What Is Syncope

  • Dr. Prerna Yadav BDS, Kothiwal Dental College & Research Centre Moradabad, India
  • Raadhika Agrawal Bachelor of Medicine and Bachelor of Surgery, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India

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The term “Syncope” originated from the Greek words “syn”(with) and “koptein”(to cut or to interrupt). Shamai A. Grossman and Madhu Badireddy have stated- "Syncope is a transient loss of consciousness and postural tone followed by spontaneous recovery.” Syncope means fainting or temporary loss of consciousness. Syncope attacks may occur in an individual unexpectedly without showing any prior warning symptoms. They may present prodromal features. Also, it can lead to life-threatening events. Syncope is a manifestation that develops due to inherent pathology, and the probable causes of syncope are diseases of the heart, brain, blood vessels,  and its related disorders, drugs, the nervous system, and obstructive blood flow to the brain. Initial identification of clinical features could help in the effective management of syncope. Approximately 1 to 3.5% of emergency cases and 6% of all hospital patients in US hospitals are syncope patients. Syncope is more common in older people already suffering from various health conditions and consuming numerous medications. Older patients often have cardiac-related syncope, while younger adults typically experience vasovagal (noncardiac) episodes with no gender predilection.

Types of syncope 

The different types of syncope comprise
Reflex SyncopeOrthostatic hypotension(OH) SyncopeCardiac Syncope
Vasovagal SyncopeClassic OHArrhythmia
Situational SyncopeInitial OHStructural heart disease
Carotid Sinus SyncopeDelayed OH
Atypical formsPostural (orthostatic) tachycardia syndrome [POTS]

Reflex syncope

It includes the disorders of the heart and blood vessels generated as an outcome of any trigger.  

  1. Vasovagal syncope:

Also known as “neurocardiogenic syncope” or “common faint.” When a person remains in a vertical position for 30 seconds- It occurs due to stress, aches, or any healthcare approach and is responsible for approximately half of the Syncope incidents. Typically represents- Prodromal symptoms include instability, sweating, becoming unconscious, dark vision, spinning of the head, vomiting, and other characteristics; the victim is generally unmoving or static.

  1. Situational syncope

Develops because of wheezing, laughter, fear, swallowing, urinating, and passing stools with the same attributable process of vasovagal syncope.

  1. Carotid sinus syncope

Arises due to physical pressure on the carotid sinus, causing hypersensitivity- factors evoking it are tight-fit neck apparel, carotid massage, neck activities, and shaving.

  1. Atypical forms

Occur due to conditions corresponding to unknown factors.

Orthostatic hypotension (oh) syncope:

It is associated with vertical positioning and blood pressure decrease (postural hypotension). It evolves due to standing, alcohol consumption, drugs(tricyclic antidepressants, diuretics, vasodilators), nausea, vomiting, loose motions, bleeding, etc.

  1. Classic OH

It is predominant in older people(taking diuretic treatment) and usually arises beside standing from 30 seconds to 3 minutes.

  1. Initial OH

It is common in weak young and older people(taking alpha-blocker medications). The situation may evolve momentarily within 30 seconds of standing, resulting in faintness and dark visions.

  1. Delayed OH

It develops due to a gradual drop in blood pressure for 3 to 45 minutes, followed by vertical standing. Other features include low back pain, weakness, faintness, exhaustion, pulsations, sight and auditory problems.

  1. Postural (orthostatic) tachycardia syndrome(POTS)

means a marked rise in heart rate(tachycardia) of more than 30 beats per minute or a standing heart rate exceeding 120 beats per minute- due to standing. The symptoms comprise weakness, exhaustion, faintness, pulsations, trembling, and hazy sight. 

Cardiac syncope:

  1. Arrhythmias

Arrhythmias are more prevalent and result from medications and electrolyte imbalance. 

  1. Structural heart disease:

The body requires more blood circulation than the heart can supply through increased output; that happens because the heart cannot pump more blood due to the underlying structural issues in the heart. Other diseases stimulating syncope are pulmonary embolus, mitral stenosis, atrial myxoma, subclavian steal syndrome, etc.

