title: Multilevel disease of the conduction system.
abstract: We found that the incidence and distribution of conduction system disease simultaneously affecting several levels of the system had been incompletely described. We therefore analysed all patients in whom conduction disease had been diagnosed and a complete electrophysiological study of the conduction system had been made, during a defined period. Patients were classified as to the presence or absence of sinus node disease, and proximal and distal atrioventricular disease. Since our hospital serves a defined population and a large proportion of all patients with conduction disease seen during the period was included, the series probably is representative of conduction disease in general. Twenty-four of the 59 patients had defects at more than one of the three levels (41%). Fifty-five per cent of the patients with sinus node disease had some kind of atrioventricular disease, while 42% of the latter had evidence of sinus node failure. The patients with multilevel disease were characterized by more severe symptoms, higher age and a higher incidence of generalized heart disease than those with single-level disease. The observations fit the concept that conduction system disease in most patients is part of a diffuse disease process progressively involving various parts of the system.
mesh_terms: D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000503:physiopathology*; D001283:Atrioventricular Node / Q000503:physiopathology; D004562:Electrocardiography; D006327:Heart Block / Q000175:diagnosis / Q000503:physiopathology*; D006334:Heart Function Tests; D006801:Humans; D012849:Sinoatrial Node / Q000503:physiopathology