Cardiomegaly - Causes, Symptoms, Diagnosis, and Treatment

What Is Cardiomegaly?

Cardiomegaly, also known as megalocardia, refers to an excessive enlargement of the heart. For the heart to be abnormally big, there has to be an increase in the cardiothoracic ratio. Its transverse diameter should be greater than or equal to fifty percent of the chest’s diameter. This means that the inner diameter of the heart should be 50 % bigger than the ribcage.

What Is the Mechanism Behind Cardiomegaly?

Two main types of cardiomyopathies (conditions that make it hard for the heart to pump blood efficiently) are accountable for cardiomegaly, specifically; dilative and hypertrophic.

• Dilative Cardiomyopathy: It is the primary reason for cardiomegaly. It occurs due to malfunction in the heart’s primary pumping chamber (left ventricle) due to a volume overload and is marked by dilation and stretching of the heart muscles.

• Hypertrophic Cardiomyopathy: It is associated with the thickening of the ventricles (blood vessels) and heart muscle walls, which can hinder blood flow and eventually lead to cardiomegaly.

What Are the Causes of Cardiomegaly?

Cardiomegaly can be caused by numerous reasons and is always a manifestation of an underlying pathological condition. The various causes are as follows:

• Congenital Heart Defects- These are defects found at the time of birth. A few examples are atrial septal defect, ventricular septal defect, and tetralogy of Fallot.

• Valvular Heart Diseases- When any heart valve is affected, it impairs the efficacy of the heart’s normal function. A few examples of valvular diseases are valvular stenosis, valvular prolapse, and aortic regurgitation.

• Pulmonary Diseases- Make it difficult for the heart to pump effectively and pump blood to the various body parts. A few examples of pulmonary diseases include pulmonary hypertension (high blood pressure affecting arteries of the lungs and heart’s right side), chronic obstructive pulmonary disorders (COPD), and pulmonary embolism (blocked arteries in the lungs). All these conditions lead to cor pulmonale, wherein the heart’s right ventricle enlarges.

• Infiltrative Diseases- Diseases such as sarcoidosis (lumps of inflammatory cells seen at various sites in the body), amyloidosis (protein deposition at unusual locations in the body), and hemochromatosis (excessive buildup of iron in multiple organs of the body) make the heart work harder to fill up blood and distribute it throughout the body.

• Systemic Diseases- Such as anemia, hyperthyroidism, and Beri-Beri put the heart in a hyperdynamic circulatory state, leading to a high output and cardiac malfunctions, including enlargement of the heart.

• Toxin-Induced Cardiomyopathies- When exposed for long, toxins or stimulants such as alcohol, cocaine, and chemotherapeutic agents (such as Doxorubicin, Cyclophosphamide, and Trastuzumab) damage and weaken the heart wall. Once the heart walls are weakened, the heart swells up to hold more blood.

• Stress-Induced Cardiomyopathy- Excessive emotional or physical stress can lead to cardiac dysfunction.

• Infectious Myocarditis- Various viral and bacterial diseases can inflame the heart muscle, impairing heart health and causing the heart to enlarge. A few examples of illnesses are HIV-AIDS (human immunodeficiency virus- acquired immunodeficiency syndrome) and subacute myocardial endocarditis.

• Peripartum Cardiomyopathy or Postpartum Cardiomyopathy- A rare type of heart failure that occurs in the last month of pregnancy.

• Heart Diseases- Heart diseases like coronary artery disease (CAD), myocardial infarction, and ischemic heart diseases are the most common causes of cardiomegaly.

• Kidney Failure- When kidney function is impaired, the heart works harder to circulate blood to the rest of the body, which leads to hypertension, eventually causing heart disease.

What Are the Symptoms of Cardiomegaly?

• Arrhythmias (abnormal heart rhythm).

• Chest pain.

• Dizziness or lightheadedness.

• Dyspnea (shortness of breath).

• Stomach bloating.

• Swelling of the lower limbs, especially in the ankles and feet.

• Fatigue.

How Does a Physician Diagnose Cardiomegaly?

The examination to diagnose cardiomegaly is an amalgamation of physical examination, family history, genetic testing, and imaging tests.

• Physical Examination: The physician uses a stethoscope to inspect heart sounds in order to identify heart malfunction. The physician will also look for signs of heart failure. A few signs of heart failure are:

• Swelling in the lower limbs, especially at the ankles.

• Crackles in the lungs due to fluid accumulation.

• Fluid accumulation in the neck veins, making them appear engorged.

• Family History and Genetic Testing: Family history and genetic tests help identify any genetically transmitted diseases.

• Imaging Tests: The following imaging tests can help diagnose cardiomegaly:

• Chest X-Ray: It records images of the lungs, heart, blood vessels, and airways using special beams of radiation called the X-ray beam.

• Cardiac CT-Scan or Cardiac Computed Tomography Scan: A non-invasive diagnostic imaging procedure that shows detailed images of the heart and its associated structures, such as blood vessels and valves. It gives more comprehensive scans when compared to those of traditional angiograms. At times, doctors may advise a ‘contrast cardiac CT’ (computed tomography). It involves injecting a special dye (also known as contrast) and helps amplify the images.

• Transthoracic Echocardiogram (TTE): Evaluation of the heart and chest wall is done using ultrasound.

• Electrocardiogram (EKG or ECG): This diagnostic test helps evaluate numerous heart conditions by assessing different electrical signals of the heart. This test involves using several electrodes, which help record the electrical signals from the heart and identify irregular and additional heartbeats.

• Stress Test: This is a diagnostic technique that records the response of the heart under stressful conditions. With the help of a stationary bike or treadmill, the heart undergoes an intense level of stress or activity. The response of the heart to the stress generated is recorded and assessed via the EKG.

• Heart Magnetic Resonance Imaging (Heart MRI): Cardiac MRI creates detailed images of the heart and its associated structures using magnetic and radio waves.

How Is Cardiomegaly Managed?

The first step in the management of cardiomegaly involves identifying its root cause. Once the root cause is identified, a treatment plan is made accordingly. In some individuals, conscious lifestyle modifications can help resolve the underlying cause, whereas, in others, physicians may advise medications or surgical interventions.

What Are the Complications of Cardiomegaly?

• Heart failure.

• Embolism.

• Cardiac arrest.

• Valvular regurgitation.

What Are the Symptoms of Hospitalization?

One should rush to the hospital if they have any of the following symptoms:

• Uneasy sensation in the chest with pain radiating to arms, neck, jaws, and back.

• Breathlessness, especially at rest.

• Light-headedness.

• Fatigue, even at rest.

Conclusion

Cardiomegaly is the enlargement of the heart and is a sign of a disease or condition that strains the heart. It could occur due to primary or acquired myopathies. It may involve the entire heart, a single or multiple chambers. In most cases, symptoms disappear once the underlying root cause has been identified and treated. Individuals with mild cardiomegaly do not elicit any symptoms and may remain undiagnosed.

Conversely, patients with severe cardiomegaly need immediate medical attention. The incidence of heart failure usually increases with age and when there are other comorbidities present. Studies show that patients diagnosed in the early stages of heart failure have a good prognosis. Hence, it is vital to get routine body check-ups so that any underlying condition can be identified as early as possible and the required intervention can be done.