Preventing Sudden Cardiac Death in Patients with Ischaemic Cardiomyopathy

Vincent Floré, Rik Willems
European Cardiology, 2012;8(2):134–8
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Abstract

Sudden cardiac death (SCD) is an important cause of mortality. In this article, we review the definition, impact and underlying aetiology of SCD. Ventricular tachyarrhythmia accounts for the majority of SCDs and can be caused by various underlying heart diseases, the most frequent being ischaemic cardiomyopathy. The most effective ways to reduce the risk of SCD in ischaemic cardiomyopathy are the optimal prevention of recurrent coronary ischaemia and the use of an implantable cardioverter-defibrillator (ICD) in high-risk patients. We discuss current patient selection for ICD implantation and focus on the need for, and possibilities to improve, SCD risk stratification.

Acknowledgements: The research leading to the results presented here has received funding from the Belgian Science Policy programme (IAPP36/10). Rik Willems is supported as a clinical researcher by the Fund for Scientific Research Flanders. The University of Leuven receives unconditional research funding from Boston Scientific and Medtronic Belgium.
Keywords
Sudden cardiac death, ventricular arrhythmia, ischaemic cardiomyopathy, implantable cardioverter-defibrillator, risk stratification, non-invasive testing
Disclosure Vincent Floré has no conflicts of interest to declare. Rik Willems has received speaker and consultancy fees from, and participated in clinical trials by, different implantable cardioverter-defibrillator manufacturers (Biotronik, Boston Scientific, Medtronic, Sorin, St Jude Medical).
Received: February 29, 2012 | Accepted March 15, 2012 | Citation European Cardiology, 2012;8(2):134–8
Correspondence: Rik Willems, Division of Cardiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium. E: rik.willems@uzleuven.be

Sudden cardiac arrest (SCA) can be defined as the abrupt cessation of cardiac activity due to an underlying cardiac cause, occurring instantaneously in a previously stable patient and in the absence of non-cardiovascular causes (e.g., trauma, intoxication, drowning, electrocution).1,2 SCA will lead to loss of consciousness within the minute due to insufficient cerebral perfusion. If no immediate action is taken to restore circulation – e.g., defibrillation – SCA will invariably lead to sudden cardiac death (SCD). In this article, we will use SCD as the common term for both SCA and SCD.

A Major Cause of Death with a High Impact on Daily Life

The mechanism underlying SCD is arrhythmic in the majority (80–90 %) of cases3 and over 80 % of the arrhythmic episodes are ventricular arrhythmia (VA): ventricular tachycardia (VT) or ventricular fibrillation (VF).4 As, in many cases, the deadly event is not witnessed (e.g., occurring during sleep and/or out of hospital), no definition of SCD is 100 % accurate.1 This explains why epidemiological data vary from report to report. However, it is clear that SCD is a very frequent cause of mortality worldwide. Incidence estimates from large population studies in the 1990s were as high as 450,000 SCD cases per year in the US,5 400,000 in Europe6 and 3,000,000 worldwide.7 SCD accounts for over 50 % of all cardiac-related deaths in the US8,9 and it is the second leading cause of death after all cancers combined.10 Even though, during the last 20 years, the significant decrease in the incidence of cardiovascular mortality has also been observed for SCD,11 SCD remains a very important health issue. Not only because its incidence remains high, but also because the abrupt and unforeseeable character of the condition leads to very low (less than 10 %) out-of-hospital survival rates11 and loss of life for people who were often free of morbidity up until right before the event.

A Prism of Possible Underlying Causes

The underlying conditions that form the substrate of, and the trigger for, VA leading to SCD are very diverse. In less than 10 % of the patients experiencing SCD, no macroscopic structural heart disease is found.12 This subgroup consists of patients with congenital electrophysiological anomalies, such as the congenital long and short QT syndromes, Brugada syndrome, catecholaminergic polymorphic VT and idiopathic VF. These conditions are a particularly important cause of death in young people. The current knowledge about the origin, detection and treatment of these individual conditions, which is continuously evolving, is beyond the scope of this article.

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