Permanent chronotropic impairment after closure of atrial or ventricular septal defect.

Objectives: Atrial and ventricular septal defects are commonly closed surgically with low rates of post-operative morbidity, and the long-term outcome has widely been described as benign. Nevertheless, there is an increasing understanding of late morbidity, and the possibility of postoperative chronotropic impairment is continuously questioned. Furthermore, potentially abnormal chronotropic responses may be associated with the recently demonstrated overrepresentation of late arrhythmias. We conducted this review to methodically describe the potential effects of surgical defect closure on the chronotropic response to exercise.

Methods: We performed a search protocol based on the 'Preferred Reporting Items for Systematic Reviews and Meta- Analyses' (PRISMA) guidelines. A data collection form was specifically developed and data were extracted from the included studies by a primary reviewer and crosschecked by a secondary reviewer.

Results: A search of electronic databases revealed 16 publications, which consistently reported an abnormal heart rate responses to exercise after surgical closure. In contrast, these and other studies convincingly showed normal chronotropic response in un-operated patients as well as after percutaneous closure. Potential mechanisms include disturbances in the sinoatrial or atrioventricular conduction system and denervation in the proximity of the aorta during the surgical procedure.

Discussion: ASD and VSD patients have abnormal heart rate responses to exercise after surgical closure, which indicates a need of change in the preoperative information given to these patients and their parents before surgical defect closure. Although there may not be any alternatives to surgery, patients should still be informed about potential long-term consequences, including the risk of chronotropic incompetence. Moreover, this review suggests that 'specialized', long-term follow up may be indicated.