title: Verapamil-induced ventricular regularity in atrial fibrillation. Effects of exercise, isoproterenol, atropine and conversion to sinus rhythm.
abstract: The effects of physical exercise, isoproterenol and atropine upon the ventricular rate and regularity were studied in 12 patients with atrial fibrillation (AF) during verapamil-induced regular ventricular rhythm. Physical exercise, isoproterenol and atropine all caused a gradual loss of ventricular regularity during AF. Verapamil caused a reduction of exercise heart rate during AF and, to a minor extent, even during sinus rhythm. The regular ventricular rhythm induced by verapamil during AF is interpreted as a total AV-nodal block with nodal escape rhythm. Possible clinical benefits of this rhythm are discussed.
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000188:drug therapy*; D001285:Atropine / Q000494:pharmacology*; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006352:Heart Ventricles / Q000187:drug effects; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D014700:Verapamil / Q000627:therapeutic use*
chemical_list: D001285:Atropine; D014700:Verapamil; D007545:Isoproterenol