Sudden cardiac death

What is sudden cardiac death?

Sudden cardiac death means that the heart stops working unexpectedly. Other terms for this are cardiovascular arrest, sudden cardiac failure or secondary death. The latter term refers to the fact that the person concerned suddenly falls unconscious, collapses and stops breathing. If you do not call the emergency services immediately ( 144) and start resuscitation measures, the affected person will die within a very short time – it only takes a few minutes.

The causes of sudden cardiac death are usually existing heart diseases that lead to cardiac arrhythmias . In principle, any heart disease can trigger cardiac arrhythmia. In adults, it is particularly often coronary heart disease (CHD). In younger people and (competitive) athletes, cardiac muscle inflammation or genetic diseases are usually to blame for cardiovascular arrest.

Immediate resuscitation measures (resuscitation) and defibrillation are particularly important. They maintain the circulation and thus the vital oxygen supply, defibrillation allows the heart to “start” again and normalize the heart rhythm. If more people intervened immediately, significantly more people could survive.

Sudden cardiac death – frequency and age

In Switzerland, around 8,000 people suffer sudden cardiac death every year – less than five percent of those affected survive the cardiovascular arrest without long-term damage. Men have a higher risk of sudden cardiac death than women, especially if they already suffer from heart disease.

In principle, sudden cardiac death can affect people of any age – from young, for example if they have a hereditary risk, to old, for example if they have heart disease. However, the risk increases with increasing age and the presence of other diseases such as diabetes or high blood pressure.

Secondary death often occurs during or immediately after physical exertion. Even young and fit athletes are not immune – on the contrary. As in many other countries, there have also been a number of cases in Switzerland in which supposedly healthy athletes have apparently collapsed and died out of nowhere on the playing field or during a running competition. Since then, Switzerland has been recording these cases on a large scale in a register (“Swiss REGistry of Athletic Related Deaths” (swissregard.ch). The information is intended to help improve resuscitation measures.

Sudden cardiac death: causes and risk factors

The most important cause of sudden cardiac death is coronary heart disease (CHD)which is associated with cardiac arrhythmia. In the case of coronary heart disease, the coronary vessels become increasingly narrow or completely blocked due to vascular calcification(arteriosclerosis). This can lead to a heart attack. In the majority of cases, a sudden heart attack triggers the cardiac arrhythmia. However, other heart diseases such as myocardial diseases, myocarditis, a congenital heart defect or congenital ion channel diseases that disrupt the heart’s electrical system are also possible causes of cardiac arrhythmia – and therefore sudden cardiac death.

However, age plays a role in determining which factors are the cause of secondary death. In adults, coronary heart disease is usually responsible for sudden cardiac death. The risk is particularly high if you have already suffered a heart attack due to CHD. In adolescents and young adults, the reason often lies in congenital heart disease. However, inflammation of the heart muscle or altered coronary arteries also play a major role at this age.

Sudden cardiac death in sportsmen and sportswomen

Sudden cardiac death in amateur and professional athletes has often made headlines in the media. Seemingly healthy footballers, runners and boxers suddenly collapse in training, in the ring or on the pitch and die. In fact, cardiovascular arrest is often associated with physical exertion, intensive sport or training.

Sudden cardiac death: risk factors

Experts are aware of a number of risk factors that can contribute to sudden cardiac death. These include:

• Age
• existing cardiac arrhythmia
• previous heart attack – the heart is already “beaten”
• Survived cardiovascular arrest
• Heart failure, when cardiac output is restricted and symptoms such as shortness of breath occur
• Hereditary heart disease associated with cardiac arrhythmia. Examples are Brugada syndrome or long QT syndrome.

There are also some factors and diseases that also affect the heart, for example:

• High blood pressure – poorly controlled blood pressure values damage the blood vessels in the heart
• Diabetes mellitus – diabetes also attacks the coronary arteries in the long term
• Increased blood lipids(cholesterol) – they are deposited in the blood vessels and increasingly constrict them
• Smoking damages the heart and blood vessels
• High alcohol consumption – damages the heart muscle
• Lack of exercise

Cardiac arrhythmias and sudden cardiac death – the connection

Cardiac arrhythmias put the heart out of rhythm. The propagation of excitation in the heart is disturbed and the heart muscle no longer receives regular and orderly electrical impulses. It can no longer contract as usual and the heart loses its normal rhythm (the so-called sinus rhythm).

