Novel mutation in the alpha-tropomyosin gene and transition from hypertrophic to hypocontractile dilated cardiomyopathy.

Abstract

Awoman born in 1960 presented at age 14 years with exertional dyspnea, sinus rhythm, and left ventricular (LV) hypertrophy as shown by ECG. Hypertrophic nonobstructive cardiomyopathy (HNCM) was diagnosed by cardiac catheterization. An outflow tract gradient at rest or exercise was excluded. An echocardiogram 5 years later showed severe septal hypertrophy (Figure 1⇓). When the patient was 30 years old, repeat right and left heart catheterization confirmed HNCM (Figure 2⇓). A biopsy showed myocyte hypertrophy, only discrete signs of myocyte disarray, and discrete interstitial fibrosis (eosin–van Gieson stain, not shown) (Figure 3⇓). When the patient was 37 years old, regression of LV hypertrophy on the ECG and systolic dysfunction were observed. The echocardiogram showed decreased systolic function and wall thinning (septum 12 mm, posterior wall 8 mm, LV end-diastolic dimension 63 mm, fractional shortening 16%). Cardiac catheterization revealed a decreased LV ejection fraction (LVEF, 36%), slightly increased end-diastolic ventricular volume (Figure 4⇓), and a significantly increased LV end-diastolic pressure (28 mm Hg). Ventricular tachycardia was documented, and an internal cardioverter/defibrillator was …