MULTIPOLAR ENDOCARDIAL MAPPING OF THE RIGHT HEART USING A BASKET CATHETER - ACUTE AND CHRONIC ANIMAL STUDIES

TRIEDMAN, J.K., ET AL.: Multipolar Endocardial Mapping of the Right He art Using a Basket Catheter: Acute and Chronic Animal Studies, The dev elopment of catheter-based ablative techniques for primary atrial and ventricular arrhythmias is likely to be assisted by improved technique s for systematic endocardial activation sequence mapping. RA mapping u sing a multielectrode basket catheter has been shown to be feasible wi th minimal acute toxicity in a prior study. The objectives of the curr ent study are to investigate: (2) the utility of the basket catheter f or mapping RV activation; and (2) the evolution of acute endocardial l esions produced by basket catheter use in both the KA and RV over 4-8 weeks time. A flexible, 5-spoke basket catheter bearing 25 electrode p airs was placed in the RA (n = 9) or the RV (n = 13) in 22 juvenile sh eep (22-56 kg). The catheter was deployed for 0.1-4.1 hr (RA) and 0.3- 3.9 hr (RV). In 20 of these 22 animals, 32 recordings were made of fil tered (30-250 Hz) bipolar electrograms and surface EGG. Electrograms w ere timed and used to construct activation sequences based on a schema tic of catheter geometry. Hearts were examined either acutely (4 RA an d 9 RV studies) or 4-8 weeks after the procedure (5 RA and 4 RV studie s). One animal undergoing RA placement had an air embolism resulting i n cardiac arrest immediately prior to basket placement; all other anim als were stable during placement. RA electrograms of sufficient qualit y to determine activation time were recorded from 82% of pairs in RA m aps, and RV electrograms from 89% of pairs in RV maps. Mean activation sequence duration in RV was 16 ms versus 47 ms in RA (P < 0.0001), ma king construction of RV maps more difficult. Acute postmortem studies of RV placement revealed a silent apical RV puncture in one animal. Su perficial abrasion or ecchymosis of RV endocardium and/or tricuspid va lve were noted in six animals. Postmortem exams in both RA and RV chro nic studies showed healed endocardial lesions, with only superficial s carring. Rapid RV activation mapping using a basket catheter is feasib le, but requires precision recording techniques. Endocardial abrasions produced in lambs both by RA and RV placement of the catheter are hea led in ( 4-8 weeks, with trivial residua. The multielectrode basket ca theter may be applicable to the mapping of tachycardias originating in or involving the right ventricle.