Cardiac Causes of Pediatric Syncope:

1. Cardiac Causes of Pediatric Syncope: Finding the Needle in the Haystack Eric Johnson, MD April 18, 2019

2. Disclosures • None

3. Objectives • List the most common causes of syncope in pediatric patients • Describe the mechanism of vasovagal syncope in one sentence • Know what to do if you suspect an arrhythmia (such as SVT) • Identify features that may be related to a life-threatening cardiac cause

4. Outline • Cases • Definition • Epidemiology • Causes • Dysautonomia • Cardiac • Clinical evaluation • When to consider referral

5. Case #1 • 13 y.o female • Unremarkable medical history • Just finished tryouts for volleyball, was standing in a circle during announcement of who made the varsity team • Felt dizzy and lightheaded, rapid palpitations, and “slumped to the floor,” losing consciousness for 1 minute • Afterward, she felt weak and had shaky hands for about 15 minutes

6. Case #2 • 5 y.o. male • At age 2, he was running during recess, collapsed, neck extended, eyes “rolled back,” appeared to stop breathing, had fine movements of shoulders and arms, and turned “purple” • Unconscious for 1 minute, seemed confused for a few seconds, then back to baseline • Since then, similar episodes about once a year

7. Definition • A sudden and transient loss of consciousness and postural tone that reverses without intervention.

8. Epidemiology • 15 – 25% experience syncope before adulthood • Disproportionately affects teenage females • 3% of all pediatric ED visits • Most cases are benign • Rarely, syncope is a harbinger of a life-threatening condition, usually cardiac

9. Pathophysiology • Critical cerebral blood flow = 60 mL/min/100 g • Cerebral perfusion is usually maintained by autoregulation • When autoregulation fails to overcome a sudden drop in systemic arterial blood pressure, pre-syncope or syncope occurs • In benign cases, this reconstitutes adequate cerebral blood flow

11. Causes • Syncope • Cardiac • Dysautonomia • Neurologic • Other • Psychogenic • Drugs/Toxins • Anemia • Hypoglycemia • Pregnancy • Breathholding • Syncope “games” • Vasovagal • Situational • POTS • Orthostatic hypotension • Structural heart disease • Arrhythmia • Myocardial dysfunction • Seizures • Migraines • Brain tumor • AV malformation • Cerebrovascular occlusive disease

12. Vasovagal • AKA neurocardiogenic, vasodepressor, simple/common faint • Prodrome lasts a few seconds to 1 minute • Dizziness, vision changes, nausea, warmth • Syncope typically lasts less than 1 minute • Associated with changes in position

13. Vasovagal Forceful contractions of an underfilled heart inappropriately activate C-fibers in the heart Increased parasympathetic tone and decreased sympathetic tone Bradycardia, vasodilation, and hypotension Reduction of cerebral perfusion Why did my child faint?

14. Vasovagal • “The nerves that help regulate your child’s heart rate and blood pressure were not working properly, which led to a temporary decrease in blood flow to the brain, and subsequent loss of consciousness.”

15. Situational • Pathophysiology and clinical presentation is similar to vasovagal • A specific trigger initiates the cascade of autonomic events leading to syncope • Sight of blood, pain, fear, hair brushing, urination

16. POTS • Postural orthostatic tachycardia syndrome • Within 10 minutes of assuming an upright position . . . • HR increase 30-40, or > 120 beats/min • Associated with exercise intolerance, chronic fatigue, GI problems, headaches, poor sleep, difficulty concentrating, psychological problems • Female: male = 5:1

17. Orthostatic hypotension • Within 3 minutes of assuming an upright position . . . • Decrease in systolic BP > 20 mmHg • Decrease in diastolic BP > 10 mmHg • Normal adrenergic vasoconstriction is inadequate • Associated with prolonged bed rest or standing

18. Orthostatic vital signs • It takes 15 minutes to do it right! • Supine for 5 minutes, then BP + HR • Stand for 3 minutes, then BP + HR • Stand for 7 more minutes, then BP + HR

19. Management of dysautonomia • Not a life threatening condition* • There is no cure, although many patients get better • Focus on improving function through: • Increase salt and water intake • Regular exercise • Avoiding triggers and caffeine • Fludrocortisone, midodrine, B-blockers, saline

20. Causes • Syncope • Cardiac • Dysautonomia • Neurologic • Other • Psychogenic • Drugs/Toxins • Anemia • Hypoglycemia • Pregnancy • Breathholding • Syncope “games” • Vasovagal • Situational • POTS • Orthostatic hypotension • Structural heart disease • Arrhythmia • Myocardial dysfunction • Seizures • Migraines • Brain tumor • AV malformation • Cerebrovascular occlusive disease

21. Hypertrophic cardiomyopathy • Ventricular hypertrophy without a hemodynamic cause • One of the most common inherited cardiomyopathies (autosomal dominant) • A heterogeneous group of disorders; outcomes depend on type and age • Disproportionately affects teenagers, annual mortality rate = 1%

22. Hypertrophic cardiomyopathy • History: • Heart failure (primarily dyspnea on exertion), chest pain (both at rest or with exertion), arrhythmias (both atrial and ventricular), syncope (15-25% of patients), or sudden death • Exam: • Systolic ejection murmur (the less full the ventricle, the louder the murmur) • Systolic regurgitant murmur

