Abstract 2738: Image Integration Using Intracardiac Ultrasound for Scar Mapping and Intervention of Ventricular Tachycardia
Background. Ventricular tachycardia (VT) ablation is an effective means to reduce ICD shocks. Intracardiac ultrasound can accurately visualize all left ventricular wall segments and quantify their function from the right atrium and ventricle. We hypothesize that intracardiac ultrasound functional quantification of wall segments with 3D image integration should provide the necessary anatomic guide to allow substrate guided ventricular tachycardia (VT) ablation.
Methods. Eighteen patients underwent VT ablation with real time intracardiac ultrasound mapping from the right atrium and ventricle with 3D image reconstruction of scar segments. The left ventricle was also scar mapped by traditional electroanatomic mapping for comparison. Images from these two scar mapping techniques were compared to each other as well as to a preprocedure transthoracic echocardiogram. Ultrasound segments were considered scared by ultrasound if they received a wall score ≥3.
Results. The average age was 65±12 years and 12 (67%) were male. Fifteen of these patients (83%) had ischemic cardiomyopathy. All had received an ICD shock to terminate ventricular tachycardia and have failed 1.4±0.6 antiarrhythmic drugs. The patients were followed for 127±33 days. Two patients (12%) had recurrence of their clinical VT (1 remained on an antiarrhythmic medication, the other had a repeat ablation). No periprocedural or long-term adverse events occurred. A total of 288 wall segments were analyzed. All three modalities were concordant in scar identification in 226 (78%) segments. The ICE segments correlated with the electroanatomic map in 248 (86%) segments versus 229 (80%) that correlated with transthoracic echocardiography and electroanatomic mapping (p = 0.046). Specifically, the intracardiac ultrasound wall motion scores were closer to the electroanatomic mapping in the basal and mid segments.
Conclusion. These data demonstrate that real time intracardiac ultrasound images provide accurate chamber geometries and scar boundaries of the left ventricle. These scar borders were much more accurate than transthoracic echocardiography scar boundaries. These data demonstrate the initial feasibility of this guidance system for ablation in patients with VT.