Syncope risk factors

Syncope is a sign of insufficient cerebral blood flow and it should be evaluated for the underlying cause. Possible underlying risk factors of cardiac syncope include older age (>60 y), male sex, presence of known ischemic heart disease, structural heart disease, previous arrhythmias, or reduced ventricular function, brief prodromes such as palpitations or sudden loss of consciousness without a prodrome, syncope during exertion, syncope in the supine position, low number of syncope episodes (1 or 2), abnormal cardiac examination, family history of inheritable conditions or premature sudden cardiac death (SCD) (<50 y of age), or presence of known congenital heart disease. Common risk factors associated with noncardiac causes of syncope include younger age, no known cardiac disease, syncope only in the standing position, positional change from supine or sitting to standing, presence of prodrome: nausea, vomiting, feeling warm, presence of specific triggers ||||( dehydration, pain, stressful stimulus, medical environment), situational triggers( cough, laugh, micturition, defecation, deglutition), history of syncope with similar characteristics and frequent recurrence

• Common risk factors associated with cardiac causes of syncope include:^[1]

• Older age (>60 y)
•  Male sex
•  Presence of known ischemic heart disease, structural heart disease, previous arrhythmias, or reduced ventricular function
•  Brief prodromes, such as palpitations, or sudden loss of consciousness without a prodrome
•  Syncope during exertion
•  Syncope in the supine position
•  Low number of syncope episodes (1 or 2)
•  Abnormal cardiac examination
• Family history of inheritable conditions or premature sudden cardiac death (SCD) (<50 y of age)
• Presence of known congenital heart disease

• Common risk factors associated with noncardiac causes of syncope include:

• Younger age
• No known cardiac disease
• Syncope only in the standing position
•  Positional change from supine or sitting to standing
•  Presence of prodrome: nausea, vomiting, feeling warmth
•  Presence of specific triggers: dehydration, pain, stressful stimulus, medical environment
•  Situational triggers: cough, laugh, micturition, defecation, deglutition
• History of syncope with similar characteristics and frequent recurrence

• Short term risk factors associated with the outcomes of syncope in the emergency department until 30 days after event include:

• Male sex
• Older age (>60 y)
• No prodrome
• Palpitation preceding loss of consciousness
• Exertional syncope
• Structural heart disease
• Heart failure
• Cerebrovascular disease
• Family history of SCD
• Trauma
• Physical Examination or Laboratory Investigation
• Evidence of bleeding
• Persistent abnormal vital signs
• Abnormal ECG
• Positive troponin

• Long term risk factors associated with the outcomes of syncope > 30 days until one year after event include:

• Male sex
• Older age
• Absence of nausea/vomiting preceding syncopal event
• Ventricular arrhythmia
• Cancer
• Structural heart disease
• Heart failure
• Cerebrovascular disease
• Diabetes mellitus
• Physical Examination or Laboratory Investigation
• Abnormal ECG
• Lower GFR
• High CHADS score ( congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke or transient ischemic attack)

• The following factors have been associated with increased risk of orthostatic syncope:^[2]
  • Sudden postural change of the head (especially upon waking in the morning)
  • Standing still for a long period
  • Certain antihypertensive drugs (e.g., diuretics, vasodilators)
  • Severe exertion with dehydration
  • Reduced “thirst drive” in elderly individuals
  • Avoidance of fluid intake in older men (to minimize prostate symptoms)
  • Excess alcohol or caffeine use
  • Straining during micturition or defecation
  • High environmental temperature (including hot baths, showers, and saunas)
  • Large meals (especially with refined carbohydrates)