CARDIOMEGALY: ENLARGEMENT OF THE HEART
By Kashaf Shehzad
ABSTRACT:
Cardiomegaly suggests enlargement of the heart. The definition is where the transverse estimation of the heart plot is more noticeable than or comparable to half of the transverse separation across of the chest (extended cardio-thoracic extent) on a back preeminent projection of a chest radiography or an enrolled tomography. It should not be confused with an expanding of the cardio mediastina format. Cardiomegaly is commonly a sign of another pathological method and presents with a couple of kinds of fundamental or picked up cardiomyopathy. It may incorporate widening of the right, left, or the two ventricles or the atria.
INTRODUCTION
Cardiomegaly means enlargement of the heart. The definition is when the transverse diameter of the cardiac silhouette is larger than or up to 50% of the transverse diameter of the chest (increased cardio-thoracic ratio) on a posterior-anterior projection of a chest radiography or a computerized tomography. It shouldn’t be confused with an enlargement of the cardio mediastinal outline. Cardiomegaly is typically a manifestation of another pathological process and presents with several sorts of primary or acquired cardiomyopathy. it may involve enlargement of the right, left, or both ventricles or the atria.
Causes of heart enlargement:
Your heart can enlarge due to a condition you’re born with — congenital — or a heart problem that develops over time. The most common causes of cardiomegaly are ischemic cardiac disease and high blood pressure. The ischemic cardiac disease occurs when narrowed arteries, caused by fatty deposits that build up in your arteries, prevent blood from getting to your heart.
Other conditions that may make your heart enlarge include:
Cardiomyopathy
Cardiomyopathy may be a progressive cardiac disease with several types. Diseases that damage the cardiac muscle can cause it to enlarge. The more damage that happens, the weaker and less able to pump the heart becomes.
Heart valve disease
Infections, connective tissue diseases, and a few medications can damage the valves that keep blood flowing within the right direction through your heart. When blood flows backwards, the heart needs to work harder to push it out.
Heart attack
During heart failure, blood flow to a part of the heart is blocked completely. the shortage of oxygen-rich blood damages the heart muscle.
Thyroid disease
The thyroid gland produces hormones that regulate the body’s metabolism. Both overproduction (hyperthyroidism) and underproduction (hypothyroidism) of those hormones can affect the pulse rate, blood pressure, and size of the heart.
Irregular cardiac rhythm (arrhythmia)
If you have an irregular heartbeat, rather than beating in its familiar lub-dub pattern, the heart flutters or beats too slowly or quickly. An irregular cardiac rhythm can cause blood to back up within the heart and eventually damage the muscle.
Congenital conditions
Congenital cardiomegaly may be a heart disorder you’re born with. Congenital heart defects that cause this symptom to include:
- Atrial ventricular septal defect (VSD), a hole within the wall separating the two upper chambers of the heart
- Ventricular septal defect (VSD), a hole within the wall separating the two lower chambers of the heart
- Coarctation of the aorta, a narrowing of the aorta, the main artery that carries blood from the heart to the whole of the body
- Patent ductus botalli, a hole within the aorta
- Ebstein’s anomaly, the issue with the valve that separates the two right chambers of the heart (atrium and ventricle)
- Tetralogy of Fallot (TOF), a mixture of birth defects that disrupt the regular flow of blood through the heart
Other possible causes of cardiomegaly include:
- Lung disease, including chronic obstructive pulmonary disease (COPD)
- Myocarditis
- Pulmonary hypertension
- Anemia
- Connective tissue diseases, like scleroderma
- Drug and alcohol use
Epidemiology
Enlargement of the heart both in the form of dilatation or hypertrophy results in a spectrum of clinical congestive heart failure syndrome with a prevalence of nearly 5.8 million people in the US. congestive heart failure with preserved Ejection Fraction (HFpEF) represents over half of these cases. The incidence of congestive heart failure increases with age, male gender, and African American race. About half of the people diagnosed with congestive heart failure die within 5 years of diagnosis.
