title: Conduction system abnormalities in symptomatic mitral valve prolapse: an electrophysiologic analysis of 60 patients.
abstract: This study examined the site of atrioventricular (AV) block in mitral valve prolapse (MVP). Sixty symptomatic patients with MVP underwent electrophysiologic study; 49 had documented arrhythmias and 28 had syncope. Eight patients had spontaneous second- or third-degree AV block and 10 had chronic bundle branch block. Electrophysiologic study revealed abnormal sinus node function in 8 patients, prolonged HV interval in 10, intra-Hisian delay in 9, and functional bundle branch block in 15. Dual AV nodal pathways were demonstrated in 24 patients. Comparison with 101 similarly symptomatic patients without MVP revealed a greater prevalence of dual AV nodal pathways in the MVP patients. Infranodal conduction abnormalities and dual AV nodal pathways are frequently revealed by electrophysiologic testing in symptomatic patients with MVP.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000503:physiopathology*; D001283:Atrioventricular Node / Q000503:physiopathology; D002037:Bundle-Branch Block / Q000503:physiopathology; D004594:Electrophysiology; D005260:Female; D006327:Heart Block / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008945:Mitral Valve Prolapse / Q000150:complications / Q000503:physiopathology*