Most Common Cause of Cardiac Arrest
The most common cause of cardiac arrest is cardiovascular disease, specifically coronary artery disease and acute coronary ischemia. 1
Overall Population
Coronary artery disease accounts for 50-60% of all cardiac arrests, making it by far the leading etiology across all age groups in adults. 1, 2
- Acute myocardial infarction is the most frequent precipitating event, complicating 5-12% of AMIs and typically occurring when >40% of left ventricular myocardium is lost. 3
- Out-of-hospital cardiac arrest is a leading cause of death, accounting for approximately 50% of all cardiovascular deaths. 4
- Among the estimated 290,000-350,000 annual cardiac arrests in the United States, coronary ischemia remains the predominant underlying pathology. 1, 2, 4
Age-Specific Considerations
Adults Over 40 Years
- Coronary artery disease with acute thrombotic occlusion of major coronary arteries is the primary mechanism. 1
- In the post-myocardial infarction population specifically, arrhythmic death accounts for approximately 5% at 2.5 years in the thrombolytic era, with the majority triggered by coronary ischemia. 1
- Autopsy studies consistently demonstrate active coronary lesions in the majority of sudden cardiac death victims in this age group. 1
Young Adults Under 40 Years
Hypertrophic cardiomyopathy is the most common cause of cardiac arrest in individuals younger than 40 years of age, affecting approximately 1 in 500 persons in the general population. 1
- Among apparently healthy young adults with out-of-hospital cardiac arrest, 55-69% have underlying cardiac causes identified at autopsy, including sudden arrhythmic death syndrome (most common in athletes) and structural heart disease. 5
- Coronary artery disease still accounts for a significant proportion even in this younger cohort, particularly among those with cardiovascular risk factors like hypertension and diabetes. 5
Clinical Implications for Initial Management
A 12-lead ECG should be obtained immediately after return of spontaneous circulation to detect ST elevation or new left bundle-branch block, as this identifies the coronary ischemia that drives the majority of arrests. 1
- Early coronary angiography should be strongly considered even in the absence of ST elevation, as studies show 62.4% of post-arrest patients without ST elevation have occlusive coronary artery disease, with 71% requiring intervention. 6
- The presenting rhythm provides diagnostic clues: ventricular fibrillation is the most common initial rhythm in sudden, unheralded cardiac arrest from coronary disease. 1
- In-hospital cardiac arrests show different patterns, with 81% presenting with nonshockable rhythms (asystole or pulseless electrical activity), though cardiac causes still predominate at 50-60%. 2
Common Pitfall to Avoid
Do not assume that modest troponin elevations after sustained ventricular tachycardia or fibrillation indicate a new myocardial infarction was the cause—prolonged arrhythmias can elevate cardiac biomarkers due to supply-demand mismatch without acute coronary occlusion. 1 However, these patients should still be treated as high-risk for recurrent events and evaluated for underlying coronary disease. 1