Key result
High ASD shunt ratios linked to ~27 msec longer Tp-e intervals, indicating increased arrhythmia risk.
Why the study?
Ventricular arrhythmias occur in patients with atrial septal defect, but whether shunt ratio impacts ventricular repolarization markers remained unassessed.
Does a high shunt ratio (≥2.0) increase ventricular repolarization heterogeneity (Tp-e interval) in patients with secundum atrial septal defect?
Observational (n=133)
Single-blind
No
Does a high shunt ratio (≥2.0) increase ventricular repolarization heterogeneity (Tp-e interval) in patients with secundum atrial septal defect?
In patients with secundum atrial septal defect, a shunt ratio ≥2.0 is associated with prolonged Tp-e intervals and higher Tp-e/QT ratios, suggesting increased susceptibility to ventricular arrhythmias.
High shunt ratio linked to longer Tp-e in ASD suggests arrhythmia vigilance but should not change practice; leaves open need for prospective validation.
Objective: Ventricular arrhythmia episodes are not infrequent in patients with atrial septal defect (ASD). Disturbance in cardiac volume and pressures may lead to enlargement and fibrosis in heart. An interatrial volume displacement through septal defect, briefly interatrial shunt, is the major reason for this complication. Prolongation of the interval between the peak and end of the T wave (Tpeak to Tend, Tp-e) on the 12-lead electrocardiogram (ECG), is utilized as a marker of ventricular arrhythmogenesis during last years. The aim of this study was to assess if there is an impact of shunt ratio on ventricular repolarization in patients with ASD by using Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio. Methods: Patient records of Samsun Training and Research Hospital were retrospectively analyzed. Electrocardiograms of 133 patients, who were diagnosed as ASD between January 2016 and December 2019 were obtained and scanned. ECG intervals were measured. Shunt ratios, right ventricle diameters and volumes were also acquired. Patients were grouped into two by their calculated shunt ratio, ratio of ≥2.0 is accepted as a high shunt group and <2.0 as a low shunt group. Results: Both groups’ baseline characteristics were similar. Right ventricular dimensions and systolic pulmonary artery pressure were higher in high shunt group. Furthermore, ASD patients with higher shunt ratio had significantly higher ECG measurements than controls, Tp-e: 103.0 (22.1) vs 76.2 (10.2); Tp-e/QT: 0.25 (0.03) vs 0.21 (0.02); Tp-e/QTc: 0.22 (0.03) vs, 0.17 (0.02); for all p<0.001). Of all ECG parameters; Tp-e (r=0.631, p<0.001), Tp-e/QT (r=0.531, p<0.001) and Tp-e/QTc (r=0.614, p<0.001) had moderate correlation with shunt ratio. Conclusion: T wave peak-to-end interval is a measure of transmural dispersion of repolarization and accepted as a surrogate for increased ventricular arrhythmogenesis risk. Our findings show that ASD patients whose shunt ratio are ≥2.0 show increased risk for arrhythmias.
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Osman Can Yontar (2020) conducted an observational in Atrial septal defect (n=133). High shunt ratio (≥2.0) vs. Low shunt ratio (<2.0) was evaluated on Tp-e interval (msec) (p=<0.001). Atrial septal defect patients with a high shunt ratio (≥2.0) had significantly longer Tp-e intervals (103.0 vs 76.2 msec) compared to those with a low shunt ratio, indicating increased arrhythmia risk.
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