How to Manage Athletes with Syncope

Unusual Cases of Syncope in the Pediatric Age Group

Syncope is common in the pediatric population and occurs in up to 15 percent of children prior to the end of adolescence. While the etiology of syncope in children is often benign and the majority of cases can be explained by isolated changes in vasomotor tone, a thorough evaluation is warranted to rule out more serious, life-threatening causes of syncope. Here, we present three atypical cases of syncope: a young judo player with recurrent syncope and dizziness, a teenage boy with syncopal episodes always preceded by stretching, and a child who experienced urticaria before losing consciousness. Herein, we review the pathophysiology, diagnosis, and management of syncope in children and adolescents.

Symptoms Preceding Sports-Related Sudden Cardiac Death in Persons Aged 1-49 Years

PURPOSE OF REVIEW

Sports-related sudden cardiac death (Sr-SCD) is a leading natural cause of death in young athletes. To prevent Sr-SCD in athletes, it is important to identify individuals at risk. This review sought to summarize the current knowledge of symptoms prior to Sr-SCD in athletes aged 1-49 years.

RECENT FINDINGS

Cardiovascular screening of athletes is a subject of interest. However, the cost of ECG screening in a young population is relatively high compared to potential benefits, and systematic screening of athletes is heavily debated. In the background population, both cardiac and non-specific symptoms are often present prior to SCD. Both cardiac and non-specific symptoms are present in up to 74% prior to Sr-SCD. The main symptoms are syncope, chest pain, palpitations and dizziness. Knowledge of symptoms could potentially be used in combination with non-invasive prediction models to prevent Sr-SCD and treat athletes at risk.

Symptoms and healthcare contact preceding sudden cardiac death in persons aged 1-49 years

Sudden Cardiac Death (SCD) is a leading cause of death among persons in their youth and early middle-age. To prevent SCD it is crucial to identify persons at high-risk of SCD. Knowledge of symptoms and medical contact prior to SCD could potentially aid in the identification of high-risk persons in the general population who would benefit from further investigation. This review aims to summarize the current knowledge of symptoms and healthcare contact preceding SCD in persons aged 1-49 years, and to explore how the symptoms differ according to SCD cause and age of the deceased. There was a high frequency of both cardiac and non-specific symptoms prior to SCD. Additionally, many SCD victims contacted the healthcare system prior to death on the basis of their symptoms and only a few were diagnosed with cardiovascular disease. This information underlines that young persons reporting potential cardiac symptoms should also be thoroughly examined. Furthermore, such symptoms could be used in combination with other easily accessible information in non-invasive prediction models aiming at identifying persons at high risk of SCD that would benefit from further investigation and possibly treatment.

Syncope as a Warning Symptom of Sudden Cardiac Death in Athletes

Clinical evaluation of syncope in the athlete remains a challenge. Although benign mechanisms predominate, syncope may be arrhythmic and precede SCD. Exercise-induced syncope should be regarded as an important alarming symptom of an underlying cardiac disease predisposing to arrhythmic cardiac arrest. All athletes with syncope require a focused and detailed workup for underlying cardiac causes, either structural or electrical. Major aim is to identify athletes at risk and to protect them from SCD. Athletes with potentially life-threatening etiologies of syncope should be restricted from competitive sports.

Sudden cardiac death in children (1-18 years): symptoms and causes of death in a nationwide setting

AIMS

Hitherto, sudden cardiac death in children (SCDc)-defined as sudden cardiac death (SCD) in the 1-18 years old-has been incompletely described in the general population. Knowledge on incidence rates, causes of death and symptoms prior to death is sparse and has been affected by reporting and referral bias.

