Thromboembolism in patients with Myocarditis

Abstract

Background: Myocarditis and dilated Cardiomyopathy continues to be an important cause of hospital admission in our part of the world. Systemic embolism due to thrombi in left ventricle is a rare but important complication of these patients. Study objectives: To determine the incidence, course and outcome of thrombo-embolism in children with dilated dysfunctioning heart due to acute myocarditis or dilated Cardiomyopathy. Design: A 5 year analysis (December 1999- Nov 04) of all children under 16 years of age admitted and diagnosed as having myocarditis or dilated Cardiomyopathy in a single tertiary care center. Patients and Methods: The charts and echocardiography records of all patients with dilated dysfunctioning heart and systemic thrombo-embolism were reviewed. Data was reviewed for mode of presentation, age, hospital course and outcome. Echocardiography data was reviewed with special reference to the size, function and presence of thrombus in LV. Results: Of all admissions to the paediatric cardiology unit over the study period, myocarditis and dilated Cardiomyopathy was the underlying lesion in 405 patients. The mean age of patients was 2.1 ± 4 years. Systemic embolism was the presenting feature in 28 (6.9%) patients (Group A); while another 17 (4.2%) developed it during the hospital stay (Group B). Another 5 patients had thrombus in the LV but did not develop embolism. All 50 patients showed seriously impaired LV function with mean ejection fraction (EF) for those with vs. those without thrombo-embolism was 17.5 ± 5.5 vs. 20.0 ± 6.9 (p = 0.08). The groups were similar with respect to other baseline characteristics, co morbid illnesses, and drug therapies other than anticoagulants. In group A 26/28 patients presented with a stroke. Only 6 had a thrombus in LV at the time of admission. All 28 patients with or without LV thrombus were treated with heparin and then oral anticoagulant warfarin. There were two deaths. In group B, 3/17 patients had thrombus in the LV on echocardiography at presentation. They were started anticoagulation but still went on to develop a stroke. There were 2 deaths in this group as well. Conclusions: Myocarditis and dilated Cardiomyopathy is an important cause of hospital admission in our set up accounting for 15% of all admissions to a paediatric cardiology unit. These patients are at risk of developing thromboembolism, which may well be the presenting feature. The risk is higher in patients with lower ejection fraction of the LV. All patients with EF below 17% should be treated with prophylactic anticoagulation. A peripheral embolic event adds to morbidity and is related to poor long-term survival in this patient group.