[Cardiac failure in hypertensive cardiopathy]

Elevated blood pressure and left ventricular hypertrophy are powerful independent predictors of heart failure. In hypertension, left ventricular hypertrophy at electrocardiography doubles the risk of heart failure. The individual absolute risk of heart failure, however, remains quite low in the absence of myocardial infarction, valvular heart disease and diabetes. For example, in a 60-year-old asymptomatic man with systolic blood pressure 160 mmHg, the risk of developing heart failure is 0.37% per year in the absence of left ventricular hypertrophy and 0.90% per year in the presence of hypertrophy. If ischemic heart disease, valvular heart disease and diabetes coexist in the same subject, the risk of heart failure rises to 5.1% and 9.5% in the absence and presence of left ventricular hypertrophy, respectively. Several mechanisms may explain the increased risk of heart failure in hypertensive subjects with left ventricular hypertrophy. Among these, increased collagen deposition in the interstitial space among myocytes could lead to impaired diffusion of oxygen and other substances towards hypertrophied myocytes, whose metabolic demand is increased. Left ventricular hypertrophy increases the risk of heart failure both at normal (diastolic) and low cardiac output. There is an inverse association between left ventricular mass and velocity of diastolic relaxation. Early diagnosis of left ventricular hypertrophy through electrocardiography or echocardiography and aggressive treatment of patients with hypertrophy are probably the best ways to prevent heart failure associated with hypertension. Controlled intervention studies clearly showed that treatment of hypertension reduces the occurrence of heart failure by 25-50%, particularly in the elderly with isolated systolic hypertension. In a sizable proportion (about 20%) of asymptomatic patients with hypertension, left ventricular systolic performance estimated by echocardiography at mid-wall level is reduced. These patients appear to be at increased risk of major cardiovascular events including heart failure.