ECHOCARDIOGRAPHIC ASSESSMENT OF SYSTOLIC AND DIASTOLIC VENTRICULAR FUNCTION AFTER FONTAN TYPE OF OPERATION

The aim of this study was to assess ventricular systolic and diastolic function after the Fontan procedure. 13 postoperative patients (pts) aged 12-29 years were prospectively evaluated with two-dimensional echocardiography equipped with automatic boundary detection (ABD) capabilities. 10 age-matched normal subjects were selected as controls. ABD waveforms of ventricular area change and the rate of area change were displayed along with the electrocardiogram and the concurrent cross sectional image. Real-time ventricular volumes by ABD were obtained with the method of discs in the apical 4-chamber view and a time-volume curve with its derivative curves was plotted. The following ABD diastolic measurements were evaluated: RFS = slope of rapid filling segment (the abrupt upslope of the curve considered to start at the opening of the mitral valve); RFFC = rapid filling phase fractional change (amount of total area or volume change that occurred at the end of the rapid filling period); AFFC = atrial filling phase fractional change (amount of the total area or volume change that occurred during atrial contraction); PFR = peak filling rate (first upward peak in diastole on the dA/dt or dV/dt waveform, normalized to end-diastolic area or volume); TPFR = time to peak filling rate (the time interval from end-systole to peak rate of area or volume change); D-RF = duration of rapid filling. Compared to normal controls, the 11 pts who had undergone the Fontan operation had decreased ( p<0.05 ) PFR (2.8 +/- 0.6 vs 4.2 +/- 0.7 EDV/sec), decreased RFS (27.2 +/- 3.7 vs 37.6 +/- 4.9 ml/sec), decreased RFFC (54 +/- 8 vs 75 +/- 6%), and increased AFFC (67 +/- 6 vs 48 +/- 5%). These diastolic filling abnormalities in the presence of a normal or nearly normal ventricular ejection fraction suggest impaired ventricular relaxation. This in turn may influence pulmonary blood flow and cardiac output in pts after the Fontan operation.