Comparison of the Frequency-Dependent Effects on the Atrioventricular Node of Verapamil, Amiodarone, Digoxin, and Diltiazem in Isolated Guinea Pig Hearts
| Autor: | Helmut A. Tritthart, Karin Kasper, Christian Schulze-Bauer, U. Stark, Decrinis M, Gerhard Stark |
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| Rok vydání: | 1995 |
| Předmět: |
Male
Digoxin medicine.medical_specialty Guinea Pigs Amiodarone In Vitro Techniques Diltiazem Electrocardiography Heart Rate Internal medicine Heart rate Animals Medicine Computer Simulation cardiovascular diseases Pharmacology business.industry Cardiac Pacing Artificial Heart Atrial fibrillation medicine.disease Atrioventricular node Electric Stimulation medicine.anatomical_structure Verapamil Atrioventricular Node cardiovascular system Cardiology Female Supraventricular tachycardia Cardiology and Cardiovascular Medicine business medicine.drug |
| Zdroj: | Journal of Cardiovascular Pharmacology. 25:330-335 |
| ISSN: | 0160-2446 |
| DOI: | 10.1097/00005344-199502000-00020 |
| Popis: | To slow ventricular rate during supraventricular tachycardia, a drug must have a strong rate-dependent depressant effect on atrioventricular (AV) conduction. We investigated the frequency-dependent effects of verapamil, amiodarone, digoxin, and diltiazem on AV conduction time (AVCT) in isolated guinea pig heart perfused by Langendorff method. Verapamil (0.01 microM), amiodarone (10 microM), digoxin (0.6 nM), and diltiazem (0.03 microM) caused comparable prolongation of AVCT and also a comparable reduction in sinus rate. To evaluate the time dependence of drug-induced alterations in AVCT, we abruptly increased the atrial pacing rate and shortened the pacing cycle length (CL) from 240 to 180 ms. The resulting time constant was longest in the presence of verapamil (tau = 194 +/- 45 beats, mean +/- SEM) and the shortest during perfusion with diltiazem (tau = 89 +/- 9 beats). The magnitude of AVCT prolongation after abrupt increase in pacing rate was significantly greater for digoxin as compared with all other drugs tested. The calculated beat-to-beat increase in AVCT evaluated by dividing the magnitude of AVCT prolongation by the time constant tau was greatest with diltiazem, which may explain the high efficacy of diltiazem in controlling ventricular rate during atrial fibrillation. |
| Databáze: | OpenAIRE |
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