From the Guidelines
Syncope should be managed by first placing the person in a supine position with legs elevated to restore blood flow to the brain, and the underlying cause should be determined through a thorough history, physical examination, and ECG, as stated in the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1. The definition of syncope is a symptom that presents with an abrupt, transient, complete loss of consciousness, associated with inability to maintain postural tone, with rapid and spontaneous recovery, and the presumed mechanism is cerebral hypoperfusion 1. Some key terms related to syncope include:
- Presyncope (near-syncope): a cognitive state in which one lacks awareness of oneself and one’s situation, with an inability to respond to stimuli
- Unexplained syncope (syncope of undetermined etiology): syncope for which a cause is undetermined after an initial evaluation
- Orthostatic intolerance: a syndrome consisting of a constellation of symptoms that include frequent, recurrent, or persistent lightheadedness, palpitations, tremulousness, generalized weakness, blurred vision, exercise intolerance, and fatigue upon standing
- Orthostatic tachycardia: a sustained increase in heart rate of $30 bpm within 10 min of moving from a recumbent to a quiet standing position
- Orthostatic hypotension (OH): a drop in systolic BP of $20 mm Hg or diastolic BP of $10 mm Hg with assumption of an upright posture The most common type of syncope is vasovagal syncope, triggered by emotional stress, pain, or prolonged standing, where blood pressure drops and heart rate slows 1. Other causes of syncope include:
- Cardiac issues (arrhythmias, structural heart disease)
- Orthostatic hypotension (blood pressure drop when standing)
- Neurological conditions
- Reflex (neurally mediated) syncope
- Carotid sinus syndrome For recurrent vasovagal syncope, preventive measures include:
- Adequate hydration
- Avoiding triggers
- Physical counterpressure maneuvers like leg crossing or hand gripping when warning symptoms occur In severe cases, medications such as fludrocortisone or midodrine may be prescribed, and beta-blockers are sometimes used but have mixed effectiveness 1. Cardiac syncope requires specific treatment of the underlying condition, which might include antiarrhythmic medications or pacemaker implantation. Anyone experiencing syncope should seek medical evaluation to determine the cause, as some forms, particularly cardiac syncope, can indicate serious underlying conditions that require prompt treatment 1.
From the Research
Definition and Classification of Syncope
- Syncope is defined as a brief loss of consciousness due to an abrupt fall in cerebral perfusion 2
- It is characterized by a relatively rapid onset, brief duration with spontaneous and full recovery 3
- The primary classifications of syncope are cardiac, reflex (neurogenic), and orthostatic 2, 4
Evaluation and Diagnosis of Syncope
- History-taking remains the most important aspect of the clinical assessment 2, 5
- A thorough history and physical examination including orthostatic assessment are crucial for making the diagnosis 3
- A 12-lead electrocardiogram (ECG) is the only instrumental test recommended for the initial evaluation of patients with suspected syncope 6
- Evaluation focuses on history, physical examination (including orthostatic blood pressure measurements), and electrocardiographic results 4
Management and Prognosis of Syncope
- The main objectives of management are to prolong survival, limit physical injuries and prevent recurrences 2
- Patients with life-threatening causes of syncope should be managed urgently and appropriately 2
- The prognosis of patients with reflex and orthostatic syncope is good; cardiac syncope is more likely to be associated with adverse outcomes 4
- Risk stratification tools, such as the Canadian Syncope Risk Score, may be beneficial in informing decisions regarding hospital admission 4