The value of cardiac magnetic resonance imaging and programmed ventricular stimulation in patients with ventricular noncompaction and ventricular arrhythmias.

INTRODUCTION Left ventricular noncompaction (LVNC) is associated with ventricular arrhythmias (VA) including premature ventricular complexes, and ventricular tachycardia (VT). The value of imaging with delayed enhancement cardiac magnetic resonance (DE-CMR) and programmed ventricular stimulation (PVS) for risk stratification in patients with VA and LVNC is unknown. The purpose of this study was to determine whether DE-CMR and PVS are beneficial for risk stratification and whether CMR helps to identify VA target sites. METHODS AND RESULTS Consecutive patients with LVNC undergoing ablation for VAs were included, all patients had preprocedure DE-CMR. A total of 23 patients (7 women, 46 ± 14 years, ejection fraction 35 ± 14) were included and followed for 2.9 ± 2.2 years. DE-CMR scar was present in 12/23 patients (52%). PVS was performed in 20/23 patients, 8/10 patients (80%) with scar were inducible for VT compared to 0/10 (0%) patients without scar (p < .001). VA target sites in patients with scarring were located adjacent to areas of scarring in all but 1 patient and ablation was successful in 15/23 patients (65%). Patients with scar had worse survival free of VT than those without scar (log rank p = .01) and patients with inducible VT had worse survival free of VT than those who were noninducible (log rank p < .001). CONCLUSIONS The presence of CMR defined scar in patients with LVNC was associated with inducible VT and worse outcomes. Inducibility for VT was associated with VT recurrence. Furthermore, CMR is beneficial in localizing the arrhythmogenic substrate in LVNC and therefore can aid in procedural planning.