A Special Muscle Fiber Surviving After Septal Line Ablation of Mitral‐Isthmus Dependent Atrial Flutter

Figures

• 

  FIGURE 1. (A) Activation maps recorded during the mitral isthmus (MI)‐dependent atrial flutter (AFL) following the septal line ablation (left panels) and during pacing from the proximal coronary sinus (CS) after the successful ablation (right panels). The white arrow indicates preferential conduction through the conduction gap toward the roof. AP, antero‐posterior; LAO, left anterior oblique; LAT, local activation time; L(R)IPV, left (right) inferior PV; L(R)SPV, left (right) superior PV; MA, mitral annulus. (B) Activation map exhibiting the ablation sites (left panel) and cardiac tracings recorded at the site of ablation (white dotted circle) initially prolonging the AFL cycle length (right panel). The yellow dotted circles indicate the sites of radiofrequency applications delivered at the conduction gap after the failed supero‐septal line ablation. The white and black dotted circles indicate the sites of additional radiofrequency applications which prolonged and did not prolong the AFL cycle length, respectively. The white arrow indicates the course of the linear ablation which gradually prolonged the AFL cycle length. The white solid circle indicates the site of radiofrequency…

• 

  FIGURE 2. Cardiac tracings exhibiting the successful ablation. The abbreviations are as in Figure 1.

• 

  FIGURE 3. Three‐dimensional computed tomography images and electroanatomic map exhibiting the relationship between Bachmann's bundle (BB) and the ablation lines (upper panels) and the histological image exhibiting the relationship between the BB and the septoatrial bundle (SAB) (lower panel). The red solid and white dotted lines in the upper panel indicate the supero‐septal ablation line (SSL) and a linear ablation perpendicular to the supero‐septal ablation line delivered from the conduction gap toward the BB. The black dotted circle in the lower panel indicates an area where the SAB connects to the BB. Image Courtesy of The Amara Yad Project‐McAlpine Collection. LA, left atrium; LAA, left atrial appendage; SVC, superior vena cava.