Characterization of Structural Changes in Arrhythmogenic Right Ventricular Cardiomyopathy With Recurrent Ventricular Tachycardia After Ablation: Insights From Repeat Electroanatomic Voltage Mapping.

BACKGROUND: Data characterizing structural changes of arrhythmogenic right ventricular (RV) cardiomyopathy are limited. METHODS: Patients presenting with left bundle branch block ventricular tachycardia in the setting of arrhythmogenic RV cardiomyopathy with procedures separated by at least 9 months were included. RESULTS: Nineteen consecutive patients (84% males; mean age 39±15 years [range, 20-76 years]) were included. All 19 patients underwent 2 detailed sinus rhythm electroanatomic endocardial voltage maps (average 385±177 points per map; range, 93-847 points). Time interval between the initial and repeat ablation procedures was mean 50±37 months (range, 9-162). No significant progression of voltage was observed (bipolar: 38 cm2 [interquartile range (IQR), 25-54] versus 53 cm2 [IQR, 25-65], P=0.09; unipolar: 116 cm2 [IQR, 61-209] versus 159 cm2 [IQR, 73-204], P=0.36) for the entire study group. There was a significant increase in RV volumes (percentage increase, 28%; 206 mL [IQR, 170-253] versus 263 mL [IQR, 204-294], P<0.001) for the entire study population. Larger scars at baseline but not changes over time were associated with a significant increase in RV volume (bipolar: Spearman ρ, 0.6965, P=0.006; unipolar: Spearman ρ, 0.5743, P=0.03). Most patients with progressive RV dilatation (8/14, 57%) had moderate (2 patients) or severe (6 patients) tricuspid regurgitation recorded at either initial or repeat ablation procedure. CONCLUSIONS: In patients with arrhythmogenic RV cardiomyopathy presenting with recurrent ventricular tachycardia, >10% increase in RV endocardial surface area of bipolar voltage consistent with scar is uncommon during the intermediate term. Most recurrent ventricular tachycardias are localized to regions of prior defined scar. Voltage indexed scar area at baseline but not changes in scar over time is associated with progressive increase in RV size and is consistent with adverse remodeling but not scar progression. Marked tricuspid regurgitation is frequently present in patients with arrhythmogenic RV cardiomyopathy who have progressive RV dilation.

Cardiac resynchronization therapy-induced acute shortening of QRS duration predicts long-term mortality only in patients with left bundle branch block.

AIMS: QRS narrowing with initiation of biventricular pacing might be an acute electrocardiographic indicator of correction of left bundle branch block (LBBB)-induced depolarization delay and asynchrony. However, its impact on prognosis remains controversial, especially in non-LBBB patients. Our goal was to evaluate the impact of QRS narrowing on long-term mortality and morbidity in a large cohort of patients undergoing cardiac resynchronization therapy (CRT) with different pre-implantation QRS types: LBBB, non-LBBB, and permanent right ventricular pacing. METHODS AND RESULTS: This study included consecutive patients who underwent CRT device implantation. Study endpoints: death from any cause or urgent heart transplantation and death from any cause/urgent heart transplantation or hospital admission for heart failure. All pre- and post-implantation electrocardiograms were analysed using digital callipers, high-amplitude augmentation, 100 mm/s paper speed, and global QRS duration measurement method. A total of 552 CRT patients entered the survival analysis. During the 9 years observation period, 232 (42.0%) and 292 (52.9%) patients met primary and secondary endpoints, respectively. QRS narrowing predicted survival in the Kaplan-Meier analysis only in patients with LBBB. Multivariate Cox regression model showed that QRS narrowing was the major determinant of both study endpoints, with hazard ratios of 0.46 and 0.43, respectively. There was a strong relationship between mortality risk and shortening/widening of the QRS, albeit only in the LBBB group. Patients with non-LBBB morphologies had unfavourable prognosis similar to that in LBBB patients without QRS narrowing. CONCLUSION: Acute QRS narrowing in patients with LBBB might be a desirable endpoint of CRT device implantation.

Is there a prognostic relevance of electrophysiological studies in bundle branch block patients?

BACKGROUND: The present European guidelines suggest a diagnostic electrophysiological (EP) study to determine indication for cardiac pacing in patients with bundle branch block and unexplained syncope. We evaluated the prognostic relevance of an EP study for mortality and the development of permanent complete atrioventricular (AV) block in patients with symptomatic bifascicular block and first-degree AV block. HYPOTHESIS: The HV interval is a poor prognostic marker to predict the development of permanent AV block in patients with symptomatic bifascicular block (BFB) and AV block I°. METHODS: Thirty consecutive patients (mean age, 74.8 ± 8.6 years; 25 males) with symptomatic BFB and first-degree AV block underwent an EP study before device implantation, according to current guidelines. For 53 ± 31 months, patients underwent yearly follow-up screening for syncope or higher-degree AV block. RESULTS: Thirty patients presented with prolonged HV interval during the EP study (mean, 82.2 ± 20.1 ms; range, 57-142 ms), classified into 3 groups: group 1, <70 ms (mean, 62 ± 4 ms; range, 57-67 ms; n = 7), group 2, >70 to ≤100 ms (mean, 80 ± 8 ms; range, 70-97 ms; n = 18), and group 3, >100 ms (mean, 119 ± 14 ms; range, 107-142 ms; n = 5). According to the guidelines, patients in groups 2 and 3 received a pacemaker. The length of the HV interval was not associated with the later development of third-degree AV block or with increased mortality. CONCLUSIONS: Our present study suggests that an indication for pacemaker implantation based solely on a diagnostic EP study with prolongation of the HV interval is not justified.

