Sudden Cardiac Death in Young People


June 1, 2019 | View PDF

Few other medical events are more devastating and psychologically traumatizing than sudden and unexpected death of a young individual. Most common causes of sudden death in this age group are accident, suicide, and violence. Sudden death secondary to heart problem is a statistically rare event that is often due to undiscovered heart defects or abnormalities. Many such heart conditions are genetically determined, and therefore, any event should be investigated in the context of the patient’s family history. Because these catastrophic events tend to occur at the time of physical activity, millions of grade school students and college athletes engaging in competitive sports are particularly relevant as a group.

Statistically, older individuals are most likely to experience sudden cardiac death (SCD). Many of them have history of coronary disease, congestive heart failure or other types of heart disorder. However, SCD is the leading cause of death in young athletes even though only 1 out of approximately 50,000 SCDs occur in this population group. Studies also demonstrate that young males are twice as likely to experience SCD as compared to young females. Of note, increased risk of SCD has not been observed in any particular ethnic group.

Terminal mechanism in almost all cases of SCD is an onset of extremely fast and disorganized electrical rhythm originating from the bottom chambers of the heart which effectively stops pumping blood to the rest of the body. This condition of electrical chaos is known as ventricular fibrillation (VF). There are many inherited (i.e. genetically transmitted) and acquired heart conditions that increase the risk of VF. Three of the more common ones in the United States are:

• Hypertrophic cardiomyopathy (HOCM): The walls of the heart are abnormally thickened in this genetically passed down condition. Microscopically, there is disorganization of muscle cell architecture which promotes electrical instability that triggers onset of VF. This condition is the most common cause of SCD in young athletes in the US.

• Long QT syndrome (LQTS): This uncommon inherited disorder is caused by genetic mutation of the ion channels of heart cell. In this so-called “channelopathy” disorder, the inability of heart to electrically relax properly after each heart beat promotes a similar condition of electrical instability which can lead to VF. Although there are many different types of LQTS, the most common one (Type I) increases the risk of VF during strenuous physical exertion or activity and is the type that is most relevant for young athletes.

• Coronary artery malformation: In this rare condition, heart (coronary) arteries are routed and connected abnormally. During exercise, a segment of this artery can become compressed and blood flow to the heart can become dangerously compromised. VF can be triggered in this setting.

Commotio cordis is another rare cause of SCD in athletes who receive a blunt force trauma to the central chest area (e.g. hockey puck, baseball, martial arts, etc). When the heart is compressed with enough physical force at a critical time its electrical cycle, VF can be triggered.

SCD can occur without any antecedent warning symptoms. However, there are certain “red flag” signs that one should look out for. The first is any family history of sudden or unexplained death prior to the age of 50. The second is any personal history of repeated fainting, especially in the setting of physical activity or exertion. In fact, the most reliable presenting symptom that specifically indicates presence of heart abnormality is history of resuscitated cardiac arrest. It is strongly recommended that you consult with a specialist as soon as possible if you have any suspicions or concerns. If a physician deems that you are at a high risk for SCD, it is very likely that he or she will strongly advise you against participating in any competitive sports. This does not mean, however, that recreational level exercises should also be avoided.

In certain heart conditions, medication can effectively reduce the risk of dangerous arrhythmia that cause SCD. In other conditions, such as HOCM, an electrical shock from a device known as ICD (implantable cardioverter-defibrillator) is the only way to terminate life-threatening arrhythmia. Decision to undergo implantation of such a device should be made only after the physician carefully weighs the pros and cons and participates in a thorough mutual discussion with the patient and family (shared decision-making).

There is currently much debate regarding what the best screening method is to identify those young individuals who are at risk for SCD. An ideal screening test should target only a specific group of people at risk rather than entire general population which will increase the cost of testing prohibitively. It should also be sensitive enough to identify all at-risk individuals while being specific enough to reliably exclude those who are at truly low or no risk. No study has shown that routine physical examinations and screening EKGs save lives in a cost-efficient manner.

Finally, the “last line of defense” is institution of timely resuscitation effort by trained personnel. Overall survival rate of cardiac arrest occurring outside the hospital setting is less than 10%. And for each minute of delay in initiating CPR, the survival rate decreases by 10%. Raising public awareness of this condition and providing opportunities for education (e.g. basic and advanced life support courses) are crucial steps to improving the outcome. In addition, there needs to be continuous improvement and measurement of the efficacy and availability of effective bystander and emergency medical service (EMS) response in order to improve the survival of patients with SCD-predisposing condition. The development of automated external defibrillators (AEDs) has allowed minimally trained persons to be able to use a defibrillator when necessary. It has led to successful establishment of public access defibrillation sites (e.g. government buildings, airports, casinos, etc) over the past 20 years. We will all need to have our hands in this together in order to save lives and improve clinical outcome.

Ashchi Heart & Vascular Center has cardiology experts on staff who specialize in managing, diagnosing and treating patients at risk for Sudden Cardiac Death. We use the latest technology and techniques to deliver the highest quality, patient-centric care. We also welcome patients seeking second opinions on their treatment options.

If you wish to make an appointment with our doctors, please contact us at (904) 222-6656 or visit our web site ( for our locations or phone numbers in three counties.

Dr. Kim is an electrophysiologist and is part of the Ashchi heart and vascular center, the center offers top notch technology to treat patients with the best experienced team in the Jacksonville, St. Augustine, Clay County, and Douglas areas. Experience, compassion and technology is what we offer to take care of our patients. Our staff manage a large population of patients with venous disease, and we manage a variety of both common and complex cases. The unique needs of patients are recognized by everyone at our practice, and we strive for exceeding the expectations of our patients.


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