What Is Ischemic cardiomyopathy?
Ischemic cardiomyopathy (CM) is the most common type of dilated cardiomyopathy. In Ischemic CM, the heart's ability to pump blood is decreased because the heart's main pumping chamber, the left ventricle, is enlarged, dilated and weak. This is caused by ischemia - a lack of blood supply to the heart muscle caused by coronary artery disease and heart attacks.
Symptoms and Causes
What are the symptoms of ischemic CM?
Symptoms may include:
- Shortness of breath
- Swelling of the legs and feet (edema)
- Fatigue (feeling overly tired), inability to exercise, or carry out activities as usual
- Angina (chest pain or pressure that occurs with exercise or physical activity and can also occur with rest or after meals) is a less common symptom
- Weight gain, cough and congestion related to fluid retention
- Palpitations or fluttering in the chest due to abnormal heart rhythms (arrhythmia)
- Dizziness or lightheadedness
- Fainting (caused by irregular heart rhythms, abnormal responses of the blood vessels during exercise, without apparent cause)
- Learn more about heart failure symptoms
What causes Ischemic CM?
Major risk factors of heart disease, such as family history, high blood pressure, smoking, diabetes, high blood cholesterol, and obesity can also place one at increased risk for cardiovascular disease and ischemic cardiomyopathy.
Diagnosis and Tests
How is Ischemic CM diagnosed?
CM is diagnosed based on your medical history (symptoms and family medical history), physical exam, and other tests. Specific tests may include blood tests, electrocardiogram (ECG), chest X-ray, echocardiogram, exercise stress test, cardiac catheterization, CT scan, MRI scan, and radionuclide studies.
Occasionally, a myocardial biopsy may be performed to determine the cause of cardiomyopathy. During a myocardial biopsy, small tissue samples are taken from the heart and examined under a microscope to determine the cause of the cardiomyopathy.
Management and Treatment
How is Ischemic CM treated?
Treatment of ischemic CM is aimed at treating coronary artery disease, improving cardiac function and reducing heart failure symptoms. Patients usually take several medications to treat CM. Doctors also recommend lifestyle changes to decrease symptoms and hospitalizations and improve quality of life. In addition, devices and surgery may be advised.
Medications are used for two reasons:
- To improve cardiac function
- To treat symptoms and prevent complications
To manage heart failure, most people improve by taking a beta-blocker and ACE inhibitor even when not having symptoms. If symptoms occur and/or worsen,digoxin, diuretics, and aldosterone inhibitors may be added. Other medications will be added as needed. For example, if you have an arrhythmia, your doctor may give you a medication to control your heart rate or lessen the occurrence of arrhythmia. Or, blood thinners may be prescribed to prevent complications when a blood clot develops in the lower heart chamber after a heart attack. Your doctor will discuss what medications are best for you.
- Diet. Once you develop symptoms such as shortness of breath or fatigue, you should restrict your intake of salt (sodium) to 2,000 to 3,000 mg per day. Follow this low-sodium diet even when your symptoms seem to have subsided. Most salt ingested comes from processed food. In addition to removing the salt shaker from the table and when cooking, read all food labels for sodium content and serving size so you can keep track of your sodium intake.
- Exercise. Your doctor will tell you if you may exercise or not. Most people with cardiomyopathy are encouraged to do non-competitive aerobic exercise. Heavy weight lifting may not be recommended.
- Cardiac Resynchronization Therapy (CRT, such as biventricular pacing): In some patients with advanced heart failure, biventricular pacing (a pacemaker that senses and initiates heartbeats in the right and left ventricle) improves survival, reduces symptoms and increases exercise capacity or tolerance. For people with heart block or some bradycardias (slow heart rates), this pacemaker will also serve to maintain an adequate heart rate.
- Implantable Cardioverter Defibrillators (ICD): ICDs are suggested for people at risk for life-threatening ventricular arrhythmias or sudden cardiac death. The ICD constantly monitors the heart rhythm. When it detects a very fast, abnormal heart rhythm, it delivers energy (shock) to the heart muscle to cause the heart to beat in a normal rhythm again. After a heart attack, life-threatening ventricular arrhythmias are more common. This is due to damaged heart muscle. Your doctor will tell you if you meet criteria to have an ICD inserted.
Both devices may be combined in a single unit, usually labeled CRT-D.
Interventional Procedures and Surgery
- Interventional procedures (angioplasty, stents) or bypass surgery may be advised to treat coronary artery disease. In addition, some patients may be candidates for surgical remodeling or reconstruction of the left ventricle or left ventricular assist devices.
- Heart transplant or other heart failure surgical options