Comparison of the right and left ventricle as a systemic ventricle during exercise in patients with congenital heart disease.
BACKGROUND
Few studies have investigated the clinical advantages of surgical correction with the morphologic left ventricle (MLV) instead of the morphologic right ventricle as a systemic ventricle (SV) in patients with congenital heart disease.


METHODS
Twenty-four healthy control subjects (group A1), 6 patients with isolated congenitally corrected transposition of the great arteries (TGA) (group A2), 16 patients with TGA who had undergone an arterial switch operation (group B1), 18 patients with TGA who had undergone a venous switch operation (group B2), 9 patients with atrioventricular and ventriculoarterial discordance who had undergone a double switch operation (group C1), and 6 patients with atrioventricular and ventriculoarterial discordance who had undergone a conventional external conduit operation from the MLV to the pulmonary artery (group C2), performed treadmill exercise testing. Their heart rate (HR), oxygen uptake (VO2), and oxygen pulse (O2 pulse), which reflects individual stroke volume, were measured, and contractile function was assessed by echocardiography.


RESULTS
The peak HR for the patients after a definitive operation were significantly lower than that in group A1 and was correlated with peak VO2 (r =.67, P <.0001). The peak VO2 and peak O2 pulse for the groups A2 and B2 were significantly lower than those for the groups A1 and B1, respectively. The peak O2 pulse data were strongly correlated with those of peak VO 2 (r = 0.91, P <.0001). The left ventricular ejection fraction was significantly lower in groups B1 and C1 than in group A1 and was correlated with peak VO 2 (r =.50, P <.01). No significant differences in VO2, HR, and O 2 pulse at peak exercise were observed between groups C1 and C2.


CONCLUSIONS
Chronotropic incompetence and an impaired response of the stroke volume of the MRV during exercise are partly responsible for the reduced exercise capacity in groups A2 and B2 compared with groups with the MLV as an SV, and the SV function at rest is also related to exercise capacity. Superiority of the double-switch operation compared with the conventional conduit operation was not observed. A longer-term follow-up is necessary before the advantages of these 2 operations can be compared.
Ohuchi
H
H
Department of Pediatrics and Thoracic Surgery, National Cardiovascular Center, Fujishiro-dai, Suita, Osaka 565, Japan.
Hiraumi
Y
Y
Tasato
H
H
Kuwahara
A
A
Chado
H
H
Toyohara
K
K
Arakaki
Y
Y
Yagihara
T
T
Kamiya
T
T
D000293:Adolescent; D000704:Analysis of Variance; D002648:Child; D002675:Child, Preschool; D004452:Echocardiography / Q000706:statistics & numerical data; D005080:Exercise Test / Q000706:statistics & numerical data; D005500:Follow-Up Studies; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D006352:Heart Ventricles / Q000503:physiopathology; D006439:Hemodynamics; D006801:Humans; D007223:Infant; D011184:Postoperative Period; D011659:Pulmonary Gas Exchange; D012044:Regression Analysis; D012129:Respiratory Function Tests / Q000706:statistics & numerical data; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right