Dilated cardiomyopathy

Dilated cardiomyopathy. It can be considered a clinical and pathophysiological syndrome characterized by myocardial dysfunction and dilation of the left ventricle or both ventricles.

Summary

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  • 1 Causes, incidence and risk factors
  • 2 Pathophysiology
  • 3 Clinical picture
  • 4 Physical exam
  • 5 Complementary exams
  • 6 Forecast
  • 7 Complications
  • 8 Special forms of cardiomyopathy
  • 9 Sources
  • 10 External links

Causes, incidence and risk factors

There are many causes that can cause this disease, including nutritional deficiencies, heart valve disease, anemia , stress , viral infections (rare), Alcoholism and its consequences | alcoholism (alcoholic cardiomyopathy) and artery disease coronary arteries.

The most common causes of dilated cardiomyopathy in children are idiopathic myocarditis, coronary heart disease, and some infections. Dilated cardiomyopathy can affect people of any age, although it is more common in adult men. Some of the risk factors in adults are obesity , cocaine use , a personal or family history of heart disorders (such as myocarditis), and alcoholism .

Pathophysiology

Multiple factors are involved in the pathophysiology of dilated cardiomyopathy. Among them, the following stand out for the knowledge and treatment of the disease:

  • Impairment of contractile function leading to a proportional decrease in ventricular ejection with increased residual volume and, secondarily, ventricular volume and pressure due to diffuse myocardial injury.
  • The initial response of the ventricle to overload in an attempt to improve contractility is an increase in the length of the sarcomeres, but when the optimum separation point between myofilaments (2.2 microns) is exceeded, not only is this objective not achieved, but even the dreaded hypertrophy occurs.
  • There is involvement of the right and left heart , with the consequent retrograde venous congestion and antegrade failure. Both congestion and decreased ejection influence renal function.
  • There is also the activation of a series of neurohormonal mechanisms that will actively participate in the pathophysiology of this disease: renin-angiotensin-aldosterone system, sympathetic nervous system, antidiuretic hormone, natriuretic factor, kallikrein-quinine system, prostaglandins, etc., without forget the participation of endothelin, cytokines or nitric oxide. These systems will determine the symptoms and evolution of the disease.
  • Lastly, some studies have shown that downward regulation of myocardial beta-adrenergic receptors occurs in chronic congestive heart failure, which is related to the severity of left ventricular dysfunction.

Clinical picture

The symptoms and signs of dilated cardiomyopathy are a consequence of systolic dysfunction and, although patients may be asymptomatic, in general they have fatigueability, dyspnea on exertion that progresses to orthopnea, and peripheral edema. Cough with exertion and / or nocturnal reports incipient pulmonary edema. A palpitations are also a frequent symptom, these may be due to sinus tachycardia that can occur even at rest, or to the development of other types of arrhythmias, both supraventricular and ventricular. Of these, the most frequent is atrial fibrillation, which appears in 25 percent of cases, almost half of the patients die suddenly, presumably due to ventricular arrhythmias.

Embolisms are very frequent, an increase in the incidence in relation to the presence of chronic or paroxysmal atrial fibrillation, a history of previous embolism, severe ventricular dysfunction or the echocardiographic finding of intracavitary thrombi. Precordial pain exists in a good percentage of patients with normal coronary arteries, translating subendocardial ischemia. A rare symptom is dysphagia, which occurs because the very distended left pulmonary vein can compress the esophagus, making it difficult for food to pass.

Physical exam

On auscultation, the first noise may be decreased, gallops by the 4th and 3rd noise are common, a systolic murmur of mitral and sometimes tricuspid insufficiency is very often heard, and the lung component of the second noise may be increased. The rhythm is usually regular, except when the patient has already fallen into atrial fibrillation, or in the presence of atrial or ventricular extrasystoles that are frequently auscultated. The skin may acquire a jaundiced tint and weight loss may occur leading to cachexia. Detection of signs of systemic venous congestion is performed by exploration of the neck veins for jugular venous hypertension, by detection of hepatomegaly, and by observation of edema in the lower limbs. In severe cases you can see ascites,

Complementary exams

  • The Electrocardiogram is systematically abnormal. There may be tachycardia, atrial fibrillation, left or right atrial growths, or both, low-voltage QRS, or large R or S voltages with or without overload, these are common findings, as well as left bundle branch block or hemiblocks of the previous subdivision. Nonspecific repolarization abnormalities are also possible, such as pathological Q waves, which would require a differential diagnosis with ischemic heart disease. Almost half of the patients, with dilated cardiomyopathy, who have undergone a 24-hour Holter, have unsupported ventricular tachycardias.
  • Chest radiography shows cardiomegaly and vascular redistribution with signs of interstitial edema, or even pleural effusions, depending on the patient’s clinical situation.
  • The echocardiogram reveals a dilated left ventricle with extremely thin walls and poor overall systolic function. In general, the existence of valvulopathies that could explain the dysfunction can be excluded. On many occasions, the atria are also enlarged and the existence of mural thrombi of different types, frequent in this entity, can be seen.
  • Doppler detects mitral and tricuspid regurgitation and quantifies its degree. The isotopes allow the ejection fraction and cardiac output to be calculated with very good reproducibility in relation to hemodynamic studies, as well as to assess global or segmental changes in contractility. It can be used as a non-invasive measure of systolic function in serial studies, being for that reason very useful for evaluating the evolution of the disease.
  • Catheterization shows a clear decrease in minute volume. The left ventricle is dilated and globally hypokinetic. Segmental coronary angiography is usually normal. The pressures, depending on the severity of the case, are usually increased both in the left chambers and in the end of diastole in the right ventricle and in the right atrium.

