- What Is It?
- In Children
- Symptoms & Signs
What is sudden cardiac arrest?
Sudden cardiac arrest is one of the highest of all medical emergencies. It occurs when the heart’s electrical system malfunctions resulting in cardiac dysfunction and the heart is unable to pump blood to the vital organs of the body.
The heart is an electrical pump, where the electricity is generated in special pacemaker cells in the upper chamber, or atrium, of the heart. This electrical spark is carried through pathways in the heart so that all the muscle cells contract at once and produce a heartbeat. This pumps blood through the heart valves and into all the organs of the body so that they can do their work.
This mechanism can break down in a variety of ways, but the final pathway in sudden death is the same: the electrical system is irritated and fails to produce electrical activity that causes the heart to beat. The heart muscle can't supply blood to the body, particularly the brain, and the body dies. Ventricular fibrillation (V-Fib) is the most common reason for sudden death in patients. Without a coordinated electrical signal, the bottom chambers of the heart (ventricles) stop beating and instead, jiggle like Jell-O. Ventricular Fibrillation is treated with electrical shock, but for it to be effective, the shock usually needs to happen within less than four to six minutes, not only for it to be effective, but also to minimize brain damage from lack of blood and oxygen supply. Automatic external defibrillators (AEDs) are commonly available in public places to allow almost anybody to treat sudden death. Less commonly, the heart can just stop beating. The absence of a heartbeat is known as asystole (asystole: a=no + systole=beat).
What are the causes of sudden cardiac arrest?
Sudden death is most often caused by heart disease. When blood vessels narrow, the heart muscle can become irritated because of a lack of blood supply. In a heart attack (acute myocardial infarction), a blood vessel becomes completely blocked by a blood clot, and there is enough irritability of the muscle to cause ventricular fibrillation. The reason many people with chest pain are admitted to the hospital is to monitor their heart rate and rhythm for signs that might lead to ventricular fibrillation. Sudden death may also be the first sign or symptom of heart disease.
- Congestive heart failure and heart valve problems, like aortic stenosis (narrowing of the aortic valve), also increase the risk of sudden cardiac arrest.
- Cardiomyopathy is a broad category of heart disease where the heart muscle does not contract properly for whatever reason. Often it is ischemic, where part of the heart muscle doesn't get an adequate blood supply for a prolonged period and no longer can efficiently pump blood. People whose ejection fractions (the amount of blood pumped out of the heart with each heartbeat) is less than 30% are at greater risk for sudden death (a normal ejection fraction is above 50%). In some people, cardiomyopathy may develop in the absence of ischemic heart disease.
- Inflammation of the heart muscle, known as myocarditis (myo=muscle + card=heart + itis= inflammation), can also cause rhythm disturbances. Diseases like sarcoidosis, amyloidosis, and infections can cause inflammation of the heart muscle.
- Some people are born with electrical conducting systems that are faulty, which places them at higher risk for rhythm disturbances. Some are due to the wiring, or electrical conduction system, like Wolff-Parkinson-White syndrome, while others are due to the structural basic structural problems within the heart, like Marfan syndrome.
- A pulmonary embolus or a blood clot in the lung can also cause sudden death. Clots form in the leg or arm and may break off and flow to the lung where they decrease the lung's ability to get oxygen from the air to the body. Risk factors for blood clots include surgery, prolonged immobilization (for example, hospitalization, long car rides or plane trips), trauma, or certain diseases like cancer.
- Blunt chest trauma, such as in a motor vehicle accident, may result in ventricular fibrillation. (please see commotio cordis below)
What about sudden cardiac arrest in the young?
In younger people, sudden death is a rare event, but since it often involves people involved in athletics, cases are often reported in the press. The most common cause is hypertrophic cardiomyopathy (hypertrophy=to grow abnormally large + cardio=heart + myopathy = diseased muscle). This disease is often hereditary, and the walls of the ventricle are larger than they should be. This makes the pumping chamber of the heart smaller, and the heart has to work harder to pump blood out of the heart. As well, the thickened muscle narrows the space for the blood to flow through the aortic valve and to the rest of the body. During exercise, this decreased blood flow can irritate the heart muscle itself and cause ventricular fibrillation, collapse, and sudden death.
Anomalous coronary arteries can also cause sudden death in the young. The heart is a muscle itself, and like any muscle, it needs a blood supply to provide oxygen for it to work. Normally, the coronary arteries lie on the surface of the heart. Anomalous arteries dive into the heart muscle itself and may be occluded when the heart muscle that surrounds the abnormally placed artery squeezes aggressively, as with exercise, shutting off blood supply to part of the heart. This irritates the electrical system and can cause ventricular fibrillation and sudden death.
