Assessment of right ventricular function during supine bicycle exercise after Mustard's operation.

Abstract

SUMMARY Right ventricular (RV) performance during supine bicycle exercise was evaluated by gated equilibrium nuclear angiography in 19 clinically well children with d-transposition of the great arteries (d-TGA), 6.4 ± 2.7 years after Mustard's operation. Comparisons were made between rest and peak exercise. The mean resting ejection fraction was 44 ± 12% (range 30-75%) and was unchanged at peak exercise. Eight children had a normal ejection fraction response, whereas 11 children had either no increase or a decrease in ejection fraction. Relative end-diastolic volumes decreased from resting values in all patients who had an abnormal ejection fraction response. Among patients whose ejection fraction increased, the end-diastolic volume increased in three, decreased in four and was unchanged in one at peak exercise. Heart rate increased 84% (range 52-135%) and systolic blood pressure increased 16% (range 0-28%) at peak exercise. There was no correlation between exercise response and age at surgery or interval since surgery. These data indicate that clinically well children after Mustard's procedure may have abnormal right ventricular function under stress, raising concerns about the ability of the right ventricle to function as the systemic ventricle.

Patients After Atrial Switch Operation for Transposition of the Great Arteries Can Not Increase Stroke Volume Under Dobutamine Stress as Opposed to Patients With Congenitally Corrected Transposition

“…Firstly, the morphologic right ventricle may not be able to meet the requirements of a systemic ventricle. [4][5][6] Secondly, a low heart rate (HR) response during exercise 7 may cause limited exercise performance. And finally, a relative preload reduction during exercise caused by the rigid atrial baffles may limit exercise performance.…”

“…And finally, a relative preload reduction during exercise caused by the rigid atrial baffles may limit exercise performance. 8,9 However, those previous studies assessed patients after the atrial switch operation either without a control group [4][5][6]9 or by comparing them to normal subjects with morphologic left ventricles in systemic position. 7,8 The ideal control group for examining the cause of limited exercise performance of patients after the atrial switch operation is very rare because it comprises patients with congenitally corrected transposition of the great arteries (ccTGA) who have not had previous heart surgery.…”

Hemodynamic residua and sequelae following intraatrial repair of transposition of the great arteries: A review

“…We believe that patients whose RVEF is approximately t/ normal or less 0 .33) have some impairment of exercise tolerance although to date we have not been able to quantify this by standardized exercise testing . Benson et al [2] showed an abnormal exercise response in terms of either a fall or no change in RVEF during exercise in 9 of 15 asymptomatic patients studied 3 .5 to 15 years after a Mustard repair . These data strongly suggest that abnormal systemic ventricular function may be a significant long-term problem in the postoperative adolescent and adult who have had an intraatrial repair .…”

Dyssynchrony and electromechanical delay are associated with focal fibrosis in the systemic right ventricle — Insights from echocardiography

“…Patients are at increasing risk of late ventricular dysfunction and sudden cardiac death. [2][3][4][5][6][7][8][9][10][11] The exact underlying pathophysiological mechanism is likely to be multifactorial. Myocardial ischaemia in the morphologically right systemic ventricle has been suggested based on the presence of perfusion defects, 9 wall motion abnormalities and features suggestive of fibrosis on late gadolinium cardiovascular magnetic resonance (CMR).…”