Chronotropic impairment after surgical or percutaneous closure of atrial septal defect

In previous studies, an attenuated heart rate response to exercise has been noted in patients after surgical closure of atrial septal defect. The aim of this study was to compare the prevalence of chronotropic impairment after surgical and percutaneous closure of atrial septal defect.

Thirty-eight pediatric patients who underwent a surgical (group A, n = 18) or transcatheter closure (group B, n = 20) of atrial septal defect in our institution were prospectively included in the study. Treadmill exercise testing was performed using the Bruce walking treadmill protocol to voluntary exhaustion, with continuous monitoring of heart rate and oxygen consumption.

All the children were in sinus rhythm, and had normal values for peak oxygen uptake and endurance time. Exercise heart rate was significantly lower than normal in group A at the end of stage 2 (Z-score = -0.71 +/- SD 1.02), and in both groups at the end of stage 3 (Z-score = -2.06 +/- 1.76 in A and -1.00 +/- 0.71 in B) and at peak exercise (Z-score = -2.78 +/- 2.14 in A and -0.81 +/- 0.75 in B). However, the heart rate response to exercise was significantly less attenuated in group B than in group A. Moreover, maximal heart rate was <-2 SD in 8/18 surgical patients but in no patient of the group B.

The chronotropic impairment is significantly less important after transcatheter closure of atrial septal defect than after surgical closure. It is an additional argument in favor of the interventional catheterization.