Today, I review, link to, and excerpt from StatPearls‘ Sudden Cardiac Death. Allison G. Yow; Venkat Rajasurya; Sandeep Sharma. Last Update: August 8, 2022.
All that follows is from the above resource.
Etiology
Coronary artery disease is the most common cause of sudden cardiac death, accounting for up to 80% of all cases. Cardiomyopathies and genetic channelopathies account for the remaining causes. The most common causes of non-ischemic sudden cardiac death are cardiomyopathy related to obesity, alcoholism, and fibrosis.
In patients younger than 35, the most common cause of sudden cardiac death is a fatal arrhythmia, usually in the context of a structurally normal heart. In patients from birth to 13 years, the primary cause is a congenital abnormality. In patients aged 14 to 24 years, the cause of sudden cardiac death is attributed to hypertrophic cardiomyopathy (HCM), arrhythmogenic right ventricular cardiomyopathy (ARVC), congenital coronary anomalies, genetic channelopathies, myocarditis, Wolff-Parkinson-White syndrome, and Marfan syndrome.
Common Causes of Sudden Cardiac Arrest[1], [2], [3]
Ischemic Heart disease
Inherited Channelopathies
Cardiomyopathies
Heart Failure
Valve disease
Congenital diseases
Epidemiology
Each year, approximately 0.1% of the United States population experiences a medical services-assessed, out-of-hospital cardiac arrest. European studies have a similar incidence ranging from 0.04% to 0.1% of the population. The median age in the US is between age 66 and 68. Males are more likely to suffer from sudden cardiac arrest.
While rare, sudden cardiac death is the leading cause of nontraumatic cause of death among young athletes. In the general population, sports-related, sudden death from any cause is 0.5 to 2.1 per 100,000 yearly. Sports-related, sudden deaths are higher in elite athletes with an incidence of 1:8,253 per year per the National Collegiate Athletic Association (NCAA). NCAA Division I male basketball players have a 1:5200 incidence of sudden death.
A circadian peak of sudden cardiac death occurs between 6 am and noon, and a smaller peak occurs in the late afternoon. The overall incidence of sudden cardiac death is higher on Mondays. [1]
History and Physical
Some patients experience palpitations, dizziness, or near syncope prior to sudden cardiac arrest. Almost half of the patients who have sudden cardiac arrests report no symptoms prior to collapse.
The American Heart Association recommends cardiovascular screening for high school and collegiate athletes. This includes an evaluation of the athlete’s personal and family history and a physical exam. [4] Screening should follow the AHA guidelines:
Personal History
Family History
Physical Examination
Routine ECG testing is not recommended for student-athletes. Students found to have an abnormal exam or those with a positive personal or family history may be referred for cardiac testing including ECG and echocardiogram.
Sudden cardiac arrest patients may demonstrate brief myoclonic or seizure-like activity.
Evaluation
Before transportation to a hospital, emergency medical services (EMS) or lay people may utilize an automated external defibrillator (AED). Once EMS arrives cardiac monitoring via ECG should occur.
Full cardiac assessment is required for cardiac arrest survivors. The following tests should be completed to establish a cause [2]:
ECG testing helps determine a diagnosis of ischemic heart disease, myocardial infarction, and inherited channelopathies. Echocardiograms evaluate for evidence of heart failure, cardiomyopathy, valvular heart disease, and congenital heart disease. Coronary angiography further evaluates coronary artery disease, congenital coronary anomalies, and coronary spasms. Exercise testing is helpful for diagnosis of ischemic heart disease, LQTS, and CPVT. Electrophysiology studies can detect the suspected arrhythmia. Procainamide can provoke Brugada syndrome regardless of the findings on the initial ECG. Cardiac MRI can detect ARVC, sarcoidosis (fibrotic cardiomyopathy), myocarditis, and myocardial injury from coronary spasms.
Treatment / Management
Treatment for sudden cardiac arrest should be initiated immediately by lay people and EMS. Treatment includes the use of an automated external defibrillator and cardiopulmonary resuscitation (CPR). CPR provides enough oxygen to the brain until a stable electrical rhythm can be established.
After transfer to a hospital, therapeutic hypothermia can be induced to limit neurologic injury and reperfusion injuries. Therapeutic hypothermia is more effective for the management of ventricular tachycardia and ventricular fibrillation but can also be used in PEA and asystole. Limitations to therapeutic hypothermia include a tympanic membrane temperature below 30 degrees at presentation, being comatose before the sudden cardiac arrest, pregnancy, inherited coagulation disorder, and the terminally ill patient.
If a patient survives the out-of-hospital cardiac arrest, long-term treatment is aimed at the underlying cause.
An implantable cardioverter defibrillator (ICD) is used for secondary prevention of sudden cardiac death in any person who has experienced arrhythmia-related syncope or survived sudden cardiac arrest.
Medication is targeted at the underlying cause of sudden cardiac arrest.
Differential Diagnosis
