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August 1, 2017 Circulation. 2017;136:e60–e122. DOI: 10.1161/CIR.0000000000000499 e90

Recommendations for Pediatric Syncope

COR LOE Recommendations

I C-LD V VS evaluation, including a detailed medical history, physical examination, family history, and a 12-lead ECG, should be performed in all pediatric patients presenting with syncope.315,618,620,624–630

See Online Data Supplement 40. Although V VS is the most common cause of pediatric syncope, cardiac syncope does represent 1.5% to 6% of pediatric cases (usually defined as up to 18 years of age).617,619,620,629,631,632 Characteristics of presenting signs and symptoms differentiating V VS from cardiac causes of syncope are generally similar to those in adults. A family history of V VS and early SCD should be sought. V VS occurs in 33% to 80% of children with syncope.624,628 Risk factors that raise suspicion of a cardiac etiology include the absence of prodromal symptoms, presence of preceding palpitations within seconds of loss of consciousness, lack of a prolonged upright posture, syncope during exercise or in response to auditory or emotional triggers, family history of SCD, abnormal physical examination, and abnormal ECG,626,627 although the specificity is modest.618,627,630,633 It should be remembered that children may not be able to clearly communicate specific symptoms. Exertional syncope has been associated with LQTS and CPVT.315,318,337,630,634 Regardless of symptoms, exertional syncope, especially mid-exertional syncope, should result in a high index of suspicion for a cardiac etiology.633

I C-LD Noninvasive diagnostic testing should be performed in pediatric patients presenting with syncope and suspected CHD, cardiomyopathy, or primary rhythm disorder.315,318,618,625,627,630,633

See Online Data Supplement 40. Channelopathies are major causes of cardiac-related syncope in young people. They may be associated with a family history of SCD, and they increase the risk of SCD in these patients.315,337,630,632,634,635 Exercise stress testing may be helpful in the diagnosis of channelopathies, such as LQTS and CPVT, which have adrenergically mediated arrhythmias. Extended monitoring is reasonable when an arrhythmia diagnosis is suspected. The types of monitoring devices, their clinical utility, and their limitations are available in Table 8. Prolonged heart rhythm monitoring can often provide a correlation between symptoms and an arrhythmia. In 5 retrospective studies of prolonged monitoring in 87 children with either syncope or presyncope, the mean diagnostic yield was 43%.636–640 Bradyarrhythmias and high-grade AV block or asystole, as well as tachyarrhythmias, SVT, and polymorphic VT, were documented.636–640 The diagnostic yield of an ICM is higher if the clinical indication was exertional syncope or the patient had underlying CHD.637,639,640

I C-EO Education on symptom awareness of prodromes and reassurance are indicated in pediatric patients with V VS.

See Online Data Supplement 40. Management of children with V VS should include reassurance about the generally benign nature of this condition.641,642 Treatment should emphasize symptom awareness and avoidance of precipitating factors that might worsen the condition, such as dehydration, standing for prolonged periods of time, hot crowded environments, and diuretic intake.

IIa C-LD Tilt-table testing can be useful for pediatric patients with suspected V VS when the diagnosis is unclear.624,629,643–650

See Online Data Supplement 40. Tilt-table testing has a diminishing role in the diagnosis of children with unexplained syncope. The sensitivity of tilt-table testing ranges from 20% to 90%,624,629,643,644,647,648,651,652 and the specificity ranges from 83% to 100%.624,643,652 Pediatric patients with episodes of V VS may exhibit convulsive movements during loss of consciousness that mimic epileptic seizures. In children with syncope and convulsions on tilt-table testing, 64% exhibited cardiac asystole with pauses >3 seconds.645 Upright tilt-table testing combined with a graded isoproterenol infusion identified 42% to 67% of patients previously thought to have a primary seizure disorder.223,649 A combined cardiology and neurology evaluation may be warranted in this group of patients with syncope and seizure-like activity.

IIa B-R In pediatric patients with V VS not responding to lifestyle measures, it is reasonable to prescribe midodrine.381,620,653

See Online Data Supplement 40. In a single-center prospective case series, pseudoephedrine reduced clinical symptoms in 94% of children with recurrent neurally mediated syncope.653 In an RCT comparing patients receiving conventional therapy (health education, tilt-table training, and salt) and midodrine with patients receiving conventional therapy alone, the recurrence rate of syncope decreased from 80% to 22%.381 In 2 prospective studies, side effects from midodrine were rare.381,653

IIb B-R Encouraging increased salt and fluid intake may be reasonable in selected pediatric patients with V VS.642 See Online Data Supplement 40. In an RCT, conventional therapy and oral rehydration salts resulted in no further recurrence of syncope in 56% of patients, versus 39% in the placebo arm (P<0.05).642

IIb C-LD The effectiveness of fludrocortisone is uncertain in pediatric patients with OH associated with syncope.389,654,655 See Online Data Supplement 40. In 2 single-center prospective case series of 0.1 mg of fludrocortisone, 83% of subjects demonstrated improvement or resolution of symptoms.654,655 In the only pediatric RCT, children with recurrent syncope did better on placebo than on fludrocortisone.389

IIb B-NR Cardiac pacing may be considered in pediatric patients with severe neurally mediated syncope secondary to pallid breath-holding spells.656,657

See Online Data Supplement 40. In 2 separate studies of 22 predominantly infants and toddlers with reflex anoxic seizures, pallid breath-holding spells, and documented prolonged asystole (pauses >4 seconds), 86% had either complete resolution or a significant reduction in the number of syncopal events with pacing.656,657 Although the studies were not powered to address the specifics of pacing programming, either single- or dual-chamber pacing significantly reduced the number of syncopal episodes compared with a sensing-only strategy.656,657 Single-chamber pacing with hysteresis appears as effective as dual-chamber pacing with rate drop response for the prevention of syncope and seizures. The beneficial response to pacing in these studies cannot exclude a placebo effect from pacemaker implantation itself; however, the young age of the patients with pallid breath-holding spells makes placebo effect less likely. The long-term outcome with pacing in this population has not been reported. Finally, it is important to remember that pallid breath-holding syncope does end, although some patients do present again at a later age with classic V VS. This should be balanced against the known complications of permanent cardiac pacing. III: No Benefit B-R Beta blockers are not beneficial in pediatric patients with V VS.655,658 See Online Data Supplement 40. In an RCT comparing metoprolol and conventional therapy, the treatment group actually had a higher recurrence rate. Side effects of beta blockers occur frequently in children.655,659

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