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Exercise capacity and systolic and diastolic ventricular function after recovery from acute dilated cardiomyopathy
M J Semigran1, C M Thaik, M A Fifer
1Department of Medicine, Massachusetts General Hospital, Boston 02114.
Insights
Even after recovery from dilated cardiomyopathy, patients show persistent issues with exercise capacity and left ventricular function. These findings highlight the long-term impact of this heart condition.
Area of Science:
- Cardiology
- Cardiovascular Physiology
Background:
- Dilated cardiomyopathy can lead to persistent ventricular structural abnormalities.
- These abnormalities may affect exercise capacity and overall ventricular function.
Purpose of the Study:
- To investigate if exercise capacity and ventricular function abnormalities persist after recovery from acute dilated cardiomyopathy.
- To compare recovered patients with healthy control subjects.
Main Methods:
- Evaluated 18 patients with resolved dilated cardiomyopathy using rest and exercise first-pass radionuclide ventriculography.
- Compared patient data with age- and gender-matched control subjects.
- Assessed myocyte necrosis via endomyocardial biopsy and antimyosin scintigraphy.
Main Results:
- Recovered patients had significantly lower peak exercise oxygen consumption and anaerobic threshold compared to controls.
- Patients exhibited increased resting and exercise left ventricular volumes but similar stroke volumes.
- Abnormalities in left ventricular diastolic filling and filling rates were observed in recovered patients.
Conclusions:
- Patients recovered from dilated cardiomyopathy demonstrate impaired aerobic exercise capacity despite normalized rest ejection fraction.
- Persistent abnormalities in left ventricular systolic and diastolic performance are evident.
- Long-term follow-up revealed potential for symptom recurrence and reduced ejection fraction.
Objectives:
This study was undertaken to determine whether abnormalities in exercise capacity or ventricular function persist after recovery from acute dilated cardiomyopathy.
Background:
Persistent ventricular structural abnormalities could cause abnormalities in exercise capacity or ventricular function.
Methods:
The results of rest and exercise first-pass radionuclide ventriculography in 18 patients who were seen within 6 months of the onset of dilated cardiomyopathy and subsequently had a normal rest left ventricular ejection fraction were compared with those of age- and gender-matched control subjects.
Results:
Patients were studied 144 +/- 34 (mean +/- SEM) days after the onset of left ventricular dysfunction at a time when heart failure symptoms had resolved. Patients with myocyte necrosis, as assessed by endomyocardial biopsy (n = 13) or antimyosin scintigraphy (n = 12), recovered more rapidly than did those without necrosis. Oxygen consumption both at peak exercise (17.7 +/- 1.2 vs. 26.1 +/- 1.5 ml/kg per min, p < 0.05) and at the anaerobic threshold (11.1 +/- 0.5 vs. 17.1 +/- 1.3 ml/kg per min, p < 0.05) was lower in the patients who had recovered from cardiomyopathy than in control subjects. Rest and exercise end-systolic and end-diastolic left ventricular volumes were greater in the patients than in the control subjects, although stroke volumes were similar. Left ventricular filling at rest was lower at diastolic filling intervals of 40% and 90%, and rest and exercise left ventricular early peak filling rate normalized for end-diastolic volume was slower in the patients than in the control subjects. At long-term follow-up of 1,082 +/- 206 days, two patients had a return of heart failure symptoms and a decrease in left ventricular ejection fraction.
Conclusions:
Despite the apparent normalization of rest left ventricular ejection fraction, patients who have recovered from dilated cardiomyopathy have abnormalities in aerobic exercise capacity and in left ventricular systolic and diastolic performance.