INDUCTION OF MEANDERING FUNCTIONAL REENTRANT WAVE-FRONT IN ISOLATED HUMAN ATRIAL TISSUES

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 a nd Results The study used the explanted hearts of five human cardiac t ransplant recipients. Three right and two left atrial tissue samples, 3.4+/-0.3 mm thick, were excised and trimmed to 3.5x3.0 cm. The isolat ed 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 constantl y superfused with 36.5 degrees C oxygenated Tyrode's solution at a rat e of 10 mL/min. After eight baseline stimuli (S-1) delivered at 400- o r 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 coupli ng 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 22 9+/-45 ms (160 to 290 ms) and persisted for 1.1+/-0.3 seconds (0.6 sec onds to 2.5 seconds), or 5.2+/-1.4 (3 to 9) cycles, before spontaneous termination. Conclusions A single meandering functional reentrant wav e front can be induced in human atrial tissues and produce rapid and i rregular electrical activity.