Patients with chronic heart failure exhibited a significantly smaller absolute increase in heart rate during 50 W of exercise compared to normal controls (22 vs 38 min-1, P<0.05).
Cross-Sectional (n=20)
Does core temperature regulation differ during exercise in chronic heart failure patients compared to normal subjects, and does it relate to chronotropic incompetence?
Chronic heart failure patients demonstrate abnormal core temperature regulation during exercise, which may contribute to chronotropic incompetence.
Absolute Event Rate: 22% vs 38%
p-value: p=<0.05
The relationship between two abnormalities of exercise physiology in chronic heart failure patients was investigated: chronotropic incompetence and decrease in core temperature. While at rest, 13 heart failure patients had an average sinus heart rate that was significantly higher than seven normals (92 +/- 13 vs. 82 +/- 10 min-1, P less than 0.05). However, during exercise, the trend of increase in sinus heart rate as a function of work load and O2 uptake was significantly greater in normals compared with heart failure (P less than 0.05), and the absolute increase in heart rate at 50 W of cycle ergometry was larger in normals compared with heart failure (38 +/- 17 vs. 22 +/- 13 min-1, P less than 0.05). Differences in core temperature regulation were also observed. In the normals, core temperature increased from 37.13 +/- 0.33 degrees C at rest to 37.37 +/- 0.31 degrees C at 50 W of exercise (P less than 0.01). In the heart failure patients, core temperature decreased from 36.99 +/- 0.33 degrees C at rest to 36.66 +/- 0.39 degrees C at 50 W of exercise (P less than 0.01). As expected, significant differences in hemodynamic and gas exchange variables were observed between the normals and the heart failure patients both at rest and during exercise. A multiple linear regression analysis was performed of heart rate changes as the dependent variable and thermoregulatory and hemodynamic changes as the independent variables to test for their influence on heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)
Stanley A. Rubin (Fri,) conducted a cross-sectional in Chronic heart failure (n=20). Chronic heart failure vs. Normal controls was evaluated on Absolute increase in heart rate at 50 W of cycle ergometry (p=<0.05). Patients with chronic heart failure exhibited a significantly smaller absolute increase in heart rate during 50 W of exercise compared to normal controls (22 vs 38 min-1, P<0.05).