What is Cardiomegaly (Enlarged Heart)?
Cardiomegaly refers to a condition where the heart is larger than normal. This enlargement is defined by the heart’s width being 50% or more of the width of the chest, as seen in an X-ray or CT scan from the back to the front of the chest. It’s important to note that this is different from an enlarged cardiomediastinal outline, which is where the heart and its surrounding structures are bigger than normal.
Cardiomegaly is typically a symptom of another problem and is associated with various types of cardiomyopathies – diseases of the heart muscle. These might be conditions someone is born with (primary) or conditions they develop (acquired). The condition can cause enlargement in any part of the heart – the left, right, or both ventricles (the lower chambers), or the atria (the upper chambers).
Many conditions involving the heart muscle, like dilated cardiomyopathy, often involve the left ventricle getting bigger and not pumping properly (systolic dysfunction). But, the right ventricle can also be affected, and the heart can even have difficulty relaxing and filling with blood (diastolic dysfunction).
What Causes Cardiomegaly (Enlarged Heart)?
Cardiomegaly, a condition where the heart enlarges, can lead to two types of heart diseases called dilated or hypertrophic cardiomyopathy. Various factors can cause this:
- Coronary artery disease, like a heart attack or lack of sufficient blood flow to the heart. This is the most common cause.
- High blood pressure that affects the heart.
- Heart valve diseases that involve narrowing or leaking of the heart’s aortic, mitral, pulmonary, or tricuspid valves, or bacterial infections in the heart lining.
- Heart disorders present from birth, like a hole in the upper or lower chambers of the heart, or other conditions like tetralogy of Fallot, Ebstein anomaly, and coarctation of the aorta.
In addition to the above, certain lung diseases can also cause cardiomegaly. These include high blood pressure in the arteries that supply blood to the lungs, chronic obstructive pulmonary disease (COPD), hypoventilation syndrome in obese people, and blood clots in the lungs with right-heart failure.
- Some infections might lead to heart inflammation. This is often due to viruses but can also occur because of HIV or Chaga disease.
- Tissue deposition diseases, such as abnormal protein build-up, sarcoidosis, underactive thyroid, acromegaly, and iron overload disorder can play a role.
- Substances like alcohol, cocaine, or certain chemotherapy drugs (like doxorubicin, cyclophosphamide, trastuzumab) and radiation can induce cardiomegaly.
- Some immune system diseases that create inflammation in the heart tissues.
- Heart rhythm problems, like atrial fibrillation and flutter that lead to rapid heartbeat-related cardiomyopathy, and a heart disorder (ARVC) that replaces right ventricle muscle with fibrous and fatty tissue.
- Systemic diseases that increase blood flow, like anemia, overactive thyroid, vitamin B1 deficiency, and artery and vein connections.
- Natural conditions such as stress cardiomyopathy, enlargement of the heart due to exercise, or increased heart size during pregnancy.
Genetic factors could also be involved, leading to hypertrophic obstructive cardiomyopathy. Lastly, cardiomegaly may also appear during late pregnancy (Peripartum cardiomyopathy) or may occur without any known cause (Idiopathic cardiomyopathy).
Risk Factors and Frequency for Cardiomegaly (Enlarged Heart)
Heart enlargement, through stretching or thickening, can lead to a variety of heart failure symptoms. This condition is quite common in the United States, affecting nearly 5.8 million people. Over half of these cases are classified as heart failure with preserved ejection fraction (HFpEF). The occurrence of heart failure is more common with increasing age, in males, and in the African American community. Sadly, about half of the people diagnosed with this condition don’t live more than five years after their diagnosis.
In adults, dilated cardiomyopathy, a kind of heart disease which makes the heart bigger and weaker, is more common in men. For children, the yearly occurrence is 0.57 cases per 100,000 per year; boys, black kids and infants below one year old are at a higher risk. Two-thirds of these children suffer from an idiopathic disease, which means the cause is unknown.
- Hypertrophic cardiomyopathy is a worldwide disease, occurring in over 50 countries.
- It affects men and women across various ethnic and racial backgrounds.
- In many regions like the USA, Europe, China, Japan and East Africa, it is a common genetic heart ailment.
- Approximately 1 in 500 people in the general population has this disease.
Signs and Symptoms of Cardiomegaly (Enlarged Heart)
Cardiomegaly, or an enlarged heart, often doesn’t show symptoms. Diagnosing this condition relies primarily on imaging methods, and a patient’s history mainly helps pinpoint what’s causing symptoms linked to heart failure. These symptoms usually indicate an overload in the bodily systems and insufficient blood flow to the organs.
