\E Induction of Meandering Functional Reentrant Wave Front in Isolated Human Atrial Tissues

Abstract

Background The purpose of this study was to test the hypothesis that a single meandering functional reentrant wave front can result in rapid and irregular electrogram activity in human atrial tissues. Methods and Results The study used the explanted hearts of five human cardiac transplant recipients. Three right and two left atrial tissue samples, 3.4±0.3 mm thick, were excised and trimmed to 3.5×3.0 cm. The isolated atrium was placed endocardial surface down in a chamber with a 477 bipolar recording electrode array built into the bottom of the tissue bath. The interelectrode distance was 1.6 mm. The tissue was constantly superfused with 36.5°C oxygenated Tyrode’s solution at a rate of 10 mL/min. After eight baseline stimuli (S 1 ) delivered at 400- or 600-ms cycle length from the edge of the tissue, a single premature stimulus (S 2 ) was given at the center of the tissue to induce reentry. A total of nine episodes of reentry were induced with S 1 -S 2 coupling intervals of 232±29 ms (range, 190 to 290 ms) and an S 2 strength of 10±3 mA (range, 5 to 15 mA). In all samples, a single meandering reentrant wave front was induced, causing irregular and rapid bipolar electrogram activity. These wave fronts had a mean cycle length of 229±45 ms (160 to 290 ms) and persisted for 1.1±0.3 seconds (0.6 seconds to 2.5 seconds), or 5.2±1.4 (3 to 9) cycles, before spontaneous termination. Conclusions A single meandering functional reentrant wave front can be induced in human atrial tissues and produce rapid and irregular electrical activity.