What is SADS?

SADS stands for Sudden Arrhythmic Death Syndrome (previously known as sudden adult death syndrome). It is a term used to describe the likely cause of sudden death in someone when a post-mortem examination has not shown any other potential cause of death (structural heart disease and coronary disease or 'hardening of the arteries' have not been seen, or are not considered sufficient to cause sudden death). Several conditions have been shown to cause SADS. These are usually electrical problems - problems with pump systems found in the walls of cells in the heart which are meant to pump salts in and out of the cell. These pump problems are called 'channelopathies' or ' ion channel disorders' and can broadly be said to include 'Long QT Syndrome' and Brugada disease. It is not possible to find these at post-mortem.

 

Can screening be done to detect channelopathies?

Although people with channelopathies have apparently normal hearts, including at post-mortem, in life it is often possible to detect abnormalities on cardiac tests such as the ECG(electrocardiogram - a recording of your heart's electrical activity), or sometimes exercise tests or 'Holter' monitors, where you wear a device for 24 hours or more to record your heart rhythm. Sometimes special medications may be given to bring out changes which are not so obvious on the ordinary resting ECG. Genetic testing is also sometimes available, but usually so far only through research centres.

 

Is there a difference between 'heart attack' and sudden death or cardiac arrest?

When medical professionals speak about heart attacks they are usually referring to a 'coronary', or a blockage in one of the heart's blood vessels. This usually causes chest pain, but it only causes collapse or sudden death in perhaps a quarter of all people who get a blockage. The medical name for a 'heart attack' is a myocardial infarction, often shortened as 'MI'. Cardiac arrest is when the heart stops beating effectively due to a sudden serious change in the heart's rhythm. This always results in collapse, and often in sudden death. Defibrillators can be used to treat some but not all causes of cardiac arrest.

 

Should families be screened if a relative dies suddenly?

If the cause of death is known to be a hereditary problem (such as some forms of cardiomyopathies, or heart muscle diseases, many causes of SADS, Marfan's disease), then immediate family should be screened as a precaution. This usually means the parents, brothers and sisters, and if appropriate the children of the deceased should be checked for evidence of the same condition (or, where the cause of death is uncertain, the relatives should be screened for any clues as to possible causes of death).

 

What should family screening involve?

Family screening should involve at the very least a discussion about possible symptoms and an ECG (electrocardiogram). Very often, but depending on the condition being screened for, more tests are needed, such as: echo cardiogram or 'echo' (ultrasound of the heart), exercise test, heart rhythm monitoring. Sometimes more sophisticated tests such as MRI scans (magnetic resonance imaging - a type of X-ray test which involves lying on a table which moves through an x-ray tunnel) or special electrical tests.

 

How often should families be screened?

Often in adults, one detailed screening visit is all that is required. If the doctor is in any way unsure they may order additional tests or suggest repeating the screening in 1 to 5 years. For some conditions there is a small chance that it could develop in later life, so repeated screening every 1 to 5 years may be suggested even if the initial results are very normal. For children or adolescents under 18, repeated visits at perhaps yearly intervals are often required. Often very young children are not screened because most of these conditions are not present at birth but appear during puberty or in later years. Also young children cannot understand enough to co-operate when the tests are being performed so useful results may not be obtained.

 

Where screening should be done?

For conditions such as Hypertrophic Cardiomyopathy, most Cardiologists can arrange for an ECG and echo to be done (ultrasound scan of the heart). For some of the more rare conditions such as Channelopathies and ARVC, the screening is best done by Specialists who deal in such problems all the time. Screening is available to the public in the National CRYP Centre, Tallaght Hospital. Access to the CRYP Centre is via referral from a Consultant or General Practitioner, often via the CRY charity. People can be referred from anywhere in the country and there is no charge to the patient, regardless of income or insurance. While focusing primarily on adolescents and young adults, there is no upper age limit for referral to the Centre.

 

What is Cardiomyopathy?

Cardiomyopathy is a term used to describe heart muscle disease. There are several different types of cardiomyopathy:

- Hypertrophic Cardiomyopathy (also called HCM, HOCM or 'hocum') is where the walls of the heart, particularly the pumping chamber on the left side (left ventricle) are thicker than normal. This is relatively common, and many people live a full normal life without any symptoms and do not require treatment. Sometimes affected people may experience chest discomfort or pain, especially during some form of activity, shortness of breath, palpitations or dizzy spells and blackouts. A very small proportion of affected people are at risk of dying suddenly. It often but not always runs in families, and can usually be diagnosed by having an ECG(electrocardiogram) and echo (ultrasound scan of the heart). Genetic tests can be useful but only in about 50% of families.

