Fig. 5

Invasive electrophysiological study. A The order of atrial activation in the patient’s right atrium, characterized by counterclockwise atrial flutter. B Atrial flutter accompanied by a large low-voltage area in the right atrium. C, D Successful restoration of sinus rhythm following ablation of atrial flutter. The arrows in C and D indicate the direction of contact force applied by the radiofrequency ablation catheter on the myocardium