Ventricular arrhythmias before and late after aortic valve replacement.

The influence of aortic valve replacement on the incidence of ventricular arrhythmias was studied by 24-hour Holter electrocardiographic monitoring in 45 patients immediately before and 14 +/- 7 months after operation. Ventricular arrhythmias were graded according to the Lown criteria. Preoperative left ventricular (LV) ejection fraction (EF) was determined by angiography and postoperative LVEF by gated blood pool scintigraphy. Repetitive ventricular arrhythmias (Lown grade 4A/B) were associated with a reduced LVEF (less than 55%) before and after operation. In 24 patients with preoperative normal LVEF (greater than or equal to 55%) (group A), mean LVEF remained unchanged after operation (72% vs 71%). Pre- and postoperative ventricular premature complex (VPC) frequency (45 +/- 99 vs 39 +/- 94 VPC/24 hours) and grade (1.3 vs 1.4) were not significantly different. However, in 17 patients with preoperative impaired LVEF (less than 55%) (group B, LVEF preoperatively 40 +/- 8%) and marked postoperative improvement (greater than 10%) (LVEF postoperatively 64 +/- 7%), mean VPC frequency decreased from 536 to 69 VPCs/24 hours and mean VPC grade was reduced from 3.8 to 1.5. Complex VPCs were found preoperatively in all 17 patients of group B, but in only 5 patients after operation. Four patients had a reduced LVEF preoperatively and it did not improve postoperatively (group C). Postoperative Holter monitoring detected ventricular tachycardia in all 4 patients. This study indicates that repetitive VPCs are infrequent in patients with normal LVEF before and late after aortic valve replacement. In patients with impaired LVEF and complex VPCs preoperatively, the postoperative improvement of LV function is usually accompanied by a reduction of frequent and complex VPCs.