Relation of biventricular function quantified by stress echocardiography to cardiopulmonary exercise capacity in adults with Mustard (atrial switch) procedure for transposition of the great arteries.
BACKGROUND
Mustard repair for transposition of the great arteries (TGA) is frequently associated with impaired systemic (right) ventricular function and sometimes exercise intolerance. We hypothesized that a simple quantitative measurement of ventricular function, during rest and pharmacological stress, could identify abnormalities and predict objective exercise capacity.


RESULTS
We quantified the performance of systemic and pulmonary (left) ventricles by using echocardiography, at rest and during dobutamine stress, in 27 adults who had undergone Mustard repair for TGA. Systolic and diastolic function of the systemic ventricle were markedly disturbed with respect to pulmonary ventricular function. We also measured exercise capacity by cardiopulmonary exercise testing for peak oxygen uptake. Exercise capacity was significantly predicted by systemic ventricular long-axis excursion both at rest (r=0.66, P<0.001) and at peak dobutamine stress (r=0.53, P=0.006) but not by pulmonary ventricular long-axis excursion at rest (r=0.04) or on stress (r=0.11). Exercise capacity was also predicted by the septal long-axis excursion at rest (r=0.61, P=0.001) but not pulmonary ventricular free wall excursion (P>0.05) or fractional shortening (P>0.05). Peak aortic velocity at maximum dobutamine stress correlated with exercise capacity (r=0.46, P=0.029) but not at rest (r=0.36). Multivariate analysis revealed systemic ventricular long-axis excursion to be the sole significant independent predictor of exercise capacity.


CONCLUSIONS
Systemic ventricular function is depressed in most patients with Mustard repair. Quantitative echocardiographic evaluation shows systemic ventricular function to be a key determinant of exercise capacity.
Li
Wei
W
Royal Brompton Hospital and Imperial College School of Medicine, London, United Kingdom.
Hornung
Tim S
TS
Francis
Darrel P
DP
O'Sullivan
Christine
C
Duncan
Alison
A
Gatzoulis
Michael
M
Henein
Michael
M
D000318:Adrenergic beta-Agonists; D000328:Adult; D002404:Catheterization; D003971:Diastole; D004280:Dobutamine; D025401:Echocardiography, Stress; D017079:Exercise Tolerance; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D010138:Pacemaker, Artificial; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D012086:Reoperation; D012146:Rest; D013599:Systole; D014188:Transposition of Great Vessels / Q000503:physiopathology / Q000601:surgery*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*
D000318:Adrenergic beta-Agonists; D004280:Dobutamine