Pathophysiology
The development of cardiac remodeling and hypertrophy is complex with genetic and non-genetic components. the foremost critical pathophysiological changes resulting in cardiomegaly include dilated hypertrophy, fibrosis, and contractile malfunction. Contractile dysfunction and abnormal myocardial remodeling can cause cardiomyopathy or dilated cardiomyopathy. Mechanical stretching, circulating neurohormones and oxidative stress are significant stimuli for the signal transduction of inflammatory cytokines and MAP kinase in cardiomyocytes. Signal transduction results in changes in structural proteins and proteins that regulate excitation-contraction. Dilated cardiomyopathy mutations lead to a reduced force of the sarcomere contraction and a discount in sarcomere content. cardiomyopathy mutations result in a molecular phenotype of hyper dynamic contractility, poor relaxation, and increased energy consumption.
Risk factors
You may be at increased risk of developing cardiomegaly if you’ve got any of the subsequent risk factors:
- High blood pressure: Having a blood pressure measurement above 140/90 millimetres of mercury.
- A family history of enlarged hearts or cardiomyopathy: If an instantaneous loved one, like a parent or sibling, has had cardiomegaly, you’ll be more susceptible.
- Congenital cardiac disease: If you’re born with a condition that affects the structure of your heart, you’ll be at increased risk.
- Heart valve disease: the heart has four valves — aortic, mitral, pulmonary and tricuspid that open and shut to direct blood flow through your heart. Conditions that damage the valves may cause the heart enlargement.
DIAGNOSIS
Your doctor will start with a physical examination and a discussion of your symptoms. variety of various tests can check the structure and performance of your heart. A chest X-ray could also be the primary test your doctor does because it can show whether your heart is enlarged.
Tests like these can help your doctor find the reason behind the enlargement:
- Echocardiogram (ECG or EKG) uses sound waves to look for problems along with your heart’s chambers.
- Electrocardiogram monitors the electrical activity in your heart. It can diagnose irregular cardiac rhythm and ischemia.
- Blood tests check for substances in your blood produced by conditions that cause cardiomegaly like thyroid disease.
- A cardiovascular test involves walking on a treadmill or pedaling a stationary bike while your cardiac rhythm and breathing are monitored. It can show how hard your heart is functioning during exercise.
- Computerized tomography (CT) scans use X-rays to provide detailed images of your heart and other structures in your chest. It can help diagnose valve disease or inflammation.
- Magnetic resonance imaging (MRI) uses strong magnets and radio waves to provide pictures of your heart.
CHEST RADIOGRAPHY:
Figure Source:
In pregnancy
During pregnancy, doctors can use a test called a fetal echocardiogram to diagnose heart defects within the unborn baby. This test uses sound waves to form pictures of the baby’s heart.
Your doctor might recommend a fetal echocardiogram if you’ve got a family history of heart enlargement or heart defects, or if your baby has a genetic disease like Down syndrome.
Treatment / Management
Treatment of mild cardiomegaly centers upon the treatment of the underlying condition. In moderate to severe cardiomegaly related to congestive heart failure, standard HF treatment guidelines also apply.
- Patients at risk of cardiomyopathy have the benefit of risk factor modification like smoking cessation, limiting alcohol intake, weight loss, exercise, and consuming a healthy diet. Recommendations include treating any underlying risk factors like hypertension, dyslipidemia, and diabetes. Other underlying conditions, including obstructive sleep disorder, arrhythmias, anaemia, and thyroid disorders also require treatment.
- Patients with early-onset hypertrophic cardiomyopathy who are asymptomatic are managed with risk factor modification and also the addition of ACE inhibitor or ARB (if intolerant to ACE) and β-blocker if there’s a history of MI or reduced ejection fraction (EF).