A healthy heart beats about 60 to 100 times per minute at rest. In the event of a cardiac arrhythmia, the heartbeat may be too fast and increase to more than 500 times per minute (tachycardia). This is the case in most cases of sudden cardiac death. The majority of those affected experience cardiac arrhythmias such as ventricular tachycardia, ventricular fibrillation or ventricular flutter. In four out of five people, cardiovascular arrest is triggered by ventricular fibrillation.

Much more rarely, the heart rhythm is too slow (bradycardia) and cardiovascular arrest occurs. The reason may be a functional failure of the sinus node, which is considered the natural pacemaker of the heart. The transmission of electrical impulses from the atria to the ventricles can also be impaired.

What all cardiac arrhythmias have in common is that the heart no longer pumps enough blood into the body and therefore no more oxygen and nutrients. The circulation collapses and the organs and tissues are no longer supplied. If the heartbeat stops completely, experts speak of asystole. This leads to death within a few minutes.

Symptoms: Sudden cardiac death happens quickly

Sudden cardiac death usually occurs quickly and sometimes without any prior warning signs. Seemingly healthy people suddenly fall over for no apparent reason. Other people can recognize sudden cardiac death by the following symptoms:

• The affected person suddenly falls over in the middle of walking, standing or doing sport, or slumps in a chair.
• It does not react to pain stimuli or when you speak to it, touch it or shake it.
• She is no longer breathing and you cannot feel her pulse.

If the circulation fails, unconsciousness occurs after just five to ten seconds, respiratory arrest also sets in immediately, and after four to five minutes the affected person is dead. You must act immediately and call the emergency services ( 144). In addition, start resuscitation measures immediately (resuscitation) and – if possible – defibrillation. This involves using a defibrillator to deliver electrical current pulses to normalize heart activity.

Sudden cardiac death: symptoms of a heart attack

Sudden cardiac death is often preceded by a heart attack, and this can be recognized by the following symptoms:

• Severe pain in the chest – crushing pain (chest or behind the breastbone). They last for at least five minutes, do not improve with rest and often radiate to other parts of the body: the arms, upper abdomen, back (between the shoulder blades), neck and jaw.
• Severe burning sensation: Some people experience the pain in the chest area as a strong burning sensation.
• Severe chest tightness: Many people experience a severe feeling of pressure, tightness or constriction in the heart area.
• Shortness of breath
• cold sweat of fear, fear of death
• Cold, pale and sallow skin
• Nausea and vomiting
• Dizziness
• Feeling of weakness
• Unconsciousness

Heart attack symptoms in women:

• Shortness of breath, severe shortness of breath – even with little physical exertion
• Pain in the upper abdomen
• Nausea and vomiting
• Feeling of pressure or tightness in the chest area instead of severe pain

Act immediately in the event of such symptoms and do not let any time pass. Call the emergency services immediately on 144. It is better to call the emergency services once more than too little. The sooner the affected person reaches the hospital and doctors begin treatment, the better the chances of survival. In this way you can save lives and possibly prevent sudden cardiac death.

Diagnosis of sudden cardiac death

The diagnosis of sudden cardiac death can usually be made quickly, based on the symptoms:

• The affected person suddenly falls or slumps over.
• It does not react to being approached, touched, shaken or pain stimuli.
• Breathing has stopped.
• A pulse can no longer be felt.

You must start resuscitation or defibrillation immediately in order to save the life of the person concerned.

Sudden cardiac death: prevention, early detection, prognosis

Sudden cardiac death is usually caused by heart disease that triggers cardiac arrhythmia. First and foremost is coronary heart disease (CHD), which affects the coronary arteries. And you can prevent this to a certain extent if you reduce or eliminate the risk factors. Some of them are also in their own hands because they are part of their lifestyle.

Important measures for the prevention of CHD are

• Don’t smoke – and if you are a smoker, try to stop smoking.
• Move a lot in everyday life and do sports.
• Make sure you eat a healthy diet (e.g. lots of fruit, vegetables, whole grains, pulses).
• Be moderate with your alcohol consumption.
• Make sure you maintain a healthy weight – if you are overweight orobese, try to lose a few kilos. If in doubt, seek professional help, for example from a nutritionist.

Sport is good for the heart, but not at all times. Take it easy after an infection (e.g. cold, flu, gastrointestinal infection) for a sufficiently long time. Cure the illness completely before you start exercising again. Otherwise, this can lead to myocarditis, which triggers cardiac arrhythmia – especially during physical exertion. Sudden cardiac death can occur.

