Ventricular arrhythmias late after aortic valve replacement and their relation to left ventricular performance

Abstract

Sudden unexplained death is a common cause of late mortality after aortic valve replacement. To evaluate the occurrence of ventricular arrhythmia in patients with aortic valve replacement, two 24 hour ambulatory electrocardiographic recordings were obtained in 45 such patients (mean age 55 years) who had undergone replacement an average of 3.3 years previously. In 43 patients, ventricular arrhythmia was detected; it was rare (mean premature ventricular complex frequency less than 1 15 min) in 18 patients (40 percent), moderately frequent (mean frequency 1− 10 15 min) in 14 patients (31 percent) and frequent (mean frequency more than 10 15 min) in 11 patients (24 percent). Multiformity was noted in 40 (89 percent), bigeminy in 27 (60 percent), couplets in 27 (60 percent) and ventricular tachycardia in 16 (36 percent) of the 45 patients studied. The occurrence of ventricular arrhythmia was not related to the predominant hemodynamic lesion or to the presence of coronary artery disease as determined at the time of preoperative cardiac catheterization. Radionuclide left ventricular ejection fraction, determined at the time of electrocardiographic monitoring in 39 patients, demonstrated normal left ventricular function (ejection fraction greater than 50 percent) in 27 patients (60 percent), moderately depressed function (ejection fraction 36 to 50 percent) in 8 (21 percent) and severe dysfunction in 4 (10 percent). When patients with abnormal versus normal left ventricular performance were compared, the mean premature ventricular complex frequency was 21 ± 26 15 min versus 5 ± 11 15 min ( p < 0.01) ; couplets occurred in 10 (83 percent) of 12 versus 13 (48 percent) of 27 patients (p < 0.05) and ventricular tachycardia in 8 (75 percent) of 12 versus 6 (22 percent) of 27 patients (p < 0.01). Patients exhibiting ventricular tachycardia had a mean left ventricular ejection fraction of 47 ± 14 percent compared with 62 ± 13 percent in patients without this arrhythmia (p < 0.005). This study indicates that significant ventricular arrhythmias, including ventricular tachycardia, are common late after aortic valve replacement. In addition, a relation exists between occurrence of arrhythmia and left ventricular function abnormalities.