What Is Sudden Cardiac Death?
Sudden cardiac death (SCD) is the medical term for an unexpected death caused by loss of heart function. Death occurs within an hour after the initial onset of symptoms. Every year, 50–100 sudden cardiac deaths occur per 1,000 deaths in Europe and North America.1 In Germany, around 65,000 people die of sudden cardiac death every year, which therefore accounts for 20 percent of all cardiovascular deaths.2 Athletes are at particularly high risk. They are two to four times more likely to experience sudden cardiac death (SCD) than the overall population.3 It is assumed, however, that sports are not responsible for the higher death rate. More likely underlying undetected heart diseases cause the sudden cardiac death in athletes by predisposing the heart to acute cardiac arrest or ventricular fibrillation when it is overstrained during exercise.
The most common cause of sudden cardiac death in middle-aged or older adults is coronary artery disease (CAD). In many cases, ventricular fibrillation precedes final cardiac failure. A heart attack, other cardiac arrhythmias, heart valvular diseases or diseases of the heart’s muscle (cardiomyopathy or myocarditis) may cause SCD. In about 55 percent of the cases, the underlying disease is unknown until after the tragic event has occurred.4
Generally speaking, anyone may suffer from sudden cardiac death. People with cardiovascular diseases, middle-aged or older people, the overweight and patients suffering from diabetes are at higher risk than young and healthy people. Smoking, lack of exercise, stress and alcohol abuse also elevate the risk. While exercise in itself does not elevate the risk, intensive physical training or participating in an athletic competition may lead to sudden cardiac death if the heart is weakened by a disease, e.g., undetected myocarditis due to an infection.
Usually, sudden cardiac death occurs without prior symptoms. Affected people collapse abruptly. They do not respond to sound or touch. Their pulse is not palpable and they stop breathing within one minute. Their pupils are enlarged and their skin may have an ashen color. Without immediate treatment to restore the heart’s rhythm, death occurs within minutes.
Sometimes, patients may experience a racing heartbeat, chest pain, shortness of breath, or feel dizzy, alerting them to a potentially dangerous heart problem. Fainting may also precede sudden cardiac death. If you experience or witness these symptoms, please seek emergency medical help immediately. Following the event, it is prudent to undergo a thorough examination from a physician, including electrocardiography (an EKG or ECG).
In case of sudden chest pain, shortness of breath and/or fainting, an emergency medical team must be called immediately. Unconscious patients without a palpable pulse have to be reanimated by cardiac massage (also called cardiopulmonary resuscitation or CPR) because three to four minutes without oxygen can cause irreversible brain damage. Basic life support should be continued until the emergency physician arrives.
In the case of ventricular fibrillation, defibrillation (cardioversion) might be an option to halt the heart rhythm disorder and to reset the heart’s normal activity. Nowadays, there are so-called automated external defibrillators (AEDs) in many public locations and public buildings. Easy to understand step-by-step instructions assist the first aider to handle these defibrillators correctly.
One of the most important measures to prevent sudden cardiac death is to diagnose cardiovascular diseases early and treat them appropriately. Athletes, in particular, should undergo regular cardiovascular examinations in order to detect hidden cardiac health issues in time. In addition, one should pursue a healthy lifestyle and avoid risk factors like lack of exercise, obesity, smoking or alcohol abuse.
1 John et al. Cardiac Arrhythmia 3 Ventricular arrhythmias and sudden cardiac death. Lancet 2012; 380: 1520–29
3 Ferreira et al. Sudden cardiac death athletes: a systematic review Sports Medicine, Arthroscopy, Rehabilitation, Therapy & Technology 2010, 2:19 doi:10.1186/1758-2555-2-19 http://www.biomedcentral.com/1758-2555/2/19