Electrocardiographic findings before and after surgery for atrial septal defect of the secundum type in middle-aged patients.
Surgery for atrial septal defect of the secundum type was performed in 84 patients over 40 years of age. Electrocardiograms were studied preoperatively and at a follow-up visit 74 months (range 22-174 months) after surgery. Preoperatively, atrial fibrillation was observed in 13% of the patients, complete right bundle branch block in 30%, and a secondary R wave (R') in lead V1 in 72%. A significant correlation was found between the amplitudes of SV6 and R'V1 and the right ventricular systolic pressure, whereas no significant correlation could be demonstrated between the shunt ratio and any of the QRS parameters. After successful surgery, the mean QRS axis in the frontal plane shifted from +99 degrees to +47 degrees (p less than 0.01), and the following highly significant (p less than 0.001) changes were noticed: increase of the amplitude of SV1, shortening of the QRS duration in V1, increase of the ratio QR'/QRS V1, shortening of the duration of SV6, and diminution of the initial forces of the P wave in V1.
D000328:Adult; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000503:physiopathology*; D006344:Heart Septal Defects, Atrial / Q000175:diagnosis* / Q000601:surgery; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged