My husband recently had a heart attack, and he also has myasthenia gravis (MG). He has no family or personal history of coronary problems, he is in great physical condition. Could the MG have contributed or be a cause of his heart attack?
The association of heart problems with myasthenia gravis (MG) has been suspected for decades, but heart problems are not believed to be a common feature or complication of MG. Many medical researchers believe some people with MG may be at an increased risk for several kinds of heart conditions, ranging from asymptomatic changes on electrocardiography (ECG) to ventricular tachycardia, myocarditis, Takotsubo cardiomyopathy, conduction disorders (heart does not beat normally), heart failure, and sudden cardiac death. However other researchers feel that myocarditis (including giant cell myocarditis) and Takotsubo cardiomyopathy are the only heart conditions increased in people with MG, and the risk for other cardiac problems is no different from the general population risk. In addition, in many descriptions of the signs and symptoms of MG, cardiac issues are not mentioned.
Most medical researchers agree that although the antibodies normally associated with MG (AChR) do not attack the heart muscle, some people with MG, especially those with thymoma, may develop antibodies against the heart muscle causing myocarditis, including giant cell myocarditis. The possible cause of the increased risk for developing Takotsubo cardiomyopathy is less clear. Takotsubo cardiomyopathy does not appear to be related to thymoma, but instead usually occurs during a myasthenia crisis. Abnormal heart rate and rhythm may be linked to complications of myocarditis, or as some medical researchers suggest, may be related to a problems within the autonomic nervous system.
Medical researchers continue to call for better studies that could determine which types of cardiac issues may be caused by MG and how to detect those at an increased risk. One concern is that the symptoms of cardiac problems including fatigue, shortness of breath and exercise intolerance are similar to symptoms of MG, so cardiac problems may be missed.
Treatment of cardiac problems in people with MG must be carefully considered because some heart medications may make other symptoms of MG worse.
Last updated: 12/30/2016
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