Prevalence and natural history of electrocardiographic left ventricular hypertrophy.

Left ventricular hypertrophy, particularly on the electrocardiogram, is an ominous, not an incidental accompaniment of hypertension and cardiovascular disease. The prevalence of electrocardiographic left ventricular hypertrophy increases with age with a slight male predominance, and one in 10 persons aged 30 to 62 can expect to have it within 12 years. At any age, cardiac enlargement on roentgenograms is twice as prevalent as electrocardiographic left ventricular hypertrophy, and in only 16 percent of those with x-ray evidence of cardiac enlargement does electrocardiographic left ventricular hypertrophy subsequently develop. Hypertension predisposes and at systolic pressures exceeding 180 mm Hg evidence of electrocardiographic left ventricular hypertrophy develops in 50 percent, with no closer relation to diastolic, than to systolic pressure. In addition to drastic curtailment of life expectancy, electrocardiographic left ventricular hypertrophy is a harbinger of serious cardiovascular disease. Definite electrocardiographic left ventricular hypertrophy is associated with an eightfold increase in cardiovascular mortality and a sixfold increase in coronary mortality. Electrocardiographic left ventricular hypertrophy with repolarization criteria more than doubles the risk of hypertension alone and carries a greater risk of cardiovascular morbidity and mortality than cardiac enlargement. It identifies hypertensive patients with a compromised coronary circulation and myocardial damage. Risk of stroke, cardiac failure, and every clinical manifestation of coronary heart disease is substantially increased. In those with electrocardiographic left ventricular hypertrophy risk of cardiac failure is three times that in those with hypertension alone. Electrocardiographic left ventricular hypertrophy based solely on voltage criteria reflects chiefly the severity and duration of associated hypertension, carrying only half the cardiovascular risk of electrocardiographic left ventricular hypertrophy with repolarization abnormality. The precise pathologic and anatomic meaning of electrocardiographic left ventricular hypertrophy is unclear in view of the modest correlations with anatomic, x-ray, ventriculographic, and electrocardiographic measures of cardiac hypertrophy. The electrocardiographic aberrations are as much a product of myocardial damage as hypertrophy, and their appearance must be regarded as a grave prognostic sign in the course of cardiovascular disease.