Key result
Enalapril and losartan reduce BP without altering autonomic balance or baroreflex sensitivity in essential hypertension.
Why the study?
Does enalapril or losartan alter autonomic function and baroreflex sensitivity in essential hypertensive patients?
RCT (n=42)
randomized
Does enalapril or losartan alter autonomic function and baroreflex sensitivity in essential hypertensive patients?
ACE inhibitors and angiotensin II receptor blockers lower blood pressure without altering resting sympathetic/parasympathetic balance, indicating a resetting of baroreflex function.
Enalapril and losartan safely lower BP without autonomic effects; confirms baroreflex resetting as the operative mechanism in essential hypertension.
OBJECTIVE: The influence of ACE-inhibition and angiotensin II ATI receptor blockade on the autonomic function and baroreflex sensitivity was investigated in hypertension. METHODS AND RESULTS: Heart rate variability was assessed in a resting condition by power spectrum analysis to evaluate the low frequency (LF) power, high frequency (HF) power and LF/HF ratio in 19 hypertensive patients and 23 normotensive controls. Moreover, the coherence between the tachogram and the systogram was evaluated, and the baroreflex gain (alphaLF-index), describing the transfer function of variability in the systolic pressure signal to variability in the RR interval, was obtained. Then a 24-h ambulatory blood pressure monitoring was performed. The 19 hypertensive patients were randomized to either enalapril or losartan treatment, and after 2 months were re-submitted to the RR variability and baroreflex study and to blood pressure monitoring. The subjects then crossed to the other antihypertensive treatment and were re-evaluated after an additional two months. No significant difference was found either in LF power and HF power and LF/HF ratio between normotensive and hypertensive subjects whereas a slight though significant difference was observed in the alphaLF-index. In hypertensive patients, both the treatments with enalapril and losartan reduced blood pressure and had no effect on heart rate. No significant change was observed in autonomic balance or in baroreflex sensitivity during the two antihypertensive treatments. CONCLUSIONS: In hypertensive patients, the angiotensin system or bradykinins do not seem to have any modulatory effect on the sympathetic/parasympathetic control of blood pressure and baroreflex sensitivity, in a resting condition. Since heart rates were unchanged by the two antihypertensive treatments despite a significant reduction of blood pressure, a resetting of baroreflex function was observed during both ACE-inhibition and angiotensin II ATI receptor blockade.
No takes yet. Share an insight, caveat, or question.
Guasti et al. (2001) conducted an RCT in essential hypertension (n=42). Enalapril vs. Losartan was evaluated on Autonomic balance and baroreflex sensitivity. Both enalapril and losartan reduced blood pressure without significantly changing autonomic balance or baroreflex sensitivity in patients with essential hypertension.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: