MULTIPOLAR ENDOCARDIAL MAPPING OF THE RIGHT ATRIUM DURING CARDIAC-CATHETERIZATION - DESCRIPTION OF A NEW TECHNIQUE

Objectives. Using a new mapping system that allows the simultaneous ac quisition of data from 25 right atrial bipolar electrodes during cardi ac catheterization, we mapped normal sinus rhythm and atrial reentrant tachycardia in 24 sheep (20 to 49 kg) and 7 pigs (25 to 35 kg). Backg round. Rapid, high resolution mapping during cardiac catheterization m ay shorten ablation procedures and permit ablation of otherwise refrac tory arrhythmias. Methods. A flexible, elliptic, basket-shaped recordi ng catheter has five spokes, each with 10 electrodes arranged as 5 bip olar pairs. Catheter shape, electrode spacing and introduction techniq ue were modified in response to the results of experiments in the firs t 23 animals. In the most recent eight animals, retraction of a string attached to the distal tip distended the basket, providing safe tissu e contact. Filtered (30 to 250 Hz) bipolar recordings from all 25 elec trode pairs, as well as a surface electrocardiogram, were recorded and digitized at 1,000 Hz using custom software. An activation map was di gitally constructed and superimposed on anteroposterior and lateral fl uoroscopic catheter images. Bipolar recordings were made in normal sin us rhythm (31 animals), with adequate signals recorded from >95% Of el ectrode pairs. Rapid burst pacing and intentional right atrial air emb olus (30 to 50 ml) induced sustained atrial reentrant tachycardia in f ive animals, which was also adequately recorded. Results. Catheter pos itioning and complete atrial mapping required <10 min after venous acc ess in the most recent eight experiments. The catheter was left in pos ition for up to 4 h. Postmortem evaluation revealed minor superficial abrasion of the venae cavae or right atrial endocardium in six animals and moderate abrasion in two. No other damage was observed. Conclusio ns. This new system may ultimately assist in mapping simple or complex atrial arrhythmias during cardiac catheterization.