Idiopathic Left Ventricular Hypertrophy

Idiopathic left ventricular hypertrophy is diagnosed when hypertrophy without dilatation appears to be present without apparent cause. Since asymmetric septal hypertrophy occurs commonly, and since it may present nonspecifically as left ventricular hypertrophy, we hypothesized that many patients with idiopathic left ventricular hypertrophy might in fact have asymmetric septal hypertrophy. We therefore evaluated echocardiographically 39 patients with idiopathic left ventricular hypertrophy diagnosed by physical findings or electrocardiographic criteria or both. All family members of patients with known asymmetric septal hypertrophy were excluded. Of the 39, 33 had asymmetric septal hypertrophy, six were normal, and none had evidence of idiopathic left ventricular hypertrophy. All six of those with normal echocardiograms had left ventricular hypertrophy solely by electrocardiographic criteria and were without cardiac symptoms, suggesting a false-positive diagnosis. If idiopathic left ventricular hypertrophy does exist as a separate entity, it must be uncommon. Most subjects believed to have this entity either have falsely positive criteria for that diagnosis or have asymmetric septal hypertrophy. (N Engl J Med 290:1047–1050, 1974)