- Patients with cardiomyopathy and symptoms of congestive heart failure are managed with diuretics and salt restriction additionally to the above therapies. All such patients should receive ACE inhibitor or ARB (if intolerant to ACE) and beta-adrenergic blocker if they have reduced EF. An ARNI (ARB plus neprilysin inhibitor) is occasionally used rather than ACE/ARB to cut back hospitalization in congestive heart failure and mortality. For patients with moderate to severe symptoms and reduced EF, the addition of aldosterone antagonists further reduces mortality. A hydralazine/nitrate combination when added to ACE inhibitor, beta-adrenergic blocker, and diuretics improve outcomes in Black patients. Digoxin is added in some patients to cut back the rate of hospitalization with heart failure; however, it doesn’t impact outcomes. An ICD (implantable cardioverter-defibrillator) is placed in patients with EF 35% or less to scale back mortality from sudden cardiac death. CRT (cardiac resynchronization) is performed with or without ICD in patients with EF 35% or less and moderate to severe symptoms with evidence of left bundle branch block
- Patients with refractory congestive heart failure should receive optimal medical management. Also, eligible patients are often considered for cardiac transplantation and bridge therapy like ventricle assist device of special consideration, no pharmacologic agent has shown benefit in HFpEF, and therefore the mainstay of treatment is controlling underlying conditions like hypertension, pulse rate in patients with atrial fibrillation, ischemia with medication and/or coronary intervention, and diuretics for fluid overload. Patients with HOCM (hypertrophic obstructive cardiomyopathy) who are asymptomatic will be safely monitored. Patients who have symptoms of HF and left ventricular outflow tract obstruction, they’ll get have the benefit of negative inotropes like a beta-adrenergic blocker, calcium channel blocker or dipyridamole. Vasodilators and diuretics should be avoided in such patients.
Complications:
The risk of complications from cardiomegaly depends on the part of the heart that’s enlarged and the cause.
Complications of an cardiomegaly can include:
- Heart failure. An enlarged heart ventricle, one among the most serious kinds of cardiomegaly, increases the chance of heart failure. In heart failure, your cardiac muscle weakens, and also the ventricles stretch (dilate) to the point that the heart can’t pump blood efficiently throughout your body.
- Blood clots. Having cardiomegaly may cause you to more at risk of forming blood clots within the lining of your heart. If clots enter your bloodstream, they will block blood flow to vital organs, even causing an attack or stroke. Clots that develop on the right side of your heart may travel to your lungs, a dangerous condition called a pulmonary embolism (PE).
- Heart murmur. For people whose hearts are enlarged, two of the heart’s four valves (the mitral and tricuspid valves) might not close properly because they become dilated, resulting in a back flow of blood. This flow creates sounds called heart murmurs. Although not necessarily harmful, heart murmurs should be monitored by your doctor.
- Cardiac arrest and sudden death. Sometimes cardiomegaly can result in disruptions in your heart’s beating rhythm. Heart rhythms that are too slow to move blood or too fast to permit the heart to beat properly may result in fainting or, in some cases, cardiopulmonary arrest or sudden death.
PREVENTION
You may not be able to prevent conditions that occur before birth. Yet you can prevent later damage to your heart which will make it enlarge by:
- Eating a heart-healthy diet high in fruits and vegetables, lean poultry, fish, low-fat dairy, and whole grains
- Limiting salt, alongside saturated and trans fats
- Avoiding tobacco and alcohol
- Doing aerobic and strength-training exercises on most days of the week
- Checking your blood pressure and cholesterol level regularly, and working along with your doctor to lower them if they’re high
You should also see your doctor for regular checkups to make sure your heart is healthy. If you’ve got a heart problem, you may also need to see a cardiologist.
AUTHOR AND EDITOR
Kashaf Shehzad , BS(hons)Biotechnology(6th semester), is very passionate about writing and has written & edited this article. She was inspired and motivated by her resource person, Miss Iqra Aslam (M Phil Bio-chemistry), Lecturer of Bio-chemistry at University of Management & Technology. This article was reviewed by Dr. Muhammad Ali.
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