Dilated Cardiomyopathy is a disease of the heart muscle
Dilated cardiomyopathy (DCM) is a form of nonischemic cardiomyopathy and is the most common kind of heart muscle disease when the heart’s lower left ventricle – which is the primary pumping chamber –stretches and dilates (expands) because of its inability to pump the blood effectively and efficiently through the body.
Initially the chambers of the heart respond by stretching and holding additional blood to pump through the body helping to strengthen the heart’s contraction, keeping the blood moving. However, this compensatory expansion is not effective over the long term as the heart muscle walls get weak over time and are unable to pump effectively and the problem starts spreading to the right ventricle and atria and also in the lower and upper chambers of the heart respectively, making the heart weak and leading to heart failure, problems in the heart valve, an enlarged heart, blood clots and irregular heartbeats (arrhythmias)
What are the typical symptoms of dilated cardiomyopathy?
Many people with dilated cardiomyopathy have no warning signs or symptoms or have only minor symptoms in the early stages while others can develop life-threatening symptoms before they are diagnosed and this progresses as heart function gradually worsens. According to the American Heart Association, Dilated cardiomyopathy most often occurs in adults aged 20 to 60. Symptoms of dilated cardiomyopathy may include:
- Shortness of breath due to exertion (dyspnea) or fatigue (excessivey tiredness)
- Weight gain, cough or congestion due to retention of fluid
- Blood vessels responses abnormally during exercise
- Inability to exercise or carrying out daily activities
- Dizziness or lightheadedness
- Difficulty in lying flat or popping up head gasping for air
- Chest pain or pressure
What are the complications that can cause or result from dilated cardiomyopathy?
Heart failure: Heart’s inability to supply the required blood from the left ventricle for proper function, leading to heart failure.
Myocardial ischemia: When oxygen supply to the heart muscle is not enough due to coronary artery disease.
Swelling of the lower extremities: Swollen ankles, feet, legs (edema) and abdomen due to fluid buildup (ascites).
Abnormal heart rhythms (Arrhythmias): If there are changes in pressure of heart chambers or structure of the heart, it can be due to Arrhythmia which can lead to syncope, palpitations, fluttering or blood clots
Sudden cardiac arrest: When the heart suddenly stops beating, causing death
Heart valve regurgitation: This is essentially a leakage of the heart valves caused by the enlargement of left ventricle making it harder for the heart valves to close tightly causing blood to flow backwards to the heart and thereby hindering the heart’s ability to pump blood effectively.
Blood clots: Blood gets clotted in the dilated left ventricle due to pooling (slow flow or statis) of the blood entering the blood stream cutting off the supply of blood to the vital organs and causing heart attacks, strokes or damaging other organs. If there is a breakage of the clot then it can lodge in the artery, disrupting the flow of blood to the brain and resulting in a cerebral stroke. Other organs can also be affected by blockages in the flow of blood to the abdomen, legs, lungs, kidney, brain, etc.
There are different types of dilated cardiomyopathy based on the underlying causes
Often, causes of dilated cardiomyopathy are difficult to pinpoint. There can be numerous factors causing the disease but the following are the typical categories:
Ischemic cardiomyopathy: Heart attack, coronary heart disease or coronary artery disease can weaken the heart and lead to dilated cardiomyopathy.
Alcoholic cardiomyopathy: When the condition is caused by excessive drinking and a poor diet.
Familial dilated cardiomyopathy: Genetic conditions can also be the cause of disease. Around one-third of people with dilated cardiomyopathy have inherited it from their parents.
Valvular cardiomyopathy: It is caused due to heart valve disease or abnormalities
Peripartum cardiomyopathy: When the complications occur and the disease develops in the last stage of pregnancy or after childbirth.
Primary cardiomyopathy: When other cardiac conditions are not found and, yet, the heart muscle is found to be weak.
Congestive cardiomyopathy: When the heart is stretched, becomes weak and heart doesn’t pump effectively.
Diabetic cardiomyopathy: It is a disorder of the heart muscle in people who have diabetes.
Idiopathic dilated cardiomyopathy: When the underlying cause or trigger of the disease is not known.
There are several other possible triggers of dilated cardiomyopathy and include the following:
Infections: Viral hepatitis, HIV and other viral infections which can lead to inflammation of the heart muscle; this can also result from infections caused by fungi, bacteria and parasites.
Diseases or conditions: High blood pressure (hypertension), thyroid disease.
Toxins: Exposure to cobalt, lead, mercury which are all toxic and can damage the heart muscle.
Drugs: Use of cocaine or amphetamines or other recreational drugs.
Medicines: Certain cancer medications such as daunorubicin or doxorubicin.
What are the tests required to diagnose dilated cardiomyopathy?
Blood tests: To check if there are any infections in the heart or presence of any metabolic disorder or toxins in the blood that can cause dilated cardiomyopathy.
Chest X-ray: To check heart and lungs if there are any changes or abnormalities in the structure, size or presence of fluid in or around the lungs.
Electrocardiogram (ECG or EKG): It records the electrical signals as they travel through your heart, patterns that indicates the sign of heart rhythms which are abnormal in nature or any problem in the left ventricle. The Holter monitor which is a ECG device might be required to record heart rhythms continuously for a period of a day or two.
