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[Effect on atrioventricular conduction of a new calcium antagonist: lacidipine. Evaluation by the Holter method]
Insights
Lacidipine, a new calcium antagonist, did not significantly alter atrioventricular (AV) conduction in patients with atrial fibrillation. This study found lacidipine and nifedipine had no effect on ventricular rhythm compared to placebo.
Area of Science:
- Cardiology
- Pharmacology
- Electrophysiology
Background:
- Atrial fibrillation (AF) is a common arrhythmia affecting ventricular rhythm.
- Calcium channel blockers are used to manage AF, but their effects on AV conduction vary.
- Lacidipine is a novel calcium antagonist whose effect on AV conduction in AF requires investigation.
Purpose of the Study:
- To evaluate the impact of lacidipine on atrioventricular (AV) conduction in patients with stable chronic atrial fibrillation.
- To compare the effects of lacidipine with placebo, nifedipine, and diltiazem on ventricular rhythm.
Main Methods:
- A single-blind, placebo-controlled study involving 10 patients with chronic AF.
- Daily Holter recordings were used to assess ventricular rhythm over consecutive 24-hour periods.
- Analysis included RR interval histograms, cumulative cycle length curves, QRS counts, and mean RR intervals.
Main Results:
- Lacidipine (4 mg b.i.d.) and nifedipine (10 mg b.i.d.) did not produce significant changes in AV conduction compared to placebo.
- Diltiazem (120 mg b.i.d.) significantly prolonged RR intervals (p < 0.01), indicating an effect on AV conduction.
- No significant differences were observed in correlation coefficients, mean hourly RR intervals, or histograms between placebo, nifedipine, and lacidipine.
Conclusions:
- Lacidipine, similar to nifedipine, demonstrates no significant effect on AV conduction in patients with chronic atrial fibrillation.
- Diltiazem exhibits a significant effect on AV conduction, prolonging RR intervals.
- These findings suggest lacidipine may not be effective in modulating ventricular response in AF through AV node blockade.
Abstract:
The modification of AV conduction induced by 4 mg b.i.d. of lacidipine (L), a new calcium antagonist, was assessed by studying the changes in ventricular rhythm in 10 patients with stable chronic atrial fibrillation (mean age 71 +/- 15) by daily Holter recordings. The study was single blind versus placebo (P), nifedipine (N) 10 mg b.i.d. and for five patients diltiazem (D) 120 mg b.i.d. Five or seven consecutive 24 hours Holter were recorded in the following order: P, P, N or L, P, N or L, D, D. For each hour, an RR histogram was drawn and the 10 per cent and 90 per cent values of the cumulative cycle length curve were computed, as were the total number of QRS, and the mean value of RR intervals. The correlation coefficient between the number of QRS from the same hour on different days, the Student t test between the mean hourly RR interval values and the comparison between the histograms did not demonstrate a significant difference between the placebo, the nifedipine and the lacidipine periods. The only significant changes were induced by diltiazem (p less than 0.01), with a significant prolongation of the RR intervals. This suggests that lacidipine, like nifedipine, has no effect on AV conduction.