IBHRE Syncope and Autonomic Disorders 1 — Questions and Answers
Question 1: What is the most common type of syncope in the general population?
- Vasovagal syncope (Correct answer)
- Cardiac syncope
- Orthostatic hypotension
- Carotid sinus syncope
Correct answer: Vasovagal syncope
Vasovagal (neurally mediated) syncope accounts for approximately 50% of all syncope cases and is the most prevalent form.
Question 2: Orthostatic hypotension is defined as a sustained reduction in systolic blood pressure of at least how many mmHg within 3 minutes of standing?
- 10 mmHg
- 20 mmHg (Correct answer)
- 30 mmHg
- 40 mmHg
Correct answer: 20 mmHg
Orthostatic hypotension requires a drop of ≥20 mmHg in systolic BP or ≥10 mmHg in diastolic BP within 3 minutes of standing.
Question 3: The cardioinhibitory type of vasovagal syncope is primarily characterized by:
- Significant bradycardia or asystole with minimal hypotension (Correct answer)
- Hypotension with little or no bradycardia
- Both equal bradycardia and hypotension
- Tachycardia followed by sudden loss of consciousness
Correct answer: Significant bradycardia or asystole with minimal hypotension
Cardioinhibitory vasovagal syncope is defined by predominant bradycardia or asystole with relatively preserved blood pressure until near loss of consciousness.
Question 4: Carotid sinus hypersensitivity is diagnosed when carotid sinus massage produces a ventricular pause of at least:
- 2 seconds
- 3 seconds (Correct answer)
- 4 seconds
- 5 seconds
Correct answer: 3 seconds
A ventricular pause of ≥3 seconds during carotid sinus massage defines the cardioinhibitory form of carotid sinus hypersensitivity.
Question 5: POTS (Postural Orthostatic Tachycardia Syndrome) is defined by a heart rate increase of at least how many beats per minute upon standing within 10 minutes, without orthostatic hypotension?
- 20 bpm
- 30 bpm (Correct answer)
- 40 bpm
- 50 bpm
Correct answer: 30 bpm
POTS requires an increase in heart rate of ≥30 bpm (or HR ≥120 bpm) within 10 minutes of standing without a concurrent drop in blood pressure ≥20 mmHg.
Question 6: Which alpha-1 adrenergic agonist is used to treat neurally mediated syncope and orthostatic hypotension by increasing peripheral vascular resistance?
- Fludrocortisone
- Midodrine (Correct answer)
- Metoprolol
- Pyridostigmine
Correct answer: Midodrine
Midodrine is a selective alpha-1 agonist that raises peripheral vascular resistance and venous return, reducing syncope recurrence and has a Class IIa recommendation for vasovagal syncope.
Question 7: The vasodepressor type of vasovagal syncope is primarily characterized by:
- Significant bradycardia without meaningful hypotension
- Hypotension with little or no bradycardia (Correct answer)
- Asystole lasting more than 3 seconds
- Tachycardia as the dominant feature
Correct answer: Hypotension with little or no bradycardia
Vasodepressor syncope is defined by predominant hypotension due to peripheral vasodilation, with heart rate decreasing by less than 10% of peak value.
IBHRE Syncope and Autonomic Disorders 1
What is the most common type of syncope in the general population?