Article

Exercise intensity is a particularly important determinant of
physiological responses to exercise training in patients with acute myocardial
infarction. Heart rate (HR) is commonly used as a practical way of prescribing
and monitoring exercise as specific intensities based on a linear relationship
between the percentage of maximum HR (%HRmax) and the percentage of maximum
oxygen consumption (%VO2max) regardless of age, gender,
or exercise mode.
OBJECTIVE: To examine the change in variability in the correlation between %HRmax
and %VO2max after acute myocardial infarction. DESIGN: Retrospective study.
SETTING: Regional cardio-cerebrovascular center at a tertiary hospital. PATIENTS:
A total of 66 patients were enrolled who were referred for cardiac rehabilitation
(CR) after percutaneous intervention, and who had reached stage 3 of the modified
Bruce Protocol (mBP) on an exercise tolerance test (ETT). METHODS: There were 54
men and 12 women with an average age of 56.7 +/- 9.48 years, ejection fraction
(EF) of 56.4% +/- 8.89%, and body mass index (BMI) of 24.73 +/- 2.86 kg/m(2). All
patients participated in a 4-week outpatient CR program and underwent ETT with a
gas analyzer to determine maximal heart rate and maximal oxygen consumption
before CR and 1 month, 3 months, and 6 months after CR. MAIN OUTCOME
MEASUREMENTS: VO2max and HRmax were defined as the highest values attained during
the ETT. The HR and VO2 values at each stage of the mBP were expressed as
percentages of their maximum. %HRmax and %VO2max were calculated at each stage of
the mBP. RESULTS: The maximum METs and VO2max significantly improved at 1 month
after CR, but not significantly at 3 and 6 months after CR. The correlation
between VO2max and HRmax progressively changed in a favorable manner during CR.
The relationship between %HRmax and %VO2max indicated a coefficient of variation
before and 1, 3, and 6 months after of 0.800, 0.826, 0.832, and 0.880,
respectively. CONCLUSIONS: This study showed that the %HRmax correlates better
with the %VO2max in the late-stage post-AMI than in the initial stage. We should
therefore set and monitor the exercise intensity using maximal oxygen consumption
in the early stage of exercise training after onset of acute myocardial
infarction.
LEVEL OF EVIDENCE: IV.
CI - Copyright (c) 2018 American Academy of Physical Medicine and Rehabilitation.
Published by Elsevier Inc. All rights reserved.

Langue : ANGLAIS