The patient with cardiomegaly may sometimes be asymptomatic for a variable period of time. Depending of the underlying disease and severity of compromise of cardiac function, the presentation may include:

• Dyspnea on exertion and on supine position
• Dizziness
• Syncope
• Palpitations
• Arrhythmia
• Fluid retention (pedal edema)

Other symptoms depending on the causative disease may have been present from before, like chest pain in cardiac ischemic disease, systemic symptoms in thyroid dysfunction or renal disease, etc.

• Pulmonary Valve Stenosis

  Causative and associated factors are: Coronary artery disease Hypertension Heart valvular disease (e.g. mitral regurgitation, pulmonary valve stenosis) Aortic coarctation Idiopathic dilated cardiomyopathy Hyperthyroidism and hypothyroidism Anemia Infective [symptoma.com]

• Hypoventilation

  Thus, the mechanism of postural left lower lobe hypoventilation in cardiomegaly is predominantly a regional loss of alveolar volume. [ncbi.nlm.nih.gov]

• Heart Disease

  Cause: There are a large number of heart diseases and other diseases that can lead to the enlargement of the heart. [symptoma.com]

  I51.5 Myocardial degeneration I51.7 Cardiomegaly I51.8 Other ill-defined heart diseases I51.81 Takotsubo syndrome I51.89 Other ill-defined heart diseases I51.9 Heart disease, unspecified I52 Other heart disorders in diseases classified elsewhere I60 [icd10data.com]

  Some people are born with heart disease. [icdlist.com]

  Cardiomegaly was probably multifactorial (chronic hypertension, ischemic heart disease and acromegaly). To our knowledge, this is the first reported case of massive cardiomegaly behaving as an intraabdominal mass. [ncbi.nlm.nih.gov]

• Heart Murmur

  ‘Manifestations include cardiomegaly, heart murmur (mitral regurgitation, aortic regurgitation), friction rub secondary to pericarditis, and congestive heart failure.’ [en.oxforddictionaries.com]

  Heart murmur: Some of the heart’s valves may not shut correctly due to cardiomegaly. This causes a backflow of blood, which leads to sounds called heart murmurs. Heart murmurs may be harmless but should be monitored. [medicalnewstoday.com]

  Some types of issues that can arise include: heart failure heart murmur blood clots causing pulmonary embolism fainting, cardiac arrest, sudden death caused by disruption in your heart’s rhythm Treatment for an enlarged heart is pinpointing which one [healthblurbs.com]

  This flow creates sounds called heart murmurs. Although not necessarily harmful, heart murmurs should be monitored. Cardiac arrest and sudden death : Some forms of enlarged heart can lead to disruptions in the heart's beating rhythm. [ipfs.io]

  Related: What is heart murmur? Causes, symptoms, risk factors, and treatment options [belmarrahealth.com]

• Cardiac Signs and Symptoms

  Cardiomegaly in the context of other specific cardiac signs or symptoms, however, does predict abnormal echo findings. [academic.oup.com]

  Although these diseases most often have non-cardiac signs and symptoms, in rare instances disease expression can be confined to only the heart [ 62 ]. [doi.org]

• Systolic Murmur

  Detection of a systolic murmur at the left upper sternal border, fixed splitting of S2, and telecardiographic evidence of cardiomegaly are important findings for the diagnosis of ASD. [acikerisim.dicle.edu.tr]

• Skin Edema

  Earlier gestational age at diagnosis, skin edema, and chromosomal abnormality were associated with higher mortality. CONCLUSIONS: Majority causes of FC were cardiac and anemic in origin. It carried high-perinatal mortality depending on the causes. [ncbi.nlm.nih.gov]

A diagnosis of cardiomegaly is frequently based on radiological findings correlated to the clinical picture. A complete medical history and physical examination is mandatory.

Investigations include:

• Routine blood analysis with tests for thyroid function and viral infections.
• Chest X-ray to assess the shape and size of the heart and lungs. Usually the Danzer method is used, and cardiothoracic ratio > 0.5 indicates cardiomegaly [9].
• Stress test to assess cardiac function
• 2 D-Echocardiogram: The size of the chambers, dimension, volume and the thickness of the walls, pumping function, valve function, volume status and pericardial effusion, and congenital heart disease can be assessed.
• Doppler study to assess valvular function and hemodynamics
• Electrocardiogram to assess heart rhythm and evidence of old infarction or ischemia.
• Cardiac computerized tomography (CT) or magnetic resonance imaging (MRI)
• Cardiac catheterization and biopsy may be rarely required in tumors or amyloidosis [10].

