Cardiomegaly | |
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Cardiomegaly on chest X-ray with a pacemaker | |
Specialty | Cardiology |
Types | Athletic heart syndrome, [1] Ventricular hypertrophy, Atrial enlargement |
Causes | Dilated cardiomyopathy, [2] [3] [4] [5] Hypertrophic cardiomyopathy. [1] [6] [7] [8] [9] |
Diagnostic method | Hypertrophic cardiomyopathy screening [10] [11] |
Cardiomegaly (sometimes megacardia or megalocardia) is a medical condition in which the heart becomes enlarged. It is more commonly referred to simply as "having an enlarged heart". It is usually the result of underlying conditions that make the heart work harder, such as obesity, heart valve disease, high blood pressure (hypertension), and coronary artery disease. Cardiomyopathy is also associated with cardiomegaly. [12]
Cardiomegaly can be serious and can result in congestive heart failure. Recent studies suggest that cardiomegaly is associated with a higher risk of sudden cardiac death. [13]
Cardiomegaly may diminish over time, but many people with an enlarged heart (dilated cardiomyopathy) need lifelong medication. [14] Having a family history of cardiomegaly may indicate an increased risk for this condition. [15]
Lifestyle factors that can help prevent cardiomegaly include eating a healthy diet, controlling blood pressure, exercise, medications, and not abusing anabolic-androgenic steroids, alcohol and cocaine. [15]
For many people, cardiomegaly is asymptomatic. For others, if the enlarged heart begins to affect the body's ability to pump blood, then symptoms associated with congestive heart failure may arise, including: [15]
The causes of cardiomegaly are not well understood and many cases have no known cause. Lifestyle-related risk factors include tobacco use and high cholesterol, high blood pressure, and diabetes. Non-lifestyle risk factors include a family history of cardiomegaly, coronary artery disease (CAD), congenital heart failure, atherosclerotic disease, valvular heart disease, exposure to cardiac toxins, sleep-disordered breathing (such as sleep apnea), sustained cardiac arrhythmias, abnormal electrocardiograms, and cardiomegaly on chest X-ray.
Research and the evidence of previous cases link the following (below) as possible causes of cardiomegaly.[ citation needed ]
The most common causes of cardiomegaly are congenital (patients are born with the condition based on a genetic inheritance), high blood pressure (which can enlarge the left ventricle causing the heart muscle to weaken over time), and coronary artery disease. In the latter case, the disease creates blockages in the heart's blood supply, leading to tissue death which causes other areas of the heart to work harder, causing the heart to expand in size.[ citation needed ]
Other possible causes include:
In recent years, a consistent theme has occurred in rock and metal drummers dying of drug overdoses and later revealed via Autopsy that they were suffering from Cardiomegaly, which may have been worsened by a mix of drug use and the toll such physical exercise takes on the heart, examples of such cases include Jimmy ‘The Rev’ Sullivan (Avenged Sevenfold) and Taylor Hawkins (Foo Fighters).
Within the heart, the working fibers of the myocardial tissue increase in size. As the heart works harder the actin and myosin filaments experience less overlap which increases the size of the myocardial fibers. If there is less overlap of the protein filaments within the sarcomeres of the muscle fibers, they will not be able to effectively pull on one another. If the heart tissue gets too big and stretches too far, then those filaments cannot effectively pull on one another to shorten the muscle fibers, impacting the heart's sliding filament mechanism. If fibers cannot shorten properly and the heart cannot contract properly, then blood cannot be effectively pumped to the lungs to be re-oxygenated or to the body to deliver oxygen to the working tissues of the body.[ citation needed ]
An enlarged heart is more susceptible to forming blood clots in the heart lining. These clots can form elsewhere in the body, potentially disrupting blood supply to other organs.
Many techniques and tests are used to diagnose an enlarged heart. These tests can be used to see how efficiently the heart is pumping, determine which chambers of the heart are enlarged, look for evidence of prior heart attacks and determine if a person has congenital heart disease.[ citation needed ]
Cardiomegaly can be classified by the main enlarged location of the heart, and/or by the structure of the enlargement.
Specific subtypes include athletic heart syndrome, which is a non-pathological condition commonly seen in sports medicine in which the heart is enlarged, and the resting heart rate is lower than normal.
Dilated cardiomyopathy is the most common type of cardiomegaly. In this condition, the walls of the left and/or right ventricles of the heart become thin and stretched. [29]
In the other types, the heart's left ventricle becomes abnormally thick. Hypertrophy is usually what causes left ventricular enlargement. Hypertrophic cardiomyopathy is typically an inherited condition. [30]
Treatments include a combination of medications and medical/surgical procedures. Below are some of the treatment options:
The exact mortality rate for people with cardiomegaly is unknown. However, many people live for a long time with an enlarged heart and, if detected early, treatment can help improve the condition and prolong their lives. [15]
Cardiology is the study of the heart. Cardiology is a branch of medicine that deals with disorders of the heart and the cardiovascular system. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease, and electrophysiology. Physicians who specialize in this field of medicine are called cardiologists, a specialty of internal medicine. Pediatric cardiologists are pediatricians who specialize in cardiology. Physicians who specialize in cardiac surgery are called cardiothoracic surgeons or cardiac surgeons, a specialty of general surgery.
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest, called the mediastinum.
