Heart rate variability and baroreflex sensitivity during fosinopril, irbesartan and atenolol therapy in hypertension

Objective: To evaluate the effects of long-term therapy with fosinopril, irbesartan and atenolol on the autonomic control of the cardiovascular system in hypertensive patients. Methods: We enrolled 58 patients (mean age 38 10 years) with never-treated mild hypertension with no evidence of target organ damage. The study was single blind. Patients were assigned to receive fosinopril 10-20 mg/day, irbesartan 150-300 mg/day or atenolol 50-100 mg/day for 14 weeks. Dosage was titrated to reach an average office blood pressure (BP) of <140/90mm Hg. Before therapy all patients underwent a 24-hour Holter ECG to evaluate heart rate variability (HRV) through nonlinear methods, 24-hour ambulatory BP monitoring (ABPM), and measurement of baroreflex sensitivity (BRS) using a Portapres device; all measurements were repeated after therapy. Results: All three therapies significantly and equally decreased BP, both office (systolic/diastolic blood pressure 152 +/- 11/97 +/- 7mm Hg vs 129 +/- 7/85 +/- 4mm Hg after fosinopril, 151 +/- 11/97 +/- 6mm Hg vs 133 +/- 9/87 +/- 8mm Hg after irbesartan, 149 +/- 13/96 +/- 9mm Hg vs 132 +/- 9/87 +/- 7mm Hg after atenolol; p < 0.001) and ABPM values. HRV calculated with nonlinear methods and BRS were significantly increased after atenolol whereas no significant change was found in the fosinopril and irbesartan treatment groups. Conclusions: All three therapies significantly and similarly reduced BP without modifying heart rate, except for atenolol, which significantly decreased it. Although angiotensin directly increases sympathetic tone, neither fosinopril nor irbesartan modified cardiovascular autonomic function; this is likely to be connected to the fairly good basal autonomic function of the population evaluated. Atenolol is associated with a significant increase in HRV and BRS probably through an improvement of parasympathetic tone.