UNCONTROLLED WHEN PRINTED
Premature Ventricular Contraction (PVC)

1

Ventricle ectopic focus premature discharge – Impulses travel using abnormal pathways resulting in an abnormal QRS complex. Bypassing the pathway causes a slow and ineffective travel as it travels cell-by-cell. The PVC can be single beat, every second (bigeminy), every third (trigemini) or run in pairs (couplets). Can occur in healthy people

QRS Complex P Wave PR Interval Rate (bpm)
>0.12s (> 3 small boxes) Absent Not Measurable Varying
Causes
  • AMI
  • Anxiety
  • CCF
  • Drug toxicity
  • Excessive caffeine or alcohol consumption
  • Heart disease
  • Mechanical stimulation
  • Reperfusion
Signs & Symptoms
  • Chest pains
  • Fatigue
  • Syncope
  • Hyperventilation
  • Skipped beat
Idioventricular Rhythm / Ventricular Escape Rhythm (IVR)

2

When the pacemaker site in the ventricles takes over as pacemaker when the AV node fails to fire at 40-60bpm. The ventricular cells fire at 20-40bpm acting as a backup generator when the AV node fails to fire. The impulses are wise and absent P-wave as there is no atria involvement.

QRS Complex P Wave PR Interval Rate (bpm)
>0.12s (> 3 small boxes) Absent Not Measurable 20 – 40bpm
Causes
  • AMI or ischemia
  • Pacemaker failure (AV or SA node)
  • Reperfusion
Signs & Symptoms
  • Chest pains
  • Shortness of breath
  • AMI symptoms
  • Peripheral oedema
  • Cyanosis
Accelerated Idioventricular Rhythm (AIVR)

3

When inherent pacemaker site beats faster than normal rate due to enhance automaticity of ventricular tissue. Excited version of IVR but does not tolerated for long periods of time.

QRS Complex P Wave PR Interval Rate (bpm)
>0.12s (> 3 small boxes) Absent Not Measurable 40 – 100 bpm
Causes
  • AMI or ischemia
  • Pacemaker failure (AV or SA node)
  • Reperfusion
Signs & Symptoms
  • Chest pains
  • Shortness of breath
  • AMI symptoms
  • Peripheral oedema
  • Cyanosis
  • Palpations
Ventricular Tachycardia (VT)

4

When dominant ectopic site in ventricles take control of heart pacing. VT may self-terminate or sustained. Causes difficulty to fill the heart between contractions to maintain cardiac output.

Self-terminating VTs may show minimum three (3) consecutive PVC’s.

QRS Complex P Wave PR Interval Rate (bpm)
>0.14s (> 3.5 small boxes) Absent Not Measurable 140 – 250 bpm
Causes
  • AMI or ischemia
  • Cardiomyopathy
  • CCF
  • Drug toxicity
  • Electrolyte disturbance
  • Heart disease
  • Medications that prolong QT interval
  • Reperfusion
Signs & Symptoms
  • Light-headedness
  • Palpations
  • Fatigue
  • Chest Pains
  • Syncope
  • Shortness of Breath
Torsades De Pointes

5

Polymorphic VT where QRS complex changes from negative to positive amplitude – Associated with prolonged QT interval causing wide QRS.

QRS Complex P Wave PR Interval Rate (bpm)
>0.14s (> 3.5 small boxes) Absent Not Measurable 140 – 250 bpm
Causes
  • AMI or ischemia
  • Cardiomyopathy
  • CCF
  • Drug toxicity
  • Electrolyte disturbance
  • Heart disease
  • Medications that prolong QT interval
  • Reperfusion
Signs & Symptoms
  • Light-headedness
  • Palpations
  • Fatigue
  • Chest Pains
  • Syncope
  • Shortness of Breath
Ventricular Fibrillation

Coarse VF:

6

Fine VF:

7

Lethal arrythmia resulting in chaotic electrical discharges from multiple foci in the ventricles. There is no cardiac output as it cannot beat in an organised fashion.

QRS Complex P Wave PR Interval Rate (bpm)
None Absent (Coarse or fine wave) Not Measurable None
Causes
  • AMI
  • Electrolyte disturbances
  • Preceded by other arrythmias
  • Cardiac Arrest causes (4 H’s & 4 T’s)
Signs & Symptoms
  • No signs of life
  • Absent or abnormal breathing
  • Loss of consciousness
Ventricular Standstill

8

Series of P-wave which slows ventricular standstill (no ventricular activity); this usually generates into asystole. Treat as if asystole.

QRS Complex P Wave PR Interval Rate (bpm)
None May be present but not sustainable Not Measurable None
Causes
  • AMI
  • Electrolyte disturbances
  • Preceded by other arrythmias
  • Cardiac Arrest causes (4 H’s & 4 T’s)
Signs & Symptoms
  • No signs of life
  • Absent or abnormal breathing
  • Loss of consciousness

References

College of Pre-Hospital Care. (2015). 12-Lead ECG Analysis: Self-Directed Learning Package. Version 3. St John Ambulance Ltd.  

Curtis, K., & Ramsden, C. (2016). Emergency and trauma care for Nurses and Paramedics (2nd ed.). Elsevier Australia.

DeLaune, S. C., Ladner, P. K., McTier, L., Tollefson, J., & Lawrence, J. (2016). Australian and New Zealand fundamentals of nursing (1st ed.). Cengage Learning Australia Pty Limited.

ECG & ECHO Learning. (2020). Clinical ECG Interpretation. https://ecgwaves.com/topic/ecg-normal-p-wave-qrs-complex-st-segment-t-wave-j-point/

Life in the Fast Lane. (2020). ECG Library. https://litfl.com/ecg-library/

St John WA Ltd. (2017). Electrocardiography (ECG). Clinical Resources. https://clinical.stjohnwa.com.au/clinical-skills/assessment/vital-signs/electrocardiography-(ecg)

WikiEM. 2020. The Global Emergency Medicine Wiki. https://www.wikem.org


Page contributors:

60825Thanh Bui, AP60825
Event Medic, Emergency Medical Technician &
Volunteer Development Officer

 

16790

Andrew Moffat, AP16790
Volunteer Training Manager & Volunteer Development Officer

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