by Ruggiero Corcella
Sudden cardiac death is death that occurs instantly, in the apparent absence of any symptoms, or in any case within an hour of the appearance of symptoms referable to the heart. A congenital alteration of the heart is often implicated
According to the Russian authorities, Alexei Navalny was the victim of “sudden death syndrome”. If this were the case, the best-known Russian dissident would share the same fate as four of the most illustrious sporting victims (and loved by Italians) of sudden cardiac death: Renato Curi, Vigor Bovolenta, Piermario Morosini, Davide Astori. And, abroad, the Danish footballer Christian Eriksen.
But what is what, from a scientific point of view, is defined as “sudden cardiac death”? That death that occurs instantly, in the apparent absence of any symptoms, or in any case within an hour of the appearance of symptoms referable to the heart (chest pain, dyspnea, etc.).
The causes of sudden cardiac death
Sudden death is in most cases caused by a serious cardiac arrhythmia, most often by ventricular fibrillation, in many cases preceded by ventricular tachycardia. Less frequently, the mechanism is represented by a bradyarrhythmia (asystole). Patients who have cardiac arrest due to ventricular fibrillation or asystole and who would be destined to die in the absence of interventions, if rescued in time with resuscitation maneuvers and appropriate interventions (primarily, ventricular defibrillation with electric shock) can be saved.
In these cases they are said to have been “resurrected” from a sudden death. The most frequent cause of sudden death is coronary artery disease. At least 30-35% of heart attack patients die suddenly before reaching hospital. About 50% of those who die later (in hospital or after discharge) die suddenly. Specifically, approximately 1-2% of patients who survive myocardial infarction die of sudden death in the first year after discharge. Other heart diseases, in addition to ischemic heart disease, are associated with a significant risk of sudden death, such as hypertrophic myocardiopathy, idiopathic dilated myocardiopathy and arrhythmogenic right ventricular dysplasia.
Long QT syndrome and Brugada syndrome
Furthermore, sudden death is the main concern and cause of death in some groups of patients who have a structurally healthy heart (i.e. normal with regards to contractile function and coronary circulation), but have alterations, mostly congenital, of the electrical activity of the heart, which predisposes them to develop ventricular tachyarrhythmias and cardiac arrest. Among these there are, in particular, the so-called long QT syndrome and Brugada syndrome.
In patients resuscitated from cardiac arrest due to ventricular fibrillation/tachycardia, the implantation of an automatic defibrillator is almost always indicated, capable of recognizing and resolving any recurrence of the potentially fatal arrhythmia with an electric shock. In fact, pharmacological therapies have generally proven to be unsuitable for preventing the recurrence of cardiac arrest.
Drugs and pacemakers
Furthermore, in patients suffering from various cardiac pathologies associated with an increased risk of sudden death, there are indications for implanting an automatic defibrillator in subgroups of patients who, despite never having had a cardiac arrest, have a rather high probability of sudden death (primary prevention). However, the use of beta blockers has reduced the risk of sudden death in some of the patient populations at risk of sudden death (in particular, those suffering from myocardial infarction and those with long QT syndrome).
In patients in whom cardiac arrest has been caused by asystole, pacemaker implantation is the definitive treatment. Many of the patients who have asystolic cardiac arrest, however, are compromised patients, with marked alteration of cardiac contractile function and with a high probability of death due to progressive heart failure or even due to the occurrence of ventricular tachycharythmias (for which they require an automatic defibrillator ).
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February 17, 2024 (modified February 17, 2024 | 6:08 pm)
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