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Background Frequent premature ventricular complexes (PVCs) have been associated with increased mortality. However, the optimal approach to the risk stratification of these patients is unclear. Objective The purpose of this study was to prospectively assess the use of cardiac magnetic resonance imaging (MRI) and programmed ventricular stimulation to identify patients with PVCs undergoing radiofrequency ablation at risk for adverse long-term outcomes. Methods A total of 321 consecutive patients (52 ± 15 years; 157 men [49%]; left ventricular ejection fraction 51% ± 12%) underwent PVC ablation between 2004 and 2015, preceded by cardiac MRI to assess for structural heart disease (SHD). Programmed stimulation was performed at the time of the ablation procedure. If ventricular tachycardia (VT) was induced in the presence of SHD, an implantable cardioverter-defibrillator (ICD) was implanted. Results SHD was identified by MRI in 64 patients (20%), and sustained monomorphic VT was inducible in 15 patients (5%). Fourteen patients had both SHD and inducible VT, and received an ICD after the procedure. The primary endpoint of VT/ventricular fibrillation or death was met in 15 patients after a median 20 months of follow-up. The combination of SHD by MRI and VT inducibility conferred independently an increased risk of adverse outcome (multivariate hazard ratio 25.73, 95% confidence interval 6.74–98.20; P Conclusion Preablation cardiac MRI and programmed stimulation can be useful for risk stratification in patients with frequent PVCs. Patients with inducible VT in the setting of SHD may benefit from ICD implantation after ablation regardless of left ventricular ejection fraction.

Knowledge of complex arrhythmogenic substrates can help plan ventricular tachycardia (VT) ablation in patients with idiopathic dilated cardiomyopathy (DCM).The purpose of this study was to assess whether preprocedural late gadolinium enhancement magnetic resonance imaging (LGE-MRI) can improve ablation outcomes in DCM.Consecutive patients (N = 96) with idiopathic DCM underwent VT ablation with open-irrigated catheters (2006-2016). Before 2012, LGE-MRI was not performed at our institution in patients with implanted devices, but it has been performed routinely in all patients after implementation of a new MRI protocol in 2012. We retrospectively compared acute and long-term outcomes of initial VT ablation procedures in patients with (n = 41) and those without (n = 55) preprocedural LGE-MRI. Procedural outcome was classified as successful if VT was not inducible postablation.The 2 groups had a similar mean age and ejection fraction, comorbidities, and frequency of epicardial ablation. Preablation LGE-MRI was independently associated with improved procedural success (63% vs 24%) by logistic regression analysis (adjusted odds ratio [OR] 7.86, P.001). This result was consistent even when patients with nondiagnostic MRIs due to artifact were included in the imaging group (OR 4.87, P = .005). Preablation imaging was also associated with improved survival free of the composite endpoint of VT recurrence, heart transplantation, or death, which was met by 11 (27%) and 33 (60%) patients in the imaging and no imaging groups, respectively, after median 7.6 months of follow-up (unadjusted log-rank P = .02). However, there was no association with long-term outcomes after adjustment for other covariates.Preprocedural imaging with LGE-MRI may be associated with improved outcomes of VT ablation in DCM.

Patients with frequent premature ventricular complexes (PVCs) are at risk of developing reversible PVC-induced cardiomyopathy (rPVC-CMP). Not all determinants of rPVC-CMP are known.To assess the impact of the QRS duration of PVCs on the development of rPVC-CMP.In a consecutive series of 294 patients with frequent idiopathic PVCs referred for PVC ablation, the width of the PVC-QRS complex was assessed. The QRS width was correlated with the presence of rPVC-CMP.The PVC-QRS width was significantly greater in patients with rPVC-CMP than in patients without rPVC-CMP (164 ± 20 ms vs 149 ± 17 ms; P.0001). The site of origin of the PVC had an impact on the PVC-QRS width, with epicardial PVCs having the broadest QRS complexes. Patients with PVCs originating from the right ventricular outflow tract or the fascicles had the narrowest QRS complexes. After adjusting for PVC burden, symptom duration, and PVC site of origin, PVC-QRS width and an epicardial PVC origin were independently associated with rPVC-CMP. Based on receiver operator characteristics analysis, a QRS duration of150 ms best differentiated patients with and without rPVC-CMP (area under the curve 0.66; sensitivity 80%; specificity 52%). The PVC burden for developing rPVC-CMP is significantly lower in patients with a PVC-QRS width of ≥150 ms than in patients with a narrower PVC-QRS complex (22% ± 13% vs 28% ± 12%; P.0001).Broader PVCs and an epicardial PVC origin are associated with the development of rPVC-CMP independent of the PVC burden.

