What is the approach to diagnosis and management of syncope?

Syncope: Diagnostic and Management Approach

The diagnosis and management of syncope should follow a structured algorithm beginning with a thorough initial evaluation consisting of detailed history, physical examination including orthostatic blood pressure measurements, and 12-lead ECG, which can establish a diagnosis in up to 50% of cases. 1, 2

Initial Evaluation

History Taking

• Focus on circumstances before the attack, including position, activity, predisposing factors, and precipitating events 1
• Document onset symptoms, including presence of prodrome, palpitations before syncope 1
• Assess recovery phase symptoms and obtain eyewitness accounts when available 1
• Determine if syncope occurred during exertion, neck turning, or in specific positions 3

Physical Examination

• Complete cardiovascular examination with attention to heart rate, rhythm, murmurs, gallops, or rubs that may indicate structural heart disease 1
• Perform orthostatic blood pressure measurements in lying, sitting, and standing positions 1
• Consider carotid sinus massage in patients over 40 years without contraindications 1

Initial Testing

• 12-lead ECG should be performed in all patients to identify potential cardiac causes 1
• Basic laboratory tests are only indicated if syncope may be due to loss of circulating volume or if a metabolic cause is suspected 3, 1

Risk Stratification

High-Risk Features (Consider Admission)

• Abnormal ECG findings (sinus bradycardia, sinoatrial blocks, 2nd or 3rd degree AV block) 1
• History of structural heart disease or heart failure 1
• Syncope during exertion or in supine position 1
• Absence of prodromal symptoms 1
• Family history of sudden cardiac death 2
• Older age (>60 years) 1
• Low blood pressure (systolic BP <90 mmHg) 1

Low-Risk Features (Consider Outpatient Management)

• Younger age 1
• No known cardiac disease 1
• Normal ECG 1
• Syncope only when standing 1
• Presence of prodromal symptoms 1
• Specific situational triggers 1

Diagnostic Algorithm Based on Initial Evaluation

Suspected Heart Disease

• Echocardiography 3
• Prolonged electrocardiographic monitoring 3
• If non-diagnostic, consider electrophysiological studies 3

Palpitations Associated with Syncope

• Electrocardiographic monitoring 3
• Echocardiography 3

Chest Pain Suggestive of Ischemia Before/After Syncope

• Stress testing 3
• Echocardiography 3
• Electrocardiographic monitoring 3

Young Patients Without Heart/Neurological Disease and Recurrent Syncope

• Tilt testing 3

Older Patients With Recurrent Syncope

• Carotid sinus massage 3

Syncope During/After Effort

• Echocardiography 3
• Stress testing 3

Signs of Autonomic Failure or Neurological Disease

• Specific diagnosis should be made with appropriate neurological testing 3

Frequent Recurrent Syncope With Multiple Somatic Complaints

• Psychiatric assessment 3

Specialized Testing Based on Initial Findings

Electrocardiographic Monitoring

• In-hospital monitoring is warranted only for high-risk patients 3
• External loop recorders may have limited utility for patients with infrequent episodes 3
• Implantable loop recorders should be considered when the mechanism remains unclear after full evaluation 3

Neurological Testing

• Brain imaging (CT/MRI) is not recommended routinely for syncope evaluation (diagnostic yield only 0.24-1%) 1
• EEG is not recommended routinely (diagnostic yield only 0.7%) 1
• Carotid artery imaging is not recommended routinely (diagnostic yield only 0.5%) 1

Management of Unexplained Syncope

• Re-appraise the entire work-up for subtle findings or new information 3
• Consider consultation with appropriate specialty services if unexplored clues to cardiac or neurological disease are present 3
• Consider implantable loop recorder for patients with clinical or ECG features suggesting arrhythmic syncope or history of recurrent syncopes with injury 3

Common Pitfalls to Avoid

• Failing to distinguish syncope from non-syncopal causes of transient loss of consciousness 1
• Ordering comprehensive laboratory panels without specific indications 1
• Overlooking orthostatic hypotension as a potential cause 1
• Neglecting medication effects as potential contributors 1
• Ordering brain imaging studies without specific neurological indications 1
• Performing routine EEG testing without specific neurological features suggesting seizure 1

Impact on Quality of Life and Morbidity

• Recurrent syncope is associated with fractures and soft-tissue injury in 12% of patients 3
• Syncope can significantly impair quality of life across multiple dimensions including mobility, usual activities, self-care, pain/discomfort, and anxiety/depression 3
• There is a significant negative relationship between frequency of syncopal episodes and overall perception of health 3