Background: In severe heart failure, increased values of cardiac troponins have been detected during decompensation. In this study, we investigated whether an increase of cardiac troponin I can be observed after symptom-limited exercise and after an exercise training session in patients with moderate heart failure.
Methods: Twenty-seven patients with moderate heart failure (New York Heart Association II-III, ejection fraction 31% +/- 8%) were compared with 9 patients with mild heart failure and 10 subjects without heart failure. They underwent a symptom-limited exercise test and a bicycle exercise training session at >80% of maximal heart rate over 20 to 30 minutes. Plasma cTnI levels were measured at baseline, after symptom-limited exercise (hourly for 5 hours), and after training (4 and 10 hours).
Results: Patients with moderate heart failure showed an increase of cTnI from 37 +/- 49 pg/mL to 73 +/- 59 pg/mL (P <.001) after symptom-limited exercise. Four patients with moderate and 1 with mild heart failure and normal cTnI values at rest showed an increase of cTnI above 100 pg/mL after acute exercise but not after training. Subjects without heart failure had lower cTnI levels at rest and significantly lower values after symptom-limited exercise and training (P <.05 for each).
Conclusion: Patients with symptomatic heart failure reveal an increase of cTnI after symptom-limited exercise at levels that indicate minor myocardial damage. The prognostic impact of this finding should, therefore, be further investigated.