Syncope Evaluation and Management

Initial Assessment

• The American College of Cardiology recommends a detailed history, physical examination, and 12-lead ECG for the initial assessment of syncope, which can identify the diagnosis in up to 50% of cases and determine whether the patient is low-risk or requires cardiac evaluation 1, 2
• A thorough history should include circumstances of the event, prodrome characteristics, precipitating factors, witness account, recovery phase, and family history, as these elements can help distinguish between vasovagal and cardiac syncope 1, 2, 3
• Orthostatic vital signs should be measured, as a drop in systolic blood pressure ≥20 mmHg or to <90 mmHg indicates orthostatic hypotension 1
• The American Heart Association suggests that a cardiovascular examination should assess for murmurs, irregular rhythm, or abnormal heart sounds, which can indicate underlying cardiac conditions 4, 1

Risk Stratification

• The American College of Cardiology states that low-risk features, such as age <45 years, syncope only when standing, clear prodromal symptoms, and normal physical examination and ECG, suggest vasovagal syncope and outpatient management 3, 1
• High-risk features, including syncope during exertion, absent or very brief prodrome, family history of sudden cardiac death, abnormal cardiac examination, and abnormal ECG, require cardiac evaluation 1, 3, 5

Diagnostic Testing

• Echocardiography is recommended when structural heart disease is suspected, based on abnormal cardiac examination, abnormal ECG, syncope during exertion, or family history of sudden cardiac death 5, 2
• Exercise stress testing is strongly recommended if syncope occurred during or immediately after physical exertion, to screen for hypertrophic cardiomyopathy, anomalous coronary arteries, and exercise-induced arrhythmias 5, 2
• Prolonged ECG monitoring should be considered if arrhythmic syncope is suspected but the initial ECG is normal 4, 5, 2

Management

• For low-risk patients with presumed vasovagal syncope, no additional testing is required, and management consists of reassurance, education, and lifestyle modifications, including increased fluid and salt intake, avoidance of triggers, and physical counterpressure maneuvers 1, 2
• For high-risk patients or unexplained syncope, further testing, such as echocardiography, exercise stress testing, or prolonged ECG monitoring, may be necessary to determine the underlying cause 5, 2, 4

Differential Diagnosis for Syncope in Adolescents

High-Risk Cardiac Causes

• The European Society of Cardiology recommends excluding high-risk cardiac causes, such as arrhythmic syncope, including Long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, Wolff-Parkinson-White syndrome, and conduction abnormalities, in adolescents with syncope 6
• Structural heart disease, including hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, anomalous coronary artery origin, and myocarditis, must be ruled out in adolescents with syncope 6
• Conduction abnormalities, such as sinus bradycardia and AV blocks, can cause syncope in adolescents 7

Reflex (Neurally-Mediated) Syncope

• The European Heart Journal states that vasovagal syncope is the most common cause of syncope in adolescents, with a family history of vasovagal syncope present in one-third of the population 6
• Situational syncope variants, including cough syncope, micturition syncope, and defecation syncope, can occur in adolescents 7

Diagnostic Approach

• A 12-lead ECG is mandatory in all patients with syncope to look for QT prolongation, Brugada pattern, pre-excitation, conduction abnormalities, signs of ischemia, and hypertrophy patterns 6
• The American Heart Association recommends a thorough history and physical examination, including orthostatic vital signs, to evaluate patients with syncope 6
• Prolonged ECG monitoring, such as Holter or event recorder, is indicated in patients with palpitations associated with syncope or suspected arrhythmic syncope with normal initial ECG 7

Seizure Disorders

• The European Heart Journal notes that seizure disorders, such as psychogenic non-epileptic seizures and psychogenic pseudosyncope, can be mistaken for syncope in adolescents 7
• A duration of unconsciousness >1 minute suggests seizure over syncope, and lateral tongue biting strongly suggests epilepsy 7

Critical Pitfalls to Avoid

• The European Society of Cardiology advises against dismissing cardiac causes based on age alone, as inherited arrhythmia syndromes and structural heart disease can present in adolescence with syncope as the first manifestation 6
• Tilt testing should not be used as a first-line diagnostic test due to its high false-positive and false-negative rates in adolescents 6

