Cardiomegaly

Author: Vanessa Mora

Editor: Nelly Sadat

 

Overview

Cardiomegaly is a condition resulting in heart enlargement, and often occurs as a symptom of acquired cardiomyopathies (Amin & Siddiqui, 2020). The condition occurs when the transverse diameter of the cardiac silhouette is equal to or exceeds 50% of the transverse diameter of the chest on a computed tomography or chest radiograph  (Amin & Siddiqui, 2020).  Dilated cardiomyopathy is the main type of heart enlargement, where the heart ventricles become thin and stretched (Amin & Siddiqui, 2020). However, heart enlargement may also be caused by hypertrophy, where the ventricles thicken (Amin & Siddiqui, 2020). An enlarged heart may not pump blood efficiently which may lead to heart failure or further cardiovascular diseases and other symptoms (Amin & Siddiqui, 2020).  

Keywords

Cardiomegaly, Heart Enlargement, Megacardia, Megalocardia, Borderline Cardiomegaly, Chronic Cardiomegaly

Epidemiology

Cardiomegaly is present worldwide, with a prevalence of 15 million people (Amin & Siddiqui, 2020). It is also one of the most common conditions in people of African American descent (Amin & Siddiqui, 2020). African American patients may inherit cardiomegaly due to the genetic variants that affect the expression of the Calcium Voltage-Gated Channel Auxiliary Subunit Beta 4 (CACNB4) gene (Xu et al.,2018). These patients are also known to have a higher prevalence for hypertension (Xu et al.,2018). Limited access to health care resources, and poor patient education, were all factors that may contribute to cardiomegaly and potentially heart failure (Xu et al.,2018).

Etiology 

Several conditions that may contribute to cardiomegaly are:

• Acromegaly,
• Alcohol and drug abuse, 
• Amyloidosis,
• Anemia, 
• Arrhythmia,
• Coronary artery disease, 
• Intense Exercise, 
• Heart attack,
• Heart valve anomalies, 
• Hypertension, 
• Hemochromatosis,
• Hypothyroidism,
• Kidney disease, 
• Obstructive sleep apnea,
• Pregnancy, 
• Pulmonary diseases,
• Sarcoidosis,
• Stress,
• Thyroid disorders, 
• Viral infections (i.e. HIV or Chaga disease), or
• Vitamin B1 deficiency (Amin & Siddiqui, 2020)

Symptoms 

Patients with cardiomegaly are asymptomatic (Amin & Siddiqui, 2020). When the condition is more severe, symptoms in symptomatic patients may include the following: 

• Anorexia, 
• Arrhythmia, 
• Chest Pain,  
• Dizziness, 
• Early satiety, 
• Fainting,
• Fatigue,
• Nausea and Vomiting, 
• Orthopnea,
• Paroxysmal nocturnal dyspnea,  
• Shortness of breath on exertion or at rest, 
• Swelling of the lower legs, hands and abdomen, or 
• Weight Gain (Amin & Siddiqui, 2020). 

Risk Factors 

Cardiomegaly may result in the heart having to pump blood harder than usual or when the heart muscle is damaged  (Amin & Siddiqui, 2020). 

Risk factors include:

• Family history of cardiomyopathy
• High blood pressure: May damage the arteries by making them more narrow, resulting in decreased blood flow and oxygen to the heart (CDC, 2020). 
• High cholesterol levels : Excess cholesterol in the heart walls build up and eventually lead to narrowing and arterial lumen blockage, affecting the amount of blood being pumped (Soliman, 2018).
• Obesity: Being overweight may lead to hypertrophy and thickening of the heart muscle, affecting the ability to pump blood efficiently. Obesity is also associated with high blood pressure,diabetes and kidney disease which may lead to cardiomegaly (Ebong et al., 2014).
• Stress: Emotional or physical stress such as grief, fear, extreme anger, and surprise causes adrenaline release resulting in rapid heartbeat and may cause muscle weakness leading to stress cardiomyopathy. Stress may also be associated with high blood pressure and increased cholesterol levels (Ramaraj, 2007). 
• Being an athlete: Intense exercise such as weight lifting, bodybuilding and wrestling  may lead to thickening of muscle, which includes heart muscle and may be the result of morphological, functional, and electrical remodeling of the heart. (Carbone et al.,2017).
• Diabetes: Diabetes may be associated with risk factors such as obesity, high blood pressure and high levels of cholesterol which may result in cardiomyopathy ( Boudina & Abel, 2010).
• Alcohol/ drug use : Substance abuse may weaken and deteriorate heart muscle, affecting the ability to pump blood efficiently (American Heart Association,2020). 

Diagnosis  

Diagnosis of cardiomegaly is commonly performed through physical imaging techniques which provides information regarding the size and function of the patient’s heart. Physicians may also confirm the diagnosis by assessing the patient’s symptoms (Alghamdi et al., 2020). 

Clinical Features 

• Chest X ray : A chest X ray is the most commonly used imaging technique to detect cardiomegaly. If the X-ray shows an enlarged cardiac silhouette with a ratio of more than 50% it may suggest cardiomegaly (Alghamdi et al.,2020).
• Echocardiogram: An echocardiogram produces a live view of the heart and valves. The image produced helps physicians monitor your heart activity and structure (Amin & Siddiqui, 2020).
• Electrocardiogram: An electrocardiogram (ECG) allows physicians to monitor heart activity and can reveal left and right ventricle hypertrophy, dilated cardiomyopathy, conduction abnormality and arrhythmia (Amin & Siddiqui, 2020).
• Cardiac MRI: Allows physicians to accurately evaluate the left and right ventricle mass, size, and function of the heart (Amin & Siddiqui, 2020).
• Stress test: A stress test provides the patient to work out on a treadmill while having pressure monitors attached to the patient’s skin. This helps physicians see how their heart functions during physical activity (Ramaraj, 2007).

