Generality
Dilated cardiomyopathy is a pathology of the heart muscle, characterized by an abnormal dilation of the left ventricle of the heart and reduced cardiac contractility.
Figure: Illustration of a normal heart (left) and a heart with dilated cardiomyopathy (right). From the site en.wikipedia.org
The disease can be an inherited or acquired disorder. Sometimes, it is not possible to identify a specific cause; in these situations, dilated cardiomyopathy is defined as idiopathic.
When present, the main symptoms of the disease are dyspnea, cardiac arrhythmias, edema in various parts of the body, a sense of persistent tiredness and chest pain.
The diagnosis may require several tests, in some cases even invasive.
A patient with dilated cardiomyopathy cannot heal, but if he is treated appropriately, he can have a better life expectancy.
A brief reference to the anatomy of the heart
The heart is a hollow organ, composed of four contractile cavities: two are on the right and are called right atrium and right ventricle ; the other two are on the left and are called left atrium and left ventricle . Through the atrium and the right ventricle passes the non-oxygenated blood, to be pumped towards the lungs; through the atrium and the left ventricle, on the other hand, passes the oxygenated blood to be pumped to the various organs and tissues of the body.
The pumping action is guaranteed by the muscular structure that constitutes the four cardiac cavities, called as a whole myocardium .
To regulate the flow of blood between the various compartments and between the heart and blood vessels, there are four valves, also known as heart valves .
What is dilated cardiomyopathy?
Dilated cardiomyopathy, also called dilated myocardiopathy, is a myocardial disease characterized by a dilation of the left ventricle of the heart, with consequent stretching of its muscular wall. In these conditions, the pumping action carried out by the left ventricle itself is less effective, therefore the organs and tissues of the body will receive less oxygen than necessary.
WHAT IS A CARDIOMYOPATHY?
The literal meaning of cardiomyopathy is: heart muscle disease . It is not by chance, therefore, that cardiomyopathies represent a series of pathologies that affect the myocardium and that are characterized by an anatomical modification of the latter. This anatomical alteration, as happens in the case of dilated cardiomyopathy, is followed by an alteration on a functional level: the heart, in fact, becomes weak and less effective in its blood pumping action.
There are at least two criteria for classifying cardiomyopathies.
The first criterion is based on the place of origin of the problem and distinguishes primary cardiomyopathies, in which only the heart is affected, from secondary cardiomyopathies, in which the problem of the myocardium depends on pathologies of other organs or particular situations.
The second criterion, instead, is based on the characteristics of the alterations that the myocardial structure undergoes and identifies four types of cardiomyopathies:
- Dilated cardiomyopathy
- Hypertrophic cardiomyopathy
- Restrictive cardiomyopathy
- Arrhythmogenic cardiomyopathy of the right ventricle
Epidemiology
Dilated cardiomyopathy is one of the most common types of myocardiopathy. Indicatively, its prevalence in the general population varies from 8 to 36 cases per 100, 000 inhabitants. It mainly affects adults aged between 20 and 60, but can also occur in children. According to some statistical studies, it is more common in males.
Causes
Dilated cardiomyopathy can be:
- An inherited disorder ( familial dilated cardiomyopathy ). About 1/3 of people with dilated cardiomyopathy have a parent with the same disorder. According to some studies, genetic defects could be located on the sex chromosome X, on an autosomal (ie non-sexual) chromosome or at the level of the mitochondrial DNA.
- An acquired disease . Dilated cardiomyopathies developed in the course of life are acquired due to a specific reason or for no apparent reason (idiopathic form).
POSSIBLE CAUSES OF DILATATIVE CARDIOMYOPATHY ACQUIRED NOT IDIOPATHIC
Non-idiopathic acquired dilated cardiomyopathy may arise due to or in the presence of:
- Heart attack, coronary heart disease and myocardial infarction ( ischemic cardiomyopathy )
- Hypertension
- Diabetes ( diabetic cardiomyopathy )
- A viral hepatitis
- Thyroid problems
- HIV infection
- Myocardial infections (which then lead to myocarditis ) supported by Coxsackie B virus or enterovirus
- A parasitic infection supported by Trypanosoma Cruzi ( Chagas disease )
- State of alcoholism, especially when combined with malnutrition (alcoholic cardiomyopathy)
- Exposure to certain toxic substances, such as cobalt or mercury
- Abuse of cocaine and amphetamines
- A chemotherapy therapy based on doxorubicin or daunorubicin
- Complicated pregnancy status ( peripartum cardiomyopathy )
NB: in brackets, in bold, the specific names that dilated cardiomyopathy takes in those specific situations have been reported.
Symptoms and Complications
Dilated cardiomyopathy can be asymptomatic (that is, free of obvious symptoms) or cause signs and symptoms very similar to those caused by heart failure or arrhythmias (ie changes in heart rhythm). Therefore, the affected person usually manifests:
- Sense of persistent fatigue
- Shortness of breath ( dyspnea ), both under stress ( dyspnea on exertion ) and at rest ( dyspnea at rest )
- Syncope
- Edema (or swelling) in the legs, hips, feet, neck veins and abdomen ( ascites )
- Chest pain that often tends to get worse after a meal
- Special heart murmurs
- Irregular beat (usually tachycardia )
WHAT DOES ASYNOMATICITY DEPEND ON?
At the moment, it is unclear why some patients with dilated cardiomyopathy do not experience any problems.
For some patients, asymptomaticity is a characteristic of early illness; for some others it is instead a problem that continues even in the advanced stages (therefore potentially very dangerous).
