What hypertrophic cardiomyopathy is and how it is treated

By Cristiano Antonino On Mar 11, 2023

Hypertrophic cardiomyopathy is a genetic disorder that causes an increase in the wall thickness of the left ventricle

What types exist? What symptoms allow it to be recognised by the specialist and what causes it?

What is hypertrophic cardiomyopathy and what types exist

Hypertrophic cardiomyopathy is a genetic disease, which leads to an increase in the wall thickness of the left ventricle.

This increase is due to an increased number of cardiac muscle cells, called myocells, and a disordered relationship between them.

Whereas, in fact, in a normal heart the myocells are oriented in orderly planes, in the case of hypertrophic cardiomyopathy these same planes are subverted.

This pathology affects between 0.2 and 0.5 per cent of the adult population.

It can present itself in different types and severity: from very mild forms to situations with significant wall enlargement.

In fact, hypertrophy may be localised in just one segment of the left ventricle or involve it entirely.

In the case of asymmetric hypertrophic cardiomyopathy, a condition in which some parts of the ventricle wall are thicker than others, hypertrophy may

involve the high septum
occur on the lateral wall;
involve thickening of only the tip part.

On the other hand, hypertrophy may also lead to an increase in the thickness of the entire ventricle wall.

In addition to the types listed above, which are determined by the location of the hypertrophy, it is also possible to distinguish between non-obstructive and obstructive hypertrophic cardiomyopathy: in this case, hypertrophy determines an impediment to the exit of blood from the left ventricle.

Symptoms of hypertrophic cardiomyopathy

Symptomatology is closely linked to the extent and location of the hypertrophy.

There are patients with mild degrees of hypertrophy and, therefore, asymptomatic, others in whom the hypertrophy is so extensive that it causes significant limitation to exertion with the onset of

shortness of breath
angina-type chest pains;
fatigue;
arrhythmias, in some cases so severe as to lead to the onset of syncope or even ventricular fibrillation, a situation that can lead to the death of the patient.

The cause of arrhythmias, among the most serious symptoms, is the chaotic orientation of cells, with the presence of fibrosis (accumulation of connective tissue) between the myocytes (muscle fibres), leading to an interruption of the normal heart rhythm.

What tests to do to reach a diagnosis of hypertrophic cardiomyopathy

Diagnosing hypertrophic cardiomyopathy involves performing

auscultation of the heart, which often shows a murmur;
electrocardiogram;
echocardiogram.

If the suspicion of disease becomes more concrete, an MRI is performed to assess not only the extent of the hypertrophy, but above all the degree and presence of fibrosis, one of the main causes of dangerous arrhythmias.

The analysis is completed by:

study of the coronary arteries;
genetic testing, useful for a more complete understanding of the situation.

What are the treatments for hypertrophic cardiomyopathy?

In the presence of a symptomatic patient, the first choice is medical therapy, basically based on the use of:

beta-blockers;
calcium antagonists;
vasodilators.

Under normal conditions, the use of medical therapy gives excellent results in terms of improving symptoms and long-term prognosis: the data in the literature tell us that the possibility of 5-year survival with good therapy is 97.5%.

In the case of patients at high risk of arrhythmias, an ICD (Implantable Cardioverter Defibrillator) is implanted instead.

This device involves inserting a probe into the right cavity of the heart, through a vein.

With an electrical discharge, the probe is able to reset the arrhythmia, if it occurs, averting the danger of ventricular fibrillation and, therefore, sudden death.

The ICD is a device that is very similar to a normal pacemaker; compared to the latter, it is also able to detect malignant arrhythmias and eliminate them.

Surgical treatment for hypertrophic obstructive cardiomyopathy

In the case of obstructive hypertrophic cardiomyopathy, surgical intervention is necessary.

The obstruction to blood flow is, in fact, responsible for a large part of the symptoms: for this reason, where medical therapy is not sufficient, the part of the hypertrophic muscle that causes the obstruction to blood flow must be removed.

It is, therefore, possible to intervene in 2 ways:

septal alcoholisation: during a coronarography test, the coronary arteries that carry blood to the septum are ‘alcoholised’ via a catheter: a substance (alcohol) is injected into them, which irreversibly damages the coronary artery itself, leading to its closure and thus to an infarction of the portion of the septum that the coronary artery serves. This procedure is rather imprecise: in fact, there is not always a coronary artery that serves only and exclusively the portion of the hypertrophied septum. Although the patient is spared the surgical trauma, the disease is not effectively treated and other complications may arise. For this reason, this procedure, after initial enthusiasm, is less and less used;
surgical treatment: the treatment of choice, therefore, in the presence of hypertrophic obstructive cardiomyopathy is surgery, which makes it possible not only to completely remove the hypertrophic part of the septum, but also to treat any other pathologies that often accompany this situation, such as, for example, certain dysfunctions of the mitral valve. The surgical procedure is relatively simple: through a small opening in the ascending aorta, the hypertrophic septum is reached by passing through the aortic valve. Once the hypertrophied area of the septum is revealed, it is removed using a scalpel. The results are excellent with a very low surgical risk (around 1%).

Patients with hypertrophic obstructive cardiomyopathy treated with surgery have the same 10-year survival rate as patients treated with medical therapy without obstruction; in contrast, patients with obstruction treated only with medical therapy have a high mortality rate (Source: Mayo Clinic).

The surgical results are extremely favourable.

Patients with hypertrophic obstructive heart disease must be treated if they are symptomatic: removal of the obstruction completely changes their life expectancy.

Drug treatment studies

Currently, studies are underway on the pharmacological treatment, with drugs inhibiting myocyte production, of the disease.

The results are, however, very preliminary and it is not yet possible to understand the real scope of these treatments and, above all, to which category of patients they can be administered.

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