ECHOCARDIOGRAPHIC IMAGING OF A BASKET CATHETER FOR MAPPING AND ABLATION OF VENTRICULAR-TACHYCARDIA IN PIGS

Our objective was to assess the feasibility and efficacy of the recent ly described left ventricular simultaneous deployment of a new multi-e lectrode mapping catheter and a standard radio-frequency ablation cath eter in pigs, with echocardiography monitoring and fluoroscopy guidanc e. Introduction and deployment of both catheters in five healthy anest hetized pigs were guided oh-line by fluoroscopy and monitored with tra nsthoracic echocardiography. Heart rate and femoral blood pressure wer e also continuously monitored. Both catheters were deployed for up to 5 hours. Three animals underwent three to five radio-frequency energy applications. Left ventricular dimensions obtained from long axis two- dimensional echocardiography imaging before and after basket-catheter deployment in the left ventricular cavity, were 3.9 +/- 0.3 versus 3.7 +/- 0.6 cm at end-diastole and 2.8 +/- 1.1 versus 2.6 +/- 0.8 cm at e nd-systole, respectively (mean +/- standard error of the mean, p > 0.0 5). Shortening fraction measured from long axis two-dimensional echoca rdiography images before and after catheter deployment was 28% +/- 10% versus 25% +/- 5%, respectively (mean +/- standard error of the mean, p > 0.05). Additional findings included the following: (1) good confo rmation of the multielectrode mapping catheter to the left ventricular dimensions during diastole; (2) absence of catheter-induced aortic an d/or mitral insufficiency, as well as left ventricular outflow tract o bstruction; (3) absence of damage to mitral and aortic valves or to th e left ventricular wall. Postmortem examination and hemodynamic measur ements confirmed these findings and showed only minor subendocardial h emorrhages; (4) radio-frequency energy application produced intracavit ary bubbles, which were demonstrable echocardiographically, enabling i dentification of the gross anatomic location of ablation sites. Echoca rdiography during simultaneous deployment of multi-electrode mapping c atheter and radio-frequency ablation catheters enables estimation of m echanical interaction with the left ventricle and detects interaction with myocardial/valvular function. During radio-frequency energy appli cation, bubble production may identify gross anatomic location of abla tion.