Frequent premature ventricular complexes (PVCs) can cause cardiomyopathy. The mechanism is not known and may be multifactorial.This study assessed the role of PVC interpolation in PVC-induced cardiomyopathy.In 51 consecutive patients (14 women, age 49 ± 15 years, ejection fraction (EF) 0.49 ± 0.14) with frequent PVCs, 24-hour Holter recordings were performed. The amount of interpolation was determined and correlated with the presence of PVC-induced cardiomyopathy. In addition, parameters measured during an electrophysiology study were correlated with the Holter findings.Fourteen of the 21 patients (67%) with cardiomyopathy had interpolated PVCs, compared with only 6 of 30 patients (20%) without PVC-induced cardiomyopathy (P.001). Patients with interpolated PVCs had a higher PVC burden than patients without interpolation (28% ± 12% vs. 15% ± 15%; P = .002). The burden of interpolated PVCs correlated with the presence of PVC cardiomyopathy (21% ± 30% vs. 4% ± 13%; P = .008). Both PVC burden and interpolation independently predicted PVC-induced cardiomyopathy (odds ratio 1.07, 95% confidence interval 1.01 to 1.13, P = .02; and odds ratio 4.43, 95% confidence interval 1.06 to 18.48, P = .04, respectively). The presence of ventriculoatrial block at a ventricular pacing cycle length of 600 ms correlated with the presence of interpolation (P = .004). Patients with interpolation had a longer mean ventriculoatrial block cycle length than patients without interpolated PVCs (520 ± 110 ms vs. 394 ± 92 ms; P = .01).The presence of interpolated PVCs was predictive of the presence of PVC cardiomyopathy. Interpolation may play an important role in the generation of PVC-induced cardiomyopathy.

Background Mapping criteria for hemodynamically tolerated, postinfarction ventricular tachycardia (VT) have been evaluated in only small series of patients. Objectives The purpose of this study was to evaluate the utility of various mapping criteria for identifying a critical VT circuit isthmus in a post hoc analysis. Methods Ninety VTs (cycle length 491 ± 84 ms) were mapped in 48 patients with a prior myocardial infarction. The mapping catheter was positioned within a protected area of the reentrant circuit of the targeted VTs at 176 sites. All sites showed concealed entrainment. The predictive values of the following mapping criteria for a successful ablation site were compared: discrete isolated potential during VT, inability to dissociate the isolated potential from the VT, endocardial activation time >70 ms, matching electrogram-QRS and stimulus-QRS intervals, VT termination without global capture during pacing, stimulus-QRS/VT cycle length ratio ≤0.7, and postpacing interval. For each criterion, the receiver operating characteristic curve was constructed, and the area under the curve was calculated to assess the discriminatory value of the criterion. Results Seventy-eight of 90 VTs (87%) were successfully ablated. The area under the receiver operating characteristic curve was largest (0.89) for matching stimulus-QRS and electrogram-QRS intervals. In combination with an isolated potential that could not be dissociated from the VT, the area under the receiver operating characteristic curve increased to 0.93. Conclusion At sites with concealed entrainment, matching stimulus-QRS and electrogram-QRS intervals were superior to other criteria in differentiating a critical isthmus from bystander or noncritical sites in postinfarction VT.

