FAQs - Frequently Asked Questions about SCD
What is sudden cardiac death (SCD)?
The heart stops working without warning ( Sudden Cardiac Arrest) (SCA ). Sufficient blood cannot be pumped to the brain, the victim faints and death follows within minutes. It occurs when the heart's inbuilt electrical system malfunctions.
What causes SCD?
In a healthy heart a "Pacemaker" (sinus node) triggers the heartbeat and electrical impulses run along pathways in the heart causing it to contract in a regular way. When it malfunctions it causes an abnormal heart rhythm "Arrhythmia" which can lead to death.
The common denominator in all cases of SCD is the development of electrical instability that leads to a fatal arrhythmia Ventricular Fibrillation ( The lower chamber of the heart quivers instead of pumping in an organised fashion).Ventricular Fibrillation does not return to normal rhythm by itself and requires immediate intervention.
Most cases of SCD are related to undetected cardiovascular disease. They can be inherited or acquired
These conditions include:
Coronary heart disease (CHD) - narrowing of the blood vessels in the heart. CHD affects young people as well as older people.
Cardiomyopathies- heart muscle abnormalities and are usually inheritable.
Hypertrophic Cardiomyopathy ( HCM)
Arrhythmogenic right ventricular cardiomyopathy (ARVC)
Dilated Cardiomyopathy ( DCM)
Congenital Heart Disease. Some may be inherited .
Diseases of the heart valves
Abnormalities in the arteries to the heart
Disease of the heart’s electrical system
Other causes of SCD include electrocution, viral infection (myocarditis), blow to the chest and
adverse reaction to drugs (legal & illegal)
What is the difference between SCD and SADS?
SCD Sudden Cardiac Death is an umbrella term used when Sudden Death occurs due to a cardiac problem. SADS Sudden Arrhythmic Death Syndrome is the term used when no definite cause of death can be found even after the heart has been examined by the pathologist.( In the past this was known as Sudden adult Death Syndrome but because it also affects children, the term now used is "Sudden Arrhythmic Death Syndrome"
Is SCD the same as a Heart Attack?
No, but SCD may occur during the course of a heart attack. A heart attack( Myocardial Infarction) is caused by the sudden blockage of an artery feeding the heart which causes it to become starved of oxygen. The part that has been starved of oxygen is damaged. which may lead to sudden cardiac death.
Does taking part in sport cause SCD?
No. Sport and physical activity is good for your heart. However if a person has a serious, undetected heart problem, sport can act as a trigger for sudden cardiac death.
How can I know if this could happen to me?
There are a number of symptoms that may indicate that you are at increased risk. These include:
- An abnormal heart rate or rhythm (arrhythmia) of unknown cause
- An unusually rapid heart rate (tachycardia) that comes and goes, even when you are at rest
- Fainting (called syncope), blackouts, of unknown cause
- Dizziness
- Breathlessness on effort
- Chest pain on exertion
- Family history of unexplained death of somebody under 50 yrs
- Family history of infant and Cot death
If you have any of these symptoms or history , you should speak to your doctor.
What tests can be done?
There is a simple way to diagnose most cardiac abnormalities. A good medical examination including a family history and having an ECG (electrocardiogram) and sometimes an Echo (echo-cardiogram). Although all the causes of sudden cardiac death cannot yet be diagnosed, it is estimated that with these two tests 50%-70% can be. A consensus document compiled by expert European Cardiologists exists since 2005. They recommend applying the Lausanne Protocol
When a person’s heart stops, can anything be done?
Yes. The "chain of survival" has 4 links that need to be made immediately to give the best chance of
survival.
1. Get help, dial 112 (the new emergency phone number that replaces 999)
2. Perform CPR ( Cardio Pulmonary Respiration)
3. Defibrillation with an Automated External Defibrillator (AED). This device delivers an electric
shock to the heart. This is the only action that can restore a normal heartbeat rhythm.
4. Advanced care by a medical team.
Where can I train in CPR and to use an AED?
A national network of 120 training sites, affiliated to the Irish Heart Foundation provide training.www.irishheart.ie