BACKGROUND: Detailed information about the topographic distribution of focal left atrial tachycardias (FLATs) is limited. METHODS AND RESULTS: A total of 143 atrial tachycardia (AT) foci were successfully ablated in 140 patients (56 men, mean age 44.6+/-17.9 years). In 36.4% (52/143 ATs), a left atrial (LA) origin of the tachycardia was identified from the site of successful ablation. In 46% (24/52) of FLATs, the site of origin (SO) was near the ostium of a pulmonary vein (PV), and in 36.5% (19/52), the SO was near the mitral annulus (MA). In the remaining ATs, the SO was in the left atrial appendage (LAA), septum, LA roof and inside the coronary sinus. P waves in V1 showed biphasic morphology with an initial negative component in most FLATs originating from the septal MA, superior MA, and LAA. However, P waves in V1 were positive in all patients with FLATs originating from PVs. Negative P waves in aVL were always observed in FLATs originating from left PVs. The mean cycle length of FLATs from PVs was significantly shorter than that from the MA. CONCLUSION: Knowledge of the topographic distribution, P-wave morphology, and tachycardia cycle length facilitates successful ablation of FLATs.
BACKGROUND: Detailed information about the topographic distribution of focal left atrial tachycardias (FLATs) is limited. METHODS AND RESULTS: A total of 143 atrial tachycardia (AT) foci were successfully ablated in 140 patients (56 men, mean age 44.6+/-17.9 years). In 36.4% (52/143 ATs), a left atrial (LA) origin of the tachycardia was identified from the site of successful ablation. In 46% (24/52) of FLATs, the site of origin (SO) was near the ostium of a pulmonary vein (PV), and in 36.5% (19/52), the SO was near the mitral annulus (MA). In the remaining ATs, the SO was in the left atrial appendage (LAA), septum, LA roof and inside the coronary sinus. P waves in V1 showed biphasic morphology with an initial negative component in most FLATs originating from the septal MA, superior MA, and LAA. However, P waves in V1 were positive in all patients with FLATs originating from PVs. Negative P waves in aVL were always observed in FLATs originating from left PVs. The mean cycle length of FLATs from PVs was significantly shorter than that from the MA. CONCLUSION: Knowledge of the topographic distribution, P-wave morphology, and tachycardia cycle length facilitates successful ablation of FLATs.