Chronic nicotine in hearts with healed ventricular myocardial infarction promotes atrial flutter that resembles typical human atrial flutter

Mizuho Miyauchi, Zhilin Qu, Yasushi Miyauchi, Sheng Mei Zhou, Hui Pak, William J. Mandel, Michael C. Fishbein, Peng Sheng Chen, Hrayr S. Karagueuzian

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The potential of chronic nicotine exposure for atrial fibrillation (AF) and atrial flutter (AFL) in hearts with and without chronic myocardial infarction (MI) remains poorly explored. MI was created in dogs by permanent occlusion of the left anterior descending coronary artery, and dogs were administered nicotine (5 mg·kg-1·day-1 sc) for 1 mo using osmotic minipumps. High-resolution epicardial (1,792 bipolar electrodes) and endocardial Halo catheters were used to map activation during induced atrial rhythms. Nicotine promoted inducible sustained AFL at a mean cycle length of 134 ± 10 ms in all MI dogs (n = 6) requiring pacing and electrical shocks for termination. No AFL could be induced in MI dogs (n = 6), control (non-MI) dogs (n = 3) not exposed to nicotine, and dogs with no MI and exposed to nicotine (n = 3). Activation maps during AFL showed a single reentrant wavefront in the right atrium that rotated either clockwise (60%) or counterclockwise (40%) around the crista terminalis and through the isthmus. Ablation of the isthmus prevented the induction of AFL. Nicotine caused a significant (P < 0.01) but highly heterogeneous increase in atrial interstitial fibrosis (2- to 10-fold increase in left and right atria, respectively) in the MI group but only a 2-fold increase in the right atrium in the non-MI group. Nicotine also flattened (P < 0.05) the slope of the epicardial monophasic action potential duration (electrical restitution) curve of both atria in the MI but not in non-MI dogs. Two-dimensional simulation in an excitable matrix containing an isthmus and nicotine's restitutional and reduced gap junctional coupling (fibrosis) parameters replicated the experiments. Chronic nicotine in hearts with MI promotes AFL that closely resembles typical human AFL. Increased atrial interstitial fibrosis and flattened electrical restitution are important substrates for the AFL.

Original languageEnglish
Pages (from-to)H2878-H2886
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume288
Issue number6 57-6
DOIs
Publication statusPublished - 2005 Jun 1

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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