The pre-participation athletic physical examination is a useful tool to screen children and adolescents for their risk of sudden cardiac arrest.
Commotio cordis is a situation in which the heart stops when the chest is hit by an object. News stories occasionally report baseball players who are hit in the chest by a ball and collapse because their heart stops beating. The heart sits behind the breastbone, and the electrical system can be short-circuited when a direct blow is sustained.
What are the signs and symptoms of sudden cardiac arrest?
Cardiac arrest symptoms and signs are not subtle:
How do medical professionals diagnose sudden cardiac arrest?
Sudden cardiac arrest is an unexpected death in a person who had no known previous diagnosis of a fatal disease or condition. The person may or may not have heart disease.
What is the treatment for sudden cardiac arrest?
The vast majority of people whose heart stops beating unexpectedly have ventricular fibrillation. The definitive treatment for this is defibrillation using electricity to shock the heart back into a regular rhythm. With technological advances, AEDs are now a routine sight wherever people congregate.
Communities that institute public CPR education, use of AEDs, and rapid activation of 911 emergency medical services have dramatically increased survival rates from sudden cardiac arrest. Unfortunately, because the brain is so sensitive to the lack of oxygen and blood flow unless treatment occurs within four to six minutes, there is a high risk of some permanent brain damage.
Should the patient survive to be transported to the hospital, the reason for the collapse and sudden death will need to be diagnosed. Regardless, the ABCs of resuscitation will be re-evaluated. Airway, Breathing, and Circulation (heartbeat and blood pressure) will be supported, and admission to an intensive care unit is most likely.
Diagnostic tests may include repeated electrocardiograms (EKGs), echocardiograms (ultrasounds of the heart), and cardiac catheterization and electrophysiologic studies, in which the electrical pathways of the heart are mapped.
Survivors of sudden cardiac arrest are often candidates for implantable cardiac defibrillators.
Is it possible to prevent sudden cardiac arrest?
Death is best treated by prevention. Most sudden death is associated with heart disease, so the at-risk population remains males older than 40 years of age who smoke, have high blood pressure, and have diabetes (the risk factors for heart attack). Other risks include syncope (fainting or loss of consciousness) and known heart disease.
Syncope, or loss of consciousness, is a significant risk factor for sudden death. While some reasons for passing out are benign, there is always a concern that the reason was an abnormal heart rhythm that subsequently spontaneously corrected. The fear is that the next episode will be a sudden cardiac arrest. Depending on the healthcare provider's suspicion based on the patient's history, physical examination, laboratory tests, and EKG, the healthcare practitioner may recommend inpatient or outpatient heart monitoring to try to find a clue as to whether the passing out was due to a deadly heart rhythm. Unfortunately, the potentially suspect rhythm may not recur, and depending on the situation, prolonged outpatient monitoring lasting weeks and months may be necessary. The use of electrophysiologic testing may help identify high-risk patients (the electrical pathways are mapped using techniques similar to heart catheterization).
In people with symptoms of chest pain, aside from making the diagnosis, monitoring both the heart rate and rhythm are emphasized. The purpose of watching people with chest pain in a hospital setting is to prevent sudden cardiac arrest.
Using implantable defibrillators in high-risk patients, especially those with markedly decreased ejection fractions can reduce the incidence of sudden cardiac arrest. These devices are placed under the skin in the chest wall and have wires that are attached to the heart itself. When they detect ventricular fibrillation, a shock is automatically delivered to the heart, restoring a heartbeat and averting sudden death.
What is the prognosis for sudden cardiac arrest?
The frequency of sudden cardiac arrest is related to the frequency of coronary artery disease. If public health initiatives work to decrease risk the factors for heart disease, the risk of sudden death should decrease as well.
In the adolescent population, increased awareness of hypertrophic cardiomyopathy and appropriate screening may decrease the frequency of sudden death.Public education and the widespread availability of AEDs will increase survival.
"Overview of sudden cardiac arrest and sudden cardiac death"
Top Sudden Cardiac Death Related Articles
Congestive Heart Failure (CHF): Symptoms, Causes, Stages, TreatmentCongestive heart failure (CHF) refers to a condition in which the heart loses the ability to function properly. Heart disease, high blood pressure, diabetes, myocarditis, and cardiomyopathies are just a few potential causes of congestive heart failure. Signs and symptoms of congestive heart failure may include fatigue, breathlessness, palpitations, angina, and edema. Physical examination, patient history, blood tests, and imaging tests are used to diagnose congestive heart failure. Treatment of heart failure consists of lifestyle modification and taking medications to decrease fluid in the body and ease the strain on the heart. The prognosis of a patient with congestive heart failure depends on the stage of the heart failure and the overall condition of the individual.
