Right atrial isolation: a new surgical treatment for supraventricular tachycardia. II. Hemodynamic effects.

Surgical isolation of the body of the right atrium presents a unique hemodynamic situation in which the synchronous right atrial contraction (kick) is lost but the synchronous left atrial contraction is preserved. The hemodynamic effects of this procedure were evaluated by pacing at selected atrial sites postoperatively to simulate (1) sinus rhythm with a synchronous right atrial kick, (2) sinus rhythm without a synchronous right atrial kick, (3) right atrial tachycardia propagated to the entire heart (propagated right atrial tachycardia), and (4) right atrial tachycardia confined to the isolated right atrium with sinus rhythm in the rest of the heart (confined right atrial tachycardia). Hemodynamic data recorded under these four conditions showed that (1) during sinus rhythm, synchrony of right atrial contraction had no significant effect on any of the hemodynamic parameters studied and (2) conversion from propagated right atrial tachycardia to confined right atrial tachycardia resulted in an increase in mean arterial pressure (65 +/- 5 to 78 +/- 3 mm Hg, p less than 0.005) and stroke volume index (9 +/- 1 to 19 +/- 3 ml/beat/m2, p less than 0.005) with a decrease in left atrial pressure (9 +/- 2 to 5 +/- 1 mm Hg, p less than 0.05) and right atrial pressure (6 +/- 1 to 5 +/- 1 mm Hg, p less than 0.05). Moreover, cardiac hemodynamic performance remained within normal limits for up to 14 weeks. Thus the right atrial isolation procedure does not adversely affect cardiac hemodynamics despite the loss of synchronous right atrial contraction during sinus rhythm, and the procedure prevents hemodynamic deterioration during right atrial tachycardia.