title: Electrophysiological studies in the sick sinus syndrome.
mesh_terms: D000368:Aged; D001146:Arrhythmia, Sinus / Q000503:physiopathology*; D001285:Atropine / Q000494:pharmacology; D002304:Cardiac Pacing, Artificial; D002648:Child; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008875:Middle Aged
chemical_list: D001285:Atropine; D007545:Isoproterenol