Abstract 12305: Exercise Capacity and Chronotropic Incompetence in Patients After Mitral Valve Surgery

IntroductionChronotropic incompetence (CI) is sometimes observed during exercise in patients who underwent cardiac surgery, however, little is known concerning the differences between patients with mitral valve (MV) and aortic valve (AV) surgery.HypothesisBecause the possibility exists that cardiac sympathetic nerves could be impaired by left atrium incision, we hypothesized that the incidence of CI was higher in patients with MV surgery (Mitral Valve Replacement and Mitral Valvuloplasty) as compared with those with AV surgery (Aortic Valve Replacement). And if so, which factor determines the exercise capacity of patients after MV surgery.MethodsWe performed cardiopulmonary exercise testing by ramp loading with ergometer exercise in total 52 patients who had undergone elective cardiac valve operation (19 patients with MV surgery, age 59.8 ± 10.2 years; 33 patients with AV surgery, age 63.5 ± 12.4 years). We analyzed chronotropic response index, peak oxygen uptake (peak VO2), peak oxygen pulse (peak VO2/HR), and blood hemoglobin concentration (Hb).ResultsThe value of chronotropic response index was significantly decreased in the patients with MV surgery compared with those with AV surgery (MV; 0.19±0.11 vs. AV; 0.40±0.18, p