Prognostic value of cardiac magnetic resonance imaging in patients with left ventricular noncompaction

Abstract

Purpose: Left ventricular noncompaction (LVNC) cardiomyopathy is usually diagnosed by echocardiography (ECHO) but cardiac magnetic resonance imaging (CMRI) has evolved as an alternative method. This study assessed the diagnostic and prognostic value of CMRI in adults with LVNC. Methods: Twenty eight pts (18m, 10f, age 52±16) with ECHO diagnosis of LVNC underwent cine and contrast-enhanced CMRI with a 1.5 T scanner. LV diameter, volume, ejection fraction, degree of mitral regurgitation, ratio of noncompacted to compacted myocardium (NC/C) and the presence and localization of late gadolinium enhancement (LGE) were determined. CMRI findings were correlated to clinical events, ECHO and angiography. Results: Sixteen pts (57%) were in heart failure NYHA III or IV, 11 (39%) had a left bundle branch block (LBBB) and 6 (23%) documented ventricular tachycardia. In 2 pts a thrombus was seen within the trabecular layer which resolved under anticoagulation, and 4 additional pts without detectable thrombus suffered a stroke. By CMRI, LV diameter in end-diastole (65±8 mm), end-systole (52±10 mm), end-diastolic volume (227±74 ml) and end-systolic volume (145±72 ml) were enlarged and ejection fraction (38±15%) was reduced, with similar values determined by ECHO and angio. The NC/C ratio was 3.3±1.5 in end-diastole and 2.6±1.5 in end-systole. No pt had right ventricular involvement. LGE was detected in 6/27 pts (22%). LGE was present in the compacted myocardial layer (n=3), in the noncompacted trabecular layer (n=5) and within the papillary muscles (n=3). LGE was seen in all 3 areas in 1 and in 2 areas in 3 pts. All 3 pts with papillary muscle LGE also had trabecular LGE and high grade mitral regurgitation, and 1 of these pts died while awaiting HTx. Thrombus and stroke occurred mainly in pts with LGE (4/6 vs 2/21 pts, p=0.01). Three of 11 pts with LBBB and 3/6 pts with ventricular tachycardia exhibited LGE. A high NC/C ratio, however, was not associated with heart failure, thrombus and stroke, LBBB, VT or ejection fraction. Conclusions: In LVNC, evaluation by CMRI and demonstration of LGE identifies pts at high risk for clinical events. Extensive LGE may predispose to thrombus formation and stroke, warranting anticoagulation. LGE within the papillary muscles is associated with high grade mitral regurgitation, aggravating heart failure in these patients.