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

Objective To study cardiopulmonary physiology during exercise in patients after extracardiac total cavopulmonary connection (ECTCPC).Methods 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 biventrieular repair were also studied as control group.Results 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,P0.05 ),SpO_2 was lower(t=2.46,P0.05) 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. Conclusions 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.