Frequency-dependent effects of calcium antagonists on atrioventricular conduction and refractoriness: demonstration and characterization in anesthetized dogs

Circulation
M Talajic, S Nattel

Abstract

Calcium-channel blockers are known to affect slow inward current in a frequency-dependent fashion. The purpose of these experiments was to study use-dependent effects of verapamil, diltiazem, and nifedipine on atrioventricular conduction in vivo. Loading and maintenance infusion techniques were developed to study each drug at a series of stable plasma concentrations in autonomically blocked dogs anesthetized with morphine and alpha-chloralose. All three agents produced changes in atrioventricular conduction and refractoriness that increased with increasing stimulation frequency. The time dependence of drug-induced changes in atrioventricular conduction was characterized both by varying the coupling of single test stimuli and by abruptly changing activation frequency. The time constants for onset of (tau on) and recovery from (tau off) block were typical for each drug, with nifedipine having a faster time constant (tau off = 0.36 +/- 0.12 sec) than verapamil (tau off = 3.2 +/- 1.0 sec, tau on = 28 +/- 8 sec) or diltiazem (tau off = 2.7 +/- 1.2 sec, tau on = 13 +/- 4 sec). The time constants for each drug were independent of concentration but the magnitude of time-dependent change increased with increasing drug concentration. We ...Continue Reading

References

Nov 14, 1977·Biochimica Et Biophysica Acta·L M Hondeghem, B G Katzung
Jul 18, 1977·Naunyn-Schmiedeberg's Archives of Pharmacology·M Kohlhardt, A Fleckenstein
Mar 1, 1985·Journal of Cardiovascular Pharmacology·S R HamannR G McAllister
Jan 1, 1985·The American Journal of Cardiology·K TheisenH Jahrmärker
Jun 1, 1985·The American Journal of Cardiology·E S GangT Peter
Jul 1, 1985·Journal of the American College of Cardiology·F MoradyR B Krol
Jan 1, 1973·Cardiovascular Research·R M HeethaarF L Meijler
Jan 1, 1982·Annual Review of Physiology·T F McDonald
Nov 1, 1983·Journal of Cardiovascular Pharmacology·S R Hamann, R G McAllister
Jan 1, 1984·Annual Review of Pharmacology and Toxicology·L M Hondeghem, B G Katzung
May 1, 1980·Pflügers Archiv : European journal of physiology·T F McDonaldW Trautwein
Aug 1, 1982·Pflügers Archiv : European journal of physiology·D PelzerT F McDonald
Feb 1, 1983·Journal of Molecular and Cellular Cardiology·S KanayaL M Hondeghem
Aug 1, 1983·The American Journal of Cardiology·S J YehD Wu
Feb 18, 1982·The American Journal of Cardiology·J J RozanskiA Castellanos

❮ Previous
Next ❯

Citations

Dec 1, 1991·Journal of Clinical Pharmacology·J S Borer
May 15, 2012·Journal of Interventional Cardiac Electrophysiology : an International Journal of Arrhythmias and Pacing·Thanh-Thuy Vo ThangFrançois Harel
Aug 1, 1996·Journal of Pharmacological and Toxicological Methods·U StarkH A Tritthart
Dec 1, 1996·Journal of Pharmacological and Toxicological Methods·I SchwarzlG Stark
Jul 1, 1995·British Journal of Pharmacology·C Lambert
May 1, 1990·Pacing and Clinical Electrophysiology : PACE·M TalajicS Nattel
Feb 1, 1996·Pacing and Clinical Electrophysiology : PACE·G StarkH A Tritthart
Mar 3, 2007·Journal of the American Veterinary Medical Association·Carrie Goldkamp, Amara H Estrada
Jan 1, 1994·Journal of Cardiovascular Electrophysiology·J BilletteA Shrier
May 4, 2006·Journal of Veterinary Pharmacology and Therapeutics·C C SchwarzwaldJ D Bonagura
May 26, 1999·Current Problems in Cardiology·M FreherM Gheorgiade
Mar 6, 1992·The American Journal of Cardiology·K A Ellenbogen
Nov 1, 1996·Cardiology Clinics·R H Falk
Jun 21, 2002·Journal of Cardiovascular Pharmacology and Therapeutics·Christian SticherlingFred Morady
Oct 13, 2009·American Journal of Physiology. Heart and Circulatory Physiology·Rafik Tadros, Jacques Billette
Aug 31, 2014·American Journal of Physiology. Heart and Circulatory Physiology·Qi JinJian Huang
Nov 1, 1990·Circulation Research·M NayebpourS Nattel

❮ Previous
Next ❯

Related Concepts

Related Feeds

Cardiology Journals

Discover the latest cardiology research in this collection of the top cardiology journals.

Cardiac Conduction System

The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Discover the latest research on the cardiac conduction system here.