Antihypertensive treatment with verapamil and amlodipine. Their effect on the functional autonomic and cardiovascular stress responses.

Many biological and psychological factors induce haemodynamic and extra-cardiovascular functional changes mediated by the autonomic nervous system. Pharmacological blood pressure reduction, as a neurovegetative stimulus, can change the arousal of the sympathetic nervous system. We evaluated the effects of two calcium channel blockers, verapamil and amlodipine, both administered as monotherapies, upon the sympathetic stress response in 23 randomized mild-to-moderate essential hypertensives (161 +/- 2/98 +/- 1 mmHg). Patients performed four stress tests (mental arithmetic, colour word Stroop, cold pressor and handgrip) while extracardiovascular and haemodynamic functions were assessed non-invasively at every heart beat, during baseline, stress and recovery phases. The sympathetic response was evaluated by computing the 'area-under-the-curve' (value x time) measured during the psychophysiological session. The session was repeated at run-in, after placebo and during treatment. After one month's treatment, baseline blood pressure was significantly reduced in patients treated with amlodipine (139 +/- 1/84 +/- 1 mmHg; P < 0.001) and verapamil (140 +/- 2/85 +/- 1 mmHg; P < 0.001). The emotional arousal (frontalis muscular contraction, skin conductance) was unchanged, but the cutaneous vascular response was reduced (P < 0.05) in patients treated with verapamil. No changes in systolic or diastolic blood pressure were detectable, but amlodipine increased the heart rate response (P < 0.05). In contrast, verapamil reduced the heart rate (P < 0.05) without depressing the cardiac output response, which was increased with amlodipine (P < 0.05). Total vascular resistance was significantly (P < 0.001) reduced with both the treatments. Consequently, functional cardiac load, expressed by pressure-rate product and cardiac power, was significantly enhanced with amlodipine and reduced with verapamil. In conclusion, the abnormal sympathetic stress response, which characterizes the hypertensive patient, might be affected by the choice of medication. Verapamil in particular, moderated emotional arousal, the vasoconstrictive response and reduced cardiac load without lowering cardiac output demands. In contrast, in patients treated with amlodipine, in whom the cardiac output response was increased, the pattern was reversed and the functional cardiac load was also increased.

Stress reactivity in responder and non-responder hypertensives treated with verapamil and enalapril.

Hypertension was found to be associated with sympathetic overdrive but it is still debated if the antihypertensive agents can differently affect the stress response in hypertensive subjects. Through a psychophysiological study, we evaluated the effect of verapamil (V) and enalapril (E), both as monotherapy and association. Office BP was successfully reduced (< 145/90 mmHg) in 11 patients treated with V (V-Resp) and in 10 patients treated with E (E-Resp). Both the drugs were prescribed in 9 patients (V+E) who did not sufficiently lower their blood pressure (N-Resp) with monotherapy. Patients performed three stressors (color word stroop, cold pressor and handgrip). Extracardiovascular and hemodynamic functions were measured during baseline, stress and recovery periods. The response was evaluated adding the changes occurred in every phase of the psychophysiological session. This was performed before run-in and after any modification of the therapeutic intervention. The emotional arousal (phrontalis muscular contraction, skin conductance, peripheral temperature) was reduced when BP was normal. No change in BP reactivity was found. HR response decreased in V-Resp and cardiac output increased in E-Resp while the vascular reaction was restrained in E-Resp and V-Resp. This was reduced also in N-Resp when they assumed V+E and normalized their arterial pressure. The findings indicate that the sympathetic reactivity may be modified by the therapy. In particular, verapamil restrained the cardiac stress response without lowering the cardiac output and was advantageously associated with enalapril to control the psychophysiological response in more resistant hypertensive patients.