Arrhythmia Flashcards
What are the 4 arrhythmias that can cause cardiac arrest?
- Ventricular fibrillation (VF)
- Ventricular tachycardia (VT)
- Pulseless electrical activity (PEA)
- Asystole
What are the 6 causes and management of cardiac arrhythmias? (6H, 5T)
6Hs:
- Hypovolemia / hypotension -> fluid resus
- Hypothermia
- H+ acidosis -> sodium bicarb
- Hypoxia -> oxygen
- Hyperkalemia -> remove potassium / dialysis
- Hypokalemia -> replace potassium
5Ts:
- Tamponade (cardiac) -> pericardiocentesis
- Tension pneumothorax -> needle compression
- Tablets / drug overdose -> antidote
- Thrombosis (pulmonary) -> thrombolytics / surgery
- Thrombosis (ACS/AMI) -> revascularization / PCI
What are the characteristics of VF?
- Irregularly irregular (disorganized electrical activity)
- Appears rapid (but heart does not pump)
- No P wave
- No PR interval
- QRS complex varies
What are the characteristics of VT?
- Regular R-R intervals (regularly irregular)
- Atrial rate cannot be determined
- Ventricular rate 150-250 bpm
- PR interval not measured
- QRS complex >0.12sec (wide and bizarre)
- Hard to see distinction between the QRS complex and T wave
- QRS complex not preceded by the P waves
What is PEA?
One of many waveforms by ECG (including sinus rhythm) without a detectable pulse
- Except VF, VT, or asystole
What are the characteristics of asystole?
- Nearly flat line
- No P wave
- PR intervals unable to be detected
- No QRS complex
Note: Increase gain/ECG size or check another lead to ensure it is not VF
How to manage VF and VT?
1) Analyse rhythm (should be VT/VF)
2) Deliver shock (120J-150J-200J)
3) 5 cycles of CPR -> Analyse rhythm
4) Give IV adrenaline 1mg after 5 mins
If refractory/recurrent VF/VT after 1st shock and 1st adrenaline:
- Give IV Adrenaline 1mg + Amiodarone 300 mg every 5 mins
- Repeat IV Adrenaline 1mg + Amiodarone 150 mg
- IV Lignocaine 1mg only if necessary
How to manage PEA and asystole?
Note: Do not give atropine or sodium bicarbonate anymore
1) Analyse rhythm (should be PEA or asystole)
2) Do not shock, continue CPR
3) Give IV adrenaline 1mg every 5 mins
4) Re-analyse rhythm
5) Continue only IV adrenaline 1 mg
When is sodium bicarbonate given?
- 50mmol only if cardiac arrest is associated with hyperkalemia or tricyclic antidepressant overdose
- Conduct regular ABG after
- Do not give after prolonged cardiac arrest
What are bradyarrhythmias?
Heart rate is irregular and less than 60 bpm
What are some examples of bradyarrhythmias?
- Sick Sinus syndrome
- 1st degree AV block
- 2nd degree AV block / Classic Wenckebach
- Left bundle branch block
- Right bundle branch block
What are the characteristics of Sick sinus rhythm?
- Due to defective AV nodes
- Irregular R-R pattern
- P wave is small and sometimes absent
What are the characteristics of 1st and 2nd degree heart block?
1st degree:
- Due to delay in AV node
- PR interval is >0.2 sec
2nd degree:
- Irregular P waves
What are the characteristics of a left and right bundle branch block?
Left:
- QRS widening is mostly seen in V4, V5 and V6
Right:
- QRS widening is mostly seen in V1 and V2
How to manage bradyarrhythmias?
Less on ECG but more on symptoms
If unstable (<90/60 mmHg and symptomatic): Drugs and Pacing
- IV Atropine 0.6mg every 5 mins (max x4)
- IV Dopamine infusion 5-20 mcg/kg/min (to increase CO)
- IV Adrenaline infusion 2-10 mcg/min
If unstable and drug therapy ^ fails:
- Begin transcutaneous pacing with analgesia and sedation
- Transvenous pacing if available
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If stable (>90/60 mmHg and asymptomatic):
- No further treatment OR
- Rhythm + hemodynamic monitoring (if Type 2 2/3deg heart block)
- Standby transcutaneous pacing in case of deterioration
