Abstract 3961: Exercise Intolerance and Ventricular Dysfunction in Adults With Congenital Heart Disease
Adults with congenital heart disease (ACHD) present a unique challenge in assessing cardiovascular impairment. Exercise, functional capacity and myocardial dysfunction in ACHD patients is not well understood. We present data myocardial performance index of systemic ventricle (SMPI) and aerobic capacity in ACHD.
METHODS: A retrospective review identified 57 subjects for analysis. They were divided into 4 groups: 16 single ventricle physiology (SV), 15 repaired tetralogy of Fallot (ToF), 13 left sided obstructive lesions (LTO), 13 dextro/levo-transposition of the great vessels (TGA) with systemic ventricles. Data from latest exercise studies having temporally related clinic visits for NHYA functional assessment and echocardiograms were used. All exercise studies were conducted using Bruce treadmill protocol with peak oxygen uptake (MVO2). SMPI was calculated from systemic atrio-ventricular valve inflow and corresponding outflow track. Simple statistics and Pearson correlation were obtained using SAS®. A p value 0.05 was statistically significant. All data reported in mean (+/− SD)
RESULTS: 57 patients (34 m; 23 f) were evaluated with mean age 23.5 (+/− 6.5) yrs; mean BSA 25.3 (+/−7) m2; mean NYHA class 1.4 (+/− 0.5); mean MVO2 33.3 (+/− 11.4) ml/kg/min and mean SMPI 0.43 (+/−0.17). We found that SMPI was inversely correlated with MVO2 (r=−0.41; p=0.005) and weakly correlated with qualitative assessment of systemic EF (r=0.27; p=0.045). There was no correlation between MVO2 and NYHA class (r=−0.14; p=0.32). Patients with SV showed the lowest MVO2 (25.3; +/− 7) and higher SMPI (0.49; +/− 0.17) while LTO demonstrated the highest MVO2 (45.6; +/−12.3) and lower SMPI (0.36; +/− 0.18). For TGA with systemic right ventricles, mean MVO2 was 31.6 (+/− 6.3) and mean SMPI was 0.51 (+/− 0.17) and repaired ToF had a mean MVO2 of 32.7 (+/− 9.1) and mean SMPI of 0.42 (+/− 0.13).
CONCLUSION: MVO2 is significantly and inversely correlated to SMPI in ACHD. Objective assessments of functional class do not correlate with subjective MVO2 findings. LTO as a group showed the best aerobic capacity and SV were the most impaired. Prospective outcome studies are needed to establish a relationship between these diagnostic measures of cardiac function and overall morbidity and mortality.