During a detailed examination, your doctor will be interested to know if you have experienced any of the following:
- Shortness of breath during physical activity or rest
- Sudden breathlessness during sleep
- Swelling in the legs and abdomen
- Tiredness and difficulty exercising
- Heart palpitations, dizziness, or fainting spells
- Chest pain
- Loss of appetite, nausea, and feeling full early on in a meal
- Family history of heart muscle disease
- Recent pregnancy or childbirth
- Other medical conditions, such as high blood pressure and diabetes.
Note that some patients with an enlarged heart still function well at rest but struggle during physical activity. Your symptoms could change with activity levels. The severity of your condition is usually classified based on your symptoms.
One commonly observed sign of Cardiomegaly is a displaced heart’s impulse. This means the place on the chest where the heart’s beat is strongest has shifted. Other symptoms relate to the size of the left and right ventricles, backflow in the heart valves, and changes caused by the heart muscle’s remodeling. These symptoms can vary based on whether a person has heart failure.
During a detailed physical check-up, the doctor might also look for:
- Rapid heartbeat due to increased nervous system activity
- Narrow pulse range due to decreased blood flow from the heart to the body
- Respiratory distress based on the condition’s severity
- Cool, blue-tinged skin because of narrowed blood vessels
- An elevated jugular vein and/or a positive abdominojugular test indicating higher blood pressure on the right side of the heart
- Ascites, swollen liver, and swelling in the legs from elevated pressure in liver and systemic veins
- Breathing sounds that crackle due to increased liquid pressure in the air sacs in the lungs
- Sounds of S3 gallop (early diastole) and S4 gallop (late diastole) indicating volume overload and inadequate heart function respectively.
Testing for Cardiomegaly (Enlarged Heart)
Diagnosing an enlarged heart, or cardiomegaly, relies mainly on imaging techniques that check the size and function of the heart. Several diagnostic tests can be used to do this:
– A chest X-ray can reveal if the heart is enlarged. The image may show that the ratio of the heart to the chest is over 50%, which indicates cardiomegaly. The x-ray can also show if specific chambers in the heart are abnormal in size. The right ventricle and right atrial may cause the heart to move in unusual ways when enlarged, while enlargement of the left ventricle can push the left border of the heart to the left. Left atrial enlargement could lead to a “double density” sign. The x-ray might also reveal signs of heart failure, including changes in the blood vessels in the lungs and signs of fluid buildup in the lungs and pleural cavities (spaces around the lungs).
– A transthoracic echocardiogram (an ultrasound of the heart) can supply additional information about the size and function of the ventricular and atrial compartments of the heart and its valves. This technology can also detect areas of the heart with abnormal motion, which could point to a decreased blood supply.
– Cardiac MRI is a newer technique that provides detailed pictures of the heart. It can examine in great detail the size, function, and “weight” of the ventricles. Moreover, it can distinguish between heart damage caused by inadequate blood supply and inflammation of the heart muscle (myocarditis).
– An electrocardiogram (ECG) can disclose signs of enlargement of the ventricles, conduction abnormalities in the heart’s electrical system, abnormal heart rhythms (arrhythmias), precursors to heart attacks (premature ventricular complexes), changes to the ST-T wave that could indicate a previous heart attack, and signs of chronic heart muscle damage.
– Blood tests can also be helpful, especially during heart failure. These might include tests for brain natriuretic peptide, troponin I, and troponin T (which can indicate heart muscle damage), tests of kidney and liver function.
In cases where the cause of the enlarged heart is still unclear, additional testing might be recommended, such as stress tests or coronary angiograms. These tests evaluate the heart’s function, particularly looking for coronary artery disease.
Treatment Options for Cardiomegaly (Enlarged Heart)
Treatment for mild cardiomegaly, or an enlarged heart, depends on dealing with the root cause of the issue. The normal guidelines for treating heart failure also work for cases of moderate to severe cardiomegaly that are linked with heart failure.
Patients who are at risk of developing cardiomyopathy can help themselves by working on altering their lifestyle habits. For example, stopping smoking, restricting the amount of alcohol consumed, losing weight, engaging in regular exercise, and maintaining a balanced diet can all have substantial positive impacts. It’s also crucial to deal with any pre-existing health conditions that might enhance the risk, such as high blood pressure, high cholesterol, diabetes, sleep apnea, abnormal heart rhythms, anemia, and thyroid disorders.