METHODS AND RESULTS

In a nationwide setting all deaths in children aged 1-18 years in Denmark in 2000-06 were included. To chart causes of death and incidence rates, death certificates and autopsy reports were collected and read. By additional use of the extensive healthcare registries in Denmark, we were also able to investigate prior disease and symptoms. During the 7-year study period there was an average of 1.11 million persons aged 1-18 years. There were a total of 1504 deaths (214 deaths per year) from 7.78 million person-years. A total of 114 (7.5%) were sudden and unexpected. A cardiac disease was known prior to death in 18% of all sudden unexpected death cases. In two-thirds of all sudden unexpected death cases no previous medical history was registered. Causes of death in autopsied cases were cardiac or unknown in 70%. Unexplained deaths, presumed to be a primary cardiac arrhythmia, accounted for 28% of autopsied sudden unexpected death cases. Autopsy rate was 77%. There were a total of 87 cases of SCDc (5.8% of all deaths). Prodromal symptoms were noted in 26% and antecedent symptoms in 45% of SCDc cases. The most frequent antecedent symptoms were seizures, dyspnoea, and syncope. In total, 61% of SCDc were not known with any prior disease; 23% were known with congenital or other heart disease prior to death. In total, 43 (49%) of all sudden unexpected deaths died of a potential inherited cardiac disease. The incidence rate of sudden unexpected death was 1.5 per 100 000 person-years. The highest possible incidence rate of SCDc was 1.1 per 100 000 person-years.

CONCLUSION

From a nationwide study of all deaths in a 7-year period more than half of all victims of SCDc experienced antecedent and/or prodromal symptoms prior to death. The incidence rate of sudden death and SCDc was 1.5 and 1.1 per 100 000 person-years, respectively. Cardiac symptoms in young persons should warrant clinical work-up and an autopsy should be performed in all cases of sudden unexpected death in which the deceased was not known with congenital heart disease prior to death. This is pivotal, in the subsequent familial cascade screening, to diagnose and treat potential inherited cardiac diseases in family members.

Blood pressure regulation X: what happens when the muscle pump is lost? Post-exercise hypotension and syncope

Syncope which occurs suddenly in the setting of recovery from exercise, known as post-exercise syncope, represents a failure of integrative physiology during recovery from exercise. We estimate that between 50 and 80% of healthy individuals will develop pre-syncopal signs and symptoms if subjected to a 15-min head-up tilt following exercise. Post-exercise syncope is most often neurally mediated syncope during recovery from exercise, with a combination of factors associated with post-exercise hypotension and loss of the muscle pump contributing to the onset of the event. One can consider the initiating reduction in blood pressure as the tip of the proverbial iceberg. What is needed is a clear model of what lies under the surface; a model that puts the observational variations in context and provides a rational framework for developing strategic physical or pharmacological countermeasures to ultimately protect cerebral perfusion and avert loss of consciousness. This review summarizes the current mechanistic understanding of post-exercise syncope and attempts to categorize the variation of the physiological processes that arise in multiple exercise settings. Newer investigations into the basic integrative physiology of recovery from exercise provide insight into the mechanisms and potential interventions that could be developed as countermeasures against post-exercise syncope. While physical counter maneuvers designed to engage the muscle pump and augment venous return are often found to be beneficial in preventing a significant drop in blood pressure after exercise, countermeasures that target the respiratory pump and pharmacological countermeasures based on the involvement of histamine receptors show promise.

Syncope in the athlete

Syncope in the athlete requires a complete evaluation, as this may be the only warning prior to an episode of sudden cardiac death. This should include a detailed history which includes specific details of the event as well as bystander descriptions when possible. Following the history should be a careful physical examination and subsequent diagnostic testing based on the individual's needs. The purpose of the evaluation is to determine if structural or electrical heart disease is present that may lead to sudden death. If absent, the patient, family and staff can be reassured that it is safe to resume athletic activity. Careful attention to the athlete with syncope may both prevent potential disasters in some, while at the same time enjoyment of intense physical activity in others.

Practical management: a systematic approach to the evaluation of exercise-related syncope in athletes

Syncope and presyncope are relatively common presentations among athletes. The distinction between post-exercise and during-exercise syncope is critically important. While the great majority of these episodes occur just after exercise and are benign, syncope can be an indication of serious underlying cardiovascular disease if it occurs during exercise. Syncope presents a challenging differential diagnosis, as well as a daunting array of diagnostic tests and advanced imaging strategies. Sequencing a proper evaluation, and deciding who requires consultation and restriction, can be difficult for the medical provider. We present a systematic approach that assists the sports physician in arriving at a diagnosis and organizing an initial management strategy.