An Overview of Dilated Cardiomyopathy Heart Failure

Cardiomyopathy is a disease of the heart muscle. Dilated cardiomyopathy is the most common type. The other two types are hypertrophic cardiomyopathy and restrictive cardiomyopathy.

In dilated cardiomyopathy, the heart muscle is weakened and unable to contract normally. To compensate, the muscle "stretches," causing the heart to dilate. This dilation is especially prominent in the left ventricle, one of the four chambers in your heart.

This article looks at the symptoms, causes, and diagnosis of dilated cardiomyopathy. It also discusses some of the ways this condition is treated.

Symptoms of Dilated Cardiomyopathy

Dilated cardiomyopathy is the most common cause of heart failure. About half of heart failure cases are due to heart failure with preserved ejection fraction.

The symptoms of this condition are the classic symptoms of heart failure. These include:

• Dyspnea (shortness of breath)
• Swelling in the feet and ankles
• Weakness
• Poor exercise tolerance
• Palpitations (skipped heartbeats)
• Lightheadedness

Causes

Anything that can weaken the heart muscle is a potential cause of dilated cardiomyopathy. This includes a large number of medical conditions, such as:

• Coronary artery disease (CAD)
• Left bundle branch block (LBBB)
• Various infections
• Hypertension
• Heart valve disease
• Nutritional deficiencies
• Alcohol or cocaine abuse
• Pregnancy
• Cardiac arrhythmias
• Sudden emotional shock
• Genetic abnormalities
• Thyroid disease
• Autoimmune disorders

Diagnosis

Heart failure is diagnosed by a combination of symptoms, exam findings, imaging, and blood tests.

On examination, doctors are evaluating for swelling in the feet and distention of the veins in the neck as a sign of excess volume. They will use their stethoscope to listen for (auscultate) the lungs for the presence of crackles indicating fluid build up and to the heart for abnormal heart sounds characteristic of heart failure or valve disease.

Imaging tests often include a chest x-ray to assess for fluid in the lungs. The most important initial imaging test, however, is an echocardiogram or ultrasound test. An echocardiogram provides key information on the function of the heart muscle and valves and the pressures within the heart.

In select cases, a cardiologist may want more advanced information about the heart muscle and a cardiac MRI will be ordered.

Because coronary artery disease can contribute to cardiomyopathy, a test to assess for blockage in the arteries is usually ordered. Noninvasive testing, such as a coronary CT angiogram or a stress nuclear test are preferred in the initial evaluation for coronary artery disease. If abnormalities show up on this initial testing, an invasive angiogram may be warranted.

A key piece of information these tests provide is the left ventricular ejection fraction (LVEF). This is the proportion of blood volume the left ventricle ejects with each heartbeat. A normal LVEF is 50% or higher, which means the left ventricle should eject at least half its blood volume. In dilated cardiomyopathy, the LVEF is usually below 50%. If you have heart failure signs and symptoms and your LVEF is greater than 50%, a common reason is heart failure with preserved ejection fraction.

The degree of reduction in LVEF is a good way for your healthcare provider to judge the amount of damage to your left ventricle. This test may be repeated over time to see if your cardiomyopathy is worsening or improving.

Treatment

Dilated cardiomyopathy may have a reversible cause. This means it may be possible to halt its progress or even reverse the damage. Your healthcare provider will consider a number of possibilities, such as:

• Coronary artery disease
• Heart valve disorders
• Nutritional deficiencies
• Hidden alcohol or cocaine usage
• Thyroid disease

The vast majority of patients with dilated cardiomyopathy can experience substantial improvement in their LVEF and symptoms with four very effective drugs that have been developed in the 40 years.

The four drug categories that should be used in almost all patients with dilated cardiomyopathy have been termed "the fantastic four," and include:

• Beta-blockers such as Coreg (carvedilol) and Toprol XL (metoprolol succinate)
• ACE inhibitors, ARBs or ARNIs, are drugs that block the activity of the renal angiotensin system
• Mineralocorticoid inhibitors (MRAs) such as Aldactone (spironolactone) and Inspra (eplerenone)
• SGLT2 inhibitors Farxiga (dapagliflozin), Jardiance (empagliflozin), and Inpefa (sotagliflozin)

For patients who have a persistently low LVEF after three months of optimal medical therapy, a cardiologist may consider implanting an electrical device called an implantable cardioverter defibrillator which can shock your heart back to normal and prevent sudden death if an abnormal rhythm develops.

Patients with LBBB and persistently low LVEF may benefit from a special pacemaker which stimulates both the right and left ventricles (cardiac resynchronization therapy)

If you or a loved one has this condition, it's a good idea to become familiar with treatment options. Discuss these options with your healthcare provider.

It is also a good idea to have a cardiologist oversee your care. A cardiologist is a physician who specializes in the heart. This will help ensure you're getting the right treatment, and it will also allow you to stay informed if there are any potential breakthroughs in treating this very serious condition.

Summary

Dilated cardiomyopathy is a weakening of the heart muscle. It is the most common cause of heart failure. With modern treatments, most patients with heart failure due to DCM experience dramatic improvement in their symptoms. In addition, a combination of medications has substantially lowered hospitalizations and death from this condition. In select patients, specialized pacemaker therapy can normalize heart function.

This condition can have a number of causes, including coronary artery disease, thyroid disease, and alcohol or cocaine abuse. Some of these conditions are reversible.

If you are diagnosed with cardiomyopathy, talk to your healthcare provider about your treatment options. It is also a good idea to consult a cardiologist.