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Cardiac function in patients with prior myocarditis
Insights
Prior myocarditis can cause hidden left-ventricular dysfunction. Asymptomatic patients showed reduced left-ventricular ejection fraction during exercise, indicating potential long-term cardiac issues.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Cardiac Imaging
Background:
- Myocarditis, an inflammation of the heart muscle, can lead to long-term cardiac sequelae.
- Assessing left-ventricular (LV) function reserve is crucial for identifying subclinical cardiac dysfunction.
- Prior myocarditis patients may have impaired LV function despite appearing asymptomatic.
Purpose of the Study:
- To evaluate left-ventricular functional reserve in asymptomatic patients with a history of myocarditis.
- To compare exercise-induced changes in left-ventricular ejection fraction (LVEF) between prior myocarditis patients and healthy controls.
- To determine if conventional resting cardiac indices can detect subclinical left-ventricular dysfunction post-myocarditis.
Main Methods:
- Gated cardiac blood-pool imaging was performed at rest and during exercise.
- Left-ventricular ejection fraction (LVEF) was measured in six asymptomatic patients with prior myocarditis and six age-matched controls.
- Coronary artery disease was excluded using coronary arteriography or clinical assessment.
Main Results:
- Resting LVEF was normal in most prior myocarditis patients, similar to controls (0.58 +/- 0.05 vs. 0.65 +/- 0.02).
- Three patients with prior myocarditis had resting LVEF < 0.50.
- During exercise, prior myocarditis patients showed an 8% decrease in mean LVEF, while controls increased LVEF by 15% (p < 0.01).
Conclusions:
- Asymptomatic patients with prior myocarditis exhibit subclinical left-ventricular dysfunction.
- Exercise stress testing reveals impaired left-ventricular functional reserve not apparent at rest.
- Long-term follow-up is recommended for individuals with a history of myocarditis to monitor cardiac health.
Abstract:
Gated cardiac blood-pool imaging under rest and exercise was used to assess left-ventricular functional reserve in six asymptomatic patients with prior myocarditis and six age matched control subjects. Coronary artery disease was excluded in three of the six patients by coronary arteriography. In the remaining three, coronary artery disease was thought unlikely on the basis of history and the presence, during exercise, of a normal ECG and normal Tl-201 myocardial image. Conventional indices of resting left-ventricular function--including cardiothoracic ratio, echocardiographic left-ventricular diameter, and percentage change in minor diameter--were normal in those with prior myocarditis. The mean resting left-ventricular ejection fraction was also normal by gated blood-pool imaging, and not significantly different from that for control patients: 0.58 +/- 0.05 and 0.65 +/- 0.02, respectively. Three patients with prior myocarditis had resting left-ventricular ejection fractions of less than 0.50. On exercise, the patients with prior myocarditis decreased their mean left-ventricular ejection fraction by an average of 8% compared with an increase of 15% in the control group (p less than 0.01). This study suggests that asymptomatic patients with prior myocarditis have left-ventricular dysfunction that may not be clinically apparent, and suggests the need for further long-term follow-up.