Dissecting the substrate for sudden cardiac death in the absence of ischemic heart disease

Abstract

d v v Sudden cardiac death (SCD) remains an enormous clinical problem, accounting for approximately 400,000 cases annually in the United States alone. Current strategies for redicting and preventing SCD focus on the primary preention of cardiovascular diseases and their associated seuelae and the identification of high-risk individuals with schemic and nonischemic cardiomyopathy. When high-risk atients are identified, appropriate medical therapy and rophylactic placement of an implantable cardioverter-debrillator (ICD) have been proven to reduce SCD and total ortality. The majority of sudden deaths occur in low-risk ndividuals with relatively preserved left ventricular funcion that do not meet criteria for ICD placement. Although he event rate of such patients is relatively low, they account or the greatest absolute number of SCD cases because the umber of patients at risk is much larger. In addition, many CD cases represent the first manifestation of cardiac disase, which greatly complicates any preventive strategy. Careful studies of the clinical characteristics and cardiac athology of SCD victims are a critical prerequisite for aining a better understanding of the potential mechanisms f SCD and formulating new preventive strategies. The ajority of SCD cases are due to coronary artery disease, ither in the form of acute coronary syndromes or chronic schemic heart disease with prior myocardial infarction. Much less is known about the substrate for SCD in the absence of ischemic heart disease. One of the major difficulties with studies of SCD victims is that autopsies are not routinely obtained in most countries, which limits the ability to draw definitive conclusions regarding the prevalence of various forms of cardiac pathology. In the present issue of HeartRhythm, Hookana et al report a study of 2,661 consecutive victims of SCD in the province of Oulu in northern Finland. A major strength of this study is that autopsies are mandatory in Finland whenever SCD is not due to a known disease, the deceased has not been treated by a physician during the patient’s last illness, or death is otherwise unex-