The effects of antihypertensive drugs on the autonomic nervous system in elderly hypertensive patients with silent myocardial ischemia.
To seek further evidence for the participation of sympathetic nervous system in the onset of transient episodes of painless ischemia, we compared the behavior of the autonomic nervous system by means of power spectrum analysis of heart rate variability in 15 elderly hypertensive men with angiographically confirmed painless coronary artery disease, and in 10 similar patients without coronary artery disease. An autoregressive algorithm was used to calculate the power spectrum density from an electrocardiographic (ECG) recording of 512 consecutive RR intervals. The power spectrum comprised two main bandwidths: a high-frequency band reflecting parasympathetic and a low-frequency band reflecting sympathetic activity. In the hypertensives with painless coronary disease sympathetic tone was also assessed after double-blind placebo-controlled administration of metoprolol (100 mg/day), amlodipine (10 mg/day), quinapril (20 mg/day), and amlodipine (5 mg/day) plus quinapril (10 mg/day). The hypertensives with painless coronary disease had significantly higher sympathetic activity than those without (low frequency: 58.0 +/- 2.0 vs 25.0 +/- 1.0, p < 0.001) but significantly lower parasympathetic activity (high frequency: 39.0 +/- 2.0 vs 60.0 +/- 2.0, p < 0.001). Treatment with metoprolol, quinapril and amlodipine plus quinapril significantly depressed sympathetic activity (p < 0.05).
Piccirillo
G
G
Institute of Geriatrics, University of Rome La Sapienza, Viale del Policlinico, 166, I-00161 Roma, Italy.
Bucca
C
C
Santagada
E
E
Monteforte
G
G
Viola
E
E
Durante
M
M
Munizzi
M R
MR
Tarantini
S
S
Cacciafesta
M
M
Marigliano
V
V