Cardiomyopathy is any disease of the heart muscle in which the heart loses its ability to pump blood effectively. The condition affects about 50,000 American adults and children. There may be multiple causes of cardiomyopathy and it may be associated with diseases involving other organs, as well as the heart.

Cardiomyopathy conditions tend to be progressive and sometimes worsen fairly quickly. Dilated cardiomyopathy is a leading cause for a heart transplant. Patients with cardiomyopathy are more likely to develop ventricular arrhythmias, which increases their risk of cardiac arrest. Certain diagnostic tests can be performed to help predict the patient's risk of cardiac arrest and guide physicians in recommending proper treatment.

What Causes Cardiomyopathy?

Viral infections that affect the heart are a major cause of cardiomyopathy. In some instances, cardiomyopathy is a result of another disease or its treatment, such as complex congenital heart disease (present at birth), nutritional deficiencies, irregular heart rhythms (arrhythmia) or certain types of chemotherapy for cancer. Sometimes, cardiomyopathy can be linked to a genetic abnormality. Other times, the cause is unknown.

Types of Cardiomyopathy

Hypertrophic Cardiomyopathy (HCM)

Hypertrophic cardiomyopathy occurs when the muscle mass of the left ventricle of the heart is thicker than normal, or the wall between the two ventricles (septum) becomes enlarged and obstructs the blood flow from the left ventricle. Because it prevents the heart from properly relaxing between beats, it fills with less blood, which limits the amount of blood pumped by the heart with each beat. A heart murmur may be heard, which is related to the obstruction below the aortic valve (valve between the left ventricle and the aorta).

Hypertrophic cardiomyopathy is a rare disease and in most cases it is inherited. It can affect men and women of all ages, and symptoms can appear in childhood or adulthood. Symptoms include shortness of breath on exertion, dizziness, fainting and angina pectoris. Some patients experience cardiac arrhythmias, which may lead to sudden death. Learn more about specialized Froedtert & the Medical College of Wisconsin's highly specialized hypertrophic cardiomyopathy program.

Dilated Cardiomyopathy

Dilated cardiomyopathy is the most frequent form of nonischemic cardiomyopathy (those not related to coronary artery disease). The cavity of the heart is enlarged and stretched (cardiac dilation) causing the heart to become weak and not pump normally. The condition occurs most often in middle-aged people and more often in men than women, but has been diagnosed in children. Most patients develop congestive heart failure.

Dilated cardiomyopathy can be caused by alcohol abuse and dietary deficiencies. It occasionally occurs as a complication of pregnancy and childbirth. Other suggested causes are: various infections (which lead to an inflammation of the heart muscle, called myocarditis), toxins, heredity and medication side effects.

Restrictive Cardiomyopathy

Restrictive cardiomyopathy, the least common type of cardiomyopathy in the US, occurs when the myocardium of the ventricles becomes excessively rigid, and the filling of the ventricles with blood between heart beats is impaired. The condition usually results from another disease, which occurs elsewhere in the body. Symptoms may include fatigue, swelling of the extremities, and difficulty breathing on exertion.

Genetic Testing for Inherited Cardiomyopathy

Cardiac MRI and other tests can be conducted by cardiac geneticists to determine if a patient has an inherited cardiomyopathy condition. Testing can confirm a diagnosis in someone showing signs of the condition. It can also identify family members at risk of developing the condition later in life so they can be screened regularly and treated as soon as heart changes begin to appear. These conditions are often associated with an electrical problem in the heart, or arrhythmia (irregular heartbeats).

In addition to hypertrophic cardiomyopathy (HCM), other genetic cardiomyopathies include:

  • Long Q-T syndrome, a hereditary disorder of the heart’s electrical rhythm that involves repeated fainting and a high risk of cardiac arrest.
  • Arrhythmogenic right ventricular dysplasia (ARVD), a genetic, progressive heart condition in which the heart’s right ventricle muscle is replaced by fat and fibrosis, causing irregular heart rhythms.
  • Brugada Syndrome, an inherited, potentially life-threatening heart rhythm disorder diagnosed when a specific abnormal heartbeat is detected by an electrocardiogram.

Treatments for cardiomyopathy often include medications, implantable defibrillators or bi-ventricular devices.

Our Cardiovascular Program continues to receive recognition as one of the top programs nationally. We are honored to provide high-quality, effective care for even the most high-risk patients.

  • In its 2024 Specialty Excellence Awards, Healthgrades recognized Froedtert Hospital as one of America’s 50 Best Hospitals for Cardiac Surgery, one of America’s 100 Best Hospitals for Cardiac Care and one of America’s 100 Best Hospitals for Coronary Intervention, as well as other specialty achievements in various areas.

    Froedtert Hospital was named one of the nation’s 50 Top Cardiovascular Hospitals™ by Fortune and PINC AI™. Froedtert Hospital demonstrated significantly higher survival rates associated with cardiac care, with fewer readmissions and complications. To select top performers, an objective, independent, quantitative research analysis was performed using publicly available data measuring cardiac care in the U.S. Those in the top 50 operated at a lower cost and had better outcomes, had significantly higher inpatient survival rates, fewer patients with complications, lower readmission rates and spent up to $5,076 less in total costs per patient case. If all hospitals operated at the level of the top 50, there would be 7,600 fewer deaths due to heart disease, 6,700 fewer patients with complications and more than $1 billion saved each year, according to the analysis.

    The Society for Vascular Surgery's Vascular Quality Initiative (SVS VQI) has awarded Froedtert Hospital three out of three stars for its active participation in the Registry Participation Program. The mission of the SVS VQI is to improve patient safety and the quality of vascular care delivery by providing web-based collection, aggregation and analysis of clinical data submitted in registry format for all patients undergoing specific vascular treatments. The VQI operates 14 vascular registries.

    The American Heart Association recognized Froedtert Hospital with its Get With the Guidelines® Heart Failure Gold Plus Award. In addition, the hospital was recognized on the AHA’s Target: Heart Failure(SM) Honor Roll and received the AHA’s Target: Type 2 Diabetes Honor Roll™ award. 

    The American Heart Association also recognized Froedtert Hospital with its Get With the Guidelines® — Coronary Artery Disease Mission: Lifeline STEMI Receiving Silver Plus and Mission: Lifeline NSTEMI Silver awards. These awards demonstrate our commitment to improving care by adhering to the latest treatment guidelines and streamlining processes to ensure timely and proper care for heart attacks.

    The American Heart Association recognized Froedtert Hospital with its Get With the Guidelines® AFib Gold Award.

    ​The Cardiovascular Intensive Care Unit (CVICU) and Neurosurgical Intensive Care Unit (NICU) at Froedtert Hospital have each received a silver-level Beacon Award for Excellence from the American Association of Critical-Care Nurses. This award recognizes unit caregivers who successfully improve patient outcomes and align practices with AACN’s six Healthy Work Environment Standards. Receiving this national three-year award with gold, silver and bronze designations, marks a significant milestone on the path to exceptional patient care and achieving a healthy work environment.