ANALYSIS OF IMPAIRED EXERCISE CAPACITY IN PATIENTS WITH CIRRHOSIS

Exercise limitation in cirrhosis is typically attributed to a cirrhoti c myopathy (without impaired oxygen utilization) and/or a cardiac chro notropic dysfunction. We performed symptom-limited cardiopulmonary exe rcise testing in 19 cirrhotics without confounding variables (cardiopu lmonary disease, beta blockade, anemia, smoking). Twelve concurrently exercised patients without cirrhosis and with normal resting pulmonary function were controls. Oxygen consumption ((V) ovet dot (O2),) at pe ak exercise, at anaerobic threshold ((V) over dot (O2)-AT), work rate (WR), and heart rate (HR) were measured. Cirrhotics had significantly lower peak WR (73 +/- 4 vs 107 +/- 7% predicted, p < 0.001), (V) over dot (O2) (72 +/- vs 98 +/- 5% predicted, P < 0.001), (V) over dot (O2) -AT (53 +/- 4 vs 71 +/- 5% predicted peak (V) over dot (O2) P < 0.01), HR (83 +/- 2 vs 91 +/- 2% predicted. P < 0.01) and were more likely t o have chronotropic dysfunction (peak HR < 85% predicted). Six cirrhot ics had normal aerobic capacity (peak (V) over dot (O2) > 80% predicte d), while 13 were abnormal. The abnormals had an earlier AT (46 +/- 2 vs 67 +/- 3% predicted peak (V) over dot (O2), P < 0.05) but no differ ence in peak HR percent predicted was found. In conclusion, two thirds of cirrhotics, without confounding factors, have significantly reduce d aerobic capacity. Cirrhotic myopathy (without impaired O-2 utilizati on) and cardiac chronotropic dysfunction do not adequately account for the observed decrease in aerobic capacity.