Prognostic Value of Compact Myocardial Thinning in Patients With Left Ventricular Noncompaction

Clinical presentations of left ventricular noncompaction (LVNC) range from asymptomatic cases to ventricular tachyarrhythmia (VT), heart failure (HF), and cerebrovascular accidents (CVA). In this multicenter study, we explored the associations between clinical and imaging characteristics and outcomes of LVNC patients and validated the predictive value of myocardial thinning identified on cardiac magnetic resonance imaging (CMR) as previously described. About 214 adult patients (54% male, mean age 41 ± 16 years) meeting the imaging criteria for LVNC were identified. Myocardial thinning was defined as a 50% or greater diameter reduction of the compacted myocardium compared to a contiguous segment on CMR. The primary endpoint was the occurrence of a major adverse cardiovascular event (MACE), defined as a composite of all-cause mortality, HF hospitalization, left ventricular assist device (LVAD) or heart transplant, cardiac resynchronization therapy (CRT), CVA/transient ischemic attacks (TIA), VT and appropriate implantable cardioverter defibrillator (ICD) therapy. Focal myocardial thinning was observed in 42 patients (20%). Over a median follow-up time of 7 years (IQR, 4 to 10 years), 54 patients (24%) experienced a primary outcome. Patients with myocardial thinning had more cumulative adverse events than those without myocardial thinning (chi-square = 29.516, log-rank < 0.001), even after matching for medical risk score. In a multivariate Cox regression model, myocardial thinning remained associated with outcomes: HR 3.052 (95% CI: 1.569 to 5.937, p = 0.001). Myocardial thinning is associated with adverse cardiovascular events in LVNC patients. Incorporating myocardial thinning into medical risk assessments can improve the prediction and management of adverse outcomes in these patients.