Local impedance-guided ablation and ultra-high density mapping versus conventional or contact force-guided ablation with mapping for treatment of cavotricuspid isthmus dependent atrial flutter

Figures

• 

  Fig. 1. Graphs of ablation metric outcomesGraphs showing overall mean ablation metrics (panels A–D) and second pass ablation metrics (panels E–H). Dots and bars represent mean and standard deviation respectively.A. Total radiofrequency ablation time. B. Time taken from first application of radiofrequency ablation to confirmation of bi-directional cavotricuspid isthmus block. C. Number of lesions required to achieve bi-directional block. D. Mean duration of radiofrequency for each lesion. E. Total second-pass radiofrequency ablation time. F. Time taken from start of second-pass ablation to confirmation of bi-directional cavotricuspid isthmus block. G. Number of lesions in the second-pass lesion set. H. Mean duration of radiofrequency for each lesion in the second-pass lesion set. ∗ = p < 0.05, ∗∗ = p < 0.005, ns = non-significant (p > 0.05) Conv, conventional; CF, contact force; LI, local impedance.

• 

  Fig. 2. Simplified diagram of the cavotricuspid isthmus showing sites of breakthrough following first-pass ablation in right anterior oblique orientationThe isthmus has been divided into three segments, based on proximity to TV, IVC or the mid-portion. Red points represent breakthrough across the line, green point shows epicardial-endocardial breakthrough lateral to line TVA, tricuspid valve annulus; IVC, inferior vena cava; CS, coronary sinus ostium; CTI, cavotricuspid isthmus.

• 

  Fig. 3. Ultra-high density 3-dimensional electroanatomic right atrial maps of the cavotricuspid isthmus (CTI) ablation line in a patient from the local impedance cohort, in left anterior oblique caudal view. There is breakthrough across the tricuspid aspect of the ablation line (panel A, red asterisk). Targeted ablation at this point resulted in bi-directional CTI block as shown in panel B. Timing is shown from the pacing electrode in the proximal coronary sinus and is displayed at the same timing in both maps; the activation wavefront is between 96 ms and 106 ms after pacing. TVA, tricuspid valve annulus; IVC, inferior vena cava; Lat RA, lateral right atrium.

• 

  Fig. 4. Ultra-high density 3-dimensional electroanatomic right atrial maps of the cavotricuspid isthmus (CTI) ablation line in a patient from the local impedance cohort, in left anterior oblique caudal view. There is epicardial-endocardial breakthrough 10.4 mm lateral to the cavotricuspid isthmus (CTI) ablation line, displaying radial spread (panel A, red asterisk). Targeted ablation at this point resulted in bi-directional CTI conduction block as shown in panel B. Timing is shown from the pacing electrode in the coronary sinus and is displayed at the same timing in both maps; the activation wavefront is between 94 ms and 104 ms after pacing. TVA, tricuspid valve annulus; IVC, inferior vena cava; Lat RA, lateral right atrium.