Sudden Cardiac Death: Epidemiology and Risk Factors

Sudden cardiac death is the most feared outcome in cardiology because it so often arrives without warning. This review lays out the uncomfortable statistics that define the problem.

The numbers reframe how prevention should be aimed. Sudden death accounts for more than 60 percent of all cardiovascular deaths and strikes 180,000 to 250,000 Americans a year. Coronary artery disease underlies roughly 80 percent of cases — and, critically, half of those victims had no prior diagnosis of heart disease. The event was their first symptom. The review also catalogs the risk multipliers: heart failure raises risk fivefold, a family history of sudden death doubles or even multiplies it ninefold, and survival after an out-of-hospital arrest remains a dismal 5 to 10 percent.

The central, sobering insight is a mismatch. The standard tool for identifying high-risk patients — a low ejection fraction qualifying for a defibrillator — misses the majority: about 65 percent of sudden-death victims have a relatively preserved ejection fraction. Our best risk marker captures only a minority of the people who actually die.

We rate the evidence strong for a review of this kind. It makes the case, implicitly, for the entire enterprise of finding coronary disease early — because for too many people, the alternative is no second chance.