Cardiomyopathy (CM) in Adults

There are many types of cardiomyopathy with differing causes:

• Dilated Cardiomyopathy (DCM): Causes the ventricles in the heart to weaken and get larger
• Hypertrophic Cardiomyopathy (HCM): Causes the heart muscle to become larger and thicker than normal
• Restrictive Cardiomyopathy (RCM): Causes the ventricles to stiffen, but the walls of the heart do not thicken
• Arrhythmogenic Right Ventricular Dysplasia (ARVD/C): Fatty or scarred tissue replaces the normal muscle tissue in the right ventricle, causing an irregular heartbeat (arrhythmia)
• Ischemic Cardiomyopathy (ICM): Causes the left ventricle to become enlarged, dilated, and weak due to ischemia (a lack of blood supply to the heart muscle caused by coronary artery disease and heart attacks)
• Transthyretin Amyloid Cardiomyopathy (ATTR-CM): Causes deposits of amyloid proteins in the left ventricle, stiffening the ventricle walls
• Left Ventricular Non-Compaction Cardiomyopathy (LVNC): Causes the muscular walls of the heart to appear thick and 'spongy'

Image Source: Center for Advanced Cardiac and Vascular Interventions

Symptoms of Cardiomyopathy result from the weakening or increased stiffness of the heart wall and may include:

• Symptoms of heart failure
• Shortness of breath with exertion, at rest, or lying down
• Leg swelling or fluid retention
• Fatigue
• Syncope (fainting) or near syncope
• Chest pressure
• Sudden cardiac arrest and death
• Some patients experience no symptoms

Inherited types of cardiomyopathy cannot be prevented. However, you can take steps to reduce your risk of coronary heart disease, high blood pressure, and heart attack, which, in turn, lowers your risk of acquired cardiomyopathies. The key to prevention is being proactive with your overall health, specifically treating initial underlying problems early to avoid cardiomyopathy complications.

Medication

For patients with reduced heart function (low ejection fraction), guideline-directed therapy for heart failure is recommended. Medications come from four different categories: beta-blockers, afterload reducers (e.g., ACE/ARB/ARNi; commonly losartan or sacubitril-valsartan), aldosterone inhibitors, and SGLP2 inhibitors (e.g., empagliflozin). These medications aim to improve symptoms and have been shown to extend life expectancy. 

Some types of cardiomyopathy have specific therapy aimed at reducing inflammation (immunosuppression in sarcoid), infiltration (iron-chelation in hemochromatosis or tafamidis in cardiac amyloid), or obstruction/fibrosis (mavacamten in hypertrophic cardiomyopathy).

Structural/Surgical Intervention

In patients with ischemic cardiomyopathy, a type of dilated cardiomyopathy, physicians may recommend stenting a heart artery to improve blood flow to the heart muscle if there was a significant blockage.

In patients with valvular cardiomyopathy, replacement or repair of a heart valve if the valve structure/function may be recommended.

In patients with hypertrophic cardiomyopathy, surgical or alcohol myectomy may be performed to remove excess muscle blocking blood outflow. 

In patients with severe symptoms and low heart function, ventricular assist devices (VAD), an electromechanical device for assisting cardiac circulation, may be implanted. In worst-case scenarios, physicians may recommend heart transplantation.

Implantable Cardioverter Defibrillator (ICD)

An implantable cardioverter defibrillator (ICD) may be recommended to protect patients from sudden cardiac arrest and death. Patients with some forms of cardiomyopathy or decreased heart function below 35% (low ejection fraction) have an increased risk of ventricular fibrillation or ventricular tachycardia. Ventricular fibrillation and tachycardia are rhythms that originate from areas of inflammation or scarring. The heart rates are often over 200 beats per minute (BPM) and do not maintain blood pressure. Defibrillation with an ICD is highly effective at restoring normal rhythm. 

In about 25% of patients with heart failure and decreased ejection fraction, there is evidence of conduction block, which occurs when there is a problem with the electrical signals that control the beating of your heart. Cardiac resynchronization therapy (CRT) uses an additional pacemaker wire to coordinate the activation of each heartbeat. This can improve the timing of contraction in the heart muscle, alleviate symptoms, and extend life expectancy. CRT therapy can be coupled with an ICD (implantable cardiac resynchronization therapy device or CRT-D) or a standalone pacemaker (implantable cardiac resynchronization therapy pacemaker or CRT-P).

Catheter Ablation

Catheter ablation of abnormal heart rhythms may be recommended to treat cardiomyopathies. Patients with cardiomyopathy often present with atrial fibrillation, atrial flutter, atrial tachycardia, ventricular tachycardia, and premature ventricular complexes (PVCs). These rhythms can be treated effectively with catheter ablation and/or rhythm medication.

Shared Decision-Making

Shared decision-making is an important component of treatment. All recommendations, including device implantation, should be made with your wishes, beliefs, and expectations considered in addition to the risks and benefits.

You can choose healthy habits to help prevent Cardiomyopathy, such as:

• Quit smoking
• Limit caffeine and avoid stimulants like energy drinks
• Avoid alcohol and illicit drug use
• Get regular exercise
• Some patients may be encouraged to participate in a cardiac rehab program
• Depending on your diagnosis, you may be told to limit endurance athletics or competitive athletics
• Check your weight regularly
• If you are overweight or obese, weight loss is recommended
• Patients may be told to limit fluid intake
• Limit salt intake
• Maintain regular follow-ups with your physician and/or medical team

A number of things can increase your risk of CM, including:

• Family history of CM, heart failure, and sudden cardiac arrest
• Long-term high blood pressure
• Past heart conditions, such as heart attack, coronary artery disease, or viral heart infections
• Obesity, which makes it harder for your heart to pump blood to the rest of your body
• Excessive alcohol or illicit drug use
• Certain chemotherapy or radiation cancer treatments
• Diabetes
• Thyroid disease
• Storage of excess iron in the body (hemochromatosis)
• Amyloidosis (buildup of amyloid proteins in organs)
• Sarcoidosis (growth of inflammatory cell clumps called granulomas throughout the body)
• Connective tissue disorders

Cardiomyopathy can lead to serious complications, such as:

• Heart failure
• Blood clots
• Heart valve problems
• Sudden cardiac arrest and death