Abstract 19084: Novel Method Using Intracardiac Myocardial Elastography Provides Real-time Assessment of Right and Left Atrial Radiofrequency Ablation Lesions in Humans
Introduction: Radiofrequency (RF) ablation is an effective method for treatment of cardiac arrhythmias; however, current assessment of RF lesion formation by measuring impedance changes, electrogram dimunition, power and catheter temperature are indirect and may be inaccurate. We present a novel, imaging modality, myocardial elastography (ME), which when used in adjunct with intracardiac echocardiography (ICE) may provide real-time assessment of RF lesion formation, and changes in tissue mechanics after lesion delivery.
Methods: 7 patients (mean age 64.3 +/- 14 years) underwent imaging of their left atrium with a 5.8-MHz ICE probe before and after RF ablation with an irrigated catheter at high frame rates (1200 Hz). The channel data was acquired on a clinical ultrasound system, image reconstruction and motion tracking were performed, and cumulative axial strains were obtained from displacement estimations. The location of the ablation lesion was confirmed using ICE imaging, electroanatomic mapping and fluoroscopy. ICE images were acquired before and after 7 RF ablations (mean power of 31 ± 3 W, mean of 38 ± 14 secs, mean impedance of 112 ± 5 Ω, catheter temperature of 31 ± 3 degrees Celsius). One ICE image was obtained as a control with the ablation catheter apposed to the atrial myocardium without RF delivery.
Results: When RF was not used, ME showed a mean absolute strain of 15.1±5.1 % before, and 16.7±7.5 % (p=NS) after catheter positioning, thus demonstrating no difference in strain due to catheter contact. ME showed a mean absolute strain of 17.1 ± 9.7 % before and 8.3 ± 6.3 % after ablation (p<0.05). This demonstrates that ME can detect changes in mechanical deformation due to RF, and that ablated regions have lower strains. After RF delivery, changes in strain were apparent when reviewed by three blinded independent operators.
Conclusions: This pilot study shows that ME, a novel imaging modality, may be used during ablation for real-time assessment of cardiac mechanical deformation and functional myocardial changes due to RF lesion delivery.
Author Disclosures: E. Wan: None. J. Grondin: None. A. Biviano: None. W. Whang: None. A. Gambhir: None. E. Konofagou: None. H. Garan: None.
- © 2014 by American Heart Association, Inc.