How is myocarditis diagnosed?
Myocarditis can best be diagnosed by examining a small piece of heart muscle under a microscope. Samples of the heart muscle are taken with a bioptome. A bioptome is a thin, flexible tube with small cutting jaws at its tip. The bioptome is inserted through a vein in your neck and positioned in the heart. Once the bioptome is in position, the cutting jaws withdraw very small heart muscle samples for analysis. You will be given a shot to numb the area where the bioptome is inserted,
but you will remain awake. You may experience minor discomfort but the procedure is usually painless. Results will be available within 48 hours.
Myocardial inflammation can be suspected on the basis of electrocardiographic results (ECG), elevated CRP and/or ESR and increased IgM (serology) against viruses known to affect the myocardium. Markers of myocardial damage (troponin or creatine kinase cardiac isoenzymes) are elevated. The ECG findings most commonly seen in myocarditis are diffuse T wave inversions, without shifts in the ST segment. The gold standard is still biopsy of the myocardium, generally done in the setting of angiography. A small tissue sample of the endocardium and myocardium is taken, and investigated by a pathologist by light microscopy and - if necessary - immunochemistry and special staining methods.
In some patients, blood tests may be done to check whether myocarditis is related to Epstein-Barr virus, hepatitis viruses, HIV or another virus. Some medical centers also have the capability to isolate certain types of viruses from the patient's stool, throat washings or other body fluids. |
