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Myocarditis in beta-thalassemia major. A cause of heart failure
D T Kremastinos1, G Tiniakos, G N Theodorakis
1Cardiology Department of Athens General Hospital, University of Athens Medical School, Greece.
Background:
Although acute pericarditis is a common complication of beta-thalassemia major, the prevalence and consequences of myocarditis in this disease have not been investigated.
Methods And Results:
A prospective 5-year follow-up study was carried out in all patients with beta-thalassemia major in whom the diagnosis of acute infectious myocarditis could be established between 1977 and 1986. A similar number of age- and sex-matched control subjects with beta-thalassemia and normal left ventricular function and no evidence of myocarditis were also followed for 5 years. Of 1048 patients with beta-thalassemia major, 47 patients (age, 15 +/- 2.5 years) with precordial chest pain were diagnosed as having acute infectious myocarditis. Myocardial biopsy was diagnostic in 26 patients, border-line in 14 patients, and nondiagnostic in 7 patients. Acute heart failure with left ventricular dysfunction (left ventricular ejection fraction, 25 +/- 11%) developed in 11 patients (23.4%) with myocarditis, and 8 of them died within 1 month to 1 year after diagnosis. Thirteen patients with myocarditis (27.6%) developed chronic heart failure (left ventricular ejection fraction, 26 +/- 13%) within 3 +/- 1.3 years, and 10 of them died within 8 +/- 3 months. Left ventricular systolic and diastolic functions of the control subjects did not change significantly during the 5-year period (left ventricular ejection fraction, 63 +/- 11% versus 65 +/- 7%; P = NS). However, left ventricular restrictive abnormalities (early diastole/late diastole, > 2.2; deceleration time, < 110 milliseconds) combined with right ventricular dilatation (> 30 mm internal diameter) and right-sided heart failure developed in 3 patients with extremely high mean serum ferritin levels. No significant difference was found in mean levels of serum ferritin and pretransfusion hemoglobin between patients with and those without myocarditis.
Conclusions:
In patients with beta-thalassemia, myocarditis appears to be involved in the pathogenesis of left ventricular systolic dysfunction, being the main cause of death. Iron overload appears to provoke left ventricular restrictive abnormalities combined with right ventricular enlargement and dysfunction.
Insights
Myocarditis is a significant cause of heart failure and death in beta-thalassemia major patients. Iron overload can also lead to restrictive heart abnormalities and right ventricular dysfunction in these individuals.
Area of Science:
- Cardiology
- Hematology
- Internal Medicine
Background:
- Acute pericarditis is a known complication of beta-thalassemia major.
- The prevalence and impact of myocarditis in beta-thalassemia major remain understudied.
Purpose of the Study:
- To investigate the prevalence and consequences of acute infectious myocarditis in patients with beta-thalassemia major.
- To assess the role of iron overload in cardiac dysfunction in this population.
Main Methods:
- A prospective 5-year follow-up study of 1048 patients with beta-thalassemia major diagnosed with acute infectious myocarditis.
- Comparison with age- and sex-matched control subjects with normal cardiac function.
- Cardiac function assessed via myocardial biopsy, left ventricular ejection fraction, and serum ferritin levels.
Main Results:
- 47 patients (4.5%) with beta-thalassemia major were diagnosed with acute infectious myocarditis.
- 23.4% of myocarditis patients developed acute heart failure with left ventricular dysfunction, with an 8/11 mortality rate.
- 27.6% developed chronic heart failure, with a 10/13 mortality rate.
- Three patients with high ferritin levels developed restrictive abnormalities, right ventricular dilatation, and right-sided heart failure.
Conclusions:
- Myocarditis is a primary cause of left ventricular systolic dysfunction and mortality in beta-thalassemia major.
- Iron overload contributes to restrictive cardiomyopathy and right ventricular dysfunction in beta-thalassemia.