title: A study of the effects of nicotine in the intact dog and the propensity for arrhythmias.
abstract: This is a study of the effects of nicotine exposure in the intact dog on the propensity for arrhythmias. The mean effective and total refractory periods were prolonged after nicotine. The diastolic current threshold was increased after nicotine in every animal, yet the threshold for repetitive firing was decreased in four animals, all of which had individually prolonged relative refractory periods. We conclude that nicotine may increase the propensity for arrhythmias when an appropriately timed premature stimulus, of sufficient strength, encounters a ventricle with sufficient dispersion of refractoriness to allow re-entrant arrhythmias to be sustained.
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000139:chemically induced*; D002245:Carbon Dioxide / Q000097:blood; D004285:Dogs; D004562:Electrocardiography; D006863:Hydrogen-Ion Concentration; D009538:Nicotine / Q000009:adverse effects*; D010100:Oxygen / Q000097:blood
chemical_list: D002245:Carbon Dioxide; D009538:Nicotine; D010100:Oxygen