Verapamil shifted sympathovagal balance toward vagal predominance compared with amlodipine, yielding a lower low- to high-frequency ratio (4.10 vs 4.66; P=0.001) despite equal BP reduction.
RCT (n=145)
Double-blind
cross-over
Does verapamil improve autonomic function compared to amlodipine in patients with mild to moderate hypertension?
In patients with mild to moderate hypertension, verapamil improves short-term autonomic control of blood pressure and shifts sympathovagal balance toward vagal predominance compared to amlodipine.
Absolute Event Rate: 4.1% vs 4.66%
p-value: p=.001
The aim of the present study was to compare the effects of a long-acting dihydropyridine (amlodipine) and a nondihydropyridine (verapamil) on autonomic function in patients with mild to moderate hypertension. A total of 145 patients with a diastolic blood pressure (BP) between 95 and 110 mm Hg received 8 weeks of verapamil sustained release (240 mg) and amlodipine (5 mg) in a prospective randomized, double blind, cross-over study, both after 4 weeks of placebo. The 24-h autonomic balance was measured by analysis of 24-h heart rate variability and short-term autonomic control of BP by baroreflex sensitivity measurements. Plasma norepinephrine was sampled at rest. Blood pressure was equally reduced from 153/100 mm Hg to 139/91 mm Hg with verapamil and 138/91 mm Hg with amlodipine, P = .50/.59. The low- to high-frequency ratio (LF/HF), reflecting sympathovagal balance, was higher with amlodipine than with verapamil (4.66 v 4.10; P = .001). Baroreflex function was improved by both treatments; however, baroreflex sensitivity (BRS) was significantly higher with verapamil than with amlodipine (8.47 v 8.06 msec/mm Hg; P = .01). Plasma norepinephrine (NE) level was higher with amlodipine than with verapamil (1.59 v 1.32 nmol/L; P < .0001). Amlodipine induces a shift in sympathovagal balance, as measured by heart rate variability indices and plasma NE, toward sympathetic predominance compared with vagal predominance with verapamil. Short-term autonomic control of BP, as assessed by BRS, is more effectively improved by verapamil than by amlodipine. These contrasting effects on autonomic function suggest that the nondihydropyridine calcium antagonist verapamil may have additional beneficial effects beyond lowering BP compared with the dihydropyridine amlodipine.
JD Lefrandt (Thu,) conducted a rct in mild to moderate hypertension (n=145). verapamil sustained release vs. amlodipine (5 mg) was evaluated on Low- to high-frequency ratio (LF/HF) reflecting sympathovagal balance (p=.001). Verapamil shifted sympathovagal balance toward vagal predominance compared with amlodipine, yielding a lower low- to high-frequency ratio (4.10 vs 4.66; P=0.001) despite equal BP reduction.