Heart enlargement, also known as cardiomegaly, occurs when the heart grows larger than usual due to other conditions. This results in a thicker or dilated heart, which affects the heart as a whole or only certain parts of it.¹ There can be enlargement of the atria, ventricles, or both.¹ Cardiomegaly indicates that a patient is experiencing another condition, which needs to be diagnosed to determine the cause of the enlarged heart. To prevent this condition from progressing to life-threatening cardiovascular complications, it must be detected early.³ It can be diagnosed in many ways; in this article, we will focus on echocardiography, which uses ultrasound (high-frequency sound waves) to assess the structure and functioning of the heart.¹

Overview of echocardiography

Echocardiography is a standard test used to show the flow of blood through the heart and its valves. A hand-held probe is placed on the chest to take pictures of the heart's valves and chambers, which healthcare professionals use to detect heart conditions. Therefore, it makes it an important tool for diagnosing heart enlargement.^4,5

The following types of echocardiography may be used:

• Transthoracic echocardiography (TTE): This is the standard echocardiogram, a noninvasive technique that forms images of the heart from the outside of the body. To enhance the quality of the images to see the heart's structures, a dye can be administered to patients intravenously
• Transesophageal echocardiography (TEE): If the TTE doesn’t provide enough information, TEE is used. It provides images of the heart in more detail, specifically looking at the main artery, the aorta. By placing a probe in the oesophagus, images of the heart are taken from inside the body, mainly looking at the aortic valve
• Stress echocardiography: This test examines how a patient's heart reacts to physical activity or stress, usually when coronary heart disease is suspected. It is carried out right before and after exercising in a hospital setting. The patient can be given medication to make their heart beat faster if they are unable to exercise
• Fetal echocardiography: This echocardiogram is carried out during pregnancy. It is also non-invasive, as a probe is placed over the pregnant woman's stomach to examine the unborn baby’s heart⁴

To perform these different types of echocardiograms, different techniques may be required:

• 2D or 3D ultrasound: Using 2D ultrasound, slices of the heart are generated on a computer, which are stacked to show a 3D structure. With a 3D ultrasound, you can see the heart's different aspects and how well it pumps blood accurately
• Doppler ultrasound: Doppler signals are used here to show the direction and how fast blood flows through the heart. It can indicate blocked/leaky valves and check for high blood pressure in the arteries
• Colour flow imaging: This shows the blood flow in the heart in colour, which can enable leaky heart valves or changes in the blood flow to be detected^4,5

Diagnosing heart enlargement with echocardiography

Echocardiograms are able to visualise the structure and function of the heart. This test measures the dimensions of heart chambers (atria, ventricles, and the overall structure of the heart) and the thickness of heart walls. In both cases, this helps to identify the type and extent of the enlargement of the heart.

Through echocardiography, different types of heart enlargement can be detected, such as:

• Left ventricular hypertrophy (LVH): A condition where the left ventricular mass increases, causing an increase in ventricle wall thickness, which occurs in 15-20% of the general population. There are several causes of it, but hypertension and aortic valve stenosis are the most common. A measurement known as the left ventricular mass index (LVMI) is obtained after the echocardiogram. LVH is detected in these patients when the LVMI value is greater than 95g/m in women and greater than 115g/m in men, according to the American Society of Echocardiography and/or European Association of Cardiovascular Imaging⁶
• Dilated cardiomyopathy (DCM): In this condition, the heart muscles become enlarged or dilated in one or both ventricles. In addition, a reduced contractility of the heart muscle is seen, which can be identified by the echocardiogram when the left ventricular ejection fraction (LVEF) is below 40%. The cause of this condition is mainly unknown, but it is progressive, leading to heart failure and death. Men are more likely to suffer from this condition than women, and survival rates are low unless transplants are given to patients at the right time⁷
• Hypertrophic cardiomyopathy (HCM): This condition can be caused by mutations in sarcomere protein genes that control the heart's ability to pump blood. The left ventricular wall thickness increases as a result. It is important to know family history in patients with HCM because 60% are caused by genetic mutations, while the others are unknown. In echocardiograms, this condition is detected in around 0.2% of the general population, making it a less common type of enlargement of the heart⁸

Identifying causes of heart enlargement with echocardiography

In general, when a heart is forced to work harder than usual it becomes enlarged, thickens, and its performance worsens. So, it is important to understand the many contributing factors to heart enlargement, which include:¹

• Coronary heart disease that can progress into a myocardial infarction (heart attack) - this is the most common cause
• Hypertension (high blood pressure)
• Arrhythmias (heart rhythm problems)
• Heart valve disease
• Viral infection causing myocarditis (inflammation of the heart muscle)
• Anaemia (low red blood cell levels)
• Pregnancy
• Congenital heart disease
• Hyperthyroidism and Hypothyroidism (overactive and underactive thyroid gland)
• COPD and Pulmonary hypertension (lung diseases)
• Hemochromatosis (build-up of iron in the heart)
• Cardiac amyloidosis (protein deposit buildup in the heart)^1,3

Echocardiography is therefore useful in identifying these specific factors that contribute to the enlargement of the heart.

Advantages of echocardiography in diagnosing heart enlargement

In the case of heart enlargement, echocardiography is one of the most important diagnostic tools for detecting heart conditions, particularly enlarged hearts. There are many advantages to this test, which is why it is important to be aware of them:

• Non-invasive: Using sound waves repeatedly on patients with continuous monitoring is safe and painless
• Portable system: The echocardiogram machine can be easily transported to patients within and outside of a hospital
• Convenient: Results are provided quickly and are reproducible to confirm the diagnosis
• Real-time imaging: A real-time image of the heart size, structure, and function can be observed immediately, along with any abnormalities
• Measurement of heart chambers: Accurately measures the size and thickness of the heart's chambers and walls, which determines whether the heart is enlarging
• Cost-effective: It is less expensive than MRI or CT scans, which are available in most hospitals
• Treatment guidance and planning: It can be used to determine the extent and cause of heart enlargement, so that the appropriate medication, surgery, or lifestyle changes can be made^6,9

Limitations of echocardiography in diagnosing heart enlargement

Although echocardiography is an effective method of testing for heart enlargement, it does have its limitations. These include:

• Limited image quality: A patient with obesity or chest deformities may have difficulties getting a clearer image of the heart, as the sound waves are unable to penetrate into the chest. It could be that the data obtained from this test is not enough to determine whether a patient has an enlarged heart
• Limited data: Some complex heart defects cannot be detected by echocardiography, so MRIs or CT scans may be needed instead
• Operator-dependent skills: The health care professional conducting the echocardiogram must be skilled, since how accurate the diagnosis will be based on the quality and interpretation of the images
• Maintenance: In the case of echocardiograms that are transported, there will be a greater need for maintenance, which can be expensive^6,9

Summary

Echocardiography is a crucial test for diagnosing heart enlargement as it provides information regarding the heart's size, structure, and function. Heart enlargement usually arises as a result of other conditions, most of which are cardiovascular, which echocardiograms can identify. Patients need to be diagnosed early to avoid these conditions from worsening into any life-threatening complications. After interpretation of the obtained data, necessary treatments can be started for patients with this condition. If your healthcare professional recommends an echocardiogram, please consider it because it will be beneficial for you if you are experiencing heart enlargement.