Arq. Bras. Cardiol. 2018; 110(6): 532-533
Prevention of Sudden Death in Hypertrophic Cardiomyopathy
DOI: 10.5935/abc.20180101
This Short Editorial is referred by the Research article "Prevention of Sudden Cardiac Death in Hypertrophic Cardiomyopathy: What has Changed in The Guidelines?".
Hypertrophic cardiomyopathy (HCM) is the most common congenital disease, and sudden death (SD), its most feared complication, was already mentioned by Donald Teare in the first description of the disease, being observed in 7 out of 8 patients. SD occurs during daily activities, after exercises and even during sleep; it may affect young athletes, which has a great impact on the media. This has required considerable effort by researchers in defining clinical factors and complementary tests that could be used in the screening of individuals at higher risk that could benefit from implantable cardioverter defibrillator (ICD) and also to prevent SD, since it is caused by tachycardia and ventricular fibrillation. HCM favors the occurrence of ventricular arrythmias – hypertrophy causes repolarization dispersion; myocyte disarray and increased fibrosis create areas of conduction block and predispose to reentry arrhythmias; and abnormalities in ion fluxes, such as calcium, during repolarization may also trigger arrhythmias. In addition, this complex arrhythmogenic substrate may be modulated by impaired autonomic response, myocardial ischemia and left ventricular outflow tract obstruction.– If we consider deaths from cardiovascular causes, in patients with HCM, they account for 0.5%-1.5% deaths a year, which is near to that of the general population. In HCM patients considered as high risk, SD may reach 2.5% of deaths a year. However, the accurate identification of these patients for preventive therapy with ICD may be challenging.
Before the guidelines were published, it was known that manifestations of HCM in children younger than 10 years old with diastolic or systolic dysfunction, SD in first-degree relatives younger than 50 years, nonsustained ventricular tachycardia, syncope and myocardial hypertrophy > 30 mm were factors associated with SD, and the last four fully considered as indications for ICD in the first guideline (2011).
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