What is Ischemic Cardiomyopathy?
Ischemic cardiomyopathy (ICM) is a condition that reduces the heart’s ability to pump blood properly. This happens due to damage caused by ischemia, which is when the heart muscle doesn’t get enough oxygen. In discussing ICM, it’s important to mention another condition called coronary artery disease (CAD). CAD happens when plaques, or fatty deposits, form in the heart’s arteries, reducing their ability to deliver nutrients and oxygen to the heart muscle that helps the heart beat.
ICM can lead to a range of health issues, ultimately causing congestive heart failure (CHF), a condition where the heart cannot pump enough blood to meet the body’s needs. At first, there’s a temporary drop in the heart’s ability to pump due to a lack of oxygen. However, if the heart muscle continues to lack oxygen for a long period, it can cause permanent damage. This damage changes the heart’s normal structure and function through a process called remodeling, primarily due to something called myocardial fibrosis, which is a kind of scarring of the heart muscle.
This remodeling process can cause the heart to function poorly, cause irregular heart rhythms (arrhythmia), and potentially disrupt the heart’s electrical system that keeps it beating regularly.
What Causes Ischemic Cardiomyopathy?
CAD, short for Coronary Artery Disease, is often the cause of a heart condition known as ischemic cardiomyopathy. This happens when the heart’s blood supply is not sufficient to meet the heart muscle’s demands, leading to the death of heart cells and scarring of the heart tissue. This can also cause an enlargement and stretching of the left part of the heart (the left ventricle).
There are certain risk factors that can increase the chances of someone developing ischemic cardiomyopathy. These risk factors can be divided into two categories: those you can change, and those you can’t.
Those risk factors you can change (modifiable) include:
– Diabetes: having high levels of sugar in your blood
– High blood pressure (hypertension)
– Smoking (tobacco use)
– High levels of fats (like cholesterol and triglyceride) in your blood (hyperlipidemia)
– Being overweight (obesity)
– Leading a sedentary, or inactive, lifestyle
Those risk factors you can’t change (non-modifiable) include:
– Getting older (age)
– Being a certain gender (men are at higher risk)
– Having a family history of heart disease (family predisposition)
Risk Factors and Frequency for Ischemic Cardiomyopathy
Coronary artery disease (CAD) is the most common cause of death among adults in the United States. According to the 2016 update from the American Heart Association, there are approximately 15.5 million adults in the country with CAD. The total number of deaths caused by this disease is around 102.6 per 100,000 people. Additionally, a heart attack, also known as a myocardial infarction, occurs every 42 seconds. Age is a key factor influencing one’s risk of developing CAD.
- CAD is the foremost cause of death in American adults.
- There are about 15.5 million US adults suffering from CAD as per 2016 reports.
- The death rate from CAD is approximately 102.6 per 100,000 people.
- A myocardial infarction, or heart attack, happens every 42 seconds.
- Age is a significant risk factor for CAD.
- In the United States, the lifetime risk of developing CAD with at least two major risk factors stands at 37.5% for men and 18.3% for women.
Signs and Symptoms of Ischemic Cardiomyopathy
When looking at a patient’s medical history for signs of chronic coronary artery disease (CAD) – a condition that impacts the blood vessels that supply the heart – doctors will often find evidence of the disease lasting for a long time or even previous heart attacks. It’s also crucial to learn about the patient’s family and lifestyle to better understand the risk factors related to CAD. People with this condition may experience different symptoms based on their bodies’ ability to compensate for the heart problem.
Interestingly, some people may not have any noticeable symptoms, while others may feel mild chest pain, shortness of breath during physical activity, or they have trouble exercising and get tired easily. In severe cases, individuals may have symptoms that are typical of heart failure, such as shortness of breath, difficulty in breathing while lying flat, low stamina, and fatigue.
