Differentiation between epicardial and endocardial conduction gaps for left atrial posterior wall isolation using peak frequency annotation algorithm

Figures

• 

  Figure 1. Electroanatomic map and residual electrograms in the left atrial posterior wall after linear left atrial roof and floor ablations. A: An Omnipolar voltage map generated using an annotation algorithm employing absolute dV/dt. The yellow lines and white arrows indicate annotated sites in the local electrograms. B: Map constructed using Omnipolar Technology Near Field (OTNF, Abbott, St. Paul, MN) annotation algorithm. The red lines and white arrows indicate annotated sites. The OTNF algorithm annotated sharp potentials slightly later than those annotated using the absolute dV/dt algorithm. In the voltage map, purple indicates regions with an amplitude of 0.5 mV or more, and gray indicates regions with <0.05 mV.

• 

  Figure 2. Emphasis maps varying a threshold in peak frequency value. Emphasis maps were constructed using the peak frequency and Omnipolar voltage maps. The area with a peak frequency value above the threshold is highlighted. The yellow arrow indicates the residual conduction, where left atrial posterior wall isolation was achieved after additional radiofrequency applications.

• 

  Figure 3. The electrograms recorded in the left atrial posterior wall (LAPW) during the additional radiofrequency (RF) application at the center of the left atrial (LA) floor line. A:Left panel: Emphasis map with a threshold at a peak frequency of >200 Hz. The yellow arrow on the central LA floor indicates the successful radiofrequency catheter ablation (RFCA) site for LAPW isolation. The grid catheter was placed in the LAPW during the RF application. The red tags represent RFCA points on the bilateral extended-encircling pulmonary vein isolation, LA roof, and floor. Right panel: The difference in annotation timing (yellow lines and white arrows) between using the absolute dV/dt and the Omnipolar Technology Near Field (OTNF, Abbott, St. Paul, MN) algorithms at the successful ablation site. B: Electrograms were recorded in the LAPW using a grid catheter during the pacing of the distal coronary sinus. After RF application at the presumed gap site for 7 seconds, the sharp components of the electrograms were delayed (red arrows) and finally disappeared after 12 seconds. Electrograms with low peak frequency retained in the LAPW box thereafter (blue arrowheads). CS = coronary sinus.