Single-loop biatrial tachycardia mimicking typical atrial flutter in a patient without a history of cardiac surgery or ablation

Figure 1. Twelve-lead electrocardiogram of clinical tachycardia.

Figure 2. Activation and voltage map of the RA during tachycardia. A: Activation map during tachycardia (left anterior oblique view). The excitation propagates in a craniocaudal direction along the RA lateral wall, but a conduction barrier exists at the 3-o’clock position of the TVA. (The lower threshold for “early meets late” was set to 25%.) In addition, mapping of the RA alone could acquire only 198 ms worth of points (60% of TCL), but could not account for the entire TCL. B: Voltage map during tachycardia and local potentials (L-R view). Spontaneous scarring (local potential voltage <0.05mV) was located traversing from the TVA to the septal and posterior RA. RA = right atrium; TCL = tachycardia cycle length; TVA = tricuspid valve annulus.

Figure 3. Activation map of right and left atrium. A: Activation map of both atria from left anterior oblique view. B: Posterior view. Star marks indicate the sites where entrainment pacing was performed, and the values show the difference between PPI and TCL. Yellow star marks indicate sites where PPI-TCL <20ms, while red star marks indicate sites where PPI-TCL ≥20ms. The pacing sites in the proximal CS and the anterior-septal LA are indicated with asterisks, corresponding to the site in Supplemental Figure 1. These Ripple maps are available in the Supplemental Videos 1 and 2. CS = coronary sinus; LA = left atrium; PPI = post-pacing interval.

Supplemental Figure 1.