Cardiac Causes of Pediatric Syncope Finding the Needle

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

Disclosures § None

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 lifethreatening cardiac cause

Outline § § Cases Definition Epidemiology Causes – Dysautonomia – Cardiac § Clinical evaluation § When to consider referral

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

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

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

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 lifethreatening condition, usually cardiac

Pathophysiology § Critical cerebral blood flow = 60 m. L/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

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

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

Vasovagal ? t in Forceful contractions of an underfilled heart inappropriately activate C-fibers in the heart a f ld i h tone and Increased parasympathetic c y decreased sympathetic tone m d i d y vasodilation, and hypotension Bradycardia, h W Reduction of cerebral perfusion

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. ”

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

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

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

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

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

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

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%

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

Coronary artery anomalies

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

Coronary artery anomalies § History: – Exertional chest pain, syncope, or sudden death § Exam: – Unrevealing

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

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

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

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)

Long QT syndrome (Roden and Spooner, 1999)

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

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

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

Clinical evaluation - History § Details about all of the events surrounding the episode are critical § Was it presyncope vs 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

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

§ 0. 1% (n=3) were due to a previously undiagnosed cardiac etiology – 2 were SVT and 1 was myocarditis

§ 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

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

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

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

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

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

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. Up. To. Date, 2017. <https: //www. texaschildrens. org/departments/anomalous-aortic-origin-coronary-artery -aaoca>

Thank You

Pediatric Cardiology (541) 222 -6160 24/7/365 Misty Carlson, MD mcarlson 2@peacehealth. org • • Eric Johnson, MD ejohnson@peacehealth. org Outpatient clinic consultations Pediatric echocardiograms Pediatric ECGs and rhythm monitors Email or phone consultations