INTRODUCTION AND EPIDEMIOLOGY
This chapter focuses on the epidemiology and pathophysiology of sudden cardiac death in adults and strategies for prevention and treatment. See Chapters 18 (“Cardiac Rhythm Arrhythmias”), 22 (“Basic Cardiopulmonary Resuscitation”), 23 (“Defibrillation and Electrical Cardioversion”), and 24 (“Cardiac Resuscitation”) for detailed discussion of resuscitation pharmacotherapy.
Sudden, unexpected, out-of-hospital cardiac arrest occurs in approximately 341,397 adult Americans each year.1 Estimated national survival of EMS-treated out-of-hospital cardiac arrest cases is 10.8%, yielding an estimated overall out-of-hospital cardiac arrest survival rate of 5.4% (EMS-treated plus deceased-on-EMS-arrival cases).1 There is substantial variability in the odds for survival across various geographic locations.2
Most episodes of sudden cardiac death occur in the home, although victims who experience cardiac arrest in a public place have a much better chance of survival.3 The initial recorded cardiac arrest rhythm is more likely to be ventricular fibrillation when cardiac arrest occurs in a public location rather than in the home, likely because patients who experience cardiac arrest in the home are typically older and more likely to have one or more chronic diseases that limit or exclude participation in activities outside the home.3 Sudden cardiac death is 30% to 80% higher among residents in the lowest compared with the highest socioeconomic quartile.4 This association is likely due to lifestyle and healthcare disparity issues.
There is a circadian pattern of sudden cardiac death and acute myocardial infarction,5,6 and both are most likely to occur within the first few hours after awakening from sleep, when there is increased sympathetic stimulation. β-Blockade provides some protection from sudden cardiac death, particularly in patients with known coronary artery disease who have had myocardial infarction and have a low ejection fraction.7
Prevalence of sudden cardiac death in adults is greatest in the age group older than 45 to 50 years, with 60% occurring in males.4 There are multiple known factors contributing to the likelihood of sudden cardiac death (Table 11-1).
TABLE 11-1Known Factors Contributing to the Likelihood of Sudden Cardiac Death ||Download (.pdf) TABLE 11-1 Known Factors Contributing to the Likelihood of Sudden Cardiac Death
Coronary artery disease
Severe left ventricular dysfunction
Congenital heart disease, especially coronary artery anomalies
Valvular heart disease
Cardiac pacemaker and conducting system disease
Risk factors and triggers
Coronary artery disease (which is often undiagnosed before the event) is the major cause of sudden cardiac death in adults and is present in 80% of cases, followed by cardiomyopathy (10% to 15%) and other miscellaneous ...