Catheter ablation of ventricular arrhythmias in left ventricular noncompaction cardiomyopathy.

BACKGROUND: There are limited data on ventricular arrhythmias (VAs) associated with left ventricular noncompaction (LVNC) cardiomyopathy. OBJECTIVES: This study aims to analyze the clinical and electrocardiographic characteristics of VAs in a group of patients with LVNC. METHODS: Forty-two nonrelated patients with LVNC and VAs were included that were evaluated at the Inherited Cardiac Disease Unit of the University Hospital Virgen Arrixaca (Murcia-Spain) (ERN Guard-Heart Centre, European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart). RESULTS: Thirteen patients (30.9%) had isolated LVNC, 27 (64.3%) had LVNC associated with dilated cardiomyopathy, and 2 (4.8%) had LVNC associated with hypertrophic cardiomyopathy. Among isolated LVNC individuals, 9 (69.2%) had premature ventricular complexes (PVCs)/nonsustained ventricular tachycardias (VTs), and 4 (30.8%) VTs (1 VT degenerating in ventricular fibrillation). In the dilated cardiomyopathy group, 11 (40.7%) patients had PVCs, 14 (51.9%) VTs, and 2 (7.4%) ventricular fibrillation. In the hypertrophic cardiomyopathy group, one patient had PVCs and the other VTs. Endocardial mapping and ablation were performed in 19 patients (45.2%): 7 ventricular outflow tracts (4 right ventricular outflow tract, 1 left coronary cusp, and 2 right coronary cusp), 2 in the left ventricular summit, 5 related to Purkinje potentials at the mid inferoseptal area, and 5 associated with endocardial scar localized in the basal anterolateral and inferolateral segments. Epicardial ablation was performed in 3 cases. CONCLUSION: The substrate of VAs in LVNC cardiomyopathy is heterogeneous, with origin in ventricular outflow tracts, Purkinje system related, and resembling scar patterns in nonischemic cardiomyopathy.

Clinical effectiveness of antiarrhythmic treatment after electrical cardioversion in patients without structural heart disease.

INTRODUCTION AND OBJECTIVES: The aim was to investigate the clinical effectiveness of using antiarrhythmic drugs after electrical cardioversion in patients without structural heart disease, including their effect on the maintenance of sinus rhythm. METHODS: In total, 528 patients with persistent atrial fibrillation but without significant structural heart disease who underwent successful electrical cardioversion at 96 Spanish hospitals were followed up for 1 year. Patients were assessed at 1, 3, 6 and 12 months. The use and effectiveness of antiarrhythmic drugs for preventing the recurrence of persistent atrial fibrillation was evaluated. RESULTS: Some 80% of patients were receiving antiarrhythmic drugs at discharge, most frequently amiodarone. No specific clinical factor was associated with greater use of antiarrhythmics. Overall, 37% of patients were in sinus rhythm at all follow-up assessments. At the 1-year assessment, 59% of patients who remained in sinus rhythm were still taking antiarrhythmic drugs. Multivariate Cox regression analysis identified weight (hazard ratio [HR]=1.01 per kg; P=.04) and no antiarrhythmic treatment (HR=1.59; P=.001) as being independently associated with the recurrence of persistent atrial fibrillation. Amiodarone tended to be better than other antiarrhythmic drugs. CONCLUSIONS: In routine clinical practice, the large majority of patients without structural heart disease received antiarrhythmic drugs, most frequently amiodarone, after successful electrical cardioversion. Drug use was the principal factor associated with the maintenance of sinus rhythm at 1 year.

Differentiation of ventricular and supraventricular tachycardias based on the analysis of the first postpacing interval after sequential anti-tachycardia pacing in implantable cardioverter-defibrillator patients.

BACKGROUND: Current discrimination algorithms do not completely avoid inappropriate tachycardia detection. OBJECTIVES: This study analyzes the discrimination capability of the changes of the first postpacing interval (FPPI) after successive bursts of anti-tachycardia pacing (ATP) trains in implantable cardioverter-defibrillator (ICD)-recorded tachycardias. METHODS: We included 50 ICD patients in this prospective study. We hypothesized that the FPPI variability (FPPIV) when comparing bursts with different numbers of beats would be shorter in ventricular tachycardias (VTs) compared with supraventricular tachycardias (SVTs). The ATP (5-10 pulses, 91% of tachycardia cycle length) was programmed for tachycardias >240 ms. RESULTS: Anti-tachycardia pacing was delivered during 37 sinus tachycardias (STs) in an exercise test, 96 induced VTs in an electrophysiological study, and 198 spontaneous episodes (144 VTs and 54 SVTs). The FPPI remained stable after all ATP bursts in VT but changed continuously in SVT; when comparing bursts of 5 and 10 pulses, the FPPIV was shorter in VT (34 +/- 65 vs.138 +/- 69, P<.0001, in all T and 12 +/- 20 vs. 138 +/- 69, P<.0001, in T>or=320 ms) than in SVT. In T>or=320 ms an FPPIV