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*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 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
Pages (from-to)H2091-H2098
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume285
Issue number5 54-5
DOIs
StatePublished - 1 Nov 2003

Keywords

  • Aging
  • Atrium
  • Conduction
  • Refractory period

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