Differential effect of right ventricular dilatation on myocardial deformation in patients with atrial septal defects and patients after tetralogy of Fallot repair.

BACKGROUND: Right ventricular (RV) volume overload results in RV dilatation in patients with atrial septal defect (ASD) and after tetralogy of Fallot (ToF) repair with pulmonary regurgitation.

AIM: Study the differential effects of chronic RV volume loading on regional and global RV deformation in patients with ASD and after TOF repair.

METHODS: We studied 85 subjects: 50 patients after ToF repair, 15 patients with unrepaired ASD and 20 age-matched controls. The ToF patients and controls underwent an echocardiography at the time of a clinically indicated MRI. The ASD patients had a routine echocardiogram including RV volume calculations. Longitudinal deformation was analyzed using 2-D speckle tracking echocardiography.

RESULTS: RV free wall global and segmental longitudinal deformation was significantly lower in ToF patients compared with ASD and controls (p<0.001). In ToF patients, there was a progressive decrease in strain values from base to apex (p<0.001), while in the ASD group there was a progressive increase (p=0.04). We found strong negative correlations between RV size and RV longitudinal strain measurements, strongest with RV length (R=0.72). When corrected for RV size, all ASD patients had normal or higher deformation values while half of the TOF patients had significantly lower values.

CONCLUSION: Global and regional myocardial RV deformation is differently affected by chronic volume loading in ASD versus TOF patients, especially regarding the apical function. This suggests a different adaptation mechanism in both diseases. Our data also suggest that strain measurements are strongly influenced by ventricular size, which should be taken into consideration when interpreting strain values.