Heart attack: symptoms, causes and everything you need to know    

1 Introduction

 Chest pain, profuse sweating, a sense of nausea and anguish: these are the main symptoms of myocardial infarction, the pathology that holds the sad record of leading cause of death in the Western world.

Feared for its high lethality and sudden onset, heart attack is defined as necrosis (i.e. death) of a part of the heart and can occur when the amount of blood directed to the heart muscle is not sufficient to meet its needs. metabolic (a condition known as ischemia).

To supply the heart are two small arteries that run on its surface, the coronary arteries, and most cases of ischemia are caused by a pathology of these vessels.

Heart attack is one of the diseases on which medical research has focused more in recent decades: today we have a thorough knowledge of this disease which has led to a significant improvement both in terms of diagnosis and treatment, and in the field of prevention. .

In this article we will try to offer all the useful information on heart attack in a clear and synthetic way. It is absolutely not intended as an alternative to specialist assistance and, in case of suspicion, we recommend that you contact your doctor or the emergency room immediately.

Heart attack and angina pectoris

Before starting to talk about myocardial infarction, it is appropriate to clarify the distinction between this and angina pectoris , another type of heart disease due to reduced blood supply.

These two pathologies present with almost completely overlapping symptoms, but they have an important difference: reversibility.

The attack of angina pectoris, in fact, resolves if the patient rests or takes antianginal drugs (such as isosorbide dinitrate, Carvasin®); in this case the heart muscle cells, although suffering, do not die and will return to their normal function over time.

Despite having a reversible character, angina pectoris should not be underestimated: it is however an indication of a cardiac perfusion problem that can evolve into a heart attack or other complications, therefore it deserves adequate treatment and follow-up. We refer further information on angina pectoris to another time, limiting ourselves in the following writing to highlight the elements that differentiate it from heart attack.

2 Causes and risk factors

Why does a heart attack occur?

A myocardial (heart) infarction occurs when for any reason the flow of blood supplying oxygen and nutrients to the organ through the coronary arteries is interrupted; typically this occurs due to blockage of the artery by cholesterol plaques, or due to blood clots that are too small to pass through the vessel.

Infarction is a multifactorial pathology, which means that many different mechanisms are involved in its genesis. It is therefore more correct, instead of indicating a single cause of disease, to speak of a series of risk factors.

If several risk factors are present, they act synergistically, exponentially increasing the risk of disease.

While the risk factors are represented by situations that persist over time, heart attack is an acute event and normally occurs at a time when our heart is facing a greater workload than normal. This happens, for example, during an intense effort or at a particularly exciting moment.

What we could define the "triggers" of heart attack are effectively summarized in a very common figure in medical textbooks and painted by the famous doctor and illustrator Frank Netter, in which a man is seen leaving a restaurant with a suitcase in hand, in the cold of a snowfall.

They are:

. The intense effort (the man lifts a suitcase and has just finished climbing a flight of stairs);

. A big meal (just left the restaurant);

. The smoke (on the ground we see a cigarette still smoking);

. Cold (cold increases blood pressure and a winter day is depicted in the image).

Below we list the main ones, divided into modifiable and non-modifiable according to whether or not it is possible to intervene on them:

Non-modifiable factors

. Male gender : Men are more at risk than women of having a heart attack and this difference appears to be linked to the protective action of estrogen (the female hormones) in women. The disparity in prevalence between the two sexes, in fact, smooths out after the menopause, that is when the production of estrogen undergoes a physiological decline.

. Advanced age : The risk of heart attack increases progressively with advancing age, remaining low up to about 45 years (for men) or until menopause (for women).

. Family history : People who have at least one case of myocardial infarction or other cardiovascular disease among their relatives are considered at risk.

Modifiable factors

. Smoking : Cigarette smoking is, after age, the main risk factor. It works through various mechanisms: it causes tachycardia (thus increasing the workload of the heart), decreases blood oxygenation and promotes the formation of thrombus (aggregates of platelets adhering to the vascular wall) which can occlude the coronary arteries.

. Atherosclerosis : Atherosclerosis is an artery disease characterized by inflammation and accumulation of fat in the vascular walls. The lipid material that is deposited in the vessels forms plaques that reduce their caliber, thus decreasing the amount of blood that can flow inside them. If the coronary arteries are affected by atherosclerosis, the risk of heart attack increases not only because the blood supply to the heart is reduced, but also because thrombi can form on the plaques which completely occlude the vessel in question.

. Hypercholesterolemia : Excess cholesterol in the blood promotes the accumulation of fats in the arteries, hence atherosclerosis. In this regard, remember that not all cholesterol is harmful, but only that contained in LDL (low density lipoprotein); HDL cholesterol(high density lipoprotein), on the other hand, has a protective function for the vessels.

. Hypertension : It is a pathological increase in blood pressure in the arteries. It is a risk factor for cardiovascular disease because it increases the workload of the heart (which has to pump blood at a higher pressure than normal) and facilitates the development of atherosclerotic plaques.

. Diabetes : Diabetes, especially if poorly controlled, damages the vessel wall making it easier for atherosclerotic plaques to form. Furthermore, diabetes can easily lead to hypertension and hypercholesterolemia, thus causing an accumulation of risk factors.

. Obesity : Obesity is also associated with several risk factors, including atherosclerosis, hypercholesterolemia, hypertension and diabetes.

. Sedentary lifestyle : The heart is a muscular organ and, as such, can be trained: 

physical activity produces a series of changes in the shape and function of the heart that protect against cardiovascular disease. A sedentary lifestyle, on the other hand, is associated with a greater risk of these pathologies, also because it is often associated with other factors mentioned above (obesity, hypercholesterolemia and hypertension ).

