Safety and efficacy of percutaneous endocardial mapping in sheep heart using a multi-electrode basket-shaped catheter

Detailed endocardial catheter mapping to explore cardiac activation patterns is usually carried out with the use of single point catheters. This method suffers from long procedural times and non-optimal resolution due to the limited number of electrodes. In order to localize endocardial electrical activation accurately, multipolar electrode catheter mapping with improved resolution is mandatory. A total of 9 sheep were studied with a newly developed, basket shaped, 8.5 F high-density multipolar catheter consisting of 8 equidistant, collapsible metallic arms, each containing 4 bipolar electrodes. Three of the arms contain radiopaque markers at different levels to determine the spatial orientation of the basket when deployed in the left ventricle. The mapping catheter, integrated with a newly developed computerized mapping system, could be successfully inserted and deployed in all sheep within 15 minutes and without hemodynamic interference. The latter was demonstrated by measuring left ventricular function before and after basket insertion with the use of a conductance catheter. Appropriate electrode-endocardial contact was demonstrated by successful bipolar pacing (2 and 5 mA) in 88% of the electrodes. High quality electrograms were obtained from 29 of the 32 mapping electrodes. Color-coded activation maps were reconstructed during both sinus rhythm and pacing. Postmortem examination of the hearts revealed no catheter-induced trauma. The novel basket shaped multi-electrode catheter facilitates safe, first and accurate endocardial mapping of electrical activity in the left ventricle during sinus rhythm and during pacing in a sheep model.