From the Guidelines
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, as defined by the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society 1.
Definition and Classification
Syncope is characterized by a sudden drop in blood flow to the brain, resulting in a brief lapse in consciousness that usually resolves quickly once the person is lying flat and blood flow to the brain is restored. The presumed mechanism is cerebral hypoperfusion, and it should not be confused with other nonsyncope causes of loss of consciousness, such as seizure, antecedent head trauma, or apparent loss of consciousness (i.e., pseudosyncope) 1.
Causes and Types
Syncope can be caused by various factors, including:
- Vasovagal reactions (the most common type, triggered by emotional stress, pain, or standing for long periods)
- Cardiac issues (such as arrhythmias or structural heart problems)
- Orthostatic hypotension (blood pressure dropping when standing up)
- Situational triggers (like coughing, urinating, or swallowing) There are also different types of syncope, including:
- Reflex (neurally mediated) syncope
- Vasovagal syncope (VVS)
- Carotid sinus syndrome
- Situational syncope
- Postural (orthostatic) tachycardia syndrome (POTS)
Management and Treatment
When someone experiences syncope, they should be placed in a supine position with legs elevated to improve blood flow to the brain. Medical attention should be sought, especially for first-time episodes or if accompanied by chest pain, shortness of breath, or occurring during exercise, as these may indicate serious underlying cardiac conditions 1.
From the Research
Definition of Syncope
- Syncope is a medical condition characterized by recurrent episodes of fainting or loss of consciousness, often caused by a temporary decrease in blood flow to the brain 2, 3, 4, 5, 6.
- It can be classified into different types, including neurocardiogenic syncope, vasovagal syncope, and orthostatic syncope, each with distinct underlying mechanisms and triggers 2, 4, 5.
Causes and Triggers of Syncope
- Neurocardiogenic syncope is often triggered by stress, pain, or fear, leading to a sudden drop in heart rate and blood pressure 2, 5.
- Vasovagal syncope is typically caused by a reflex of the involuntary nervous system, resulting in a decrease in heart rate and blood pressure 4.
- Orthostatic syncope occurs when an individual experiences a sudden drop in blood pressure upon standing, often due to dehydration, medication, or underlying medical conditions 6.
Diagnosis and Treatment of Syncope
- Diagnosis of syncope typically involves a combination of medical history, physical examination, and diagnostic tests such as tilt table testing and electrocardiography 2, 3, 5.
- Treatment of syncope depends on the underlying cause and may involve lifestyle modifications, such as increasing fluid and salt intake, as well as medication, including midodrine and fludrocortisone 2, 3, 4, 5, 6.
- Midodrine and fludrocortisone have been shown to be effective in reducing the frequency and severity of syncope episodes, with midodrine increasing venous return and fludrocortisone increasing blood volume 2, 3, 5, 6.