Sudden cardiac death

Sudden cardiac death: description

Sudden cardiac death (second death) is one of the leading causes of death in Germany, according to experts. It is estimated that around 800,000 to 900,000 deaths annually in Germany cause about 100,000 to 200,000 deaths from sudden cardiac death.

In the vast majority of cases, sudden cardiac death can be attributed to severe heart disease. In many cases, this heart disease is already noticeable in advance. Sudden cardiac death could thus be prevented in many cases by timely clarification and diagnosis.

However, sudden cardiac death very rarely affects perfectly healthy and young people without significant discomfort. Sometimes a genetic disease is detected retrospectively, which favors severe cardiac arrhythmias. But it can not be understood in each case a clear cause. However, scientists now know certain triggers that can provoke a sudden cardiac death. These include intense physical exertion and emotionally charged events.

Sudden cardiac death: symptoms

A sudden cardiac death is first shown by a sudden unconsciousness of the person concerned. Within a short time also spontaneous breathing stops. The unconsciousness is caused by a cardiac arrest (sudden cardiac arrest): The heart no longer pumps enough blood into the brain and the other organs. Due to the resulting lack of oxygen (hypoxia), the brain function fails. Without oxygen, the brain cells die within a few minutes. In the affected person, no pulse is palpable and his pupils widen. If this condition is not resolved within a few minutes, the death (sudden cardiac death) occurs after a short time.

Often a sudden cardiac death occurs without any warning. According to the Oregon Sudden Unexpected Death Study, however, more than half of the cases are preceded by second-death deaths. These include symptoms that may indicate possible damage to the heart. In the vast majority of cases, sudden cardiac death can be attributed to heart disease that has been present for some time. Typical symptoms of heart disease that favors sudden cardiac death include:

• Pressure or tightness in the left chest, especially under stress: Possible indication of a chronic circulatory disorder in coronary heart disease or heart attack.
• Dizziness or fainting: Sometimes triggered by cardiac arrhythmias that cause mild oxygen deficiency in the brain.
• Shortness of breath and water retention (edema): Typical of heart failure (heart failure).
• Pronounced cardiac arrhythmia: Too fast (tachycardia) or too slow (bradycardia) can indicate an impending dangerous cardiac arrhythmia.

However, these symptoms do not necessarily indicate an impending sudden cardiac death. Especially cardiac arrhythmias occur in perfectly healthy people and are harmless in many cases. However, if you notice any such symptoms, you should have the complaints cleared up by a doctor. This can often prevent a sudden cardiac death in an emergency.

Sudden cardiac death: causes and risk factors

Sudden cardiac death has many possible causes. Common to these causes, however, is that they usually lead to a serious heart arrhythmia and thus to cardiac arrest. The most common cause of sudden cardiac death is cardiac arrhythmia, which physicians refer to as ventricular fibrillation. With ventricular fibrillation, the electrical arousal of the heart is completely uncoordinated and chaotic. Due to the asynchronous electrical activity of the heart muscle can no longer contract contractually, but jerks high-frequency, but without significant pump power.

Without sufficient pumping function of the heart, the organs can no longer be supplied with blood and therefore no longer be supplied with vital oxygen. Due to the lack of oxygen (hypoxia) in the brain, a functional failure develops within a few seconds, rendering the affected person unconscious. Without the brain function, spontaneous breathing also ceases after about a minute, further exacerbating the lack of oxygen.

In the vast majority of cases, sudden cardiac death can be attributed to a serious heart disease:

• Very often (about 80 percent of cases): coronary heart disease (CHD)
• Often (10 to 15 percent of cases): diseases of the heart muscle (cardiomyopathy, myocarditis) or structural defects (heart valve damage)
• Rare (about 5 percent of cases): Disorders of the electrical conduction system of the heart (Long-QT syndrome, Brugada syndrome, arrhythmogenic right ventricular cardiomyopathy)

Researchers suggest that in addition to these predisposing diseases also a concrete trigger necessary for sudden cardiac death. For example, in the case of underlying heart disease, scientists expect the following situations and substances to be potential causes of sudden cardiac death:

• Acute circulatory disorder of the coronary arteries (“myocardial infarction”), usually in pre-existing coronary heart disease
• pronounced physical effort such as intense sports
• emotional stress situations
• Medications that affect the conduction of stimuli in the heart (such as so-called QT-prolonging medications)
• Drugs like alcohol, cocaine and amphetamines
• Shifts of blood salts (electrolyte disturbances)

Sudden cardiac death: examinations and diagnosis

A sudden cardiac death can only be averted in the acute emergency situation by an immediate and correct diagnosis of the underlying cardiac arrhythmia. This is possible with the electrocardiogram (ECG). This allows the doctor to recognize what measures he needs to take in the emergency situation.

However, diseases that promote sudden cardiac death can already be diagnosed before such a life-threatening event occurs. In particular, if someone already has complaints that indicate a heart disease, and thus potentially threatens a sudden cardiac death, urgent medical examination should be made. This can diagnose and treat serious heart disease before a sudden cardiac death can occur.

Doctor-patient conversation

The first person to contact for any symptoms that may indicate heart disease is a general practitioner or a specialist in internal medicine and cardiology (cardiologist). Before the actual examinations, the doctor can already find out by specific questions (collection of the medical history = medical history), whether a heart disease is considered and which examinations are necessary for the diagnosis. For example, the doctor might ask you the following questions:

• Do you notice any pressure or tightness in the chest when exercising physically?
• Does this sensation radiate to other parts of the body, such as the neck, jaw, or left arm?
• Have there been situations lately that made you dizzy without a reason?
• Have you fainted lately?
• Have you noticed water retention, for example, on the ankles?
• Are you experiencing respiratory distress when exercising physically, such as when climbing stairs?
• Did you notice “heart stumbling”?

