Cardiomyopathy: symptoms, diagnosis and treatment

By Cristiano Antonino On Mar 22, 2023

Cardiomyopathy is a pathology that affects the heart muscle and is characterised by an anatomical-functional alteration that reduces its contractile capacity

Depending on the changes affecting the myocardium, cardiomyopathy can be distinguished into various types: dilated, hypertrophic, restrictive or right ventricular arrhythmogenic.

The disease can be hereditary or acquired and usually involves symptoms such as syncope, dyspnoea, altered heart rhythm and oedema in different parts of the body.

There is no single cure for cardiomyopathy, but patients who suffer from it can be guaranteed a better life expectancy if they follow appropriate therapy.

How does the heart work?

The heart consists of striated muscle tissue surrounded by a fibrous sac called the pericardium.

It is shaped like a truncated cone, weighs about 250-300 grams in adults, is 13-15 cm long, 9-10 cm wide and 6 cm thick.

It is a hollow organ with four cavities.

Two are located on the right and are called the right atrium and right ventricle, while the other two are located on the left and are called the left atrium and left ventricle.

Unoxygenated blood arrives at the heart from the hollow veins and passes through the right atrium and right ventricle, to be pumped from there to the lungs.

The oxygenated blood in the lungs, which is destined for the organs and tissues, returns to the heart and passes into the left atrium and ventricle instead.

This continuous action is made possible by the myocardium, the muscular structure of the four cardiac cavities.

The flow of blood is also regulated by four valves, called cardiac valves, which control the entry and exit between the various cavities and between the heart and the blood vessels.

Cardiomyopathy: what is it?

Also referred to as ‘heart muscle disease’, cardiomyopathy refers to an anatomical change in the myocardium that causes dysfunction in the heart.

Patients suffering from this disease have a heart that is less effective in pumping blood and is therefore weak.

There are various types of cardiomyopathy and criteria for classifying this condition

If we consider the origin of the problem, we can distinguish in:

Primary cardiomyopathies: in which only the heart is affected.
Secondary cardiomyopathies: resulting from local or systemic pathologies affecting other organs, which affect the heart.

If we take into account the alterations undergone by the myocardial structure, we can distinguish cardiomyopathy into:

Dilated cardiomyopathy
hypertrophic cardiomyopathy
Restrictive cardiomyopathy
Arrhythmogenic right ventricular cardiomyopathy

Dilated cardiomyopathy

Dilated cardiomyopathy is characterised by dilatation of the right or left ventricle or both ventricles of the heart.

This condition causes the muscle wall to stretch and become thinner.

It is the most common form of the condition.

It mainly affects adult patients between the ages of 20 and 60 and is more common among men.

It can develop as a result of predisposing genetic factors, hypertension, diabetes, a complicated pregnancy, parasitic or viral infections, but also alcoholism, cocaine and amphetamine use, and contact with toxic substances.

Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is characterised by the enlargement of myocardial cells and the resulting thickening of the ventricular walls.

This condition causes the cavities of the right and left ventricle to shrink, reducing the amount of blood that can be pumped by the heart.

The causes are usually genetic, but the condition can also be caused by thyroid problems or diabetes, or be the result of long-standing uncontrolled hypertension.

Restrictive cardiomyopathy

Restrictive cardiomyopathy is characterised by the stiffening of myocardial tissue that is no longer able to relax after contraction.

This prevents the heart from filling properly with blood.

This alteration of the myocardium is caused by the presence of fibrous and scar tissue on both ventricles.

It is linked to the presence of predisposing genetic factors or diseases such as sarcoidosis, amyloidosis, haemochromatosis; the use of chemotherapy drugs is also a risk factor.

Right ventricular arthymogenic cardiomyopathy

Right ventricular arthymogenic cardiomyopathy is characterised by necrosis, i.e. death, of the myocardium, which is replaced by scar tissue.

Normally, the right side of the heart contains the electrical system that controls heart rhythm, which is why this condition causes arrhythmias.

This condition, fortunately rare, is most common in adolescents and is among the causes of cardiac and sudden death in young athletes.

Its causes are mainly genetic.

Cardiomyopathy: causes

Cardiomyopathy may have a genetic cause and be classified as a hereditary disease.

Studies have shown that the disease is linked to genetic defects on the X sex chromosome, at the mitochondrial DNA level or on an autosomal chromosome.

When it is not genetically based, cardiomyopathy can be an acquired disease, i.e. developed in the course of life.

In some cases, cardiomyopathy arises for no apparent reason, in which case it is referred to as idiopathic.

In the case of non-idiopathic acquired cardiomyopathy, on the other hand, there are numerous causes, including the aforementioned hypertension, diabetes, a complicated pregnancy, amphetamine and cocaine abuse, and thyroid disorders.

The disease can also be a consequence of previous heart disease, such as previous episodes of myocardial infarction, valvulopathy or coronary artery disease.

Other causes are chemotherapy with doxorubicin or daunorubicin; alcoholism associated with malnutrition; exposure to toxic substances, such as cobalt or mercury; obesity; endocrine or storage diseases such as acromegaly, haemochromatosis, amyloidosis, sarcoidosis; and myocardial infections.

Factors that can lead to cardiomyopathy include AIDS (HIV infection), parasitic infections sustained by Trypanosoma Cruzi, muscular dystrophies, persistent cardiac arrhythmias and nutritional problems.

Symptoms

Cardiomyopathy may be asymptomatic or present with symptoms indicating arrhythmias or heart failure.

Patients suffering from this condition usually complain of persistent fatigue, dyspnoea (shortness of breath), both at rest and under stress.

Syncope, chest pain that worsens after meals, tachycardia and oedema in the legs, hips, feet, neck veins and abdomen are also present.

The absence of symptoms is more common in individuals suffering from dilated or hypertrophic cardiomyopathy.

To date, it is unclear why cardiomyopathy presents asymptomatically in some patients, either in the early or more advanced stages.

Diagnosis

The diagnosis of cardiomyopathy is made during a cardiological examination with non-invasive tests.

Usually the cardiologist, after examining the patient and auscultating the heart area with the phonendoscope, prescribes blood tests, electrocardiogram, echocardiogram, chest X-ray; in selected cases nuclear magnetic resonance imaging or CT scan, and stress tests.

If these tests are not sufficient to reach a complete diagnosis, invasive procedures such as coronarography and myocardial biopsy can be used.

Cardiomyopathy: complications

Depending on the type, cardiomyopathy can lead to certain complications.

The most common is heart failure, which involves a reduction in ventricular function resulting in insufficient blood supply to organs and tissues.

Valvular regurgitation, characterised by malfunctioning heart valves, also occurs in some patients.

Cardiomyopathy can also cause cardiac arrest, facilitate the development of pulmonary embolisms and aggravation of existing arrhythmias.

Cardiomyopathy: can it be cured?

Patients suffering from cardiomyopathy are unlikely to recover, but can follow therapies to improve quality of life and reduce symptoms.

The treatment for this condition is the result of a combination of medication and, where necessary, the implantation of cardiac devices (pacemaker, cardioverter defibrillator and left ventricular assist device).

When drug therapy and the use of cardiac devices is not sufficient, surgical therapy (septal myectomy or alcohol ablation of the septum – in the case of hypertrophic cardiomyopathy) or heart transplantation is possible.

The latter is a particularly delicate operation with many complications.

Prognosis

Over the years, cardiomyopathy has been the focus of numerous studies and today, several treatments are possible to reduce symptoms and improve the life of those affected.

Therefore, patients who suffer from cardiomyopathy and follow the correct treatment course can have a good life expectancy.