- Dilated Cardiomyopathy (also known as DCM) is where the heart is larger than normal, but the walls are usually normal thickness or even slightly thinned. This may result in 'heart failure', where people experience shortness of breath on exercise or when lying flat, or extreme fatigue. The most common cause is coronary disease or 'hardening of the arteries', especially after heart attack(s). Sometimes there is no coronary disease, and the condition may run in families, or may be though to have occurred as a result of a viral infection. It is diagnosed by doing an ECG and echo (ultrasound scan of the heart), although additional tests are often done to look for the cause.

- Arrhythmogenic Right Ventricular Cardiomyopathy (also known as ARVC or ARVD) is thought to be a rare condition affecting the right side of the heart more than the left. It often runs in families. It may not cause any symptoms, or can cause palpitations, dizzy spells, blackouts, or in a small proportion of people it can cause heart failure or sudden death. It can be hard to diagnose in its milder form - tests used include ECG, echo, exercise test, heart rhythm monitoring and sometimes MRI scans of the heart.

 

What are Palpitations?

Palpitation is a term used to describe an awareness of a change in the heart rhythm. It can feel like skipped beats (the heart seems to miss a beat and after a gap the next beat is felt as a heavy thud), or you may notice that the heart suddenly starts racing, even if you are doing nothing. It can last for anything from seconds to hours or even days.

 

Are all palpitations potentially serious?

Most people experience some palpitations during their lifetime. Sensations of missed beats are most likely to occur during illnesses such as colds or flu, or if you are over-tired, stressed have drunk too much coffee / tea / alcohol/or other stimulant drinks (e.g. Red Bull), or with certain medications like Sudafed or drugs like Ecstasy or Cocaine. A sensation of the heart racing for minutes or hours is reasonably common, especially in young adults, and may indicate an electrical short circuit in the heart. This is often associated with an uncomfortable awareness of your heart thumping in your chest and/or pounding in your neck. These types of palpitations often stop themselves, although you may sometimes need to consult your doctor. They are usually not serious or life-threatening. Any form of palpitations that cause you to feel dizzy, give you chest pain, make you very short of breath or cause you to faint / blackout could be serious and you should seek medical advice.

 

What is the link between sudden death and sports?

People who have cardiac problems (and may be unaware of them) carry a slightly higher risk of dying suddenly during periods of fairly intensive activity than at other times. This is why as a precaution if someone is diagnosed with a cardiac disorder they will often be advised to avoid competitive sport or endurance training.

 

Shouldn't everyone or at least those  who participate in sport be screened for cardiac disease?

The risk of someone who has no symptoms of heart disease and no history of heart disease or sudden death in their family dying during sporting activity is very small (perhaps 1 in 100,000). Some countries (certain states of the USA and Italy) do screen everybody but this can cause unforeseen problems as there is sometimes a grey area between normal and abnormal tests, and having possible abnormalities detected may influence career choices, ability to take out insurance, mortgages etc. There is no right answer to this question, but concentrating efforts initially on those with symptoms or possible heart disease in the family would probably be most useful.

 

What are an AED and an ICD?

Is there a difference? Defibrillators are machines that can deliver an electrical shock to the heart to knock it out of a potentially fatal rhythm disorder. Most people are familiar with the machine with paddles in hospitals, as seen on TV programmes such as 'ER'. There is a move to have user-friendly clever versions of these machines available in public places (airports, sports stadium, shopping centre etc). These devices with a built-in computer which will recognise the rhythm and deliver the treatment are called Automated External Defibrillators. It is intended that there are easy to follow instructions on them so that if someone collapses staff members or possibly even passers by can attach the machines and possibly save a life. An ICD is an Implantable Cardioverter Defibrillator. This is a miniature version of the defibrillator which is placed under the skin in someone who is considered to be at high risk of having a fatal rhythm problem. Wires are passed down a vein under the collarbone to the heart, and the battery box with built-in computer chip is placed under the skin on the front of the chest. This is a like a pacemaker(can treat slow heart beats), but can also recognise when the heart rhythm has changed to a life threatening one and deliver a shock internally.

 

If ICDs save lives shouldn't everyone have one?

If ICDs save lives shouldn't everyone have one? ICDs do save lives but are expensive and require changing of the battery and possibly the wires every 5 to 8 years. There are also risks of complications when the device is being fitted or changed, and this can sometimes also be fatal. Therefore they are best used in people where the risk of dying suddenly is high enough that it is greater than the risk of complications of the device. This is more important than the cost of the device.