Sudden cardiac death: physical examination

As part of the physical examination, the doctor will get a first impression of your heart function by feeling your pulse and listening with your stethoscope your heart (auscultation). It can thus determine whether the heart is beating regularly and at the right speed (heart rate), and whether pathological heart sounds may be noticeable due to structural heart problems (such as diseased heart valves).

In addition, during physical examination, water retention (edema) can be detected. Especially edema on the feet and legs can indicate a heart failure.

Listening to the lungs is part of the routine check-up, as heart problems can often affect the lungs as well. For example, in case of heart failure, water may accumulate in the lungs (pulmonary edema). It is also important to measure the blood pressure.

Sudden cardiac death: further examinations

Depending on the result of the anamnesis and physical examination, the attending physician will arrange for further examinations for further clarification. Almost always an electrocardiogram (ECG) is created. This can detect a variety of pathological changes in the heart, through which a sudden cardiac death can be favored. Since a normal ECG records only a few heart beats, in some cases a recording over 24 hours is necessary (long-term ECG). This is particularly useful in the question of only occasionally occurring cardiac arrhythmias.

Very often, the doctor also causes an ultrasound of the heart (UKG, echocardiography). In particular structural heart diseases such as a thickened heart wall, an enlarged heart or damage to the heart valves can be identified. Also useful is an X-ray examination of the chest (chest X-ray), to be able to assess any pathological changes in the heart and lungs well.

If there is a suspicion of arteriosclerosis of the coronary arteries (coronary heart disease, CHD), a more complicated diagnosis is usually necessary: ​​First of all, this involves a so-called stress ECG on a bicycle ergometer. While the patient is pedaling on a bicycle, an ECG is recorded. Many pathological changes only show up in the ECG after physical exertion.

If there are indications of coronary heart disease, further examinations may be required, such as cardiac catheterization (= coronary angiography), stress echocardiography or other imaging such as myocardial scintigraphy (nuclear medicine examination of the heart muscle). Sudden cardiac death is by far the most common cause of coronary heart disease (CHD).

Sudden cardiac death: treatment

Despite the many possible causes, a serious cardiac arrhythmia is ultimately the immediate cause of sudden cardiac death. This is usually a case of so-called ventricular fibrillation, more rarely slow (bradycardiac) cardiac arrhythmia or sudden cardiac arrest (asystole). An impending sudden cardiac death is an absolute emergency requiring immediate correct diagnosis and immediate countermeasures. Otherwise, the affected person is dead within a few minutes.

For the first responder, the following procedure is recommended if a person suddenly collapses unconscious and a sudden cardiac death threatens:

emergency call (Tel .: 112) and ask those in the vicinity for help.

Short Check pulse and respiration. In addition, one should take a look into the unconscious’s mouth and check if a foreign body is blocking the airway.

In the absence of pulse and lack of breathing immediately with the Cardiopulmonary resuscitation Begin: Alternately, one makes 30 chest compressions over the sternum and 2 mouth-to-mouth or mouth-to-nose resuscitations. If two or more first-aiders are on-site, they should alternate after every 30: 2 cycle so as not to tire.

If available, you should be a first responder automated external defibrillator (AED) deploy. These are now placed in many public places (banks, town halls, etc.) or in public transport (metro stations, trains, etc.). The devices are very easy to install and guide the helper with an announcement step by step through the necessary measures. After attaching the electrodes, the AED automatically analyzes the heart rhythm and only triggers an electric shock if there is a defibrillatable cardiac arrhythmia (VF, Pulseless Ventricular Tachycardia). Rapid deployment of a defibrillator can be life-saving!

Sudden cardiac death: That’s what the emergency doctor does

For a summoned emergency physician, the primary goal in the emergency situation is to avert the acute danger to life and to transport the patient stabilized to a corresponding clinic. There, the cause of the cardiovascular arrest can then be clarified exactly. The ambulance doctor basically also follows the above-mentioned scheme. First, an ECG is performed on-site to analyze the heart rhythm during ongoing cardiopulmonary resuscitation. If the defibrillation is insufficient or there is a non-shockable cardiac arrhythmia (asystole, pulsatile electrical activity), the ambulance may try to restore normal heart rhythm with medication such as epinephrine. Sudden cardiac death can often be prevented by the immediate intervention of trained helpers.

Sudden cardiac death: disease course and prognosis

In the case of imminent sudden cardiac death, the course of the disease and the prognosis are decisively influenced by how quickly appropriate countermeasures are taken after the occurrence of a cardiac arrest. Due to the cardiac arrest occurs within minutes without treatment without irreversible damage to the brain. If too much time passes between the cardiac arrest and a successful resuscitation, severe brain damage can be left behind, making the patient a nursing case.

A sudden cardiac death can be prevented by two measures in many cases:

First, symptoms that indicate potential heart disease should not be ignored. Through simple examinations, threatening heart disease, which is often responsible for sudden cardiac death, can be diagnosed and treated early.

Second, there is an increased chance that a sudden cardiac death will be survived if a defibrillator is quickly on hand and used as promptly as possible along with proper cardiopulmonary resuscitation. Both are taught in first aid courses, which should be repeated regularly (according to experts at least every two to three years). Only then can you effectively help someone in an emergency sudden cardiac death threatening.