Sudden Death and Myocarditis

Sudden death syndrome (SDS) refers to an umbrella of cardiac conditions, such as myocarditis, that can lead to sudden cardiac arrest and even death. It presents as sustained abnormal electrical activity within the heart. Sudden death due to a loss of heart function typically occurs within one hour of symptoms beginning, which may include:

• Dizziness
• Trouble breathing
• Loss of consciousness
• A fluttering feeling in the heart or heart palpitations
• Unexplained chest pain and/or fainting, especially when exercising

However, in some cases, symptoms may not be present at all, and victims may die instantly. Unfortunately, many people don’t know they have SDS until a cardiac event occurs. Sudden cardiac death is responsible for up to half of heart disease deaths, and in many cases, it can affect young athletes with underlying genetic heart disease or those who have experienced a viral or bacterial infection reaching the heart.

A majority of sudden death cases are linked to coronary heart disease, heart attacks, and heart failure. While the incidence of sudden death from myocarditis in older adults is unknown, roughly 1-9% of deceased patients are found to have evidence of cardiac inflammation. However, in young adults, nearly 20% of sudden death cases are linked to myocarditis. Further, up to half of sudden death victims with HIV show evidence of myocarditis during their autopsy.

Other acquired and hereditary cardiac conditions may also lead to sudden death, including:

• Left ventricular hypertrophy, which is an enlarged heart due to high blood pressure
• Hypertrophic cardiomyopathy or arrhythmogenic right ventricular cardiomyopathy, which are both caused by genetic mutations in heart proteins
• Mitral valve prolapse, which is mainly caused by infections
• Congenital coronary artery anomalies, which are due to inherited defects

A small percentage of cases may occur without evidence of structural heart disease.

There is no evidence that caffeine is a risk factor associated with sudden death. However, there is an increased risk of sudden death for people who:

• Have high blood pressure
• Have high cholesterol (high LDL and low HDL)
• Smoke cigarettes
• Are physically inactive and/or obese
• Have diabetes mellitus
• Have a family history of premature or sudden death

In addition, the risk increases during exercise and for up to 30 minutes after strenuous activity, though this risk is extremely low. This risk is lower in those who regularly exercise, though people with inherited heart diseases are at a higher risk – even if they work out routinely.

It is possible to decrease the risk of these factors by:

• Effectively treating and managing high cholesterol, high blood pressure, and/or diabetes
• Adopting a heart-healthy diet and exercising regularly
• Quitting smoking and moderating alcohol consumption
• Using implantable cardioverter-defibrillator (ICD) devices in survivors of SDS episodes
• Administering anti-arrhythmic drugs to prevent abnormal electrical heart signals

Generally, no. However, those at risk can undergo stress testing, ECG monitoring, or other screenings, and if issues are identified, they may benefit from specific interventions.

If you have additional questions about the link between myocarditis and sudden death that were not answered here, please do not hesitate to contact Myocarditis Foundation for more information. You can also play a vital role in helping us find answers about myocarditis and heart disease by donating today.