Catheter Ablation of Atrial Tachyarrhythmia in Patients with Prior Valvular Surgery: The Limitation of the Surface Electrocardiography

Background: Postoperative atrial tachyarrhythmia may be caused by the focal or reentrant mechanism. The diagnostic potential of the surface electrocardiography (ECG) might be limited because of the presence of surgical scar and interatrial conduction delay. Methods: Eight patients with prior valvular surgery underwent Catheter ablation for drug-refractory and symptomatic atrial tachyarrhythmia. The 12-lead ECGs during tachycardia were evaluated. Group 1 consisted of 5 patients with negative flutter waves in inferior leads and leads V5-6, positive waves in leads V1-V2. Group 2 consisted of 3 patients with ECG presentations different from those in group 1. Results: Electrophysiologic study and three-dimensional electroanatomic mapping showed 2 typical right atrial (RA) flutter, 1 left atrial (LA) double loop scar-related flutter, 1 scar-related RA atypical flutter and 1 scar-related aortic root atrial tachycardia in group 1; 1 RA typical flutter, 1 RA appendage atrial tachycardia and 1 atrioventricular nodal reentrant tachycardia in group 2. The ECG presentation of RA typical flutter can not diagnose the true isthmus dependent RA flutter (Area under curve 0.533). Conclusions: Among the patients with prior valvular surgery and atrial tachyarrhythmia, 37.5% patients presented a typical RA flutter. However, the diagnositc ability of the 12-lead ECG for those patients is limited.