Intracardiac and surface ECG recordings during electrophysiologic study and radiofrequency catheter ablation of typical atrial flutter

Three surface ECG leads (I, aVF, V1) and intracardiac recordings from the high right atrium (HRA), a mapping catheter in the isthmus between the tricuspid valve and inferior vena cava (TV-IVC) (HBE1-2), eight recordings from a catheter extending from the lateral right atrial wall through the TV-IVC isthmus and into the ostium of the coronary sinus (CS15-1 to CS1-2), and right ventricular apex (RVA3-4) in a patient with typical atrial flutter. The tip of the mapping catheter was initially positioned on the tricuspid annulus, and then dragged through the TV-IVC isthmus to the ostium of the IVC during RF application; atrial flutter terminated. Note that the atrial activation (A) blocks between CS7-8 and CS5-6, which on fluoroscopy corresponded to the position of the mapping catheter.