Forecast

The prognosis varies. Some patients remain stable for a long time, others gradually worsen, and others worsen rapidly. Cardiomyopathy can only be corrected if the underlying disease can be cured. In children, about a third fully recover, another third recover but continue to have some heart problems and the remaining third die.

Complications

  • Congestive heart failure
  • Arrhythmias
  • Pulmonary edema
  • Side effects of medications, such as:
  1. low blood pressure or dizziness and fainting
  2. lupus reaction (a group of symptoms including rash and arthritis)
  3. gastrointestinal discomfort or headache

Special forms of cardiomyopathy

Alcoholic cardiomyopathy

It is the main cause of nonischemic dilated cardiomyopathy. Although in some cases the established cardiac damage progresses without remedy despite withdrawal, this cardiomyopathy usually has the great advantage that the prognosis is often favorable with the elimination of the poison, contrary to what happens with the idiopathic form, whose prognosis is in many cases unfortunate.

The damage attributed to alcohol is explained by three elementary mechanisms: direct damage to the myocardium, the influence on deficiency processes (thiamine) and, in certain cases, by alcohol additives or their presentations (cobalt). Today it seems proven that the organic damage derived from alcohol consumption is related to the direct toxic effect of ethanol, with the dose of ethanol ingested being the main determinant for developing both cardiomyopathy and ethyl myopathy.

The clinical, hemodynamic and radiological findings of alcoholic cardiomyopathy are indistinguishable from dilated cardiomyopathy of any other or idiopathic etiology. The pathology data is also nonspecific, and edema of the vascular wall and perivascular fibrosis of the intramyocardial coronary arteries are observed, which has led to the hypothesis that ethyl heart disease is actually the result of ischemia of the coronary territories. intramural.

Peripartum cardiomyopathy

The tendency to recurrence with successive pregnancies has been verified, and it seems to be more frequent in multiparous and middle-aged patients. It is also more frequent in cases of twin pregnancy and toxemia gravidarum. Cardiomyopathy in the

Sarcoidosis

Sarcoidosis may debut as a picture of rapidly implantable congestive cardiomyopathy and rapid clinical deterioration.

In this disease, granulomas form that can replace large areas of the myocardium, which can cause dysfunction of the papillary muscles or formation of ventricular aneurysms.

In many cases, the initial diagnosis may be myocardial infarction, since the granulomatous areas cause Q waves on the ECG and perfusion defects on the scintigraphy.

Often there are also bundle branch block and atrioventricular blocks, and arrhythmias.

Cobalt-dilated cardiomyopathy

This syndrome was described in the mid-sixties of the last century in Canada, the USA and Europe. It was a picture of fulminant congestive heart failure that appeared in people who drank a certain brand of beer to which cobalt sulfate had been added as a foam stabilizer. Once the toxin was removed, the syndrome has not been described again.

Anthracycline dilated cardiomyopathy

Anthracyclines (adriamycin and doxorubicin) are an example of a direct toxic effect on the heart muscle. Anthracyclines can lead to acute toxicity that can manifest as myocarditis, pericarditis, arrhythmias, and decreased ejection fraction. They can also cause late toxicity consisting of dilated cardiomyopathy indistinguishable from idiopathic.

Right ventricular cardiomyopathy

Fibrosis of the right ventricle, or replacement of the muscle by adipose tissue, characterizes this process. It is more frequent in men and its clinic is composed of syncopal pictures, palpitations and risk of sudden death.

Dilated cardiomyopathy and HIV

Cardiomyopathy associated with HIV infection has been revealed in various studies, and ventricular dilation and systolic dysfunction are frequently observed. The risk factors for the development of this cardiomyopathy are not known, but it seems more frequent in individuals addicted to drugs than in homosexuals. The histological findings usually correspond to myocarditis, therefore it is considered that these patients present a dilated cardiomyopathy as a terminal manifestation of that.

Virus-dilated cardiomyopathy

A good portion of idiopathic cardiomyopathy is thought to be secondary to acute viral myocarditis. The reason why some cases progress to chronic forms of dilated cardiomyopathy is not fully established, but certain immune mechanisms are involved in this perpetuation of the disease. This has been the basis for using prednisone and other immunosuppressants in the treatment of myocarditis, without being able to demonstrate any benefit in survival, symptoms or ejection fraction.

Cardiac involvement is not uncommon in infections with Coxsakie A and B virus, ECHO, adenovirus, influenza, rubella, or polio; which can cause an acute form of dilated cardiomyopathy that typically appears several weeks after a fever episode frequently associated with upper airway symptoms. In most cases they evolve rapidly and heal without sequelae, although in 10 percent they evolve into a chronic form indistinguishable from idiopathic dilated cardiomyopathy, which occurs much less frequently since influenza, rubella, and Poliomyelitis are more controlled through vaccination campaigns.

Chagas disease cardiomyopathy

Its etiological agent is Trypanosoma Cruzei. The cardiomyopathy that it produces presents with an acute phase, which is followed by a very long latency period and a chronic phase that affects around a third of infected individuals and is manifested by cardiomegaly and congestive heart failure. Acute cardiomyopathy is due to the multiplication of the parasite in the cardiac muscle fibers, which can be identified in them and causes an intense inflammatory reaction. Prevention It is recommended to consume a well-balanced and nutritious diet, exercise to improve the condition of the heart, quit smoking and minimize alcohol consumption.

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