• Cardiomegaly on Chest X-ray

  Abramoff and Pruitt who used bedside ultrasound to evaluate a patient with cardiomegaly on chest X-ray. Their patient had a history of untreated hypothyroidism and presented to the ED with a chief complaint of shortness of breath. [em.emory.edu]

  Specialty: Cardiology MeSH Code: D006332 ICD 9 Code: 429.3 Cardiomegaly on chest X-ray and a pacemaker Source: Wikipedia Coding Notes for I51.7 Info for medical coders on how to properly use this ICD-10 code Inclusion Terms: Inclusion Terms Inclusion [icd.codes]

  […] on chest X-ray. [en.wikipedia.org]

Treatment depends on the underlying cause. Treatment options include:

• Medications: Required for control of underlying disease, like hypertension, thyroid disease or infections. Diuretics may be given for certain conditions. Angiotensin-converting enzyme inhibitors and beta-blockers given for hypertension may have beneficial effects on cardiac function.
• Medical procedures: Cardiac catheterization with stenting can improve blood flow to the heart muscle in coronary artery disease. Implantable cardioverter-defibrillator can manage arrhythmias.
• Surgical procedures: For valvular disease. Severe congestive heart failure may require cardiac transplant.
• Lifestyle management: Stop use of alcohol, drug, or medication causing cardiomegaly. Diet, cessation of smoking, exercise and medication to help control high blood pressure is recommended.

Cardiomegaly leads to reduction in intrathoracic space and limits the ability of the lungs to fill adequately, leading to pulmonary dysfunction. Pulmonary embolism, cardiac arrest and sudden death may occur as complications of cardiomegaly. Congestive heart failure is a common outcome. Prognostic considerations depend on the underlying disease.

Causative and associated factors are [3] [4] [5] [6]:

• Coronary artery disease
• Hypertension
• Heart valvular disease (e.g. mitral regurgitation, pulmonary valve stenosis)
• Aortic coarctation
• Idiopathic dilated cardiomyopathy
• Hyperthyroidism and hypothyroidism
• Anemia
• Infective endocarditis
• Viral myocarditis (for example due to coxsackie virus)
• Rheumatic heart disease
• Chronic kidney disease leading to uremia 
• Previous myocardial infarction
• Lifestyle factors (sedentary lifestyle, obesity)
• Pregnancy (peripartum cardiomyopathy)
• Alcohol or cocaine abuse
• HIV infection
• Genetic and inherited conditions like congenital heart disease
• Sickle cell disease
• Hemochromatosis 
• Pericardial effusion
• Cardiac amyloidosis
• Athletic heart syndrome
• Atrial septal defect
• Primary congestive heart failure, or secondary congestive heart failure
• Connective tissue disease (e.g. systemic lupus erythematosus (SLE))
• Dilated cardiomyopathy due to thiamine deficiency
• Hypertrophic cardiomyopathy
• Hypoalbuminemia from malnutrition and chronic liver disease
• Glycogen storage disease type 2
• Myocardial fibroelastosis
• Primary tumors of the heart
• Drugs such as doxorubicin
• Acromegaly 
• Age related

Apart from the etiological factors, a family history of cardiomyopathy leads to increased risk of developing cardiomegaly. Specific prevalence of cardiomegaly, it being a sign and not a disease, is difficult to assess, and the epidemiological factors of underlying conditions are relevant.

