Relationship between ventricular function assessed by tissue Doppler imaging and exercise capacity in patients after repair of tetralogy of Fallot: an observational study

Abstract

The present study aims to study the relationship between tissue Doppler echocardiography (TDE) indices of right ventricle and exercise capacity in patients after total correction for tetralogy of Fallot (ToF). This cross-sectional observational study included 20 patients, after undergoing total correction procedure for ToF diagnosed with mild/moderate pulmonary regurgitation and 30 age-matched healthy children. In the postoperative period, patients were invited to hospital for evaluation of the ventricular functions by 2D, M-mode, Doppler (DE) echocardiography and TDE and exercise testing to evaluate the effort capacity. Statistical analysis was performed using Mann-Whitney U and Chi-square tests, and Pearson correlation analysis. Compared with the controls; the mitral annular peak systolic flow velocity (Sm) value was significantly lower, while isovolumic contraction time (IVCT), isovolumic relaxation time (IVRT) and myocardial performance index (MPI) values obtained at the tricuspid and mitral (MV) valves were significantly higher (p<0.05 for all) in patients after ToF repair. There was a negative correlation between the exercise period and the total correction age (r=-0.20, p=0.015) and the same negative correlation existed between the exercise period and METS (r=-0.25, p=0.010). MV IVCT with DE and TDE was found to be correlated with METS (r=-0.45, p=0.04). Left ventricular MPI was found to be correlated with maximum heart rate (r=-0.20, p=0.03). By DE, tricuspid valve deceleration time and Sm peak flow velocity with TDE were significantly correlated with METS (r=-0.30, p=0.04; r=-025, p=0.005, respectively). MPI calculated with TDE was correlated with maximum heart rate (r=-0.15, <0.01). Even if patients, undergone total correction surgery for ToF were asymptomatic or had minimal clinical symptoms, MPI index assessed by pulse wave TDE and exercise testing may allow early diagnosis of right ventricle dysfunction.