title: Intermittent ventricular parasystole due to entrance block failure.
mesh_terms: D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000503:physiopathology; D004562:Electrocardiography; D006327:Heart Block / Q000628:therapy*; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D010138:Pacemaker, Artificial