Clinical features

  • Syncope results from a temporary reduction in blood flow to the brain, causing loss of consciousness, often occurring suddenly without showing any prior warning symptoms. Clinical traits include dizziness, vomiting, perspiration, weakness, and distorted vision. The patient returns quickly to his normal senses and awareness.
  • Older individuals and those troubled with memory or paying attention might experience memory loss after returning to their senses- Fatigue might take longer to recover. 
  • Most syncope attacks might be unnoticed in older people due to memory loss and loss of consciousness.
  • Amnesia for loss of consciousness is common in patients with carotid sinus syndrome, regardless of how they initially presented.
  • Many fall situations occur together with syncope in older patients with certain heart conditions.
  • These terms, “Syncope” and “Fall,” are independent conditions with different triggers, but these may sometimes occur parallel.


There may be numerous factors leading to syncope

  1. Medications

Some medications that can trigger syncope are 

  • Diuretics, Vasodilators- Calcium channel blockers, Hydrazine, Angiotensin-converting enzyme inhibitors. .
  • Antihypertensive drugs- Clonidine, Labetalol, Alpha methyldopa, Guanethidine.
  • Medications related to tachycardia- Amiodarone, Disopyramide, Quinidine.
  • Digoxin
  • Psychoactive drugs-  Tricyclic antidepressants, Phenothiazines, Barbiturates.
  • Alcohol
  1. Reflex syncope factors
    • Carotid sinus syncope
    • Common faint(Vasovagal syncope)
    • Situational syncope- bleeding, wheezing, syncope triggered by or during swallowing, urination, passing stools, pain in internal organs after a workout, stress, Glossopharyngeal, and Trigeminal neuralgia. 
  1. Orthostatic hypotension syncope
    • Growing age
    • Antihypertensive drugs and other medications
    • Hot weather
    • Bleeding, Loose motions, Fever, Addison’s disease, 
    • Primary and secondary autonomic failure syndromes- Multiple system atrophy, Parkinson’s disease, diabetic neuropathy, Amyloid neuropathy.
  1. Cardiac arrhythmias
    • Bradycardia or Tachycardia syndrome
    • Failure of implanted medical devices(ICD, pacemaker)
  1. Structural heart disease
    • Myocardial infarction
    • Pericardial disease
    • Pulmonary embolism
    • Atrial myxoma
    • Obstructive cardiomyopathy
  1. Abnormal blood flow to the brain
    • Vascular steal syndromes.


  • The first step: Healthcare professionals should take a detailed medical history, evaluate its causative factor, query the ongoing medication information, and perform a thorough physical-examination- it helps in the early recognition of clinical symptoms and making a clear-cut diagnosis, which allows to manage syncope effectively. 
  • When assessing syncope- syncope’s corresponding longevity and prior and after events are crucial for an adequate diagnosis. 
  • Positioning of the patient during the episode: standing suggests vasovagal, while supine may indicate neuro-cardiac causes.
  • In physical examination- abnormal vital signs indicate underlying issues like orthostatic hypotension or cardiovascular problems.
  • Cardiovascular and neurological exams are done to uncover the clinical traits referring to vascular disease, heart failure, or potential cerebrovascular events.
  • Vasovagal syncope is more prevalent.
  • Diagnostic tests are guided by history and examination.
  • Hemoglobin, electrolytes, glucose, and ECG are used in all the critical cases of syncope.
  • Cardiac enzyme testing, continuous monitoring, echocardiogram, Holter monitor, CT head, carotid Doppler ultrasound, MRI brain, and MRA  are some essential investigations to detect cardiovascular factors. 
  • EEG is recommended to differentiate seizures from syncope.
  • The tilt table test is preferred in frequent, unexplained syncope without cardiac disease and to infer the presence of vasovagal and orthostatic hypotension syncope.

Differential diagnosis

  • Seizures, Panic attacks, Hypoglycemia, Some Epilepsy cases, Hyperventilation with hypocapnia, and other metabolic disorders.

Treatment and management

The most crucial approach to treatment is to find out the causative agent of the syncope- and manage accordingly. 

  • Any trauma resulting from a sudden fall during syncope is managed.
  • During a sudden, generally unexpected syncope attack, sit down the patient immediately and elevate their legs, particularly for reflex postural hypotension events.
  • After any syncopal attack, the patient should not be allowed to get up quickly;- keep patients in a horizontal position to prevent recurrence.
  • Precautions

Patient education is significant for safety because it prevents future syncope attacks. Patients with a history of Syncope should follow certain precautions such as avoiding driving alone, staying away from stress, continuous standing, exhaustion, heights, gatherings, or crowds, extreme climatic conditions like severe hot/cold weather, and being hydrated with regular fluids consumption.