Pathological Features  

Blood tests: Your doctor may order blood tests to check serum levels of brain natriuretic peptide, this protein is made by your heart and blood vessels. If the levels of BNP are elevated  (100 pg/mL) then it may be an indication of heart failure (Amin & Siddiqui, 2020).

Genetic screening: If the cause of cardiomegaly can’t be identified, genetic screening may be performed to see if the disease is inherited (ie: CACNB4 gene suggests:Dilated cardiomyopathy) (Xu et al., 2018).

Treatment Protocol 

Treatment of cardiomegaly is advertently associated with the treatment of heart failure, where standard heart failure treatment guidelines may apply (Amin & Siddiqui, 2020).Spironolactone, angiotensin-converting enzyme inhibitors (ACEIs), and β-blockers are treatment options that have been shown to reduce heart failure symptoms and mortality (Amin & Siddiqui, 2020).

Pharmacological Treatment Protocol 

Patients with early onset cardiomyopathy are treated with ACE inhibitors or ARB (if intolerant to ACE) and β-blockers. (Ashley & Niebauer, 2004). ACE inhibitors and β-blockers are drug classes recommended for initial therapy for adults with hypertension, which improve blood flow and decrease the workload on the heart (Herman et al., 2020)

Patients with cardiomyopathy and symptoms of heart failure are managed with diuretics and salt restriction in addition to ACE inhibitors and β-blockers if they have reduced EF (Amin & Siddiqui, 2020).

For patients with moderate to severe symptoms, they are also treated with aldosterone and Digoxin (Amin & Siddiqui, 2020). The primary mechanism of Digoxin and Aldosterone is inhibition of the sodium– potassium adenosine triphosphatase (Na–K–ATPase) enzyme (Ahmed, Young, & Gheorghiade, 2007). Suppression of this enzyme in myocardial cells increases heart-muscle contractions and slows down heart beat in patients with heart failure (Ahmed, Young, & Gheorghiade, 2007)

 Non-Pharmacological Treatment Protocol

Patients with associated risk factors listed above may benefit from modification such as no smoking, limiting alcohol intake, weight loss through exercise and consuming a healthy diet. As well as, treating any underlying risk conditions such as  hypertension, diabetes, sleep apnea, arrhythmias, anemia, and thyroid disorders (Amin & Siddiqui, 2020). 

Articles on Misdiagnosis

Endlicher, E., Fürst, A., Strotzer, M., Messmann, H., Kerner, T., Schölmerich, J., & G. Lock. (1999). “Cardiomegaly and pneumonia”–a misdiagnosis in long-standing achalasia. Dtsch Med Wochenschr, 124(13), 386-90. DOI: 10.1055/s-2007-1024322. 

Puri, A., Vijay, K., Chaudhary, G., Narain, V.S., Sethi, R., & P. Aga. (2012). A rare case of huge cardiomegaly. Journal of the American College of Cardiology, 60(19), 1985. DOI: 10.1016/j.jacc.2012.04.061. 

Delgado-Montero, et al. (2014). An unusual case of cardiomegaly. Circulation, 129(3), 396-398. DOI: 10.1161/CIRCULATIONAHA.112.000099.

References 

Ahmed, A., Young, J. B., & M. Gheorghiade. (2007). The underuse of digoxin in heart failure, and approaches to appropriate use. CMAJ : Canadian Medical Association journal = journal de l’Association medicale canadienne, 176(5): 641–643. 

Alghamdi, S. S., Abdelaziz, I., Albadri, M., Alyanbaawi, S., Aljondi, R., & A. Tajaldeen (2020). Study of cardiomegaly using chest x-ray. Journal of Radiation Research and Applied Sciences, 13(1): 460-467. 

Amin H, & W.J. Siddiqui (2020). Cardiomegaly. Treasure Island (FL): StatPearls Publishing.

Ashley E.A., & J. Niebauer. Cardiology Explained. London: Remedica; 2004. Chapter 7, Heart failure.

Boudina, S., & E. D. Abel. (2010). Diabetic cardiomyopathy, causes and effects. Reviews in endocrine & metabolic disorders, 11(1): 31–39. 

Carbone, A., D’Andrea, A., Riegler, L., Scarafile, R., Pezzullo, E., Martone, F., America, R., Liccardo, B., Galderisi, M., Bossone, E., & R. Calabrò. (2017). Cardiac damage in athlete’s heart: when the “supernormal” heart fails!. World journal of cardiology, 9(6): 470–480. 

CDC. (2020). High Blood Pressure Symptoms and Causes. 

Ebong, I. A., Goff, D. C., Jr, Rodriguez, C. J., Chen, H., & A. G. Bertoni. (2014). Mechanisms of heart failure in obesity. Obesity research & clinical practice, 8(6): e540–e548. 

Herman L.L., Padala S.A., Annamaraju P., et al. (2020). Angiotensin converting enzyme inhibitors (ACEI). Treasure Island (FL): StatPearls Publishing.

Ramaraj R. (2007). Stress cardiomyopathy: aetiology and management. Postgraduate medical journal, 83(982): 543–546. 

Soliman G. A. (2018). Dietary cholesterol and the lack of evidence in cardiovascular disease. Nutrients, 10(6): 780. 

Xu, H., Ii, G. D., Shetty, A., Parihar, A., Dave, T., Robinson, S., & S. Liggett. (2018). A genome-wide association study of idiopathic dilated cardiomyopathy in african americans. Journal of Personalized Medicine, 8(1): 11.