Syncope Evaluation and Management in High-Risk Patients

Immediate Risk Stratification and Essential Next Steps

• The American College of Cardiology recommends that patients with age >70 years, established coronary artery disease (CAD), and prior transient ischemic attack (TIA) undergo thorough cardiac evaluation due to elevated risk for cardiac syncope 8
• The European Heart Society suggests that syncope triggered by laughing, a Valsalva-like maneuver, could represent situational syncope, but in elderly patients with cardiac history, arrhythmia must be excluded first 9
• Polypharmacy with multiple vasodilators significantly increases the risk of drug-induced orthostatic hypotension, according to the American Heart Association 10
• Non-compliance with continuous positive airway pressure (CPAP) for obstructive sleep apnea (OSA) may contribute to arrhythmia risk, as stated by the American College of Cardiology 8

Diagnostic Evaluation

• The European Heart Journal recommends obtaining and reviewing a 12-lead electrocardiogram (ECG) immediately to look for QT prolongation, conduction abnormalities, ventricular ectopy, or signs of ischemia 8
• Orthostatic vital signs testing should be performed by measuring blood pressure and heart rate supine, then at 1 and 3 minutes after standing, as suggested by the European Heart Journal 9
• A drop in systolic blood pressure ≥20 mmHg or to <90 mmHg indicates orthostatic hypotension, according to the European Heart Journal 9

Management and Prevention

• Reducing or withdrawing hypotensive medications is beneficial in selected elderly patients with syncope, as recommended by the American Heart Association 10
• The American College of Cardiology suggests that indapamide and irbesartan are both implicated in medication-related syncope, especially in elderly patients 10
• Venlafaxine can cause orthostatic hypotension and should be reviewed, according to the American Heart Association 10
• Consider reducing diuretic dose first if orthostatic hypotension is confirmed, as recommended by the American Heart Association 10

Differential Diagnosis and Critical Pitfalls

• The American College of Cardiology states that elderly patients on multiple vasoactive drugs have the highest prevalence of medication-related syncope 10
• CAD with left ventricular (LV) hypertrophy and diastolic dysfunction increases the risk of both bradyarrhythmias and tachyarrhythmias, according to the American College of Cardiology 8
• Do not dismiss syncope as simple vasovagal syncope based on the situational trigger alone—age and comorbidities demand thorough cardiac evaluation, as recommended by the American College of Cardiology 11
• Do not perform carotid sinus massage given a history of TIA, as stated by the American College of Cardiology 8

Syncope Evaluation and Management

Initial Assessment

• The American Heart Association recommends that all patients presenting with syncope require an initial evaluation consisting of detailed history, physical examination with orthostatic vital signs, and 12-lead ECG, which alone establishes the diagnosis in 23-50% of cases and determines whether cardiac evaluation or hospital admission is needed 12
• The American College of Cardiology suggests focusing on specific elements in the history to distinguish cardiac from non-cardiac causes, including circumstances of the event, activity at onset, prodromal symptoms, and triggers 12
• Known structural heart disease or heart failure has a 95% sensitivity for cardiac syncope, according to the American Heart Association 12
• The American College of Cardiology recommends a cardiovascular examination, including murmurs, gallops, rubs, and irregular rhythm, as part of the physical examination 13

Risk Stratification

• The American Heart Association identifies high-risk features for syncope, including age >60 years, male sex, known ischemic heart disease, structural heart disease, or reduced ventricular function, syncope during exertion or in supine position, brief or absent prodrome, and abnormal cardiac examination or ECG 12
• The American College of Cardiology recommends hospital admission and cardiac evaluation for patients with high-risk features 12

Laboratory Testing

• The American College of Cardiology suggests that routine comprehensive laboratory testing is not useful and should not be performed, but targeted tests may be ordered when clinically indicated, such as electrolytes, BUN, creatinine, and BNP and high-sensitivity troponin 12, 13

Additional Diagnostic Testing

• The American College of Cardiology recommends transthoracic echocardiography when structural heart disease is suspected, based on abnormal cardiac examination, ECG, or syncope during exertion 13
• The American College of Cardiology suggests cardiac monitoring, including Holter monitor, external loop recorder, or implantable loop recorder, when arrhythmic syncope is suspected, with the choice based on the frequency of events 13
• The American College of Cardiology recommends exercise stress testing for syncope during or immediately after exertion to screen for hypertrophic cardiomyopathy, anomalous coronary arteries, and exercise-induced arrhythmias 13

Management of Unexplained Syncope

• The American College of Cardiology recommends reappraising the entire workup, considering specialty consultation, and considering implantable loop recorder for recurrent episodes when no diagnosis is established after initial evaluation 13