A case of unstable atrial tachycardia due to intermittent firing focus from the right inferior pulmonary vein following cavo-tricuspid isthmus dependent atrial flutter

This case report describes a patient with incessant atrial tachycardia (AT) who underwent catheter ablation. During electrophysiological study, the stable AT circuit spontaneously shifted to unstable AT due to intermittent frequent firing from the right inferior pulmonary vein (PV) after termination of cavo-tricuspid isthmus dependent atrial flutter. A macroreentrant AT circuit was observed after electrical isolation of right inferior PV potentials. These findings suggest that the presence of rapid activated firing is likely to be associated with the development of instability in the AT circuit. This may lead to a greater understanding of the physiology of atrial tachyarrhythmia as a simple clinical model.