American Heart Association comment regarding MMWR CDC's reporting of patients with dilated cardiomyopathy after they received smallpox vaccine

American Heart Association
Friday, 11 July 2003

In this week's MMWR the CDC reported two patients who contracted dilated cardiomyopathy (DCM) three months after receiving the smallpox vaccine. Smallpox vaccinations have not been previously associated with DCM.

According to Augustus O. Grant, M.D., Ph.D., American Heart Association President, these two adverse event reports should raise awareness that an inflammatory reaction from the vaccine could be a potential mediating factor in cardiomyopathy. Myocarditis, which involves an inflammatory reaction, has been seen in increased numbers in patients receiving smallpox vaccination.

However, in roughly half of all investigated cases of DCM, there is no identified cause, and even pinpointing the time that heart dysfunction began can be difficult. With only two cases reported out of 38,000 vaccinations, it is not possible to determine if the smallpox vaccine caused the DCM.

DCM is a type of heart disease characterized by an enlarged, poorly functioning heart that can cause shortness of breath. Although it can sometimes resolve, in other cases it can lead to heart failure and death. It is essential that patients with DCM receive appropriate treatment.

In March 2003 the CDC reported that some patients who received the vaccine developed coronary heart disease.

The American Heart Association plans to publish an online summary of the MMWR CDC report in Circulation: Journal of the American Heart Association to reach cardiologists and other heart specialists. "We hope that these measures will help stimulate reporting of any additional cases," says Grant.

The American Heart Association urges people who have been vaccinated for smallpox to be aware of the symptoms of myocarditis and cardiomyopathy and to contact their healthcare provider with any concern about their heart health.

These symptoms include chest pain or discomfort, palpitations, shortness of breath or ankle swelling, and/or unusual fatigue.

For more information, or to contact American Heart Association, see their website at: www.americanheart.org