The heart is a muscle, so just as myositis causes inflammation in other muscles in the body, inflammation can also occur in the heart muscle. Recent research suggests that, in a myositis patient, the process of inflammation in the heart occurs in the same way it does in skeletal muscles. Other recent research findings have identified an antibody biomarker, antimitochondrial antibody (AMA), that is associated with severe heart disease in myositis patients.
Inflammation in the heart muscle (called myocarditis) can lead to fibrosis (scarring). Myositis patients can develop a number of cardiovascular problems as a result of inflammation and fibrosis, including:
Cardiomyopathy is any disease of the heart muscle. When the heart becomes weaker it is can’t pump blood through the body as effectively, and it can’t maintain a normal electrical rhythm.
Arrhythmias – If scarring develops in an area of the heart involved in the heart’s nerve conduction system, it can lead to arrhythmias (irregular heart beat), some of which can be fatal.
Congestive heart failure – Scarring in the heart muscle can reduce the strength of heart muscle contraction, which can cause fluid to back up into the lungs, other organs, and even the hands and feet, a condition known as congestive heart failure.
Atherosclerosis (hardening of the arteries) – Patients with any inflammatory disease have an increased risk of atherosclerosis due to inflammation, which narrows the blood vessels that supply the heart with blood. Blockages of these arteries is what causes myocardial infarction (heart attack).
All myositis patients should be evaluated regularly for heart disease, especially if they have risk factors.
Risk factors for cardiovascular complications in myositis include those that apply for all people:
Family history of cardiovascular disease – If someone in your family has had a heart attack or stroke, you are at a higher risk for having cardiovascular disease.
Hypertension (high blood pressure)
Hypercholesterolemia (high cholesterol)
Diagnosis of cardiovascular complications typically involves the following:
Electrocardiogram (EKG) is a basic test that shows the electrical activity of the heart over a period of time.
Echocardiogram is a sonogram of the heart, which shows an image of the heart along with how it is functioning.
Lipid profile is a screening set of blood tests that measures cholesterol and triglycerides. It is used to assess one’s risk for cardiovascular disease.
Other tests may be performed, depending on the individual patient, their family history, or some abnormality found on another diagnostic test. These may include:
Holter monitor is a portable EKG device that monitors the heart for an extended period of time (at least 24 hours) in order to detect abnormalities that may occur at irregular intervals or in relation to certain activities.
Cardiac stress test measures the heart’s ability to respond to the stress of exercise or certain medications in a controlled environment. The patient is asked to walk a treadmill or is given the medication while connected to an EKG machine, which records how the heart responds.
Magnetic resonance imaging (MRI) can determine if symptoms are related to inflammation in the muscle of the heart or are related to disease in the blood vessels.
Treatment of cardiovascular disease in myositis is best when the plan of care is coordinated between the rheumatologist (who attends to the myositis side of the disease) and the cardiologist (who attends to the heart disease).
Treatment of the underlying myositis is of primary importance. Immunosuppressant medications are used to treat both myositis and cardiovascular inflammation. There are, however, some special considerations that must be addressed in the treatment plan for myositis with cardiovascular involvement.
While prednisone is by far the most important immunosuppressant medication available and is the drug of choice for initial treatment of myositis, prednisone use places one at a higher risk for atherosclerosis. As a result, the physician may start second-line therapy together with steroids right from the beginning, so they can start tapering the steroid sooner.
Other management includes addressing those cardiovascular risk factors that can be modified, such as quitting smoking, controlling diabetes and high blood pressure, and addressing high cholesterol levels.
Additional information about cardiovascular disease in myositis can be found in the Myositis Library section of this website.
Myositis and heart disease – video presentation by TMA medical advisor Dr. Christina Charles-Schoeman at the 2017 TMA Annual Conference