Circadian variation in blood pressure and heart rate in nonhypertensive congestive heart failure

This study was designed to determine whether decreases in the circadian variability of arterial blood pressure and heart rate measured in ambulatory patients would correlate with neurohumoral indices of the severity of congestive heart failure not the result of systemic arterial hypertension, and whether treatment with angiotensin-converting enzyme (ACE) inhibitors would restore a more normal pattern. The study also examined the ability of ambulatory blood pressure monitoring to discern pharmacodynamic patterns in patients with congestive heart failure, which is associated with decreased variability in circadian variations in blood pressure and heart rate among hospitalized patients. Increased plasma norepinephrine, renin activity, and atrial natriuretic peptide (ANP) have a positive correlation with worsening clinical status. ACE inhibitors have been found to be beneficial in the treatment of congestive heart failure. Ambulatory 24-h blood pressure and neurohumoral measurements were recorded in 30 patients with congestive heart failure (class II-IV, New York Heart Association) before treatment with lisinopril or captopril and repeated after 6 weeks of treatment. Fourier analysis was used as a curve-smoothing technique to compare the pharmacodynamics of the two ACE inhibitors. The absolute amplitude of systolic blood pressure correlated inversely with plasma norepinephrine and ANP (p = 0.004) but not with renin activity. Mean 24-h systemic arterial blood pressure did not decrease significantly after treatment with ACE inhibitors. An increase in absolute amplitude of systolic blood pressure correlated inversely with baseline amplitude (p < 0.00001). Inspection of the Fourier-smoothed curves demonstrated differences in the circadian effect of lisinopril and captopril on systolic blood pressure and rate-pressure product. Ambulatory 24-h blood pressure monitoring may prove useful in the assessment of the severity and treatment of congestive heart failure.