Cardiomyopathy is a group of primary diseases of the heart muscle. Early on there may be few or no symptoms. As the disease worsens, shortness of breath, feeling tired, and swelling of the legs may occur, due to the onset of heart failure. An irregular heart beat and fainting may occur. Those affected are at an increased risk of sudden cardiac death.
Aortic stenosis is the narrowing of the exit of the left ventricle of the heart, such that problems result. It may occur at the aortic valve as well as above and below this level. It typically gets worse over time. Symptoms often come on gradually with a decreased ability to exercise often occurring first. If heart failure, loss of consciousness, or heart related chest pain occur due to AS the outcomes are worse. Loss of consciousness typically occurs with standing or exercising. Signs of heart failure include shortness of breath especially when lying down, at night, or with exercise, and swelling of the legs. Thickening of the valve without narrowing is known as aortic sclerosis.
Palpitations are perceived abnormalities of the heartbeat characterized by awareness of cardiac muscle contractions in the chest, which is further characterized by the hard, fast and/or irregular beatings of the heart.
Hypertrophic cardiomyopathy is a condition in which muscle tissues of the heart become thickened without an obvious cause. The parts of the heart most commonly affected are the interventricular septum and the ventricles. This results in the heart being less able to pump blood effectively and also may cause electrical conduction problems. Specifically, within the bundle branches that conduct impulses through the interventricular septum and into the Purkinje fibers, as these are responsible for the depolarization of contractile cells of both ventricles.
Dilated cardiomyopathy (DCM) is a condition in which the heart becomes enlarged and cannot pump blood effectively. Symptoms vary from none to feeling tired, leg swelling, and shortness of breath. It may also result in chest pain or fainting. Complications can include heart failure, heart valve disease, or an irregular heartbeat.
Mitral regurgitation(MR), also known as mitral insufficiency or mitral incompetence, is a form of valvular heart disease in which the mitral valve is insufficient and does not close properly when the heart pumps out blood. It is the abnormal leaking of blood backwards – regurgitation from the left ventricle, through the mitral valve, into the left atrium, when the left ventricle contracts. Mitral regurgitation is the most common form of valvular heart disease.
Aortic valve replacement is a procedure whereby the failing aortic valve of a patient's heart is replaced with an artificial heart valve. The aortic valve may need to be replaced because:
Left ventricular hypertrophy (LVH) is thickening of the heart muscle of the left ventricle of the heart, that is, left-sided ventricular hypertrophy and resulting increased left ventricular mass.
Cardiac catheterization is the insertion of a catheter into a chamber or vessel of the heart. This is done both for diagnostic and interventional purposes.
Ventricular hypertrophy (VH) is thickening of the walls of a ventricle of the heart. Although left ventricular hypertrophy (LVH) is more common, right ventricular hypertrophy (RVH), as well as concurrent hypertrophy of both ventricles can also occur.
Valvular heart disease is any cardiovascular disease process involving one or more of the four valves of the heart. These conditions occur largely as a consequence of aging, but may also be the result of congenital (inborn) abnormalities or specific disease or physiologic processes including rheumatic heart disease and pregnancy.
Loeffler endocarditis is a form of heart disease characterized by a stiffened, poorly-functioning heart caused by infiltration of the heart by white blood cells known as eosinophils. Restrictive cardiomyopathy is a disease of the heart muscle which results in impaired diastolic filling of the heart ventricles, i.e. the large heart chambers which pump blood into the pulmonary or systemic circulation. Diastole is the part of the cardiac contraction-relaxation cycle in which the heart fills with venous blood after the emptying done during its previous systole.
Athletic heart syndrome (AHS) is a non-pathological condition commonly seen in sports medicine in which the human heart is enlarged, and the resting heart rate is lower than normal.
Noncompaction cardiomyopathy (NCC) is a rare congenital disease of heart muscle that affects both children and adults. It results from abnormal prenatal development of heart muscle.
Alcoholic cardiomyopathy (ACM) is a disease in which the long-term consumption of alcohol leads to heart failure. ACM is a type of dilated cardiomyopathy. The heart is unable to pump blood efficiently, leading to heart failure. It can affect other parts of the body if the heart failure is severe. It is most common in males between the ages of 35 and 50.
The following outline is provided as an overview of and topical guide to cardiology, the branch of medicine dealing with disorders of the human heart. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease and electrophysiology. Physicians who specialize in cardiology are called cardiologists.
A ventricular outflow tract obstruction is a heart condition in which either the right or left ventricular outflow tract is blocked or obstructed. These obstructions represent a spectrum of disorders. Majority of these cases are congenital, but some are acquired throughout life.
Ischemic cardiomyopathy is a type of cardiomyopathy caused by a narrowing of the coronary arteries which supply blood to the heart. Typically, patients with ischemic cardiomyopathy have a history of acute myocardial infarction, however, it may occur in patients with coronary artery disease, but without a past history of acute myocardial infarction. This cardiomyopathy is one of the leading causes of sudden cardiac death. The adjective ischemic means characteristic of, or accompanied by, ischemia — local anemia due to mechanical obstruction of the blood supply.
Types...Hypertrophic cardiomyopathy, Left ventricular hypertrophy (LVH), Intense, prolonged athletic training
Mechanisms of Action:ACE inhibitors act by inhibiting one of several proteases responsible for cleaving the decapeptide Ang I to form the octapeptide Ang II. Because ACE is also the enzyme that degrades bradykinin, ACE inhibitors increase circulating and tissue levels of bradykinin (Fig. 8.4).