title: Simultaneous occurrence of two parasystolic pacemakers.
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000503:physiopathology; D004562:Electrocardiography; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male