Objective: To examine retrospectively the changes in ECG parameters over time and their correlation with other quantitative right ventricular (RV) function parameters in patients with chronic RV pressure overload caused by congenital heart disease.
Methods: 48 patients with chronic RV pressure overload caused by the following congenital heart diseases were studied: nine with congenitally corrected transposition of the great arteries (TGA), 12 with surgically corrected TGA, and 27 with a subpulmonary pressure overloaded RV. QRS duration and dispersion were measured manually from standard ECG recorded twice within five years. RV end diastolic volume (EDV) and RV mass were determined by magnetic resonance imaging. Brain natriuretic peptide (BNP) plasma concentrations were measured.
Results: QRS duration and QRS dispersion increased in all patient groups during the follow up period. QRS duration increased significantly in the congenitally corrected TGA (p = 0.04) and the subpulmonary pressure overloaded RV groups (p = 0.01). QRS dispersion increased significantly in patients with surgically corrected TGA (p = 0.03) and in the subpulmonary pressure overloaded RV group (p = 0.02). A significant correlation was found between QRS duration and RVEDV (r = 0.71, p < 0.0001). RV mass was significantly correlated with QRS duration in patients with tetralogy of Fallot (r = 0.67, p = 0.01). Mean (SD) plasma brain natriuretic peptide concentrations (6.6 (5.4) pmol/l) were increased compared with normal reference values but no correlation was found with ECG parameters or RV systolic pressure. No malignant arrhythmia or sudden death occurred.
Conclusions: ECG parameters worsened gradually in asymptomatic or minimally symptomatic patients with chronic RV pressure overload, regardless of the nature of their congenital heart disease. In all patients, a significant positive correlation was found between QRS duration and RVEDV. In patients with tetralogy of Fallot there was also a correlation between QRS duration and RV mass.