WHEN TO CONTACT THE DOCTOR?
In the presence of dyspnea, unusual tiredness, chest pain and / or leg edema (or swelling in other parts of the body), it is always advisable to contact the treating physician immediately, in order to undergo clinical tests and find out the causes of the disorders .
Attention: those who have a family member with dilated cardiomyopathy (therefore the risk of a hereditary predisposition) should undergo periodic cardiological checks, in order to monitor the health of their heart, and a specific genetic test .
COMPLICATIONS
Dilated cardiomyopathy can lead to various complications, some of which are also very serious. Here is what they consist of:
- Heart failure . It consists of reduced left ventricular function, which leads to insufficient blood supply to organs and tissues.
- Involvement of the left atrium and the right half of the heart . In the long run, the myocardial alteration also affects the left atrium and the right ventricle.
- Valve regurgitation . It occurs when the heart valves, altered in the structure, no longer work as they should, allowing the blood to turn back where it started.
- Cardiac arrest .
- Pulmonary embolism, due to an aggravation of the edema.
- Worsening of the arrhythmias present.
Diagnosis
To diagnose dilated cardiomyopathy, the doctor (usually a cardiologist ) uses various non-invasive or minimally invasive tests, such as:
- Blood analysis
- RX-thorax, nuclear magnetic resonance and / or CT scan
- Electrocardiogram
- Echocardiogram
- Stress test
First, however, they are generally expected: a thorough physical examination and a thorough analysis of the patient's clinical and family history .
Figure: chest radiograph of a patient with dilated cardiomyopathy. From the site: learningradiology.com
If all these tests do not provide sufficient information, it is necessary to use different invasive procedures for cardiac catheterization.
EXAMINATION OBJECTIVE
During the physical examination, the doctor visits the patient and asks him to describe the symptoms felt. The visit consists mainly of auscultation of the heart, using a stethoscope; this check is aimed at identifying any characteristic blows or noises emitted by the cardiac contraction.
CARDIAC CATHETERISM
The techniques of cardiac catheterization foresee the insertion, in an important artery of the body, of a particular catheter, conducted then up to the heart. Once this seat is reached, the catheter can:
- Record the heart rhythm, providing useful information about rhythm alterations (actual catheterization of the heart).
- Be used to release, within the coronary arteries, a contrast fluid visible to X-rays ( coronarography ). The diffusion of the liquid, therefore, allows to see if there are obstructions inside the coronaries.
- Be used to collect a small sample of myocardial tissue, which will then be analyzed in the laboratory ( myocardial biopsy ).
Cardiac catheterization procedures are considered invasive for three reasons: for the introduction and conduction of the catheters through the arterial vessels, for the use of a contrast liquid and, finally, for exposure to X-rays.
Treatment
A heart with dilated cardiomyopathy cannot heal. However, thanks to a combination of drugs - and the possible implantation of some cardiac devices, such as the pacemaker or the cardioverter defibrillator - it is possible to partially improve the symptoms.
If, due to the extreme gravity of the situation, the drugs and cardiac devices should not give the desired results, the treatment that remains available is the heart transplant, a delicate surgery that is easily prone to complications.
PHARMACOLOGICAL THERAPY
Drug therapy depends on the causes. The drugs that could be prescribed are:
- Hypotensives, to reduce blood pressure when it is high.
- ACE-inhibitors
- Angiotensin II receptor antagonists
- Beta blockers
- Calcium channel blockers
- The bradicardizzanti, to slow down the cardiac rhythm.
- Beta blockers
- Calcium channel blockers
- Digoxin
- Antiarrhythmics, to normalize the heart rhythm.
- Diuretics, to reduce too high sodium levels and contain edema.
- Anticoagulants (eg warfarin) to dissolve blood clots and prevent their formation.
NB: as will be noted, some drugs have a dual function (for example calcium channel blockers).
IMPLANTABLE DEVICES
The system of the following cardiac devices also depends on the causes:
- Biventricular pacemaker . It is a small electronic implantable device, which serves to regulate the heart rate of a heart from irregular heartbeat, too slow or too fast. To learn more, you can consult the article dedicated to the pacemaker.
- Implantable cardioverter defibrillator (ICD) . It looks like a pacemaker, with the difference that only occurs when the heart's rhythm changes. In fact, it is capable of picking up any variation in the heart rate and making the right remedy, by emitting an electric discharge.
- Left ventricular assist device (LVAD) . Implanted in the abdomen or chest, it helps the heart in its blood pumping action. In some cases, it may represent a temporary remedy, pending a heart transplant.
SOME USEFUL REMEDIES
For patients with dilated cardiomyopathy, doctors recommend: staying active (NB: the activity must be commensurate with the severity of the pathology); not smoking; do not use alcohol and drugs; maintain a normal body weight; and finally, adopt a healthy and balanced diet.
Prevention
If it is true that certain dilated cardiomyopathies (for example the hereditary and idiopathic forms) are, for different reasons, impossible to prevent, it is also true that the acquired forms, caused by a wrong lifestyle, are partly preventable.
Here's how:
- Not smoking
- Do not take drugs
- Don't drink alcohol or at least take it in the right amounts
- Eat healthy
- Maintain a normal body weight
- Practice physical activity constantly
- Sleep and rest according to the needs of the body
Prognosis
In recent years, treatments for heart disorders have been extensively refined. Therefore, expectations and quality of life have also increased for patients with dilated cardiomyopathy.