  • Vasovagal syncope
    • The initial management should be preventing syncope-provoking triggers. Tilt training and supplemental dosage of salt and fluids.
    •  Necessary medications, such as beta-blockers, SSRIs, hydrofludrocortisone, proamatine, etc, are administered as required.
  • Orthostatic hypotension
    • The OH syncope-triggering drugs like diuretics and vasodilators are stopped, Intravenous fluids in hypovolemic patients, and Compression stocking for balancing the venous return. The drug Promatine is preferable in critical cases.
    • The patient’s position is moderately altered while getting up from a supine or perched pose.
  • Cardiac and vascular disorders
    • Cardiologists treat the causal factor initially in such cases. The disposition of the patient is quite challenging.
    • Syncope due to hidden pathology can be hazardous.
    • Patient follow-up is essential with the respective healthcare professionals and cardiologists.
    • Risk stratification tools (like the Boston Syncope Criteria) help determine the need for admission based on factors such as
      • Prior cardiac history disorders- valvular disease, Left ventricular dysfunction, and dysrhythmia.
      • Relative complaints of disease with chest pain, dyspnea, and palpations.
      • ECG abnormalities- ischemia, dysrhythmia.


The trauma from sudden syncope falls can be severe (while driving or any outdoor physical activity).


How can I prevent syncope? 

Ensure proper hydration and a balanced diet, recognize and steer clear of stress and prolonged standing, and seek immediate medical help if warning signs occur. .

How common is syncope?

Approximately 1 to 3.5% of emergency cases and 6% of all hospital patients in US hospitals are syncope patients. Syncope is more common in older people already suffering from various health conditions and consuming numerous medications.

What can I expect if I have syncope?

You might encounter a sudden, short-lived loss of consciousness; seeking a comprehensive assessment from a healthcare provider is crucial to knowing the root cause and obtaining proper care.

Is syncope a severe medical condition?

While syncope itself is not a disease, it can be an indicator of hidden pathology. Depending on the cause, syncope may require medical attention and management.

When should I see a doctor? 

You should see a doctor if you experience syncope, especially if it happens suddenly, is accompanied by chest pain, shortness of breath, or neurological symptoms, or if you have a history of heart conditions or recurrent episodes.


Syncope, commonly called fainting, is a temporary loss of consciousness typically caused by a brief reduction in blood flow to the brain. Various factors, including emotional stress, cardiac issues, certain medications, or sudden changes in posture, can trigger it. Early recognition, lifestyle adjustments, and seeking medical advice are crucial in managing and reducing the risk of syncope. Understanding the potential causes and appropriate preventive measures is essential for individuals prone to this condition. 


  1. Professor R. A. Kenny . Chapter 57 - SYNCOPE [Internet]. Microsoft Word - syncopeRAKuntracked.doc. Department of Geriatric Medicine and Institute of Neuroscience Trinity College Dublin Ireland; 2012 [cited 2023 Oct 19]. Available from: https://www.rand.org/content/dam/rand/www/external/labor/aging/rsi/rsi_papers/2012/kenny3.pdf
  2. Grossman SA, Badireddy M. Syncope [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2022 [cited 2023 Oct 19]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK442006/
  3. Erika Hutt Centeno, MD, Kenneth A. Mayuga, MD, Fetnat Fouad-Tarazi, MD (retired staff), Laura Shoemaker, DO, Fredrick Jaeger, DO. Syncope [Internet]. www.clevelandclinicmeded.com. Cleveland Clinic; 2018 [cited 2023 Oct 19]. Available from: https://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/cardiology/syncope/

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This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Dr Prerna Yadav

Bachelor of Dental Surgery- BDS, Kothiwal Dental College & Research Centre Moradabad, India

Dr. Prerna Yadav is an accomplished Dental Surgeon with 8 years of clinical expertise. With a passion for knowledge and research, she pursued an Advanced PG Diploma in Pharmacovigilance & Clinical Research. A Certified Medical Writer as well, Prerna possesses a unique blend of dental proficiency and medical communication finesse. Her journey is a testament to dedication and an unwavering commitment to both patient care and advancing medical knowledge.

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