23. Coronary artery anomalies

24. Coronary artery anomalies • Many variations • Incidence of both coming off the same sinus of Valsalva ~ 0.1 to 0.3% of births • The left coronary coming off the right sinus has higher mortality

25. Coronary artery anomalies • History: • Exertional chest pain, syncope, or sudden death • Exam: • Unrevealing

26. Supraventricular tachycardia (SVT) (Kim and Knight, 2017)

27. SVT • History • Palpitations (due to an atrial arrhythmia), lightheadedness, dizziness, syncope, chest pain, sudden death • Exam • Unrevealing

29. SVT • If a patient is having an episode of likely SVT (heart rate > 150 beats/min at rest, can be much higher): • Take blood pressure if able, consider calling pediatric cardiologist • If doing fine, get an ECG • If not, try vagal maneuvers (such as Valsalva) • Or consider local ED / 911

30. Long QT syndrome • Disorder of ventricular repolarization • May be congenital (channelopathy) or acquired (often drug-related) • Borderline QTc = 0.44 to 0.46 msec (Sanatani et al, 2016)

31. Long QT syndrome (Roden and Spooner, 1999)

32. Long QT syndrome • History: • Palpitations, syncope, cardiac arrest, sudden death • Family history of congenital deafness, drownings, or accidents without precipitating factors • Exam: • Unrevealing

33. Acute myocarditis • Inflammation of the myocardium • Pediatric patients can present with acute or fulminant disease • Most common etiology is viral infection • Coxsackie A and B, and adenovirus • Syncope may be due to ventricular dysfunction or arrhythmia

34. Acute myocarditis • History • Ranges from subclinical to sudden death • Often with viral prodrome • Heart failure: dyspnea, exercise intolerance, gastrointestinal symptoms • Exam • Tachypnea, tachycardia, rales, gallop, regurgitant murmur, friction rub, hepatomegaly

35. Clinical evaluation - History • Details about all of the events surrounding the episode are critical • Was it presyncopevs true syncope? • Are there risk factors for dehydration? • How long was the patient unconscious? • Family history of vasovagal episodes, cardiomyopathy, ICD, long QT, sudden death

36. Cross sectional study of 3,445 patients (age < 18) • Presented with syncope or near-syncope to 2 EDs in Atlanta from 2009 to 2013

37. 0.1% (n=3) were due to a previously undiagnosed cardiac etiology • 2 were SVT and 1 was myocarditis

38. The presence of 2 out of 4 of the following historical features was 100% sensitive and 100% specific • Absence of a prodrome • Chest pain leading up to syncope • Palpitations leading up to syncope • Syncope during exercise

39. Clinical evaluation - Exam • Distressed? • Pale? • Count a heart rate (a key skill!) • A heart rate >150 at rest may be SVT, and >220 at rest is SVT until proven otherwise • If possible, take a blood pressure • If possible listen for a heart murmur

40. Referral is indicated for patients who: • received CPR* • were cardioverted (external or ICD)* • have findings consistent with a cardiac cause for syncope • have recurrent episodes consistent with dysautonomia • would benefit from parental reassurance

41. Case #1 • 13 y.o. female with palpitations and syncope after volleyball • Supine HR: 58 BP: 108/50 • Standing (3 min) HR: 114 BP: 105/81 • Standing (10 min) HR: 120 BP: 77/56 • POTS

42. Case #2 • 5 y.o. male with syncope while running

43. Summary • Dysautonomia is the most common cause of syncope in pediatric patients • A thorough history is the key to distinguishing potentially dangerous etiologies • Practice counting high heart rates • Call us with concern for arrhythmia, or syncope with exercise/palpitations/chest pain (especially when there is no prodrome) • If a patient has known cardiovascular disease, make a written plan with family and/or provider

44. References • Allen, H. Syncope: Avoid the Knee-Jerk Echo. AAP Gateway Journals Blog. 2016 Apr 12. • Cannon, B, and Wackel, P. Syncope. Pediatric in Review. 2016 Apr;37(4):159-68. • Hurst, D, et al. Syncope in the pediatric emergency department – can we predict cardiac disease based on history alone? J Emer Med. 2015;49(1):1-7. • Kim, S, and Knight, B. Long term risk of Wolff-Parkinson-White pattern and syndrome. Trends in Cardiovascular Medicine. Article in press. 2017 • Reybrouck, T, and Ector, H. Syncope and Assessment of Autonomic Function in Children. Moss and Adams’ Heart Disease in Infants, Children, and Adolescents, Chapter 12. Lippincott Williams & Wilkins. 2008. • Roden, D, and Spooner, P. Inherited Long QT Syndromes. Journal of Cardiovascular Electrophysiology. 1999 Dec;10(12):1664-83. • Sanatani, S, et al. Canadian Cardiovascular Society and Canadian Pediatric Cardiology Association Position Statement on the Approach to Syncope in the Pediatric Patient. J CJC. Article in press. 2016. • UpToDate, 2017. • <https://www.texaschildrens.org/departments/anomalous-aortic-origin-coronary-artery-aaoca>

45. Thank You

46. Misty Carlson, MD mcarlson2@peacehealth.org Eric Johnson, MD ejohnson@peacehealth.org Pediatric Cardiology(541) 222-6160 24/7/365 • Outpatient clinic consultations • Pediatric echocardiograms • Pediatric ECGs and rhythm monitors • Email or phone consultations