Right Atrium–Dominant Single‐Loop Biatrial Tachycardia Mimicking Reverse Typical Atrial Flutter After Mitral Valve Repair via a Superior Transseptal Approach

Figures

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  FIGURE 1. Twelve‐lead electrocardiogram of clinical tachycardia. The electrocardiogram showed a flutter‐wave morphology resembling reverse typical AFL, with a biphasic flutter wave in lead V1.

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  FIGURE 2. Activation map of the RA during tachycardia from (A) the right anterior oblique view and (B) the left lateral view. RA activation mapping appeared to span nearly the entire TCL and demonstrated clockwise activation around the tricuspid annulus (TA), mimicking reverse typical AFL. The early‐meets‐late region and representative local electrograms recorded at the indicated sites are shown. Stars indicate the sites where entrainment pacing was performed, and the values show the difference between PPI and TCL. Yellow stars indicate sites where PPI‐TCL < 20 ms, while red stars indicate sites where PPI‐TCL ≥ 20 ms. PPI, post‐pacing interval; RA, right atrium; TA, tricuspid annulus; TCL, tachycardia cycle length.

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  FIGURE 3. Voltage map of (A) RA from the left lateral view and (B) LA from anteroposterior view during tachycardia. Representative local electrograms recorded at the indicated sites are shown. A long transverse low‐voltage area (local voltage < 0.1 mV) extended from the RA septum across the fossa ovalis toward the RPV region, with a corresponding low‐voltage area in the opposing anteroseptal MA, consistent with the surgical septal incision. LA, left atrium; MA, mitral annulus; RA, right atrium; RPV, right pulmonary vein; TA, tricuspid annulus.

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  FIGURE 4. Activation map of RA from the left anterior oblique view and LA from the anteroposterior view during tachycardia. The activation maps demonstrate an RA‐dominant single‐loop biatrial tachycardia predominantly rotating around the TA, involving only a limited portion of the LA septum. LA activation covered 94 ms, corresponding to approximately 33% of the 280‐ms tachycardia cycle length, and no activation gap remained after completion of the biatrial activation map. Local electrograms from representative sites along the proposed tachycardia circuit are shown. Stars indicate the sites where entrainment pacing was performed, and the values show the difference between PPI and TCL. Yellow stars indicate sites where PPI‐TCL < 20 ms, while red stars indicate sites where PPI‐TCL ≥ 20 ms. LA, left atrium; MA, mitral annulus; PPI, post‐pacing interval; RA, right atrium; TA, tricuspid annulus; TCL, tachycardia cycle length.