Heart attack: causes, symptoms, therapies

What is it

The heart is the most important organ of the cardiovascular system. It is formed by a muscle, the myocardium, which continuously pumps blood to the whole body.

Heart attack is the death (necrosis) of the muscle tissue of the heart due to lack of oxygen. It can affect more or less extensive parts of the organ causing consequences of varying severity. At its origin is partial or total occlusion of the coronary arteries, the vessels that surround and nourish the heart muscle.

The severity of the heart attack depends on both the location and extent of the damage suffered by the heart, as well as the timeliness of treatment.

Causes

The cause of heart attack is ischemia, that is, the lack of blood supply, and therefore oxygen, to the muscle that makes up the heart.

In most cases it is due to narrowing or total closure of one or more coronary arteries, the arteries that supply the heart muscle, caused by atherosclerosis.

Atherosclerosis is a disease that causes the loss of elasticity of the vessels and the formation of accumulations of fat (plaques), cholesterol and other substances inside them, hindering the normal passage of blood and causing a heart attack.

The main factors that predispose to atherosclerosis are: high blood pressure (arterial hypertension), high levels of cholesterol and triglycerides in the blood, diabetes, obesity, smoking habits.

Another cause of coronary artery disease that can increase the risk of heart attack (but also stroke and pulmonary embolism) is the presence of blood clots, due to the detachment of a part of the plaque present in a blood vessel, which can completely obstruct the artery.

Common symptoms

Myocardial infarction can begin suddenly and can occur during a significant effort, when the effort is over, after an intense emotion, but also at rest. It is characterized by typical symptoms, in most cases easily identifiable.

The main symptoms of heart attack are tightness in the chest and pain of varying degrees, often very intense and that can persist for a few hours.

In particular, localized chest pain is one of the symptoms most commonly associated with heart attack: however, about a third of people affected by heart attack do not experience it. These are the patients, as well as those with other non-specific symptoms, who tend to wait longer before going to the emergency room. For this reason, mortality among them is double compared to those who manifest the classic symptoms of this pathology.

The localization of pain during a heart attack can be around the site of the heart or retrosternal. The pain can also radiate to the shoulders, back (particularly in the space between the two shoulder blades), arms (particularly on the left side of the body), jaw, neck and throat. In some cases, a burning sensation prevails in the chest.

More rarely, the infarction can be silent, free of warning symptoms, and due to a sudden and prolonged contraction of a coronary artery that obstructs the passage of blood.

Sometimes the heart attack can be preceded by more vague signs such as fatigue, shortness of breath, stomach upset comparable to those of indigestion, cold sweats, agitation, pallor, tingling in the left arm.

A condition similar to heart attack, but less serious because the oxygen deficiency is not so prolonged as to cause necrosis, is angina pectoris, characterized by chest pain that lasts for up to 30 minutes. Angina often precedes in time, for days or months, the onset of the actual heart attack.

Heart attack in women

Despite a set of characteristic symptoms, heart attack remains a subjective experience, which can manifest itself in very different ways depending on the individual.

A separate discussion concerns the infarction in the female sex. It is believed that women are less prone to cardiovascular disease, and therefore also to heart attack and stroke. In fact, this is only true during childbearing age, when they benefit from the protection induced by the presence of estrogen.

The abrupt drop in estrogen that occurs with menopause exposes women to an increased risk of experiencing these diseases, so much so that in old age cardiovascular diseases represent the first cause of death.

Only in recent years, moreover, it has been understood that in women the heart attack manifests itself differently than in men, often causing difficulties in recognizing it, both by women themselves and by doctors, with a consequent delay in diagnosis that can prove fatal in some cases.

The symptoms are usually more nuanced, chest pain may be present, but more often the heart attack manifests itself with atypical symptoms: difficulty breathing, stomach pain, severe nausea, vomiting, cold sweats and dizziness, extreme tiredness, widespread back pain, often mistaken for flu or gastroesophageal reflux problems . For women, these symptoms should therefore be considered warning signs that should not be underestimated.