Asymptomatic patients with early onset cardiomyopathy are usually managed by modifying these risk factors and adding specific medications. These include an angiotensin-converting enzyme (ACE) inhibitor or ARB (used if ACE inhibitors cause side effects) and a beta-blocker in cases where there’s a history of a heart attack or reduced pumping efficiency of the heart.
Patients who have cardiomyopathy and are showing signs of heart failure are recommended to limit their salt intake and may also be prescribed diuretics, which help to rid the body of excess fluid, on top of the aforementioned interventions. If such patients are also experiencing reduced heart efficiency, they should take an ACE inhibitor or ARB, and a beta-blocker. Some of these patients may also be given an ARNI, which is a combination of ARB and another heart medication, to decrease the risk of heart failure hospitalization and death. More severe cases may be treated with additional drugs to further reduce the risk of death. In some situations, a device may be implanted to regulate the heart’s rhythm and prevent sudden cardiac death. Extreme cases could consider heart transplantation and other advanced medical therapies.
Currently, no drug has been found to be helpful in a specific type of heart failure, called HFpEF. The primary treatments in such cases involve managing underlying conditions like high blood pressure and heart rate in patients experiencing irregular heart rhythms such as atrial fibrillation. If necessary, a procedure may be performed to improve blood flow through the heart.
Scientists are currently researching new ways to treat heart disease, including enhancing the body’s natural defenses against heart damage and altering specific parts of our genetic code. The goal is to better manage these conditions and decrease the number of people suffering from heart failure, especially those with diabetes.
What else can Cardiomegaly (Enlarged Heart) be?
When medical professionals look at a chest X-ray, they sometimes see a condition referred to as cardiomegaly, which simply means that the heart appears larger than normal. There are several reasons why this might happen:
- Pericardial effusion: a collection of excess fluid around the heart.
- Anterior mediastinal mass: a lump or growth in the area of the chest that separates the lungs.
- Prominent epicardial fat pad: extra visible fat around the outer layer of the heart.
- Mediastinal widening: enlargement of the space in the chest between the lungs, often due to conditions affecting the lungs or aorta (the main artery in the body).
- Expiratory radiograph: This term refers to the X-ray taken when the patient breathes out, which might make the heart appear bigger due to the decrease in lung volume.
- AP projection: This means an X-ray was taken from front to back, which can make the heart look larger due to the angle.
- Thymus tumor: a growth in the thymus, a small organ in the upper chest under the breastbone, could cause the heart to appear larger on the X-ray.
- Cardiac neoplasms: These are tumours or abnormal growths in the heart.
- Myocarditis: This is a condition where the heart muscle becomes inflamed.
These are all possible reasons why the heart might appear larger on a chest X-ray, and each one will help doctors determine the next best step for diagnosis and treatment.
What to expect with Cardiomegaly (Enlarged Heart)
Despite advancements in medical treatments, the mortality rate for patients with symptomatic heart failure (HF) remains high. Roughly, 30% of these patients do not survive the first year, and half do not survive beyond five years. The intensity of symptoms, old age, and hospitalization for HF significantly increase the risk of death.
The outlook for patients with dilated cardiomyopathy (an illness that enlarges and weakens the heart’s main pumping chamber) is not very optimistic. Most of such patients develop chronic heart failure eventually, and many require a heart transplant or a device to help their heart function, which could lead to further health issues.
Around half of these patients don’t survive beyond five years. For those with hypertrophic cardiomyopathy, a condition that thickens heart muscle and affects its functioning, death rates of 1% to 4% have been reported. However, these figures have improved significantly over the past 20 years. Even though most patients do not show symptoms, the first sign of the condition is often sudden death due to dangerous irregular heart rhythms. The mortality rate is highest among young individuals.
Possible Complications When Diagnosed with Cardiomegaly (Enlarged Heart)
Cardiomegaly, or an enlarged heart, can be caused by many different medical conditions, which means the potential complications can also vary greatly. It’s important to be aware of these possible complications:
- Decompensated heart failure – where the heart can’t pump enough blood to meet the body’s needs
- Sudden cardiac death and malignant ventricular arrhythmias – where the heart suddenly stops beating or beats irregularly
- Thromboembolism secondary to mural thrombi – where a blood clot forms in the heart and can potentially break off and cause a blockage elsewhere in the body
Preventing Cardiomegaly (Enlarged Heart)
It’s crucial for patients to follow their doctor’s instructions about taking their medication, sticking to certain dietary restrictions, and keeping regular follow-up appointments. This helps ensure the best possible results. Additionally, if a family member is diagnosed with a heart condition called hypertrophic obstructive cardiomyopathy, it’s important for the whole family to go through a screening procedure to identify if others may also be affected.
