Study of cardiopulmonary adaptation during exercise in patients after extracardiac conduit total cavopulmonary connection

Abstract

To study cardiopulmonary physiology during exercise in patients after extracardiac total cavopulmonary connection (ECTCPC). Twenty-six patients were studied after ECTCPC by exercise testing with bicycle treadmill protocol. Heart rate (HR), blood pressure (BP), respiratory frequency (RF) and pulse oxygen saturation (SpO(2)) were measured continuously; twenty-six patients suffered from Fallot 4 underwent biventricular repair were also studied as control group. In ECTCPC group, HR, BP, SpO(2) and RF all increased with exercise below 3 grade; when exceed 4 grade, BP, SpO(2) decreased and RF kept increasing. Compared with control group, HR, RF were higher (t = 2.13, P < 0.05; t = 2.31, P < 0.05), SpO(2) was lower (t = 2.46, P < 0.05) under the quiescent condition; When exceed 3 grade, HR, BP, SpO(2) decreased more significantly, but RF increased continuously. In fenestration group after ECTCPC, HR reached the top at 5 grades, but in group without fenestration it reached the top at 3 grades; In the whole process of exercising, RF kept higher and SpO(2) kept lower in fenestration group. The ECTCPC patients showed obviously exercise limitation. Totally bypass of sinoatrial node in this operation may have some adverse effects on the integer regulation of HR.