Role of surface electrocardiogram precordial leads in localizing different anatomic sites of ectopic atrial tachycardia arising from lower right atrium in pediatric population

Background

The study was designed to examine P wave morphology (PWM) in precordial leads (V₁–V₆) during ectopic atrial tachycardia (EAT) originating from low right atrium (RA) to identify the anatomic sites of these foci in children.

Methods

Twenty‐three consecutive pediatric patients (56% females, mean age 8.5 ± 2.5) with EAT originating from the low RA underwent detailed atrial endocardial activation mapping and radiofrequency ablation. PWM during EAT was analyzed using standard 12‐lead ECG in relation to successful ablation sites in RA.

Results

Ectopic atrial tachycardia originated from coronary sinus ostium (CSo) in 12 patients, nonseptal tricuspid annulus (TA) in five, lower crista terminalis (CT) in three and lower free wall in three. In lead V₁, PWM showed a positive pattern during EAT originating from CSo (8/12) 91.7% sensitivity, 100% specificity, 100% positive predictive value (PPV), 100% negative predictive value (NPV)]. A negative pattern was observed in EAT originating from lower free wall (1/3) and nonseptal TA (5/5) 50% sensitivity, 100% specificity, 100% PPV, 75% NPV], while isoelectric pattern was in EAT originating from lower CT (3/3) 100% sensitivity, 100% specificity, 100% PPV, 100% NPV]. In leads V₃–V₆, PWM showed a negative pattern in at least two consecutive leads during EAT from CSo (12/12), nonseptal TA (5/5) and lower free wall (3/3) while it was positive in EAT originating from lower CT (3/3) 100% sensitivity, 95% specificity, 75% PPV and 100% NPV].

Conclusions

P wave morphology in precordial leads can help differentiate the anatomic sites of EAT from lower RA with high PPVs and NPVs.