The diagnosis of heart attack occurs by means of certain examinations; In particular, an electrocardiogram and blood test should be performed to detect the possible presence of cardiac enzymes that the necrosis heart muscle tissue releases following the heart attack.

Complications

Lack of oxygen causes myocardial cells to die. As a result, the part of the heart damaged by the heart attack is no longer able to contract. For this reason, the greater the affected area, the less the heart’s ability to pump blood, causing sometimes irreversible disability.

The most serious complication of heart attack is cardiac arrest that can result in death.

Therapies

Acting quickly is critical, as half of heart attack deaths occur within the first few hours of symptom onset.

In the last 50 years, medicine has made enormous progress, which has made it possible to improve the prognosis of heart attacks. Among these, the effectiveness of the immediate administration of thrombolytic drugsto dissolve the clot, as well as mechanical reopening procedures such as angioplasty, stents and coronary artery bypass or,all interventions that lose much of their effectiveness if performed more than six hours after the onset of symptoms.

Coronary angioplasty is a non-surgical procedure through which the occluded vessel is reopened. It consists in the introduction of an inflatable “balloon” capable of dilating the coronary artery once it reaches the point of maximum narrowing. Inside the unblocked artery is then placed a stent, ie a mesh prosthesis, which allows you to keep it “open”.

It is an operation (under local anesthesia and lasting about an hour) that must be performed as soon as possible to prevent the damage to the heart muscle from continuing and becoming irreversible.

When angioplasty is not possible, a coronary bypass is implanted which, by forming a channel between the obstructed coronary artery and the aorta, creates an alternative route to blood flow.

The care of patients affected by heart attack and the execution of these procedures require the availability of laboratories and operating rooms 24 hours a day; However, not all cardiology units are equipped in this sense.

In addition to the procedures just described, the patient is given drugs of various types, which must also be taken later: anticoagulants and antiplatelet agents (typically acetylsalicylic acid to prevent the formation of clots), beta blockers to reduce the risk of death in the period following the heart attack, ACE inhibitors (angiotensin-converting enzyme inhibitors) to prevent the development of heart failure, especially in cases where extensive heart damage is present, and statins to maintain normal cholesterol levels.

Preventing heart attack

In all cardiovascular diseases, prevention is very important, which is achieved by modifying risk factors. In addition to age, gender and family history, which represent non-modifiable risk factors, there are others on which it is possible to intervene.

An active lifestyle, which includes at least 20-30 minutes of physical activity a day, is useful for preventing cardiovascular problems; Following a diet rich in calories and fat, on the contrary, increases blood lipid levels, favoring the onset of atherosclerosis, and therefore should be avoided.

Also risk factors are arterial hypertension and excess glucose in the blood that over time can cause kidney failure, in turn associated with increased cardiovascular risk.

With particular regard to arterial hypertension, the following table shows the normal values of systolic and diastolic blood pressure, expressed in millimeters of mercury (mmHg), and the degrees of hypertension, according to a classification of the World Health Organization.

Other fundamental prevention measures are the maintenance of a healthy weight and the abolition of smoking, even after the acute event: in the months following a heart attack, in fact, the risk of death is very high.

It is in fact a very critical period, during which the patient is sent to a path of cardiac rehabilitation to gradually resume their physical abilities. Rehabilitation usually begins in the hospital, and is then continued in hospital or outpatient practice, depending on the severity of the heart attack, individual recovery capacity and the presence of other diseases.

When to consult your doctor

As soon as symptoms of a heart attack appear, it is imperative to contact an emergency service (118) which can guarantee the arrival of appropriate assistance and resuscitation in case of cardiac arrest. The use of the defibrillator, in case of cardiovascular arrest, must be immediate; the probability that it will be effective decreases with the passing of the minutes.

The more timely the intervention, the better the chances of survival since the risk of death is maximum in the first hour after the onset of symptoms and the amount of heart tissue saved from necrosis is proportional to the speed of restoration of blood circulation.