Frequent idiopathic premature ventricular complexes (PVCs) can result in a reversible form of cardiomyopathy. In this study, the determinants of PVC-induced left ventricular (LV) dysfunction were assessed.The subjects of this study were 241 consecutive patients (115 men [48%], mean age 48 ± 14 years) referred for ablation of frequent PVCs. One hundred eighty patients (75%) experienced palpitations and 61 (25%) did not. The PVC burden was determined by 24-hour Holter monitoring, and echocardiograms were performed to assess LV function. An LV ejection fraction of50% was considered abnormal.LV ejection fraction (mean 0.36 ± 0.09) was present in 76 of 241 patients (32%). There was a higher prevalence of males among the patients with PVC cardiomyopathy compared to patients with normal LV function (51/76 [67%] vs 64/165 [39%]; P.0001). The mean PVC burden was significantly higher in patients with PVC cardiomyopathy than in patients with normal LV function (28% ± 12% vs 15% ± 13%; P.0001). Among symptomatic patients, those with cardiomyopathy had a significantly longer duration of palpitations (135 ± 118 months) compared with patients with normal LV function (35 ± 52 months; P.0001). The proportion of asymptomatic patients was significantly higher in the presence of cardiomyopathy (36/76, 47%) than in normal LV function (25/165, 15%; P.0001). Symptom duration of 30 to 60 months, symptom duration60 months, the absence of symptoms, and the PVC burden in asymptomatic patients were independent predictors of impaired LV function (adjusted odds ratio [95% confidence interval]: 4.0 [1.1-14.4], 20.1 [6.3-64.1], 13.1 [4.1-37.8], and 2.1 [1.2-3.6], respectively).The duration of palpitations and the absence of symptoms are independently associated with PVC-induced cardiomyopathy.

Pace mapping has been used to identify the site of origin of focal ventricular arrhythmias. The spatial resolution of pace mapping has not been adequately quantified using currently available three-dimensional mapping systems.The purpose of this study was to determine the spatial resolution of pace mapping in patients with idiopathic ventricular tachycardia or premature ventricular contractions originating in the right ventricular outflow tract.In 16 patients with idiopathic ventricular tachycardia/ectopy from the right ventricular outflow tract, comparisons and classifications of pace maps were performed by two observers (good pace map: match10/12 leads; inadequate pace map: matchor =10/12 leads) and a customized MATLAB 6.0 program (assessing correlation coefficient and normalized root mean square of the difference (nRMSd) between test and template signals). With an electroanatomic mapping system, the correlation coefficient of each pace map was correlated with the distance between the pacing site and the effective ablation site. The endocardial area within the 10-ms activation isochrone was measured.The ablation procedure was effective in all patients. Sites with good pace maps had a higher correlation coefficient and lower nRMSd than sites with inadequate pace maps (correlation coefficient: 0.96 +/- 0.03 vs 0.76 +/- 0.18, P.0001; nRMSd: 0.41 +/- 0.16 vs 0.89 +/- 0.39, P.0001). Using receiver operating characteristic curves, appropriate cutoff values were0.94 for correlation coefficient (sensitivity 81%, specificity 89%) andor =0.54 for nRMSd (sensitivity 76%, specificity 80%). Good pace maps were located a mean of 7.3 +/- 5.0 mm from the effective ablation site and had a mean activation time of -24 +/- 7 ms. However, in 3 (18%) of 16 patients, the best pace map was inadequate at the effective ablation site, with an endocardial activation time at these sites of -25 +/- 12 ms. Pace maps with correlation coefficientor =0.94 were confined to an area of 1.8 +/- 0.6 cm2. The 10-ms isochrone measured 1.2 +/- 0.7 cm2.The spatial resolution of a good pace map for targeting ventricular tachycardia/ectopy is 1.8 cm2 in the right ventricular outflow tract and therefore is inferior to the spatial resolution of activation mapping as assessed by isochronal activation. In approximately 20% of patients, pace mapping is unreliable in identifying the site of origin, possibly due a deeper site of origin and preferential conduction via fibers connecting the focus to the endocardial surface.