OBJECTIVE To assess left ventricular function in adult Fallot patients with residual pulmonary regurgitation.

SETTING The radiology department of a tertiary referral centre.

PATIENTS 14 patients with chronic pulmonary regurgitation and right ventricular volume overload after repair of tetralogy of Fallot and 10 healthy subjects were studied using magnetic resonance imaging.

MAIN OUTCOME MEASURES Biventricular volumes, global biventricular function, and regional left ventricular function were assessed in all subjects.

RESULTS The amount of pulmonary regurgitation in patients (mean (SD)) was 25 (18)% of forward flow and correlated significantly with right ventricular enlargement (p < 0.05). Left ventricular end diastolic volume was decreased in patients (78 (11) v 88 (10) ml/m²; p < 0.05), ejection fraction was not significantly altered (59 (5)% v 55 (7)%; NS). No significant correlation was found between pulmonary regurgitation and left ventricular function. Overall left ventricular end diastolic wall thickness was significantly lower in patients (5.06 (0.72) v 6.06 (1.06) mm; p < 0.05), predominantly in the free wall. At the apical level, left ventricular systolic wall thickening was 20% higher in Fallot patients (p < 0.05). Left ventricular shape was normal.

CONCLUSIONS Adult Fallot patients with mild chronic pulmonary regurgitation and subsequent right ventricular enlargement showed a normal left ventricular shape and global function. Although the left ventricular free wall had reduced wall thickness, compensatory hypercontractility of the apex may contribute to preserved global function.