Do you know what is Sudden Cardiac Death?
When you hear about a young person dropping dead, you may think “heart attack.” But sudden cardiac arrest (also referred to as sudden cardiac death) is different.
A heart attack stems from a circulation problem of the heart, according to the Sudden Cardiac Arrest Association. It happens when a sudden blockage in a coronary artery severely reduces or cuts off blood flow to the heart, damaging heart muscle.
In contrast, a sudden cardiac arrest (SCA) is due to an “electrical” problem in the heart. It happens when electrical signals that control the heart’s pumping ability essentially short-circuit. Suddenly, the heart may beat dangerously fast, causing the heart’s ventricles, its main pumping chambers, to quiver or flutter instead of pumping blood in a coordinated fashion. This rhythm disturbance, called ventricular fibrillation, occurs in response to an underlying heart condition that may or may not has been detected.
It is characterized by the unexpected loss of heart function, breathing, and consciousness, and it usually strikes without warning.
Two-thirds of SCA victims are unaware they have underlying heart conditions. Unfortunately, the condition is usually fatal, as only 6% to 7% of those who experience SCA survive, thus the majority succumb to sudden cardiac death (SCD).
Who’s at Risk of SCD?
For children under the age of 14, there are very few instances of sudden cardiac death. For people aged 35 and under, there are 12 young sudden deaths every week, which is around 600 every year. It’s one of the most common causes of death in young people after suicide and road traffic accidents. In fact, it’s the most common cause of death in young athletes.
Why is that?
About one in 300 people have an underlying cardiac condition that is potentially life-threatening. When one engages in sport, one tends to push the body to its limits. A person with an underlying heart condition, the chances of him\her having a cardiac arrest is three to four times higher than with somebody who isn’t pushing their body to the same limits. This is why there is a focus on screening.
What causes Young Sudden Cardiac Death?
In younger people, the most common causes are:
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.
Long QT syndrome an inherited heart rhythm disorder can cause fast, chaotic heartbeats, often leading to fainting. Young people with long QT syndrome have an increased risk of sudden death.
Other causes of sudden cardiac death in young people include structural abnormalities of the heart, such as undetected heart disease that was present at birth (congenital) and heart muscle abnormalities.
Other causes include inflammation of the heart muscle, which can be caused by viruses and other illnesses. Besides long QT syndrome, other abnormalities of the heart’s electrical system, such as Brugada syndrome, can cause sudden death.
Commotio cordis is a situation in which the heart stops when the chest is hit by an object. News stories occasionally report of 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.
Are there any warning signs?
In 20 percent of young sudden deaths, there are some warning signs, the red flags are exercise-related chest pain or exercise-related passing out(syncope). However, in 80 percent of cases, there are no warning signs at all, which is why parents are encouraged to put their child forward for cardiac screening when their child turns 14.
What are the symptoms of sudden cardiac arrest?
- The heart stops beating and blood is not supplied to the body.
- Almost immediate loss of consciousness occurs.
- The person will fall or slump over.
- No pulse is felt (palpable).
- No signs of breathing.
Can sudden death in young people be prevented?
Sometimes. If one is at high risk of sudden cardiac death, the doctor usually suggests avoiding competitive sports. Depending on underlying condition, medical or surgical treatments might be appropriate to reduce your risk of sudden death.
Another option for some, such as those with hypertrophic cardiomyopathy, is an implantable cardioverter-defibrillator (ICD). This pager-sized device implanted in the patient’s chest like a pacemaker continuously monitors the heartbeat. If a life-threatening arrhythmia occurs, the ICD delivers electrical shocks to restore a normal heart rhythm.
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 being an abnormal heart rhythm to be subsequently spontaneously corrected. The fear is that the next episode can 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. Depending on the situation, prolonged outpatient monitoring lasting weeks and months may be necessary. 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.
How does screening help?
Young people are screened with an electrocardiogram (ECG or EKG), which records the electrical signals in the heart. However, this type of screening is expensive and can produce false-positive results — indications that an abnormality or disease is present when it isn’t — which can cause unnecessary worry and additional tests.
It’s not clear that routine exams given before athletes are cleared to play competitive sports can prevent sudden cardiac death. However, they might help identify some who are at increased risk.
For anyone with a family history or risk factors for conditions that cause sudden cardiac death, further screening is recommended. Repeat screening of family members is recommended over time, even if the first heart evaluation was normal.
Importance of screening at age of 14
The vast majority of sudden deaths occur after the pubertal spurt which is whys screening after the age of 14 years old is recommended. Before the age of 14, the heart is changing. So whilst conditions can be identified before then, waiting until the child has gone through that pubertal spurt is preferred when there are fewer changes in the heart. There are very few sudden deaths before the age of 14, but there can be a lot of false positives, a lot of abnormalities identified known as juvenile ECG patterns — meaning the young person has to then be tested regularly until they have gone through their growth spurt.
Should young people with a heart defect avoid physical activity?
If one is at risk of sudden cardiac death, one should talk to the doctor about physical activity. Whether he/she can participate in exercise or sports depending on the condition.
For some disorders, such as hypertrophic cardiomyopathy, it’s often recommended that one must avoid most competitive sport. But this doesn’t mean one needs to avoid exercise.
Thus young population needs to be made aware of appropriate screening along with health education including heart problems.