Emergency medicine: Dysrhythmia and paps Flashcards
What are the possible differentials for tachycardia?
- SVT - AF, Atrial flutter, paroxysmal SVT, WPW syndrome
- VT
- VF
What are the adverse symptoms of tachycardia that emergency action in the resuscitation council pathway? What is the action?
Shock, syncope, myocardial ichaemia or HF
- DC cardioversion (max 3 times)
- Call for expert help
- Amiodarone 300mg IV bolus –> repeat shock –> 900mg IV infusion over 24hrs
What are the symptoms of tachycardias? include red flags?
Palpitations, Dyspnoea (SoB), Anxiety, Sweating, Syncope/Collapse
Red flags - low GCS, chest pain, signs of PE or stroke, HF or Hypotension
Explain the ECG changes for: SVT, AF, VT, VF
- SVT - tachycardia > 140bpm, regular (or irregular if AF), narrow QRS complex, p waves (but may be difficult to see as merge with QRS; absent if AF)
- AF - Tachycardia, Absent p waves, Narrow QRS complex
- VT - Extreme tachycardia, Broad QRS complex, absent p waves, regular rhythm
- VF - Extreme tachycardia up to 500bpm, absent p waves, QRS complex and T waves
Explain the different management pathways for (a) unstable tachycardia (b) stable narrow QRS irregular (c) stable narrow QRS regular
(A) Unstable tachycardia
- DC cardioversion (3 attempts)
- Amiodarone IV 300mg over 10-20 mins
- Repeat shock
- Amiodarone IV 900mg over 24hrs
(B) Stable narrow QRS - irregular (probable AF)
- Rate control
a. BB (anything but soltalol) or
b. rate limiting CCB (diltiazam or verapamil)
c. add digoxin if control inadequate - Rhythm control
a. if <48hrs use IV amiodarone or flecanide
b. if >48hrs use DC cardioversion (consider 4 wks amiodarone prior)
c. if HF consider digoxin or amiodarone
c. Anti-coagulate all patients with Heparin or LMWH
(C) Stable narrow QRS - regular
- Vagal manœuvres - 25% of paroxysmal AF resolves
- 10s of carotid sinus massage, valsava techniques, hold head under icy cold water, blow into syringe aiming to push out plunger - Adenosine 6mg –> if no effect can repeat twice with 12mg (3mg max)
3a. IF rhythm returns it is probably re-entrant paroxysmal SVT - monitor with 24hr 12 lead ECG,
3b. IF rhythm DOES NOT return it may be atrial flutter (saw tooth appearance on ECG with absent p waves, tachycardia)
- Call for help
- Control rate with BB
What are the main causes of AF?
IHD or HF (most common in middle aged), MI (22%), PE, Thyrotoxicosis, Alcohol or Caffeine induced
What are the investigations and results for VT?
- ECG - extreme tachycardia >150, broad complex QRS, no p waves, but regular rhythm
- Bloods - especially U+E (see K+ and Mg+ changes, often low)
Explain the treatment for broad complex tachycardias?
- Determine if regular or irregular QRS.
- Always follow ABCDE and treat appropriate changes
- If pulseless conduct CPR
Regular QRS (likely VT) - Restore rhythm 1. Amiodarone 300mg bolus then 900mg IV infusion over 24hrs or DC cardioversion
If VF
- ABCDE
- Likely cardiac arrest (uneresposnvie, not breathing, no pulse) start ALS
- consider Vasopressin 40 units bolus
- Restore sinus rhythm using 300mg amiodarone bolus then 900mg IV infusion over 24hrs
Which tachycardia are you likely to have hypomagnesaemia? How would you treat this?
VT - treat with IV magnesium
What are the adverse features of bradycardia?
HF, myocardial ichaemia (IHD), shock, syncope
What are the management options for bradycardia?
- ABCDE approach - monitor and treat all appropriate abnormalities
- Identify adverse features: shock, syncope, HF or myocardial ischaemia - if present:
- Atropine 500mcg IV - check for adequate response, if not:
4a. repeat Atropine dose every 2-3 mins until response (max 3mg)
4b. Transcutaneous pacing
4c. Adrenaline 5-10mcg or Isoprenaline 5mcg or Glycopyrrolate or IV glucagon (if brady is due to BB or CCB), dopamine or aminophylline
What are the symptomatic and investigative features of complete heart block?
- Palpitations, chest pain, dyspnoea, pallor, cold, signs of shock (i.e. low HR, BP)
- Adverse features: shock, syncope, signs of HF or myocardial ischaemia (IHD)
- Examination - raised JVP with cannon waves (JVP)
- ECG - complete dissociation of p wave from QRS complex, bradycardia of 40-50bpm usually, narrow QRS (proximal lesion), broad QRS (distal lesion)
Which type of complete heart block is most likely to respond to atropine?
Narrow QRS complete heart block - proximal lesion
When would you use Vasopressin and at what dose?
Refractory VF
40 units bolus IV
What are the features of wolf-parkinson white syndrome? and what type of tachycardia is it?
WPW is a SVT classed as re-entrant tachycardia characterised by a closed loop conduction system between atria and ventricles (pathway of kent)
ECG changes - delta waves, tachycardia, narrow complex QRS
