About Giant Cell Myocarditis

In the case of Giant Cell Myocarditis, the most lethal form, which is characterized by rapid deterioration, the prognosis is less favorable than in other forms of myocarditis. In the late 1980s and 1990s, the average time from the start of symptoms to death or transplantation was only 5 months in GCM. Historically, many patients died before their name could be placed on a transplant list. Lack of availability of information in the medical community about this rare disease presents the greatest challenge. But there is hope. For the best outcome, an accurate, early diagnosis may allow for treatment and long term survival.

What is Giant Cell Myocarditis?

Giant cell myocarditis is a very rare disease that is difficult to diagnose. The symptoms vary from simple fatigue to sudden death. Once a diagnosis is made it is easy to look back and connect these symptoms with giant cell myocarditis. But these same symptoms could have been due to a variety of non-life threatening conditions. Even if someone were taken to a hospital with minor unexplained symptoms a proper diagnosis would most likely not be made. Myocarditis (enlarged heart) can be detected by a variety of non-invasive techniques. But giant cell myocarditis can only be diagnosed by a heart biopsy. In either case there must be some evidence of heart failure to trigger this type of testing. Typically when a patient exhibits heart failure the disease is attacking the heart very aggressively and the only option is immediate treatment. With proper treatment the rate of death or heart transplantation is less than 50% one year after symptom onset.

What causes giant cell myocarditis?

The cause of giant cell myocarditis is not known, but observations in human tissue and experimental data from a Lewis Rat model suggest that the disease is mediated by T lymphocytes.

If the cause of giant cell myocarditis is unknown, how can it be induced in rats?

Experimental giant cell myocarditis can be produced in the Lewis rat by auto immunization with myosin.

Is giant cell myocarditis new?

No. Giant cell myocarditis was first described in 1905.

Why has no one heard of it?

Giant cell myocarditis is a very rare disease. Therefore many physicians are not familiar with giant cell myocarditis.

How is giant cell myocarditis diagnosed?

Giant cell myocarditis can only be diagnosed with an endomyocardial (heart) biopsy.

Can the biopsy results be confused with a different disorder?

Giant cell myocarditis can be confused with cardiac sarcoidosis. Therefore all suspected cases should be reviewed by an experienced cardiac pathologist.

How is a endomyocardial biopsy performed?

A thin tube called a catheter is inserted into a vein or artery, usually in the groin or neck. The catheter is guided using x-ray or echocardiogram (sonogram for the heart) and placed inside of the heart. Then an instrument called a bioptome is inserted into the catheter and used to remove a small section of the heart from the inside.

What are some of the treatments for giant cell myocarditis?

One treatment is to give the patient a variety of immunosupressive drugs combined with steroids. Another option is a heart transplant.

The goal of immunosupression therapy is to delay heart transplantion. The need for a transplant my be delayed by months or even years. Since each case is unique there is not a typical time.

What is the expected life span of a giant cell myocarditis transplant patient?

Post-transplantation survival is approximately 71% at five years despite a 25% rate of giant cell infiltration in the donor heart. To confirm these findings, a randomized trial of immunosuppression including muromonab-CD3, cyclosporine, and steroids is underway.

Does giant cell myocarditis reoccur in transplant patients?

Giant cell myocarditis reoccurs in approximately 25% of transplant patients. Generally giant cell myocarditis is not as severe in a transplant patient.

Why is giant cell myocarditis in a transplant patient not as severe?

The exact reason is not known. But the disease may be less aggressive because the patients are on immunosuppressive drugs to prevent rejection of the donor heart.

What type of treatment for giant cell myocarditis is used in a transplant patient?

The treatment depends to some degree on the presentation, but may consist of steroids for 2-3 months.

How is giant cell myocarditis detected in a transplant patient?

The diagnosis is made by heart biopsy, which is routinely performed in the post-transplant patient to look for rejection of the donor heart.

If giant cell myocarditis occurs in a transplant patient how long does it typically take to appear?

The range of time to recurrence is wide, from 3 weeks to 9 years after transplant, with an average time of about 1 year.