Assessment and Significance of Left Ventricular Mass by Cardiovascular Magnetic Resonance in Hypertrophic Cardiomyopathy

Objectives Our aim was to assess the distribution and clinical significance of left ventricular (LV) mass in patients with hypertrophic cardiomyopathy (HCM). Background Hypertrophic cardiomyopathy is defined echocardiographically by unexplained left ventricular wall thickening. Left ventricular mass, quantifiable by modern cardiovascular magnetic resonance techniques, has not been systematically assessed in this disease. Methods In 264 HCM patients (age 43 ± 18 years; 75% men), LV mass by cardiovascular magnetic resonance was measured, indexed by body surface area, and compared with that in 606 healthy control subjects. Results The LV mass index in HCM patients significantly exceeded that of control subjects (104 ± 40 g/m 2 vs. 61 ± 10 g/m 2 in men and 89 ± 33 g/m 2 vs. 47 ± 7 g/m 2 in women; both p 2 = 0.38; p 2 vs. 89 ± 33 g/m 2 in women; p 2 vs. 96 ± 37 g/m 2 in nonobstructives; p 30 mm was more specific (90%, with 41% sensitivity). Conclusions In distinction to prior perceptions, LV mass index was normal in about 20% of patients with definite HCM phenotype. Therefore, increased LV mass is not a requirement for establishing the clinical diagnosis of HCM. The LV mass correlated weakly with maximal wall thickness, and proved more sensitive in predicting outcome.