794-6 Functional Capacity in Adult Patients with Mustard Correction

Abstract

The effect of prolonged support of the systemic circulation by the right ventricle was assessed in adult survivors of the Mustard operation. Forty five adult patients (32 male) aged 21.7 +/-3.3 years (mean +/-S.D) were studied. They had undergone Mustard's operation for correction of complete transposition 19.1 +/-2.6 years previously at 2.6 +/-3.1 years of age. Cardiopulmonary function was assessed using maximal bicycle ergometry with respiratory mass spectrometry. Systemic ventricular ejection fraction (SVEF) was measured at rest (r) and with exercise (ex) by radionuclide angiography. Thirtyfour patients additionally had magnetic resonance imaging to measure ventricular dimensions. Results were compared with normals [mean (SD)] Max. Work load kpm VO2 max AT SVEF (r) SVEF (ex) SVTh SVD % NYHA 1 or 2 Mustard 673 * 17.1 * 11.5 * 45.4 * 51.1 * 14.0 * 40.4 + 92 (179) (4.9) (4.0) (10.9) (14.7) (3.7) (7.4) Normal 1117 43.4 24.2 59.9 70.6 9.3 32.5 100 (190) (10.1) (4.7) (8.7) (7.7) (1.0) (3.5) AT = anaerobic threshold, VO2 max = maximal oxygen consumption, SVD = systemic ventricular diameter (mm), SVTh = wall thickness (mm) * p < 0.01 + p < 005 There was no significant difference in maxima I heart rate or maximal blood pressure with exercise between the groups. There was no correlation between ventricular dimensionlthickness and ejection fraction either at rest or exercise. Maximal work load was correlated with ejection fraction on exercise (p < 0.05). Thus adult Mustard patients have dilated. hypertrophied systemic ventricles with reduced ejection fraction compared with controls. Formal functional assessment demonstrates significant impairment despite patients leading normal or near normal lives.