Electrocardiographic Changes in Ostium Secundum Atrial Septal Defect- Before and After Shunt Closure- A Retrospective Cohort Analysis

Introduction: Atrial Septal Defect by virtue of its left to right shunt induces geometric and electrical remodeling of the right sided chambers of the heart which produces prototypical changes in the Electrocardiogram. Various patterns produced by ASD in the ECG can give a clue in diagnosing the defect. Reversal of remodeling after the shunt closure and its accompanying changes in ECG are also helpful in follow up of these patients Methodology: This is a retrospective cohort analysis, wherein, ECG of the patients who have undergone ASD closure by percutaneous device closure or surgical closure during the study period,were obtained from hospital records and they were followed up. After screening, 60 patients met the inclusion criteria and were included in the study. ECG of the patients before closure of ASD and on immediate post procedure day, 2 weeks, 1month, 3 months, 6 months and 1year were obtained and analyzed.

Results: Mean age of the study population was 28.4 ± 09 years. In analysis of ECG after closure of ASD, the mean QRS axis reduced from 108 ± 10 to 70 ±12 degrees (P = 0.016), mean QRS duration reduced from 123 ± 30 ms to 80 ± 27 ms (P= 0.28). Mean PR interval reduced from 188 ± 30 ms to 123 ± 24 ms (P value= 0.09). The Crochetage Sign disappeared in the 2 patients who had it before closure of the defect. The amplitude of R' wave in rSR' in right precordial leads reduced over 2 years. rR' and qR pattern in right precordial leads reverted to rSr' pattern in 10 out of 12 patients. The other 2 patients who did not show reversal had residual shunt. No clinically significant complete heart block was observed in any patient.

Conclusion: ECG forms as an easily available tool for diagnosis of ASD as well as in assessing the success of closure in the follow up after the closure of ASD by surgical or percutaneous device therapy. Failure of reversal of electrocardiographic signs of ASD after the closure should prompt search for residual shunt or pulmonary complications.