During a physical check-up, doctors may notice a series of signs that suggest a heart issue. This can include:
- Crackling sounds at the base of both lungs
- An extra recurrent heart sound known as an S3 gallop, which usually happens when the left part of the heart is enlarged
- A heartbeat that can be felt further to the left than normal
- Abnormal or noisy blood flow in the neck arteries
- Swelling in the neck veins
- A bodily response where the liver causes the neck veins to swell
- Swelling in both lower legs
Testing for Ischemic Cardiomyopathy
If your doctor suspects that you have ischemic cardiomyopathy – a disease in which your heart muscle is weakened due to insufficient blood flow – they will use a series of tests to confirm diagnosis and understand the condition better.
A chest x-ray is a simple and quick test that takes pictures of the organs and structures inside your chest. It can show if your heart is enlarged (cardiomegaly), a common symptom of ischemic cardiomyopathy. It may also reveal other signs of heart failure such as fluid in the lungs (pulmonary congestion), abnormal lines in the lungs (Kerley B lines), fluid around the lungs (pleural effusion), and blunting of the space between the diaphragm and ribs.
An electrocardiogram or ECG is a test that records the electrical activity of your heart. It gives your doctor information about your heart rate, rhythm, and whether you’ve had any previous episodes of reduced blood flow to the heart. It can also indicate if any part of your heart is enlarged and how well your heart’s electrical system is working.
A transthoracic echocardiography (TTE) is an ultrasound-based test that uses sound waves to create a detailed picture of your heart. It lets your doctor see your heart’s structure, as well as your heart valves and how well they are working. It also measures how well your heart can pump blood (systolic/diastolic function), if any part of your heart’s wall is moving abnormally, and if there’s any abnormal fluid around your heart.
A cardiac stress test checks how well your heart works under physical stress. Depending on your health status and ability to exercise, different types of stress tests might be used. These tests can help diagnose whether your heart is not getting enough blood supply (ischemia) and also provide information about the viability of your heart muscle tissue.
Coronary angiography is a test that uses dye and special x-rays to show the inside of your coronary arteries. It helps your doctor see where and how much your arteries are blocked and how well blood is flowing to your heart. During the same procedure, your doctor might perform a percutaneous coronary intervention (PCI), where a tiny balloon is expanded inside your blocked artery, followed by the placement of a small metal tube (stent) to keep the artery open.
CT Coronary Angiography (CTCA) uses a CT scanner to take pictures of your coronary arteries. This is particularly useful for low-intermediate risk patients.
Brain natriuretic peptide (BNP) test is a blood test used to measure levels of a protein called BNP that your heart produces when it’s under stress. High levels suggest that you have heart failure.
Cardiac Magnetic Resonance Imaging (MRI) helps differentiate between ischemic and non-ischemic cardiomyopathies. It uses a compound called gadolinium to help see damage to the heart muscle (fibrosis) and whether there are areas of the heart that could recover with treatment.
Nuclear medicine imaging, including a test called 99mTechnetium sestamibi myocardial perfusion imaging, is used to assess the viability (functionality) of heart muscle tissue. It helps to locate areas of the heart muscle that are “hibernating”, or alive but not functioning properly, which may benefit from procedures to restore blood flow.
Treatment Options for Ischemic Cardiomyopathy
Ischemic cardiomyopathy, a heart problem caused by narrowed or blocked blood vessels, is primarily managed with medication and lifestyle changes like quitting smoking, exercising, and changing diet. However, some patients may benefit from a medical procedure for re-establishing good blood flow to the heart, known as revascularization. The goal is to rejuvenate areas of the heart muscle that aren’t receiving adequate blood flow.
As part of their therapy, patients may be given medications like aspirin. Aspirin has been shown to greatly reduce heart disease and increase survival rates. Other medications that may help include beta-blockers—an example of a beta-blocker is atenolol or metoprolol. These medications help slow your heart rate and decrease its workload, lowering the heart’s need for oxygen.
High potent statins, another group of medicines, help to reduce harmful cholesterol levels, which can increase survival rates in patients with heart-related diseases.
Drugs known as angiotensin-converting enzyme (ACE) inhibitors, like enalapril and lisinopril, can be beneficial for heart health. ACE inhibitors lower blood pressure and reduce strain on the heart.
