Related Experiment Videos
Electrophysiologic effects of the calcium antagonist isradipine, a double-blind placebo-controlled study
V Kühlkamp1, F Maier, L Seipel
1Medizinische Klinik Abteilung III, Eberhard-Karls-Universität Tübingen, F.R.G.
Insights
Isradipine, a calcium channel blocker, significantly lowered blood pressure in patients. However, it did not significantly alter cardiac electrophysiology compared to placebo.
Area of Science:
- Cardiology
- Clinical Electrophysiology
- Pharmacology
Background:
- Calcium channel blockers are widely used in cardiovascular medicine.
- Understanding the electrophysiologic effects of specific agents like isradipine is crucial for patient management.
- Previous studies have not fully elucidated isradipine's impact on cardiac electrical activity.
Purpose of the Study:
- To evaluate the electrophysiologic effects of the calcium channel antagonist isradipine.
- To compare these effects against a placebo in a double-blind study.
Main Methods:
- A double-blind study involving 18 patients, with 9 receiving isradipine and 9 receiving placebo.
- Assessment of cardiac electrophysiologic parameters including sinus cycle length, sinus node recovery time, and atrioventricular nodal function.
- Measurement of systolic and diastolic blood pressure.
Main Results:
- Isradipine significantly reduced both systolic (P<0.01) and diastolic (P<0.05) blood pressure.
- Sinus cycle length decreased significantly in both the isradipine and placebo groups, with no significant difference between them.
- No significant effects of isradipine were observed on sinus node recovery time, atrioventricular nodal effective refractory period, AH interval, or PR interval.
Conclusions:
- Isradipine effectively lowers systolic and diastolic blood pressure.
- The drug does not significantly impact cardiac electrophysiological parameters related to sinus node function or atrioventricular conduction.
- Isradipine's cardiovascular effects are primarily related to blood pressure reduction rather than direct electrophysiologic modulation.
Abstract:
The electrophysiologic effects of the calcium channel antagonist isradipine in comparison to placebo were evaluated in a double-blind study with 9 patients in each group. The two patient groups were not different with respect to their cardiac disease, baseline electrophysiologic parameters, or blood pressure. Isradipine significantly decreased the systolic (P less than 0.01) and diastolic (P less than 0.05) blood pressure, whereas sinus cycle length was significantly (P less than 0.05) decreased in the placebo group and the isradipine group with no difference between the groups. The influence of isradipine and placebo on sinus node recovery time, effective refractory period of the atrioventricular node, intranodal conduction time (AH interval) and PR interval were not significant. In conclusion, isradipine significantly decreased systolic and diastolic blood pressure. The decrease in sinus cycle length after intravenous isradipine was not significantly different from the decrease seen in the placebo group. Atrioventricular conduction was not significantly affected.