👤 Marcel J Kofflard

To investigate the outcome of cardiac evaluation and the risk stratification for sudden cardiac death (SCD) in asymptomatic hypertrophic cardiomyopathy (HCM) mutation carriers. Seventy-six HCM mutation carriers from 32 families identified by predictive DNA testing underwent cardiac evaluation including history, examination, electrocardiography, Doppler echocardiography, exercise testing, and 24 h Holter monitoring. The published diagnostic criteria for HCM in adult members of affected families were used to diagnose HCM. Thirty-three (43%) men and 43 (57%) women with a mean age of 42 years (range 16-79) were examined; in 31 (41%) HCM was diagnosed. Disease penetrance was age related and men were more often affected than women (P = 0.04). Myosin Binding Protein C (MYBPC3) mutation carriers were affected at higher age than Myosin Heavy Chain (MYH7) mutation carriers (P = 0.01). Risk factors for SCD were present in affected and unaffected carriers. Hypertrophic cardiomyopathy was diagnosed in 41% of carriers. Disease penetrance was age dependent, warranting repeated cardiologic evaluation. The MYBPC3 mutation carriers were affected at higher age than MYH7 mutation carriers. Risk factors for SCD were present in carriers with and without HCM. Follow-up studies are necessary to evaluate the effectiveness of risk stratification for SCD in this population. Show less

To test the hypothesis that carriers of Dutch founder mutations in cardiac myosin-binding protein C (MYBPC3), without left ventricular hypertrophy (LVH) or electrocardiographic abnormalities, have diastolic dysfunction on tissue Doppler imaging (TDI), which can be used for the screening of family members in the hypertrophic cardiomyopathy (HCM) population. TDI is a more sensitive technique for the assessment of left ventricular contraction and relaxation abnormalities than is conventional echocardiography. Echocardiographic studies including TDI were performed in genotyped hypertrophic cardiomyopathy patients (genotype-positive, G+/LVH+; n = 27), mutation carriers without LVH (G+/LVH-; n = 27), and healthy controls (n = 55). The identified mutations in MYBPC3 in the G+/LVH+ subjects were c.2864₂₈₆₅delCT (12 subjects), c.2373dupG (n = 8), and p. Arg943X (n = 7). In the G+/LVH- subjects, the following mutations were identified: c.2864₂₈₆₅delCT (n = 11), c.2373dupG (n = 8), and p. Arg943X (n = 8). Mean TDI-derived systolic and early and late diastolic mitral annular velocities were significantly lower in the G+/LVH+ subjects compared with the other groups. However, there was no difference between controls and G+/LVH- subjects. Mean TDI-derived late mitral annular diastolic velocities were significantly higher in the G+/LVH- subjects compared with controls and G+/LVH+ subjects. Using a cut-off value of mean +/- 2 SD, an abnormal late mitral annular diastolic velocity was found in 14 (51%) of G+/LVH- patients. There was no difference among the 3 different mutations. In contrast to earlier reports, mean mitral annular systolic velocity and early mitral annular diastolic velocity velocities were not reduced in G+/LVH- subjects, and TDI velocities were not sufficiently sensitive for determination of the affected status of an individual subject. Our findings, however, support the theory that diastolic dysfunction is a primary component of pre-clinical HCM. Show less