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Influence of Amiodarone and Dronedarone on the Force-Interval Dependence of Rat Myocardium

Dina S Kondratieva1, Sergey A Afanasiev1, Sergey V Popov1

  • 1Cardiology Research Institute, Tomsk NRMC, Russia.

Biomed Research International
|August 30, 2018
PubMed

Insights

Amiodarone and dronedarone impact heart muscle contraction force. Both drugs increase post-contraction potentiation, with amiodarone showing a more pronounced effect than dronedarone.

Area of Science:

  • Cardiology
  • Pharmacology
  • Physiology

Background:

  • Amiodarone and dronedarone are antiarrhythmic drugs acting on cardiomyocyte ion currents.
  • Their precise effects on intracellular calcium (Ca2+) levels and calcium cycling remain unclear.
  • Calcium cycling influences muscle contraction and force-interval dependence.

Purpose of the Study:

  • To investigate the impact of amiodarone and dronedarone on the force-interval relationship in cardiac muscle.
  • To evaluate how these drugs affect calcium handling and contractility.

Main Methods:

  • Experiments were conducted on male Wistar rat papillary muscles.
  • Muscles were perfused with Krebs-Henseleit solution at 36.5°C and stimulated at 0.5 Hz.
  • Post-rest and extrasystolic potentiation tests were performed before and after drug exposure (10-6 M amiodarone or dronedarone).

Main Results:

  • Both amiodarone and dronedarone decreased the amplitude of extrasystolic contractions.
  • Post-extrasystolic contractions after short intervals were increased by both drugs.
  • Post-rest contractions were enhanced by amiodarone and dronedarone, with amiodarone showing a stronger effect.

Conclusions:

  • Dronedarone decreases cardiomyocyte sarcolemmal excitability more than amiodarone.
  • Amiodarone and dronedarone enhance post-extrasystolic and post-rest potentiation.
  • Amiodarone exhibits a more significant potentiation effect compared to dronedarone.

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