Echocardiogram: It uses sound waves that produces images of the heart to check if there is any enlargement of the left ventricle, see the amount of blood ejected from the heart with every beat and validate if the flow of blood is in the right direction.
Exercise stress test: An exercise test can be performed on a treadmill attaching electrodes to measure heart rate and intake of oxygen.
CT or MRI scan: To check the heart’s pumping chambers for their size and function.
Cardiac catheterization: This is an invasive procedure in which a long and narrow tube is threaded in the arm through a blood vessel going into your heart and enables the doctor to check the coronary arteries on X-ray and measure the pressure in the heart. There can be more invasive tests to check the pumping of the heart or to scrutinize blockages of blood vessels with the help of cardiac catheterization. A coronary angiography may be required to examine the condition of the coronary arteries in which a dye is injected into the coronary arteries.
Genetic screening or counseling: If no cause is identified the then screening of family members may be suggested to check if the disease is inherited.
Myocardial biopsy, or heart biopsy: This is done using a microscope to example a small sample of harvested heart muscle tissue to check for the symptoms of cardiomyopathy.
How do you treat dilated cardiomyopathy?
Dilated cardiomyopathy can be treated primarily with combinations of medicines depending on the symptoms and include the following categories:
ACE inhibitors: Angiotensin-converting enzyme inhibitors widen or dilate the blood vessels (vasodilators). They increase blood flow in the heart, lower blood pressure and decrease the workload of the heart, thereby improving its functionality. An example of an ACE inhibitor is Enalapril.
Side effects: low blood pressure, problems in the kidney or liver, low count of white blood cells.
Angiotensin II receptor blockers: It is an alternative for those who are unable to tolerate ACE inhibitors
Side effects: Diarrhea, dizziness or cramps in muscles.
Beta blockers: It slows down the heart rate, mitigating the risk of stress hormones causing heart failure or abnormal heart rhythms, reduces blood pressure and heart’s workload preventing further damage and improves the overall function of the heart. Examples of Beta blockers include metoprolol (Lopressor and Toprol XL) and carvedilol (Coreg).
Side effects: Low blood pressure, dizziness.
Diuretics: Also known as water pills, these are blood-thinning medications which help in eliminating excess fluid from the lungs for normal breathing. An example is Digoxin (Digitalis) which strengthens the contractions of the heart muscles, its ability to pump blood, slows down the heartbeat, reduces symptoms of heart failure. Other medications such as aspirin or Warfarin prevent clotting of blood.
Side effects: Excessive bleeding or bruising
What are some of the non-medication treatments or implantable devices used to treat dilated cardiomyopathy?
There is no cure for Dilated Cardiomyopathy but treatments can help in managing or controlling the symptoms and prevent complications. One of the following treatments may be required depending on the severity of the symptoms and how severely the heart is affected by the disease which includes:
Cardiac resynchronization using a biventricular pacemaker:
Leads (tiny wires) are implanted into the right ventricle and coronary sinus vein or usually in the right atrium through a vein (under the collar bone) helping the heart to beat in a more balanced and regular manner and helping improve the coordination between the heart chambers. It is also known as AV synchrony. It helps the ventricles to contract with more force, stimulating the right and left ventricles to pump together. It sends sending electrical impulses to the heart through the leads which helps people with dilated cardiomyopathy by improving heart blockages, unduly slow heart rates (bradycardias) and other symptoms.
Implantable cardioverter defibrillators (ICD). ICDs are useful when there is life-threatening arrhythmias or to prevent sudden cardiac death with fibrillation or sustained ventricular tachycardia. It is a battery powered pulse generator device placed under the skin (below the collar bone). It can also be implanted through blood vessels to avoid open-heart surgery. Leads or thin wires connect the device to the heart, keeping track of the heart rate. It detects abnormal heart rhythm and restores it back to normal by delivering an electric shock whenever needed.
Surgery. Conventional surgeries for coronary artery disease or valvular disease may be recommended. Some people may be eligible for surgical repair of the left ventricle or placement of a cardiac assist device.
Left ventricular assist device (LVAD): It is a mechanical device or pump that is placed in the abdomen or chest and attached to the heart, helping the left ventricle (the main pumping chamber) of the heart to pump blood more effectively to the entire body.
Heart transplant: When all the medications and treatments fail to work and if the condition of the patient doesn’t improve, leading to heart failure, a heart transplant can be performed to increase the chances of survival. It is done by removal of the diseased heart and replacing it with a healthy heart from a deceased donor.
What are the self-care strategies to manage the symptoms of dilated cardiomyopathy?
To make heart stronger maintain a healthy lifestyle and habits that help in preventing or minimizing the effect of the disease which include the following:
- Quit smoking or drinking alcohol, or drink only in moderation.
- Quit using cocaine or other recreational drugs.
- Maintain a healthy and low sodium (salt) diet.
- Avoid too much exertion and get enough rest and sleep.
- Control your weight.
- Follow a regular cardiovascular exercise regimen as recommended by a doctor.