Arrhythmias

Question 1

What are the diff types of arrhythmias?

Answer 1

1. Vfib
2. VT/PVT
3. PEA
4. Asystole
5. Bradyarrhythmias
6. Tachyarrhythmias

Question 2

What are the characteristics of VFib? (regularity, rate, p wave, pr interval, qrs complex)

Answer 2

Regularity: No regularity shape of QRS complex as all electrical activity is disorganised (*cannot conduct properly)

Rate: Appears rapid but disorganised electrical activity prevents heart from pumping (*cannot calculate cos no patterns)

P wave: Absent

PR interval: Absent

QRS complex: Ventricle complex varies/broad

Question 3

What are the characteristics of VT? (regularity, rate, p wave, pr interval, qrs complex)

Answer 3

Regularity: R-R interval are usually but not always regular

Rate:
- Atrial rate not determined, v occasional p wave
- Ventricular rate: 150-250bpm

P wave:
- QRS complexes not preceded by P waves
- occasional p wave in strip but not associated with ventricular rhythm

PR interval: Not measured (ventricular rhythm)

QRS complex:
- >0.12s
- wide and bizarre
- difficult to see a separation between QRS complex and T wave (*difficult to diagnose if it’s a QRS complex/QRS complex with T wave)

Question 4

What are the management for VFib/VT?

Answer 4

1. Airway
2. Ventilation
3. Compression
4. Defib
5. Drugs
   
   • IV Adrenaline 1mg q3-5min
     If refractory/recurrent
   • IV Adrenaline 1mg q3-5min
   • IV Amidarone 300mg, repeat at 150mg (maintenance dose) if necessary
   • IV Lignocaine 1-1.5mg/kg, repeat if necessary (*second line with magnesium)

Question 5

What should be done for post cardiac arrest care?

Answer 5

1. Targeted tempt mgt (33-36; lower tempt to allow VS to stabilise)
2. Avoid hyperoxia - SpO2 94-99% (prevent reperfusion injury)
3. IV Amidarone infusion 1mg/min x6hrs then 0.5mg/min x18hrs
4. IV therapy to maintain adequate perfusion
   
   • optimise BP, HR, urinary output/renal perfusion
5. Administer antiarrhythmias as continuous infusion pump of req
   
   • stabilise cardiac function
   • inotropes like dopamine improve cardiac o/p and renal perfusion
6. Closely monitor VS - maintain BP >90/60mmHg before trf to ICU
7. 12-lead ECG after ROSC to exclude coronary involvement

Question 6

What waveform will be found in PEA?

Answer 6

Any waveform except VFib, VT/asystole (will not have any detectable pulse)

Question 7

What are the 5H & 5Ts of PEA causes and their management?

Answer 7

5H
1. Hypovolemia - Fluid resus
2. Hypoxia - Ventilation
3. Hydrogen ion acidosis - NaHCO3 1mEq/kg
4. Hyperk - remove k/dialysis
5. Hypok - replace K
6. Hypothermia - Warm pt

5T
1. Tablet (OD/accident) - Antidote
2. Tamponade (cardiac) - pericardiocentesis
3. Tension (pulm) - Needle decompression
4. Thrombosis (coronary/ACS) - resus, revascularisarion, PCI
5. Thrombosis (pulm) - thrombolysis, surgery

Other causes:
1. E imbalance
2. Sepsis
3. Large MI
4. Hypogly (*need TRO cos it’s associated with PEA)
5. Trauma

Question 8

What are the characteristics of asystole?
(regularity, rate, p wave, pr interval, qrs complex)

Answer 8

Regularity: Nearly flat line

Rate: No rate

P wave: Absent

PR interval: Unable to be measured; absent

QRS complex: Absent

*NOTE: fine VF may be mistaken for asystole (to check with another lead - esp chest lead where QRS complex is prominent) OR ( increase ECG size) OR (stop ventilation for a few seconds)

*whenever in doubt, continue chest compressions and reassess after 2min of cpr/5 cycles

Question 9

What is the management for PEA and asystole?

Answer 9

1. Airway mgt
2. Ventilation
3. Cardiac compression
4. IV access
5. IV adrenaline 1mg q3-5mins
   
   • for PEA:
     > other drugs are based off etiology of cardiac arrest (e.g. K, Ca, antidote)
     > antidote is no longer recommended (no therapeutic benefit)
     > NaHCO3 is not recommended for prolonged cardiac arrest (only for hyperk/tricyclic antidepressant OD - if continuous infusion is used, need regular ABG monitoring)
   • for asystole:
     > after 15-20mins of resus = dism chances of recovery
     > exceptions include near drowning, poisoning, hypothermia (less commonly)

Question 10

How do bradyarrhythmias come about?

Answer 10

By various kinds of heart blocks like:

1. Sick sinus syndrome (defective sinus node)
   
   • irregular RR pattern
   • may not be able to see p wave/absent p wave
2. 1st degree heart block
   
   • delay at AV node
   • sometimes PR interval >0.2sec
3. 2nd degree heart block
   
   • increased delay at AV node until p wave is not conducted
4. Bundle branch block
   
   • widened QRS for R & L bundle branch block
     a) Left bundle branch block (widened QRS complex wave in V4-6)
     b) Right bundle branch block (more widened QRS in V1-2) [rabbit ear/RR pattern]

Question 11

What is the general management of bradyarrythmia?

Answer 11

Based on pt symptoms and less on accurate ECG diagnosis
- when there is a heart block = symptom of complete blackout
> dont see bradyarrhythmia when pt is conscious
> need to do 24hr ECG monitoring to detect bradyarrhythmias at certain phases of a day (*v severe = continuous process of monitoring)

Question 12

How to manage bradyarrhythmias in conscious pt?

Answer 12

1. Assess responsiveness
2. Assess ABCs/VS
3. Obtain hx
4. PE
5. Administer O2
6. IV access
7. Defib/Monitor
8. 12 lead ECG
   
   • if bradycardia with pulse (HR <60) + <90/60mmHg & symptomatic = UNSTABLE
     > To give DRUGS/PACING
     ~ first line
     1. IV Atropine 0.6mg q3-5min (*max 4 doses - may cause paradoxical bradycardia post heart transplant)
     2. IV Dopamine infusion 5-20mcg/kg/min (increase CO)
     3. IV adrenaline infusion 2-10mcg/kg/min
     ~ if drug therapy fails
     1. Begin transcutaneous pacing with analgesia & sedation
     2. Transvenous pacing (if available)

• if bradycardia with pulse (HR <60) + >90/60 mmHg & no symptomatic = STABLE
  > to MONITOR (no further tx needed for bradycardia)
  ~ if it’s T2 2nd degree heart block/3rd degree heart block
  1. Rhythm & harmodynamic monitoring
  2. Standby for transcutaneous pacing in event of deterioration
  (*depend on age & comorbidities - case by case basis + possibility for vitals to crash/deteriorate & black out)

Question 13

What are the diff types of tachyarrhythmias?

Answer 13

1. Supraventricular tachycardia (SVT)
   
   • tachyarrhythmias generating above the AV node
2. Atrial flutter
3. AFib
   
   • can lead to a lot of embolic stroke (*impt to manage AFib to prevent formation of clot & turn into embolus)

*atrial activity/rate is >240-320bpm = need to be managed well