title: Rate-dependent variation in the duration of the QRS complex with left anterior fascicular block.
abstract: The case of a 67-year-old man with combined ischemic and valvular heart disease is presented. Electrocardiographic abnormalities included left anterior fascicular block with a variable duration of the QRS complex. The width of the QRS complex was dependent on the length of the cycle, being broader with short than with long preceding R-R intervals. This is interpreted as a tachycardia-dependent focal block coexisting with a fixed delay in fascicular conduction.
mesh_terms: D000368:Aged; D001022:Aortic Valve Insufficiency / Q000150:complications; D002037:Bundle-Branch Block / Q000175:diagnosis*; D003327:Coronary Disease / Q000150:complications; D004562:Electrocardiography; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D013610:Tachycardia / Q000150:complications