ABSTRACT
BACKGROUND: In practice, chronic heart failure is often not treated with angiotensin-converting enzyme inhibitors. One reason is the fear of first-dose hypotension. In the majority of patients, this condition is asymptomatic and the consequences are unexpected. Presently, little is known of its epidemiology. METHODS AND RESULTS: This was a prospective, 48-hour observational study of 160 patients with chronic heart failure due to systolic dysfunction, previously untreated with angiotensin-converting enzyme inhibitors, randomly drawn from the clinical practice of selected cardiologists across India. The primary outcome was a change in the mean arterial pressure during the first 24-hours after the first dose of an angiotensin-converting enzyme inhibitor. In 131/160 patients (81.9%) with no hypotensive symptoms, the incidence of first-dose hypotension (maximum 24-hour fall in mean arterial pressure greater than 10% from baseline) was 56/131 (42.7%). Pre-treatment diastolic pressure had a negative, independent association with 24-hour change in mean arterial pressure, accounting for 29% (R2=0.29, p<0.01) of its variability, and its predictive value was greater with pro-drug angiotensin-converting enzyme inhibitors. The incidence of first-dose hypotension increased from 1 patient (4.8%) at a pre-treatment diastolic pressure of 50-70 mmHg to 35 patients (42.7%) at 71-90 mmHg, p<0.01. CONCLUSIONS: The incidence of first-dose hypotension with angiotensin-converting enzyme inhibitors in outpatients with chronic heart failure due to systolic dysfunction is high. Pre-treatment diastolic pressure is an independent risk factor, and its predictive value increases with pro-drug angiotensin-converting enzyme inhibitors. This could help physicians to anticipate asymptomatic first-dose hypotension and increase the utilization of these agents in heart failure.