794–4 Compensated Pulmonic Insufficiency: Is the Right Ventricular Response to Exercise Normal?

Chronic right ventricular (RV) volume overload due to pulmonic insufficiency (PI) can unpredictably lead to irreversible RV failure. We sought to assess the effect of chronic volume overload on RV exercise response. 10 patients (2 male, 8 female, mean age 24 yrs) with compensated moderate to severe PI due to surgically corrected Tetralogy of Fallot or pulmonic stenosis and 7 controls (4 male, 3 female, mean age 29 yrs) were studied on a symptom limited stationary cycle progressive ramp protocol with measurement of VO2 and respiratory quotient. Stress echocardiography was performed at rest and during exercise (mid=RQ 0.85, 100%=peak). RV function was described as end diastolic RV area (RVEDA), end diastolic RV/LV area ratio (RV/LV) and percent systolic RV area change (%RVAΔ), the latter a reflection of RV ejection fraction.Resultspatients (P)controls (c)restmid100%restmid100%RVEDA*28.526.424.719.216.113.8RV/LV**0.980.950.970.560.530.49%RVAΔ†0.370.360.340.340.410.43By ANOVA P vs C*P<0.005**p<0001Although there was no significant difference in percent systolic RV area change at rest, in patients RV systolic function declined during exercise as compared with an increase in controls, †p<0.001. Cardiac index, HR, and BP did not significantly differ between patients and controls. VO2 max was reduced in patients with PI (23.0 vs 38.8ml/kg/min, p<0.001), but was not predicted by any resting echocardiographic variable. However, in controls larger RVEDA was associated with a greater exercise capacity. The change in RV systolic performance during exercise was associated with resting RVEDA, RV/LV and %RVAΔ, p<0.005.ConclusionPatients with compensated significant PI have an abnormal RV response to exercise demonstrable by stress echocardiography. This may have implications for the timing of pulmonic valve replacement