Background The diagnostic value of ECG and echocardiography for familial hypertrophic cardiomyopathy (FHC) has not been reassessed since the development of molecular genetics. The aim of the study was to evaluate it in adults, with the genetic status used as the criterion of reference.

Methods and Results Ten families with previously identified mutations were studied (9 mutations in 3 genes). ECG and echocardiography were analyzed in 155 adults, of whom 77 were genetically affected and 78 unaffected. The major diagnostic criteria were, for echocardiography, a left ventricular wall thickness >13 mm and, for ECG, abnormal Q waves, left ventricular hypertrophy, and marked ST-T changes. Minor ECG and echographic abnormalities were also analyzed. (1) Sensitivity and specificity of major criteria were 61% and 97% for ECG and 62% and 100% for echocardiography. (2) Sensitivity but not specificity was age related (from 50% at <30 years to 94% at >50 years old, P<.01) and sex related (83% in men versus 57% in women, P=.01). (3) Sensitivity was improved by the addition of minor criteria and by the association of ECG and echocardiography. The negative predictive value was therefore very good (95%) at >30 years of age. (4) Healthy carriers without any ECG or echocardiographic abnormality represented 17% of genetically affected adults.

Conclusions ECG and echocardiography have similar diagnostic values for FHC in adults, with an excellent specificity and a lower sensitivity. The association of the two techniques allows a better evaluation of the risk of being genetically affected in families with hypertrophic cardiomyopathy.