Restrictive cardiomyopathy is a condition that tends to affect elderly patients; the two ventricles of the heart, i.e. the lower chambers, stiffen because scar tissue gradually replaces normal heart muscle tissue, and the consequence is the loss of elasticity and relaxation capacity, so the ventricle is no longer able to function properly and the person develops complications such as heart failure (inability to pump enough blood) and/or arrhythmias (changes in the heartbeat).
Compared to dilated and hypertrophic cardiomyopathy, the restrictive form is rarer and in most patients the cause is idiopathic, ie unknown; otherwise, among the most relevant causes of restrictive cardiomyopathy we find:
- Accumulation of abnormal substances.
- Hemochromatosis is a disease characterized by excessive accumulation of iron in the body.
- Sarcoidosis, a condition that causes inflammation in numerous districts, is probably caused by an abnormal and unjustified inflammatory response to as yet unknown agents.
- Amyloidosis is a disease in which abnormal proteins accumulate in various organs, including one’s heart.
- Replacement of heart tissue with scar tissue
- Connective tissue disorders (e.g. scleroderma )
- Some cancer treatments ( radiotherapy and chemotherapy )
Although the heart is still able to contract adequately, it loses the ability to relax between one beat and the next; this makes it more difficult to ensure the correct filling of blood, which therefore tends to stagnate in the body (causing among other things an accumulation of fluids in the body, especially in the lower limbs).
As the walls of the heart’s lower chambers (ventricles) become progressively stiffer and lose the ability to expand when they fill with blood, the pump function becomes less effective over time.
If the extent of the damage is minimal, the patient may not feel any disturbance, or live with very mild symptoms that do not impact the quality of life; other subjects instead undergo a progressive worsening that can lead to development:
- Cough and shortness of breath (initially in case of exertion, then also at rest, which thus reduces the possibility of activity/movement)
- Swelling of the legs and feet (edema)
- Weight gain (due to water retention )
- Nausea, bloating , and poor appetite (related to fluid retention)
- Palpitations (due to an abnormal heart rhythm )
Less commonly it is observed:
- Episodes of syncope (fainting)
- Chest pain or pressure (usually occurs with physical activity, but can also occur with rest or after meals).
The main complications of restrictive cardiomyopathy include:
- Heart failure
- Stroke due to clot formation
- Increased risk of pregnancy complications
- Sudden cardiac death (rare).
Unfortunately, the prognosis is not optimal, because the diagnosis is often made when the disease is already at an advanced stage.
Unlike other forms of cardiomyopathy, in the case of the restrictive form the size of the heart remains normal, so much so that it enters a differential diagnosis with constrictive pericarditis, an inflammation of the pericardium (the membrane that surrounds the heart)
The diagnosis of restrictive cardiomyopathy is mainly conducted through:
- Medical examination (history and physical examination)
- Chest x-ray
- Stress test
- Cardiac catheterization
- Magnetic resonance
- Biopsy (rarely)
The therapeutic approach consists of a combination of drugs and lifestyle improvement, although unfortunately there is no definitive cure and therefore the treatment is basically symptomatic.
A careful diet (particularly in a way that sees the intake of salt drastically limited) and the regular practice of physical activity, compatibly with one’s state of health, are aspects that are as fundamental as they are often neglected. Losing weight, quitting smoking and more generally leading a healthy life can have practical implications that determine the prognosis of the condition.
Among the most commonly prescribed medicines for this purpose we find for example:
- Beta-blockers (drugs that slow the heartbeat and reduce blood pressure)
- Ace inhibitors (to counteract high blood pressure )
- Diuretics (to reduce water retention)
- Digoxin (to increase cardiac contraction force)
- Anticoagulant drugs.
In severe cases, heart transplantation may be necessary.