Cardiomegaly is of two types:

• Dilative cardiomegaly: The enlargement of the heart results from the dilation of the myocardium. Dilated cardiomyopathy, the most common form of non-ischemic cardiomyopathy, leads to cardiomegaly. There is no wall hypertrophy in dilated cardiomyopathy, but left ventricular cavity size is increased with impairment in systolic function. Viral myocarditis for instance results in dilative cardiomegaly [7].
• Hypertrophic cardiomegaly: The cardiac muscle undergoes hypertrophy when a high workload is imposed for a prolonged period of time. Physiological and reversible cardiac hypertrophy is seen in athletes and pregnant women. Pathologic hypertrophy is the result of diseases that lead to increased demand on the heart, e.g., hypertension, cardiac valvular disease, and myocardial infarction. Chronic hypertension results in left ventricular hypertrophy due to increased afterload on the left ventricle [8]. In general, increased stress on myocardium to maintain stroke volume leads to muscle hypertrophy. In heart failure, a diminished ejection fraction leads to more stress on myocardium to maintain cardiac output. Left ventricular failure leads to enlargement of the remaining heart chambers as well.

Timely diagnosis and aggressive management of common cardiovascular diseases like hypertension, ischemic heart disease, etc., can prevent the development of cardiomegaly. Regular follow-up during the treatment of the causative diseases can prevent the complications of cardiomegaly. Once cardiomegaly has developed, proper and regular treatment can halt the enlargement and improve cardiac function.

Cardiomegaly is an abnormal enlargement of the heart that can arise from a number of underlying diseases and some physiological factors. Common associations are hypertension, coronary artery disease and cardiac valvular disease, endocarditis and genetic conditions. Exertional dyspnea, palpitations, arrhythmias, fatigue, and pedal edema are common presenting features. Cardiomegaly may lead to congestive cardiac failure [2].

Definition: Cardiomegaly is the enlargement of the heart due to any underlying disease.

Cause: There are a large number of heart diseases and other diseases that can lead to the enlargement of the heart. These include high blood pressure, coronary artery disease, chronic kidney and liver disease, infections of the heart, anemia, thyroid gland disease, diseases of the valves of the heart, sickle cell disease, and congenital heart diseases, to name a few.

Symptoms: Patient may experience shortness of breath, especially on exertion or lying down. There may be difficulty in breathing. Palpitations and dizziness may be there. In case of acute chest pain, severe difficulty in breathing and fainting, there is a possibility of a myocardial infarction, and one must seek emergency treatment. There may be fluid accumulation and swelling of the feet. Other symptoms may occur according to the underlying disease.

Diagnosis: The doctor will take a detailed history and carry out a detailed physical examination. You may require an electrocardiogram and stress test on a treadmill. The diagnosis of cardiomegaly requires an X-ray of the chest, and other studies of the heart like 2-D and Doppler echocardiography, computed tomography and magnetic resonance imaging. Rarely, a biopsy of the heart may be required.

Treatment and follow-up: The treatment is according to the causative disease. You will be advised to stop smoking and start certain diet or exercise regimes according to you condition. Medication will be given to control the disease and prevent further enlargement of the heart. Proper and prolonged follow-up is essential and sometimes lifelong treatment may be required. In some cased, medical or surgical procedures may be required.

1. Bonow RO, Mann DL, Zipes DP et al. Braunwald's Heart Disease, A Textbook of Cardiovascular Medicine. W B Saunders Company; 2012.
2. American Heart Association. Enlarged heart. Updated: Mar 27, 2013. Accessed: Feb 23, 2015
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4. Chiu B, Sergi C. Dilated cardiomyopathy: etio-morphologic investigation. Front Biosci (Schol Ed). 2010; 2:112-6.
5. Campbell M. Schultz JC, Hilliard AA, Cooper LT, Rihal CS. Diagnosis and treatment of viral myocarditis. Mayo Clin Proc. 2009; 84(11):1001-9.
6. Natural history of coarctation of the aorta. Br Heart J. Sep 1970; 32(5):633-40.
7. Jefferies JL, Towbin JA. Dilated cardiomyopathy. Lancet. 2010; 375(9716):752-62.
8. Cingolani HE, Perez NG, Aiello EA, et al. Early signals after stretch leading to cardiac hypertrophy. Key role of NHE-1. Front Biosci. 2008; 13:7096-114.
9. Chon SB, Oh WS, Cho JH, Kim SS, Lee SJ. Calculation of the cardiothoracic ratio from portable anteroposterior chest radiography. J Korean Med Sci. 2011; 26(11):1446-53.
10. Lawler PR, Bergmark BA, Laubach JP, Lakdawala NK. Having a heavy heart: approaches to infiltrative cardiomyopathy. Circulation. 2014; 129(16):1703-11.