53%), but the 6-month VT burden was reduced by ≥75% in 79%. Recurrence rates were low after complete procedural success (18%), but high after both partial success (77%) and failure (73%). Non-complete procedural success was the strongest predictor of VT recurrence (hazard ratio, 8.20; 95% confidence interval, 2.37-28.43; P=0.001)., Conclusions: Although 53% of patients had VT during follow-up, the 6-month VT burden was decreased by ≥75% in 79%. Recurrence rates are low after complete procedural success, but high after both partial success and failure. Non-complete procedural success was the strongest predictor of VT recurrence.

Background: Chronic right ventricular (RV) apical pacing has a detrimental effect on left ventricular (LV) function. However, the acute effects of RV apical pacing on LV mechanics remain unclear. The purpose of the study was to assess the acute impact of RV apical pacing on global LV function, evaluating LV contraction synchrony and LV shortening and twist, using 2D speckle-tracking strain imaging., Methods and Results: A group of 25 patients with structural normal hearts referred for electrophysiological study were studied. Two-dimensional echocardiography was performed at baseline and during RV apical pacing at the time of the electrophysiological study. Changes in LV synchrony and mechanics (longitudinal shortening and twist) were assessed using speckle-tracking strain imaging. In addition, 25 controls matched by age, sex, and LV function were studied during sinus rhythm. The group of patients (44+/-12 years, 10 men) and the group of controls (48+/-3 years, 8 men) showed comparable LV synchrony, LV longitudinal shortening, and LV twist at baseline. However, during RV apical pacing, a more dyssynchronous LV contraction was observed in the patients (from 21 ms [Q(1):10, Q(3):53] to 91 ms [Q(1):40, Q(3):204], P<0.001) together with an impairment in LV longitudinal shortening (from -18.3+/-3.5% to -11.8+/-3.6%, P<0.001) and in LV twist (from 12.4+/-3.7 degrees to 9.7+/-2.6 degrees , P=0.001)., Conclusions: During RV apical pacing, an acute induction of LV dyssynchrony is observed. In addition, LV longitudinal shortening and LV twist are acutely impaired.