Objectives: Secundum atrial defect (ASDs) causes changing in cardiac hemodynamics dependent on the defect size and shunt volume including volume overload, stress extends to tissues in the cardiac conduction system and manifests as intra-atrial or intra-ventricular conduction delay. The aim of the study is to evaluate that ECG findings in patients with atrial septal defect can help determine the shunt rate. Methods: This retrospective study included 74 patients with ASDs. Standard 12-lead ECG and right precordial electrocardiographic recordings (V3R, V4R, V5R, and V6R) were obtained from all patients. QT intervals were measured manually from ECG on paper prints. According to shunt ratio (Qp/Qs), the patients divided into two groups as <1.5 group 1; 1.5> Group 2. Results: The mean ages of Group1 and Group2 were similar (p>0.05). There were no significant differences between the two groups between RA (right atrium) diameters, RV (right ventricle) diameter (p>0.05). V4RQTmax were 321.2±26.4 msec; 351.1±33.6 msec, respectively (p<0.05) and V5RQTmax were 319.2±22.6 msec; 350.1±32.3 msec, respectively, (p<0.05), which were found to be significantly different. Conclusion: Were obtained that the right precordial leads could be used to estimate the shunt ratio of patients with secundum ASD. Keywords: Electrocardiography; right precordial lead; secundum atrial defect
Corresponding Author: Saricam E.