Cardio - Syncope

Question 1

what are the 4 main types of syncope?

Answer 1

1. Reflex syncope: temporarily decreased HR and BP… reduced cerebral perfusion.
   - vasovagal syncope
   - carotid sinus hypersensitivity
   - situational syncope (e.g. micturition)
2. Cardiac syncope: cardiac pathology causes reduction in CO.
   - arrythmias (more common in middle-aged pts)
   - structural cardiac pathology causing outflow obstruction (e.g. aortic stenosis, hypertrophic obstructive cardiomyopathy)
   - massive PE
3. Orthostatic syncope: reduced intravascular volume or blunted autonomic response… low BP on sitting/standing… decreased cerebral perfusion.
   - dehydration
   - drugs
   - autonomic instability
   - baroreceptor dysfunction (in hypertensive pts)
4. Cerebrovascular syncope (rarer): non-cardiac structural causes of reduced cerebral perfusion.
   - vertebrobasilar insufficiency
   - subclavian steal
   - aortic dissection

Question 2

suggest possible drugs that can cause syncope

Answer 2

• diuretics and ACEi: reduced blood volume and vasodilation
• B-blockers: inability to increase HR on standing
• a-blockers: inability to vasoconstrict major capacitance vessels
• CCBs: inability to vasoconstrict and some are negatively inotropic/chronotropic

Question 3

what is the most common cause of syncope in:

• younger pts?
• older pts?

Answer 3

• young: vasovagal syncope

- old: drugs

Question 4

what is the common cause of syncope that has no warning?

Answer 4

cardiac arrythmia (some may have palpitations) or massive PE

Question 5

what is the common cause of syncope preceded by dizziness, pallor, clamminess?

Answer 5

vasovagal syncope

Question 6

how long does LoC in vasovagal/cardiac syncope last vs epileptic seizure?

Answer 6

syncope: seconds
seizure: can last minutes

Question 7

how long does it take to recover in vasovagal or cardiac syncope and seizure?

Answer 7

• vasovagal: rapid recovery on sitting or lying
• cardiac: rapid spontaneous recovery
• seizure: confusion for 5-30 mns

Question 8

which Ix should be performed on anyone with LoC?

Answer 8

1. O2 sats - may reveal hypoxia, e.g. in PE
2. Bloods:
   
   • capillary blood glucose - ?hypoglycaemia
   • FBC - ?anaemia
   • UandE - ?electrolyte abnormality
3. ECG - ?arrythmia