Sinus node function and conduction system before and after surgery for secundum atrial septal defect: an...

Area of Science:

• Cardiology
• Electrophysiology
• Pediatric Heart Surgery

Background:

• Atrial septal defects (ASD) are associated with arrhythmias and electrophysiologic disturbances.
• These disturbances can arise from the defect itself or surgical intervention.

Purpose of the Study:

• To evaluate the impact of surgical ASD closure on cardiac electrophysiologic parameters in children.
• To assess changes in sinus node (SN) function, conduction intervals, and refractory periods before and after ASD repair.

Main Methods:

• Electrophysiologic studies were conducted on 18 children before and after surgical ASD closure.
• Parameters assessed included corrected SN recovery time, AH interval, and atrial and atrioventricular (AV) nodal refractory periods.

Main Results:

• Preoperatively, corrected SN recovery time and AH interval were prolonged in most patients.
• Postoperatively, significant improvements were observed in SN recovery time (in sinus rhythm), AH interval, and AV nodal refractory periods.
• The pacing rate for second-degree AV block increased, indicating improved AV conduction.

Conclusions:

• Surgical closure of ASDs positively impacts cardiac electrophysiology by improving AV conduction and SN function, likely due to reduced right-sided heart volume overload.
• Despite overall improvements, potential loss of SN function postoperatively warrants consideration, possibly related to the surgical procedure.