Age-related sensitivity to nicotine for inducible atrial tachycardia and atrial fibrillation

Hideki Hayashi, Chikaya Omichi, Yasushi Miyauchi, William J. Mandel, Shien Fong Lin, Peng Sheng Chen, Hrayr S. Karagueuzian

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

The influence of nicotine in modulating vulnerability to atrial tachycardia and fibrillation (AT/AF) remains ill defined. The isolated hearts of six young (2-3 mo) and six old (22-24 mo) male Fischer 344 rats were Langendorff perfused at 5 ml/min with oxygenated Tyrode solution at 37°C, and the whole heart was also superfused with warmed oxygenated Tyrode solution at 15 ml/min. Nicotine prolonged the interatrial conduction time and effective refractory period that were significantly (P < 0.05) higher in the old than in the young rats in a concentration-dependent manner. Nicotine had a biphasic effect on burst atrial pacing-induced AT in both groups, increasing it at 10-30 ng/ml while decreasing it at 50-100 ng/ml (P < 0.01). Nicotine at 10-100 ng/ml increased burst atrial pacing-induced AF in the young rats but suppressed it in the old rats (P < 0.01). Optical mapping showed the presence of multiple independent wavefronts during AF and a single periodic large wavefront during AT in both groups. Nicotine, at concentrations found in the blood of smokers (30-85 ng/ml), exerts biphasic effects on inducible AT/AF in young rats and suppresses it in the old rats by causing high degrees of interatrial conduction block.

Original languageEnglish (US)
Pages (from-to)H2091-H2098
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume285
Issue number5 54-5
DOIs
StatePublished - Nov 2003

Keywords

  • Aging
  • Atrium
  • Conduction
  • Refractory period

ASJC Scopus subject areas

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

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