SYNCOPE

Question 1

CAUSES of SYNCOPE

Answer 1

Neurally mediated syncope (NMS) - also called reflex syncope:

1. Vasovagal syncope (common faint).
2. Situational syncope - eg, cough, sneeze, gastrointestinal stimulation (swallowing, defecation, visceral pain), micturition.
3. Carotid sinus hypersensitivity.
4. Glossopharyngeal neuralgia.

Orthostatic hypotension (postural hypotension).

Autonomic failure - eg, multiple system atrophy, Parkinson’s disease, diabetes, amyloidosis.

1. Medications - eg, antihypertensives.
2. Hypovolaemia - eg, haemorrhage, vomiting, diarrhoea, Addison’s disease.
3. Post-exercise.
4. Postprandial.

Cardiac arrhythmias:

1. Sick sinus syndrome, atrioventricular (AV) conduction system disease.
2. Paroxysmal SVT, VT.
3. Inherited syndromes - eg, long QT syndrome, Brugada’s syndrome.
4. Malfunction of pacemaker or implantable cardioverter defibrillator (ICD).
5. Drug-induced arrhythmias.

Structural cardiac or cardiopulmonary disease:
Obstructive cardiac valvular disease.
Acute coronary syndrome.
Hypertrophic obstructive cardiomyopathy.
Atrial myxoma.
Acute aortic dissection.
Pericardial disease or tamponade.
Pulmonary embolus or pulmonary hypertension.

Cerebrovascular:
Vascular steal syndromes - eg, subclavian steal syndrome.

Substance abuse, alcohol intoxication.

Psychogenic: factitious, anxiety, panic attacks, hyperventilation.

Question 2

Clinical or ECG features suggesting arrhythmic syncope

Answer 2

1. Syncope during exercise or whilst supine.
2. Palpitations at the time of syncope.
3. FHx of sudden cardiac death.
4. Non-sustained VT.
5. Bifascicular block (RBBB and either LAF or LPF block).
6. Bradycardia with pulse heart rate below 50 or sinoatrial block in the absence of negative chronotropic drugs (eg, beta-blockers) or physical training.
7. QRS complex longer than 120 milliseconds.
8. Prolonged or short QT interval.
9. Right bundle branch block pattern with ST elevation in leads V1-V3 (Brugada pattern).
10. Features suggestive of arrhythmogenic right ventricular cardiomyopathy.

Question 3

features of vasovagal (neurocardiogenic) syncope

Answer 3

1. Due to reflex bradycardia ± peripheral vasodilatation provoked by emotion, pain, fear or standing too long.
2. Onset is over seconds (not instantaneous), and is often preceded by nausea, pallor, sweating and closing in of visual fields (pre-syncope).
3. It cannot occur if lying down.
4. The patient falls to the ground, being unconscious for ~2min. Brief clonic jerking of the limbs may occur (reflex anoxic convulsion due to cerebral hypoperfusion), but there is no stiffening or tonic →clonic sequence.
5. Urinary incontinence is uncommon (but can occur), and there is no tongue-biting.
6. Post-ictal recovery is rapid.

Question 4

features of epilepsy

Answer 4

Attacks vary with the type of seizure, but certain features are more suggestive of epilepsy:

attacks when asleep or lying down;

aura;

identifiable triggers, eg tv; altered breathing;

cyanosis;

typical tonic-clonic movements;

incontinence of urine;

tongue-biting (ask about a sore tongue after the fit);

prolonged post-ictal drowsiness,

confusion, amnesia and transient focal paralysis (Todd’s palsy).

Question 5

history of blackouts

Answer 5

Ask a witness:

• Does the patient lose awareness?
  
  • Does the patient injure himself?
  • Does the patient move? Are they stiff or floppy? (Not everything that twitches is epilepsy—a few clonic jerks may occur with syncope or arrhythmias, but are not preceded by a tonic phase. Ask for exact details of movements.)
  • Is there incontinence? (More common in epilepsy, but can occur with syncope.)
  • Is the complexion changed? (Cyanosis suggests epilepsy; white or red suggests arrhythmia, but may also occur in temporal lobe seizures.)
  • Does the patient bite the side of his tongue? (Suggests epilepsy.)
  • What is the patient’s pulse like? (Abnormalities suggest a cardiological cause.)
  • Any associated symptoms (palpitations, sweats, pallor, chest pain, dyspnoea)?
  • How long does the attack last?
  • If a ‘drop attack’, is the patient always sleepy? (Narcolepsy, [link].)

Before the attack:

* Is there any warning?—eg typical epileptic aura or cardiac pre-syncope.
* In what circumstances do attacks occur? (If watching tv, presume epilepsy).
* Can the patient prevent attacks?

After the attack:

* How much does the patient remember about the attack afterwards?
* Muscle ache afterwards suggests a tonic-clonic seizure.
* Is the patient confused or sleepy? (Suggests epilepsy).

Background to attacks:

* When did they start?
* Are they getting more frequent?
* Is anyone else in the family getting them? Sudden arrhythmic death syndrome (sads)1 may leave no cardiac trace at post mortem, or there may be hereditary cardiomyopathy.