Diagnostic procedure for pediatric syncope. A 2024 revision of the 2018 Chinese Pediatric Cardiology Society guidelines

(a) For children with normal physical examination and normal routine ECG findings, ECG is generally not helpful in determining a possible etiology for pediatric syncope. For children with possible structural heart defects, after medical history and physical examination, ECG is a screening tool to detect abnormal cardiac structure or function.
(b) Holter ECG is a common test to determine the cause of syncope. However, because syncope is unpredictable, regular monitoring for only 24 hours makes it difficult to either confirm or thoroughly rule out the association between arrhythmia and syncope. Holter may help in diagnosing various causes of syncope, including asymptomatic sinus bradycardia, atrioventricular block, and supraventricular or ventricular tachycardia. For children with recurrent syncope, Holter ECG and implantable loop recorder (ILP) are important for diagnosis and differential diagnosis. For children with syncope induced by sports and emotions, an exercise test should be performed to detect potential arrhythmias with appropriate staff and equipment at hand to manage serious arrhythmias.
(c) For patients with suspected sick sinus syndrome, atrioventricular conduction abnormalities, or all ventricular and supraventricular arrhythmias, the diagnosis can be confirmed by cardiac electrophysiological studies when necessary.
(d) For patients with suspected pulmonary hypertension or coronary heart disease, although ECG cannot clarify the diagnosis, cardiac catheterization and angiocardiography may be considered.
(e) For patients with suspected hereditary disease, such as ion channel diseases, cardiomyopathy, or genetic metabolic diseases, and for those with a family history of genetic heart disease or sudden death, the diagnosis may be confirmed by metabolic disorder screening or genetic tests.

Abbreviations: CHD congenital heart disease, ECG electrocardiogram, HUTT head-up tilt test, ILP implantable loop recorder, OH orthostatic hypotension, OHT orthostatic hypertension, POTS postural orthostatic tachycardia syndrome, SHT sitting hypertension, SS situational syncope, STS sitting tachycardia syndrome, VVS vasovagal syncope, VVS-CI vasovagal syncope cardioinhibitory type, VVS-M vasovagal syncope mixed type, and VVS-VI vasovagal syncope vasoinhibitory type.

(From: Wang C, Liao Y, Wang S, et al. Guidelines for the diagnosis and treatment of neurally mediated syncope in children and adolescents (revised 2024). World J Pediatr 2024;20[10]:983-1002. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)