title: Cycle length alternation in supraventricular tachycardia after administration of verapamil.
mesh_terms: D000328:Adult; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D013610:Tachycardia / Q000188:drug therapy*; D014700:Verapamil / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D014700:Verapamil