Preventing sudden cardiac death – having diseases treated

In addition, have existing underlying illnesses such as high blood pressure, diabetes mellitus or high cholesterol levels adequately treated. In addition to medication, a healthy lifestyle also helps here.

If you suffer from a heart condition such as a congenital heart defect, cardiac insufficiency, coronary heart disease or cardiac arrhythmia, the following applies:

• Get adequate treatment for your condition (e.g. medication, dilatation of narrowed vessels, stents, bypass).
• You should also come to us for regular check-ups. We can recognize a possible risk even if you do not yet have any symptoms.
• If you have a family history of hereditary heart disease, it is advisable for family members to undergo a cardiological examination. Even an ECG or ultrasound can provide valuable information.
• Regular visits to the doctor are also important if you have already survived a heart attack or cardiovascular arrest. After a cardiac arrest, an implantable cardioverter/defibrillator (ICD ) can help and offer protection against a recurrence. These are small electrical impulse devices that are implanted. When problems arise, they help the heart.

Even these measures cannot prevent sudden cardiac death 100 percent. But you can reduce the risk of your heart going on strike.

Course and prognosis of sudden cardiac death

Sudden cardiac death is a very serious matter that requires immediate and courageous intervention and action. Otherwise, the chances of survival for those affected are minimal, as the following figures for Switzerland show:

• In Switzerland, less than five percent survive a cardiac arrest and suffer a sudden cardiac death.
• Only five to 13 percent of people who suffer an out-of-hospital cardiac arrest and are treated in hospital survive until they eventually leave the hospital.
• The ambulance service reaches very few patients in time, i.e. within the critical period of three to five minutes after the onset of sudden cardiac death.

The only chance of survival a patient has is immediate resuscitation measures and the use of a defibrillator. These life-saving devices are now available in many public places such as airports, train stations, sports stadiums, cinemas, museums and public transport. Even laypersons can easily operate defibrillators and thus interrupt a life-threatening cardiac arrhythmia (usually ventricular fibrillation). After switching on, the devices give the corresponding instructions, which are extremely easy to implement. Defibrillation can get the heart beating normally again and thus save the affected person’s life. The only mistake you can make in this situation is to do nothing and wait for the emergency services.

Sudden cardiac death: treatment must start immediately!

Sudden cardiac death is an emergency in which you must call the emergency services immediately (telephone number 144). You must also administer first aid yourself quickly until the emergency services arrive. Resuscitation is best carried out according to the Swiss Heart Foundation’s scheme – try to internalize it visually:

In cardiopulmonary resuscitation, the correct pressure point during chest compressions is important:

• Chest center
• lower half of the sternum
• Press in 5 to 6 centimeters deep

For experienced first aiders, it is recommended to perform both chest compressions and mouth-to-mouth resuscitation (rescue breathing) (ratio 30:2). Otherwise, chest compressions alone are also effective. To find the right rhythm, the song “Staying alive” by the Bee Gees is helpful.

Perform cardiopulmonary resuscitation until the emergency services arrive.

Proceed as follows with the defibrillator:

• Switch on the defibrillator and follow the instructions.
• Hold electrodes to the unconscious patient’s chest wall and trigger a dosed electric shock.
• This electric shock is intended to rebalance the electrical activity of the heart so that it begins to beat normally again.

Defibrillation stops the ventricular fibrillation. But even after this, you must continue to support and strengthen the heart by compressing the chest and ventilating.

Sudden cardiac death - further treatments

The subsequent treatment in the ambulance and hospital depends on the underlying disease responsible for the sudden cardiac death. Doctors must provide adequate treatment to reduce the risk of a new cardiac arrest. In the case of coronary heart disease, for example, the following options are available:

• Cardiac catheterizationDilation of blocked coronary arteries using a small balloon as part of a cardiac catheter. We then often implant a small vascular support (stent) to stabilize the vessel and prevent it from re-occluding.
• Bypass operationWe create a “bypass” around the blocked vessel.
• Drugs that inhibit blood clotting.
• An implantable cardioverter/defibrillator (ICD) helps to prevent future cardiac arrhythmias and thus sudden cardiac death. We implant this small electric shock device under the skin. It detects cardiac arrhythmia and automatically delivers small electric shocks if necessary.