Amlodipine in patients with stable angina pectoris treated with beta-blockers. Double-blind comparison with placebo

The significance of amlodipine on autonomic nervous system adjustment (ANSA method): a new approach in the treatment of hypertension

INTRODUCTION

Cardiovascular autonomic modulation is altered in patients with essential hypertension.

OBJECTIVE

To evaluate acute and long-term effects of amlodipine on cardiovascular autonomic function and haemodynamic status in patients with mild essential hypertension.

METHODS

Ninety patients (43 male, mean age 52.12 +/- 10.7) years with mild hypertension were tested before, 30 minutes after the first 5 mg oral dose of amlodipine and three weeks after monotherapy with amlodipine. A comprehensive study protocol was done including finger blood pressure variability (BPV) and heart rate variability (HRV) beat-to-beat analysis with impedance cardiography, ECG with software short-term HRV and nonlinear analysis, 24-hour Holter ECG monitoring with QT and HRV analysis, 24-hour blood pressure (BP) monitoring with systolic and diastolic BPV analysis, cardiovascular autonomic reflex tests, cold pressure test, mental stress test. The patients were also divided into sympathetic and parasympathetic groups, depending on predominance in short time spectral analysis of sympathovagal balance according to low frequency and high frequency values.

RESULTS

We confirmed a significant systolic and diastolic BP reduction, and a reduction of pulse pressure during day, night and early morning hours. The reduction of supraventricular and ventricular ectopic beats during the night was also achieved with therapy, but without statistical significance. The increment of sympathetic activity in early phase of amlodipine therapy was without statistical significance and persistence of sympathetic predominance after a few weeks of therapy detected based on the results of short-term spectral HRV analysis. All time domain parameters of long-term HRV analysis were decreased and low frequency amongst spectral parameters. Amlodipne reduced baroreflex sensitivity after three weeks of therapy, but increased it immediately after the administration of the first dose.

CONCLUSION

The results of the study showed that amlodipine affected autonomic modulation as a shift to sympathetic hyperactivity, but without statistical significance. In the selected group of patients with vagal predominance in sympathovagal balance, amlodipine increased sympathetic and decreases vagal activity. Therefore we conclude that amlodipine mostly exerts impact on autonomic function modulation in patients with vagal predominance in resting state.

Efficacy of monotherapy compared with combined antianginal drugs in the treatment of chronic stable angina pectoris: a meta-analysis

OBJECTIVE

To determine the relative efficacy of antianginal drugs administered as monotherapy or in combination in patients with chronic stable angina.

METHODS

A meta-analysis was performed on randomized trials, published in English between 1980 and 1999, that directly compared combined treatment and monotherapy. Twenty-two articles were included, all on the comparison of -blocker monotherapies to their combination with a calcium antagonist and 10 on the comparison of calcium antagonist monotherapies to their combination with a -blocker.

RESULTS

Time to 1 mm ST-segment depression, total exercise duration and time to onset of anginal pain were significantly increased with the combined therapy compared to -blocker alone (by 8, 5 and 12%, respectively). Only time to 1 mm ST-segment depression was significantly increased with the combined therapy compared to calcium antagonist alone (by 9%). For all these parameters, the adjusted differences were significant only within 6 h following drug intake and were not significant after 6 h. No analysis of safety data could be performed.

CONCLUSION

As far as exercise testing is concerned, the combination of a calcium antagonist and a -blocker is statistically more effective than either monotherapy. Further studies are needed to confirm the higher efficacy after the first 6 h following drug intake.