Abstract 16621: Holter Monitoring in Patients With Left Ventricular Noncompaction

Introduction: Multiple arrhythmias including ventricular tachycardia (VT) and atrial fibrillation (AF) have been reported in patients with left ventricular noncompaction (LVNC). We sought to determine the frequency of rhythm abnormalities on Holter monitoring, and their association with all-cause mortality, in patients with LVNC. Methods: Imaging databases from 2000-2016 were reviewed to identify patients with LVNC. On transthoracic echocardiography (TTE), LVNC was defined as: end systolic noncompacted: compacted (NC:C) ratio>2 and end diastolic epicardium to trough: epicardium to peak trabeculation (X:Y) ratio<0.5. Holter monitor reports from the medical record were evaluated. VT was defined as ≥3 consecutive beats of ventricular origin. All-cause mortality was obtained from a web-based research and location service (Accurint). We used a proportional hazards model to determine associations of Holter variables with all-cause mortality. Results: Among 340 LVNC patients, Holter reports were available for 177 patients (median age 45 years, interquartile range [IQR] 33-61; 45% females). On TTE, the median NC:C ratio was 2.7 (IQR 2.4-3.2) and X:Y ratio was 0.25 (IQR 0.20-0.28). The median ejection fraction (EF) was 48% (IQR 33-58). 48 patients (27%) had at least one episode of VT (median 4 episodes, IQR 2-4). The median longest duration of VT was 5 beats (IQR 4-9) and maximum rate was 148 beats per minute (IQR: 125-169). PVC burden >5% and 20% was present in 13% and 5% of patients respectively. Patients with EF<50% were more likely to have VT (43% vs 16%, p=0.0003) and PVC burden >5% (19% vs 7%, p=0.03). AF was infrequent (N=5, all persistent). All-cause mortality was 12% over median 6.9 years of follow up (IQR: 3.6-11.3 years). Presence of VT and PVC burden on Holter monitoring were not associated with all-cause mortality (p>0.05). Among patients with VT, the number, longest duration, and fastest rate of VT episodes were not associated with all-cause mortality. Conclusions: Ventricular tachycardia on Holter monitoring is common among patients with LVNC, especially those with a reduced EF. However, the clinical significance of this finding is uncertain, and presence of VT was not associated with long term all-cause mortality.