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[Normal maximal functional capacity in patients with congestive heart failure due to Chagas' cardiomyopathy]

C Mady1, R H Cardosa, B M Ianni

  • 1Instituto do Coração do Hospital das Clínicas-FMUSP, São Paulo.

Arquivos Brasileiros De Cardiologia
|July 1, 1996
PubMed

Insights

Patients with Chagas cardiomyopathy may have maximal oxygen consumption (VO2max) above 20mL/kg-1/min-1, but this does not indicate normal functional capacity. Further assessment is needed for these heart failure patients.

Area of Science:

  • Cardiology
  • Exercise Physiology
  • Infectious Diseases

Background:

  • Chagas' cardiomyopathy is a significant cause of heart failure.
  • Assessing functional capacity in these patients is crucial for management.
  • Maximal oxygen consumption (VO2max) is a key indicator of cardiorespiratory fitness.

Purpose of the Study:

  • To compare maximal oxygen consumption (VO2max) and left ventricular ejection fraction (EF) in patients with Chagas' cardiomyopathy and VO2max > 20mL/kg-1/min-1 against normal individuals.
  • To evaluate if a VO2max > 20mL/kg-1/min-1 in Chagas' cardiomyopathy patients reflects normal functional capacity.

Main Methods:

  • 104 male patients with Chagas' cardiomyopathy (functional class II-IV) and 23 healthy sedentary males were studied.
  • Maximal oxygen consumption (VO2max) was measured using a metabolic cart.
  • Left ventricular ejection fraction (EF) was assessed via transthoracic echocardiography.

Main Results:

  • 35.6% of Chagas' cardiomyopathy patients had VO2max > 20mL/kg-1/min-1 (mean 24.5 +/- 2.9 mL/kg-1/min-1) with significantly lower EF (42 +/- 11.7%) compared to controls.
  • Control group had higher VO2max (mean 33.3 +/- 5.6 mL/kg-1/min-1) and EF (75.1 +/- 3.2%).
  • Statistically significant differences in VO2max and EF were observed between the groups (p < 0.0001).

Conclusions:

  • Patients with heart failure due to Chagas disease can exhibit VO2max values exceeding 20mL/kg-1/min-1.
  • A VO2max > 20mL/kg-1/min-1 in these patients does not equate to normal maximal functional capacity.
  • This highlights the need for careful interpretation of VO2max in Chagas cardiomyopathy patients.
Abstract

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