Effect of bundle branch block on microvolt T-wave alternans and electrophysiologic testing in patients with ischemic cardiomyopathy.

BACKGROUND: T-wave alternans (TWA) and electrophysiology study (EPS) are used for risk stratification for sudden death. OBJECTIVE: The purpose of the study was to determine the effect of bundle branch block or intraventricular conduction delay on TWA and EPS. METHODS: 386 patients with coronary artery disease, nonsustained ventricular tachycardia, and left ventricular ejection fraction < or =40% underwent TWA and EPS, and were followed for 40 +/- 19 months. RESULTS: Patients with wide QRS were more likely than narrow QRS patients to have nonnegative TWA (77% vs 63%, P <.01) or positive EPS (60% vs 48%, P = .03). Nonnegative TWA predicted the combined endpoint of ventricular tachyarrhythmia or death in narrow QRS (HR = 1.64, P = .04) but not wide QRS patients (HR = 1.04, P = .91). Similarly, positive EPS predicted the combined endpoint in narrow QRS (HR = 2.28, P <.001) but not wide QRS patients (HR = 0.94, P = .84). In multivariate analysis, QRS width and TWA, as well as QRS width and EPS, were independent predictors of events. There was no TWA- or EPS-based difference in arrhythmia-free survival within any specific wide QRS morphology. CONCLUSION: TWA and EPS are more often abnormal in patients with a wide QRS than in those with a narrow QRS. In patients with narrow QRS, both TWA and EPS stratify patients according to their risk of ventricular tachyarrhythmia or death. However, among patients with a wide QRS, regardless of specific QRS morphology, the risk is high and comparable regardless of TWA or EPS results. Therefore, the only truly low-risk group consists of those patients with negative test results and a narrow QRS.

T-wave alternans in patients with right ventricular tachycardia.

Microvolt T-wave alternans has been proposed as a new risk marker for ventricular arrhythmias. However, the clinical significance of T-wave alternans in patients with ventricular tachycardia (VT) originating from the right ventricle has been unknown. The study population consisted of 20 patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) or idiopathic VT. T-wave alternans was measured during bicycle exercise testing using the CH 2000 system. Of the 7 patients with ARVC, 6 (86%) were positive for T-wave alternans. On the other hand, only 1 (8%) of 13 patients with idiopathic VT originating from the right-ventricular outflow tract was positive for T-wave alternans.

Value of non-invasive and invasive studies in patients with bundle branch block, syncope and history of myocardial infarction.

UNLABELLED: The prognosis of patients with bundle branch block (BBB) and myocardial infarction (MI) is poor, particularly for patients suffering from syncope. The purpose of this study was to investigate the diagnostic value of some techniques for the evaluation of the mechanism of syncope in patients with MI and BBB and their prognosis. METHODS: We prospectively obtained the results of clinical history, 24 h Holter monitoring, left ventricular ejection fraction (LVEF), signal-averaged ECG (SAECG) and programmed ventricular stimulation in 130 patients with syncope, MI and BBB. 81 of them had right (R)BBB and 49-left (L)BBB. RESULTS: Ventricular tachycardia (VT) was identified as the main cause of syncope in patients with MI and BBB: 68% of them had inducible VT. The sensitivity (se) and specificity (sp) of non sustained VT on Holter monitoring for the detection of VT were respectively 42.5 and 47% in patients with RBBB, 62 and 36% in those with LBBB; se and sp of LVEF <40% were 67.5% and 65% in patients with RBBB, 85 and 9% in those with LBBB; se and sp of the combination of 2 of the 3 SAECG criteria, QRS duration > 155 ms, LAS duration >30 ms and RMS 40 < 17 microV were respectively 50 and 57% in patients with RBBB; se and sp of the combination of 2 of the 3 criteria QRS duration >165 ms, LAS duration >40 ms and RMS 40 <17 microV were 73 and 55.5%) in patients with LBBB. During the follow-up (4.7 years +/- 2.5), 12 patients died suddenly and 12 patients died from heart failure. Univariate and multivariate analysis revealed than only the induction of VT was a significant predictor of sudden death. A long QRS duration (> 165 ms) and induction of VT were independent predictors of total cardiac mortality. CONCLUSION: Among noninvasive studies, only the determination of filtered QRS duration was a significant predictor of cardiac mortality in the case of a prolongation (> 165 ms). Sudden death was only predicted by the induction of sustained VT. Because of the high incidence of inducible sustained VT, the low value of Holter monitoring and decreased LVEF for the prediction of ventricular arrhythmias and the poor prognosis of patients with inducible VT and low LVEF, systematic programmed ventricular stimulation is indicated in patients with MI, syncope and BBB, whatever the non-invasive studies results.