Risk Factors Associated with Cardiac Syncope in Pediatric Patients

Background: Syncope is defined as loss of consciousness due to global cerebral hypoperfusion. It is a common pediatric complaint and affects approximately 15% of children younger than 18 years old. Although usually benign, the exclusion of cardiac origin for syncope is of utmost importance in the clinical setting due to the association of cardiac syncope with morbidity and sudden death.

Methods: Retrospective chart review of patients aged 4 to 18 years old referred to our tertiary care center, over a 5-year period from January 1, 2016 to December 31, 2020. Syncope was defined as a sudden and transient loss of consciousness and postural tone, with spontaneous recovery. Children without loss of consciousness were excluded. We collected demographic, clinical data, and results from electrocardiography (ECG), echocardiogram, tilt table test, holter monitoring, exercise stress test, and cardiac MRI when available. Based on previous studies we collected the following risk variables for cardiac syncope: associated chest pain, associated palpitations, associated significant trauma, syncope during exertion, absence of prodromal symptoms, past medical history, cardiac history, and family history of cardiac disease. High risk patients had 2 or more risk variables present and low risk patients had only 1 risk variable present. Final diagnosis was also collected from medical records.

Results: Of the initial 745 referrals with chief complain of syncope, passing out, or dizziness, 473 patients met our inclusion criteria. 62.2% were female and the mean (SD) age was 13.3 ± 3.3 years. There were 85 patients in the high-risk group, 158 in the low-risk group and 230 had no risk factors. The final diagnosis was vasovagal syncope in 425, cardiac syncope in 9, neurological disorder in 13, other in 14 patients and 7 pending further workup at this time. Of the 9 cardiac syncope patients, all patients had at least one risk factor: 7 were in the high-risk group and 2 in the low-risk group. Syncope associated with exertion (p = 0.028) and lack of prodromal symptoms (p = 0.040) were associated to cardiac syncope. Using binary logistic regression, none of the risk factors remain statistically significant. However, ECG abnormality was found to be significantly associated with cardiac syncope (p = 0.001) and this persisted by binary logistic regression (p = 0.019). Most common etiologies of cardiac syncope were atrioventricular block (n = 3) and Wolff-Parkinson White (n = 3).

Conclusion: Pediatric cardiac syncope is a rare but important etiology of syncope in the pediatric population. All patients with cardiac etiology of syncope were found to have at least one positive specific risk factor. Therefore, most cases could be identified with an algorithm allowing for risk stratification. This has the potential to decrease resource utilization, and healthcare costs in this population.