title: Ventilatory anaerobic threshold before and after cardiac valve surgery.
abstract: The purpose of this study was to objectively assess exercise tolerance before and after cardiac valve surgery by using an objectively determined ventilatory anaerobic threshold (AT). Nine patients (mean age: 38.2 +/- 8.1 years) with predominantly mitral regurgitant lesions were studied by a symptomatic maximal treadmill exercise test which included a determination of AT. The mean lengths of time from preoperative exercise testing to cardiac surgery, and from surgery to postoperative exercise testing were 5.9 +/- 4.0 and 12.1 +/- 8.3 months, respectively. The determination of AT on data plots was performed after blinding to patient identification and pre- vs postoperative status. After surgery, the clinical symptoms and NYHA class improved significantly with a decrease in the cardio-thoracic ratio and echocardiographic diastolic dimensions. The mean peak VO2 (ml/kg/min) increased significantly from 20.2 +/- 7.1 to 29.7 +/- 7.9 (p < 0.01). Together with these changes, AT (ml/kg/min in VO2) increased from a mean of 14.8 +/- 4.8 to 22.8 +/- 5.5 (p < 0.01). In conclusion, symptomatic improvement and an increase in peak oxygen uptake after cardiac valve surgery were accompanied by a significant increase in the objectively determined AT. AT determined in a blind manner provides an objective means of evaluating exercise tolerance when a double-blind intervention cannot be performed.
authors: Department of Cardiovascular Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
authors: H
authors: H
authors: Nishijima
authors: I
authors: I
authors: Sato
authors: N
authors: N
authors: Matsumura
authors: T
authors: T
authors: Mikami
authors: M
authors: M
authors: Nishida
authors: K
authors: K
authors: Yonezawa
authors: H
authors: H
authors: Yasuda
mesh_terms: D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology*; D001794:Blood Pressure; D004452:Echocardiography; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006350:Heart Valve Prosthesis; D006351:Heart Valves / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D014692:Ventilation-Perfusion Ratio