Another class of medication known as angiotensin II receptor blockers (ARB), which includes medicines like valsartan and losartan, also help to lower blood pressure. However, these are often preferred if the patient has side effects like cough from ACE inhibitors.
There are also medicines like hydralazine and nitrate for patients who can’t tolerate ACEI or ARB.
Another group of drugs, angiotensin receptor neprilysin inhibitors (ARNI), have been shown in recent studies to reduce hospitalizations and deaths related to heart failure.
Spironolactone, a potassium-sparing diuretic, has shown to be beneficial to patients with severe heart failure. Some patients might be given digoxin to help manage symptoms and decrease hospitalizations for heart failure, although it’s not known to reduce death rates.
Patients might also be recommended to take drugs like ranolazine that help to control chest pain.
Furthermore, some patients with severe ischemic cardiomyopathy may benefit from having an implanted cardioverter defibrillator (ICD) or a pacemaker that helps correct abnormal heart rhythms.
Finally, in severe circumstances where no other therapies provide relief, a heart transplant may be considered as the only remaining option.
What else can Ischemic Cardiomyopathy be?
Ischemic cardiomyopathy is a condition that results in enlarged heart chambers (ventricles) and can show up as a reduced percentage of blood being pumped out of the large, pumping chamber on the left side of the heart (left ventricular ejection fraction) in an echocardiogram. It can also cause symptoms of heart failure in patients whose bodies can’t compensate for the disease. However, there are many other conditions that might look like this.
For instance, patients who are under severe physical or mental stress, or have taken certain types of stimulating drugs, can show abnormal heart wall movements and reduced left ventricular ejection fraction. This is often referred to as Takotsubo cardiomyopathy, or stress cardiomyopathy. This can be distinguished from Ischemic cardiomyopathy based on who it typically affects and certain tests performed during a heart catheterization.
Other conditions that a physician might consider include:
- Thyrotoxicosis (an excessive amount of thyroid hormones in the body)
- Beriberi caused by a lack of vitamin B1 (thiamine)
- Cardiac tamponade (pressure on the heart caused by fluid in the sac around the heart)
- Poisoning from heavy metals
- Late-stage hypertrophic cardiomyopathy (a disease where the heart muscle becomes abnormally thick)
- Myocarditis (inflammation of the heart muscle)
- Restrictive cardiomyopathy (a condition where the heart chambers become stiff and can’t fill with blood properly)
What to expect with Ischemic Cardiomyopathy
The outlook for ischemic cardiomyopathy, a type of heart disease, depends on the stage and duration of the disease. One key factor that affects this outlook is myocardial viability, which refers to the health and function of the heart muscle. Greater myocardial viability usually leads to better outcomes for patients who undergo revascularization, a procedure that improves blood flow to the heart, because it suggests that the heart muscle can recover.
On the other hand, patients who have non-viable myocardial injury, meaning heart muscle that’s permanently damaged, are usually recommended to manage their condition with medication as prescribed by their doctor. Along with suitable treatment and changes to their lifestyle, such as healthier eating and regular exercise, the progress of ischemic cardiomyopathy can be significantly slowed down.
Possible Complications When Diagnosed with Ischemic Cardiomyopathy
Ischemic cardiomyopathy can cause a variety of complications. The most frequent one is the onset of clinical congestive heart failure, which is typically the way Ischemic Cardiomyopathy first shows itself. As the heart grows, its natural electrical pathways alter, leading to irregular heart rhythms. These abnormal heart rhythms could be life-threatening.
Various Complications:
- Clinical congestive heart failure
- Abnormal heart rhythms
- Potential life-threatening situations
Preventing Ischemic Cardiomyopathy
Changing the way you live and consistently taking your prescribed medicines are key elements in treating ICM (Ischemic Cardiomyopathy, a condition where your heart muscles are weak due to less blood and oxygen). Healthcare professionals will recommend changes like healthy eating, regular exercise, and quitting smoking. In addition, they will also educate you on how to manage other related conditions like diabetes, problems with fat levels in your blood (dyslipidemia), and high blood pressure (hypertension).