Does a Dying Person Know They Are Dying?A conscious dying person can know if they are on the verge of dying. Some feel immense pain for hours before dying, while others die in seconds.
Echocardiogram (Echocardiography, Diagnostic Cardiac Ultrasound)Echocardiogram is a test using ultrasound to provide pictures of the heart's valves and chambers. There are several types of echocardiograms, for example, transthoracic echocardiogram, transesophageal echocardiogram (TEE), stress echocardiogram, dobutamine or adenosine/sestamibi stress echocardiogram, and and intravascular ultrasound.
Electrocardiogram (ECG or EKG)An electrocardiogram is known by the acronyms "ECG" or "EKG" more commonly used for this noninvasive procedure to record the electrical activity of the heart. An EKG generally is performed as part of a routine physical exam, part of a cardiac exercise stress test, or part of the evaluation of symptoms. Symptoms evaluated include palpitations, fainting, shortness of breath, dizziness, fainting, or chest pain.
Fainting (Syncope): Guide to Causes, Symptoms, Treatment and PreventionFainting, also referred to as blacking out, syncope, or temporary loss of consciousness has many causes. Often a person will have signs or symptoms prior to the fainting episode. Diagnosis and treatment depends upon the cause of the fainting or syncope episode.
Heart Detail PictureThe heart is composed of specialized cardiac muscle, and it is four-chambered, with a right atrium and ventricle, and an anatomically separate left atrium and ventricle. See a picture of Heart Detail and learn more about the health topic.
Cardiac Arrest: What You Should KnowCardiac arrest is a serious medical emergency that requires immediate medical care. Use this WebMD slideshow to know whether you are at risk for cardiac arrest and what you can do if it happens to a loved one.
CAD SlideshowWhat is heart disease (coronary artery disease)? Learn about the causes of heart disease, arrhythmias and myopathy. Symptoms of heart disease include chest pain and shortness of breath. Explore heart disease diagnosis, treatment, and prevention.
Heart Disease: Causes of a Heart AttackHeart disease prevention includes controlling risk factors like diet, exercise, and stress. Heart disease symptoms in women may differ from men. Use a heart disease risk calculator to determine your heart attack risk.
Arrhythmias (Abnormal Heart Rhythms): Types, Triggers, Warning Signs, and TreatmentHeart rhythm disorders vary from minor palpitations, premature atrial contractions (PACs), premature ventricular contractions (PVCs), sinus tachycardia, and sinus bradycardia, to abnormal heart rhythms such as tachycardia, ventricular fibrillation, ventricular flutter, atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia (PSVT), Wolf-Parkinson-White syndrome, brachycardia, or heart blocks. Treatment is dependent upon the type of heart rhythm disorder.
What Is a Heart Transplant?Heart transplant consists of three operations: 1) harvesting the heart from the donor, 2) removing the recipient's damaged heart, and 3) the implantation of the donor heart. The selection and distribution of donor hearts is a careful process so that the hearts are distributed fairly. For the patient requiring a heart transplant, all other important organs in the body must be in good shape. The most common complication of heart transplant is organ rejection.
How the Heart WorksThe heart is a very important organ in the body. It is responsible for continuously pumping oxygen and nutrient-rich blood throughout your body to sustain life. It is a fist-sized muscle that beats (expands and contracts) 100,000 times per day, pumping a total of five or six quarts of blood each minute, or about 2,000 gallons per day.
How Long Can You Live With an Implanted Defibrillator?An implantable cardioverter-defibrillator (ICD) is an electronic device that tracks the heart rate and restores a normal rhythm, if required. It is first-line treatment for patients who are at risk of sudden cardiac death. ICD is useful in reducing the death rate amongst patients suffering from cardiac arrest, heart failure, reduced ejection fraction (reduced amount of blood pumped out of heart’s chambers), specific structural heart diseases. An ICD detects and corrects the abnormal rhythm of the heart.
Implantable Cardiac Defibrillators
An implantable cardiac defibrillator is a device that is inserted into the chest to prevent sudden death from an irregular heartbeat. If the heart develops a life-threatening tachycardia (rapid heart rate), the device administers an electric shock to restore normal rhythm. Cell phones, MRI scanners, metal detectors, and certain heavy-duty electrical powered equipment may interfere with an implantable cardiac defibrillator.
Cardiac Arrest QuizTake the Sudden Cardiac Arrest Quiz. Learning about this potentially deadly condition may save a life.