[Electrophysiological characterization and efficacy of radiofrequency ablation of focal atrial tachycardia originating from the left atrial appendage].

OBJECTIVE

To analyze the electrophysiological characteristics and efficacy of radiofrequency catheter ablation (RFA) of focal atrial tachycardia (AT) originating from the left atrial appendage (LAA).

METHODS

Electrophysiologic study and RFA were performed in 9 patients (4 female) with focal AT originating from the LAA. Atrial appendage angiography was performed to identify the origin of AT. P waves were classified as negative, positive, isoelectric, or biphasic.

RESULTS

The mean age was (21 +/- 9) years. AT occurred spontaneously or was induced by isoproterenol infusion rather than programmed extrastimulation and burst atrial pacing. A characteristic P-wave morphology and endocardial activation pattern were observed. Positive P-wave in inferior leads was seen in all patients, upright or biphasic (+/-) component P wave was observed in lead V1, isoelectric component or an upright component P wave with low amplitude ( < 0.1 mV) was seen in lead V2-V6. Earliest endocardial activity occurred at the distal coronary sinus (CS) in all patients. The earliest endocardial activation at the successful RFA site occurred (36.7 +/- 7.9) ms before the onset of P wave. RFA was successful in all 9 patients immediately post procedure. AT reoccurred in 2 patients within 1 month post RFA and AT disappeared post the 2nd-RFA. AT reoccurred in 1 patient and terminated after the 3rd RFA. At the final follow-up (12 +/ 5) months, all 9 patients were free of arrhythmias without antiarrhythmic drugs.

CONCLUSIONS

The LAA is an uncommon site of origin for focal AT. The characteristic P wave and activation timing are suggestive for focal AT originating from the LAA. LAA focal ablation is safe and effective for patients with focal AT originating from the LAA.