Cardiomyopathy Diagnosis: What Happens During A Myocardial Biopsy?

Although very helpful in everyday practice, some heart conditions cannot be diagnosed via regular clinical tests. Science and technology have made significant progress since the ‘50s when the first open-heart biopsy took place, paving the way for safer and more effective heart diagnostic techniques. 

Studies show that about one third of all diagnoses in patients with cardiomyopathy of unknown origin remain unidentified using these conventional techniques. In these cases, a biopsy is of extreme importance. This way, patients can get the treatment that’s best suited specifically for them. 

Myocardial biopsy is an interventional diagnostic method that involves taking a sample from your heart’s muscle tissue and then examining it under a microscope. During this procedure, a doctor uses a special kind of catheter, called a “bioptome”, which is essentially a long, thin tube with a grasping device on its end. This catheter is inserted in your blood vessels in the neck, arm, or most commonly, groin. The doctors then manipulate it through the blood vessels all the way to the heart, using X-rays for navigation. The ultimate goal is to remove heart tissue samples that later undergo further examination.

Do I need a myocardial biopsy?

The purpose of myocardial biopsy is to find evidence of heart tissue damage, such as:

• Heart weakness (cardiomyopathy)
• Inflammation (myocarditis)
• Heart tumors
• Drug toxicity monitoring
• Organ rejection after heart transplant
• Any other heart disease or symptom with an unknown cause

There are situations in which this procedure should not always be performed, primarily because it may bring more risk than benefit. These categories include patients with bleeding disorders, prior history of heart attacks, presence of blood clots, specific birth defects, and one specific type of cardiomyopathy where heart muscle tissue is replaced by fat, called arrhythmogenic right ventricular dysplasia (ARVD).

How is a myocardial biopsy performed? 

A myocardial biopsy is performed in hospitals, mostly in special procedure rooms in radiology departments, and then the heart tissue is analyzed in a lab. It is done under local anesthesia, meaning that you’ll be awake on the operating table during the whole procedure, which can last from one to several hours. The doctors will give you some sedatives to calm you down, and also, you’ll receive a local numbing medicine. You will be connected to a heart monitor, so the doctors can record your condition.

Then, the surgeon chooses the most practical incision location. A small incision on your arm, neck, or groin is made. Depending on what part of the heart surgeons needs to navigate to, they will put a catheter either through an artery or a vein. Next, with the help of an ultrasound or X-ray, the catheter is gently threaded through the blood vessels until it reaches the main heart chambers. This catheter, being hollow, acts as a guide for the bioptome, which is then lead all the way through the catheter to the heart. Ultimately, the bioptome cuts and removes a few small samples of the heart muscle tissue. Then, the catheter is gently removed from your body, and the surgeon will apply pressure to the incision wound to stop it from bleeding. The samples are immediately sent to a laboratory for analysis.

When the procedure is done, doctors will continue to monitor your condition for some time. If everything is OK, you can go home. For the next few days or weeks, you should avoid heavy physical activities so the wound will heal more quickly.

The laboratory staff performs several types of analysis:

• Pathohistological, where the samples are viewed under a microscope
• Immunohistochemistry, which helps in diagnosing abnormal cells
• Molecular techniques that can identify microorganisms in small concentrations.

After the lab work is all done, your doctor will contact you to explain you the results, tell you the precise diagnosis, and choose the right treatment option for you. 

Myocardial biopsy: Role in cardiomyopathy diagnosis

There are four main types of cardiomyopathy, each with specific characteristics. However, the main cause can’t always be identified. These causes may include viruses, alcoholism, previously untreated diseases, or can be genetic.

In dilated cardiomyopathy the chambers of your heart become stretched, and the muscle is seen as pale and flabby. Unfortunately, this is not enough to make a definitive diagnosis, so in this case the doctors must exclude all the other causes (e.g. alcoholism, heart failure caused by pregnancy…) before diagnosing it.

In hypertrophic cardiomyopathy the heart muscle is very thick and stiff, and the heart muscle fibers are larger with bizarre looking cell elements, and seen running in all directions. Only when these features present together it is possible to confirm the diagnosis, again only in combination with previous test results.

In restrictive cardiomyopathy the heart muscle becomes stiff but doesn’t thicken. A biopsy can show specific disorders that can be associated with the disease.

In arrhythmogenic right ventricular dysplasia (ARVD), a biopsy can show signs of inflammation or evidence of immune-factor involvement. 

Other than this, a myocardial biopsy can prove the existence of several other heart conditions and diseases, such as amyloidosis (abnormal concentrations of proteins called amyloids), sarcoidosis (a systemic inflammatory disease), hemochromatosis (a disorder where iron builds up in the body), heart tumors, and many more. 

Are there any risks involved with myocardial biopsy?

Myocardial biopsy is a safe and relatively simple procedure, and serious complications are extremely unlikely. You may expect minor bleeding at the place of the incision. Complicated cases of bleeding may occur if the blood vessels or the heart muscle are damaged during the procedure. Although uncommon, irregular heartbeats may continue to last over a long period of time, and may require further corrections. Other complications, such as stroke and death, are extremely rare, especially keeping in mind that these sorts of procedures are performed by experienced surgeons.