Background: Radiofrequency catheter ablation of ectopic atrial tachycardia(EAT) has merged as the primary therapeutic option. Three-dimensional mapping system(CARTO짰) has been introduced with the potential to facilitate mapping of complex atrial tachycardia. We report early experience of electroanatomical mapping guided catheter ablation for EAT. Methods and Results: Electroanatomical mapping of the atria was done in five patients(2 males, 39.6짹18.37 years) during atrial tachycardia. Average duration of symptoms was 96 months. Two patients had sinoatrial reentrant tachycardia(SART) and three had atrial tachycardia originating from the right superior pulmonic vein. Two patients with SART had concealed bypass tracts in the left side. Acute procedural success was 100%. One patient with EAT had a transient total pulmonic venous spasm after the procedure. One case of SART recurred at a mean follow up of 5.12 months. Other results are as follows: Conclusion: Three-dimensional electroanatomical mapping provides an efficacious guide for localization of the focal origin of atrial tachycardia. It allows accurate renavigation to the site of earliest activation, thereby guiding successful ablation of the foci in atrial tachycardias.

	Tachy	Activation time		Map time		No of point		Volume(cc)		No of application
	CL(msec)	RA	LA	RA	LA	RA	LA	RA	LA	RA	LA
EAT 1	220	102	104	24	11	62	45	45.27	21.52	2	2
EAT 2	232	110	95	39	48	107	76	64.47	57.57	3	11
EAT 3	385	97	99	30	50	77	80	126.29	79.74	1	9
SART 1	412	124	.	122	.	218	.	112.74	.	4	.
SART 2	440	92	.	25	.	117	.	56.28	.	3	.
CL: cycle length, Scale of activation time:msec, Scale of map time: minutes.