3 Symptoms

Although the presentation of the heart attack can be very subjective, the clinical picture is usually dominated by a single symptom: chest pain .

This pain has very specific characteristics, which are:

. Quality : Described as a feeling of weight, tightness or burning in the chest. It is very strong, so much so as to cause in the patient a strong anguish or even the feeling of imminent death.

. Location : It is deep and is located in the center of the chest, just behind the breastbone. It can also irradiate to other sites, including the left arm, neck, jaw, back, or upper abdomen.

. Duration : The typical duration is around 30-40 minutes, unlike the pain of angina pectoris which lasts a maximum of 20 minutes.

. Incoercibility : Another characteristic that distinguishes heart attack pain from angina is that, unlike angina, it does not resolve if the patient rests or takes antianginal drugs.

Such characterized pain should make one suspect the event taking place and deserves to be taken care of by the nearest emergency room service.

On the other hand, there are patients in whom a heart attack occurs in a more subtle way, sometimes without causing any pain: in this case we speak of "silent heart attack". People at risk of developing a silent heart attack are those with reduced pain sensitivity, such as long-time diabetics.

In addition to pain, the symptoms of a heart attack can include:

. cold sweats,

. tachycardia ,

. breathing difficulties ( dyspnoea ),

. nausea and vomiting ,

. loss of strength ( asthenia ),

confusion.

4 Diagnosis

The suspicion of myocardial infarction is placed starting from the clinical picture of the patient, that is, on the basis of his symptoms and physical examination. The subsequent diagnostic process includes:

. Troponin : Troponin I is an enzyme contained in the cells of the heart that is released into the blood only when they die. The presence of this marker in detectable quantities is therefore a very specific index and means that there has been heart distress in the previous hours. It is certainly the most useful test for diagnosis and is also used in monitoring heart attack patients.

. ECG : Electro-Cardio-Graphy is an exam that allows you to record the electrical activity of the heart giving it a graphic representation, called electrocardiographic trace. By interpreting it, the specialist can confirm the presence of a heart attack and hypothesize its location. Although it has now been outdated as a diagnostic tool, it remains very useful for monitoring the functional recovery of the heart and the possible onset of arrhythmic complications.

. Echocardiography : Ultrasound of the heart allows you to see the heart muscle directly, studying its size, shape and movements. It allows to evaluate the functionality of the heart by measuring the amount of blood that is expelled with each beat; moreover, it allows to precisely locate the infarcted area (which does not contract, unlike the healthy myocardium) and to estimate its extension.

. Coronarography : It is a more invasive method that involves the execution of an x-ray after injecting a contrast medium into the coronary arteries. It provides an image of the cardiac circulation from which information is obtained on the state of the coronary arteries and on the presence of stenosis (ie narrowing) or occlusions. Information on the coronary circulation can be useful for planning a possible revascularization surgery.

5 Prognosis and complications

Myocardial infarction is a serious disease, which is fatal in about 30% of cases (half of which die before even reaching the hospital).

Furthermore, those who survive the acute event run the risk of incurring complications such as:

. Pericarditis : It is the inflammation of the pericardium, which is the protective membrane that lines the heart. It manifests as pain and fever and resolves in most cases after short-term drug treatment.

. Arrhythmias : Arrhythmias are when the heart stops contracting in rhythm and begins to beat in a disorderly fashion. Arrhythmias are a common complication in post heart attack, the severity of which varies from situation to situation: they can be completely harmless or more dangerous, up to requiring the implantation of a pacemaker.

. Mitral Insufficiency : The mitral is one of the four heart valves and is held in place by small muscular appendages called papillary muscles. If these muscles are affected by the heart attack it may be that the valve becomes incontinent, thus making the heart's contractions less effective.

    Heart failure : If the heart's function is severely compromised, it will no longer be able to meet the body's circulatory needs. It is a situation that requires lifelong drug therapy.

. Heart rupture : Most fearful complication of heart attack , the rupture of one of the heart walls inevitably leads to the patient's death.

6 Treatment and care

"Time is muscle" is a typical phrase that is used to emphasize the urgency of the heart attack: it means that every minute wasted before starting therapy is equivalent to the death of a part of the heart muscle.

The first measure to be implemented in the event of a heart attack is therefore to send the patient immediately to the emergency room, where he can receive the most appropriate treatment.

Unfortunately, this treatment is not curative (dead cells cannot in any way be replaced), but has the sole purpose of limiting the damage by preventing the infarcted area from spreading. An attempt is therefore made to revascularize the heart, that is, to restore a valid blood flow to the affected area. This can be achieved in two ways:

Thrombolysis : It is a pharmacological treatment aimed at dissolving any thrombi that have occluded the coronary arteries. Obviously, it is effective only when the heart attack is secondary to thrombosis and, even in this case, it must be administered promptly to have an effect.

Surgical intervention : The surgical intervention can be performed in thoracotomy (i.e. opening the patient's chest) or by catheterization (going up with an instrument through a blood vessel to reach the heart). In any case, the procedure involves the placement of a stent, a metal retina that dilates the coronary artery where it should be narrowed or frankly occluded.

If the patient survives the acute phase, a therapeutic protocol will then be planned with the aim of preventing the onset of new heart attacks. This usually consists of a long-term drug treatment combined with a rehabilitation process, but if the coronary circulation is severely compromised it could include angioplasty surgery.

7 Prevention

Heart attack can be prevented by acting on the modifiable risk factors of the disease, already described in the section dedicated to them. Effective prevention strategies include

.  adopting a healthy diet,

.  the recovery of your healthy weight,

.  regular physical activity (at least twice a week and lasting thirty minutes)

.  and the cessation of smoking.