Cardiovascular magnetic resonance predictors of heart failure in hypertrophic cardiomyopathy: the role of myocardial replacement fibrosis and the microcirculation.

INTRODUCTION: Heart failure (HF) in hypertrophic cardiomyopathy (HCM) is associated with high morbidity and mortality. Predictors of HF, in particular the role of myocardial fibrosis and microvascular ischemia remain unclear. We assessed the predictive value of cardiovascular magnetic resonance (CMR) for development of HF in HCM in an observational cohort study. METHODS: Serial patients with HCM underwent CMR, including adenosine first-pass perfusion, left atrial (LA) and left ventricular (LV) volumes indexed to body surface area (i) and late gadolinium enhancement (%LGE- as a % of total myocardial mass). We used a composite endpoint of HF death, cardiac transplantation, and progression to NYHA class III/IV. RESULTS: A total of 543 patients with HCM underwent CMR, of whom 94 met the composite endpoint at baseline. The remaining 449 patients were followed for a median of 5.6 years. Thirty nine patients (8.7%) reached the composite endpoint of HF death (n = 7), cardiac transplantation (n = 2) and progression to NYHA class III/IV (n = 20). The annual incidence of HF was 2.0 per 100 person-years, 95% CI (1.6-2.6). Age, previous non-sustained ventricular tachycardia, LV end-systolic volume indexed to body surface area (LVESVI), LA volume index ; LV ejection fraction, %LGE and presence of mitral regurgitation were significant univariable predictors of HF, with LVESVI (Hazard ratio (HR) 1.44, 95% confidence interval (95% CI) 1.16-1.78, p = 0.001), %LGE per 10% (HR 1.44, 95%CI 1.14-1.82, p = 0.002) age (HR 1.37, 95% CI 1.06-1.77, p = 0.02) and mitral regurgitation (HR 2.6, p = 0.02) remaining independently predictive on multivariable analysis. The presence or extent of inducible perfusion defect assessed using a visual score did not predict outcome (p = 0.16, p = 0.27 respectively). DISCUSSION: The annual incidence of HF in a contemporary ambulatory HCM population undergoing CMR is low. Myocardial fibrosis and LVESVI are strongly predictive of future HF, however CMR visual assessment of myocardial perfusion was not.

A rare finding of giant accessory mitral valve tissue: a case report.

BACKGROUND: Accessory mitral valve tissue (AMVT) is a rare anomaly that can be detected in the first decade. It is associated with other congenital cardiac abnormalities, such as ventricular septal defect. When detected in adulthood, it is usually an incidental finding on echocardiography. Symptomatic individuals can present with breathlessness, syncope, and features of distal tissue embolization. Cardiac surgery is indicated in those with significant left ventricular outflow tract obstruction. CASE SUMMARY: A 45-year-old man without any significant medical history was referred due to an abnormal electrocardiogram. He was asymptomatic from a cardiac perspective. Echocardiography revealed the presence of a giant mobile mass attached to the anterior mitral valve leaflet and prolapsing into the left ventricular outflow tract (LVOT). This was classified as Type IIB2 AMVT. As there was no dynamic outflow tract obstruction on subsequent treadmill stress echocardiography, and in the absence of other coexistent congenital abnormality, surgical excision was not performed. DISCUSSION: It is important to exclude significant obstruction when a large AMVT is seen to be prolapsing into the LVOT. Three-dimensional echocardiography is the tool of choice for anatomical classification and to assess for concomitant congenital cardiac abnormalities.