A rare focal atrial tachycardia arising from the proximal middle cardiac vein: a case report.

Background: Focal atrial tachycardia (FAT) always originates from atrium specific sites and can be successfully cured by radiofrequency (RF) ablation. However, the middle cardiac vein (MCV) is a rare site of focal atrial tachycardia. Herein, we present a case of a 20-year-old young woman with FAT. Electrophysiological examination showed FAT arising from the proximal middle cardiac vein (pMCV), and successful RF ablation was applied with a low power and short-ablation.

Case Presentation: A 20-year-old woman with no structural heart disease suffered recurrent supraventricular tachycardia for 1 year. Physical examination, laboratory studies and the echocardiography results of this patient were normal. A 12-lead electrocardiogram (ECG) showed a narrow QRS and long RP tachycardia which was always triggered by a sinus rhythm. The patient underwent an electrophysiological study and found the earliest activation was in the proximal MCV (pMCV). After a low power and short-ablation, AT was terminated and noninducible by programmed pacing with or without isoproterenol infusion.

Conclusion: This case presented a rare case of FAT arising from the pMCV. We demonstrate that low power and short-ablation are effective in AT arising from specific areas such as the coronary sinus ostium and pMCV.