Incessant Atrial Tachycardia:P-Wave Morphology and Echocardiographic Characteristics

Background: Incessant atrial tachycardia (AT) is a kind of sustained supraventricular tachycardia. P-wave morphology in surface ECG is a useful criterion to recognize anatomical origination of AT. In the present study, the origination of incessant AT on the basis of P-wave morphology before electrophysiology study (EPS) and echocardiographic criteria alteration before and after ablation were assessed. Methods: In this case series, 185 patients (mean age =43±18 y; age range =16 to 87 y) with AT were enrolled. Of these patients, 37 (10% of all cases of AT) had incessant AT. The P-wave morphology of all 12 leads acquired from surface ECG was recorded before EPS, and the origin of incessant AT was diagnosed. Alterations in echocardiographic characteristics such as ejection fraction (EF), end-diastolic diameter (EDD), and end-systolic diameter (ESD) were all measured before and after ablation. Results: The study of surface ECG showed that the negative P wave in lead I was a characteristic parameter for AT originating from the left atrial appendage with 100% sensitivity and 96.8% specificity. A negative or positive/negative P wave in lead V1 was seen in right atrial appendage AT with 100% sensitivity and 79.3% specificity, and a negative or positive/negative P wave in lead V1 originating from the crista terminals had 80% sensitivity and 68.8% specificity. In AT originating from the coronary sinus, a negative P wave in the inferior leads (sensitivity of 100%, specificity of 97%) and a positive P wave in lead aVR were the characteristic parameters. The mean value of left ventricular ejection fraction before and after ablation was 41.76±12.5 and 48.5±8.15, respectively (P<0.01), and a significant change due to this alteration was seen in terms of the duration of tachycardia (P<0.01). The mean of left ventricular end-diastolic diameter (LVEDD) and systolic diameter (LVESD) was 5.60±0.75 and 4.40±0.79, respectively, which significantly changed to 4.67±0.53 and 3.51±0.59 after ablation (P<0.01). Conclusions: A significant relationship was seen between P-wave morphology and the origin of incessant AT. The ablation of incessant AT conferred improvement in EF, LVEDD, and LVESD (P<0.00).