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

• AMI
• Anxiety
• CCF
• Drug toxicity
• Excessive caffeine or alcohol consumption
• Heart disease
• Mechanical stimulation
• Reperfusion
  

• Chest pains
• Fatigue
• Syncope
• Hyperventilation
• Skipped beat

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.

• AMI or ischemia
• Pacemaker failure (AV or SA node)
• Reperfusion

• Chest pains
• Shortness of breath
• AMI symptoms
• Peripheral oedema
• Cyanosis

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.

• AMI or ischemia
• Pacemaker failure (AV or SA node)
• Reperfusion

• Chest pains
• Shortness of breath
• AMI symptoms
• Peripheral oedema
• Cyanosis
• Palpations

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.

• AMI or ischemia
• Cardiomyopathy
• CCF
• Drug toxicity
• Electrolyte disturbance
• Heart disease
• Medications that prolong QT interval
• Reperfusion

• Light-headedness
• Palpations
• Fatigue
• Chest Pains
• Syncope
• Shortness of Breath

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

• AMI or ischemia
• Cardiomyopathy
• CCF
• Drug toxicity
• Electrolyte disturbance
• Heart disease
• Medications that prolong QT interval
• Reperfusion

• Light-headedness
• Palpations
• Fatigue
• Chest Pains
• Syncope
• Shortness of Breath

Coarse VF:

Fine VF:

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.

• AMI
• Electrolyte disturbances
• Preceded by other arrythmias
• Cardiac Arrest causes (4 H’s & 4 T’s)

• No signs of life
• Absent or abnormal breathing
• Loss of consciousness

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

• AMI
• Electrolyte disturbances
• Preceded by other arrythmias
• Cardiac Arrest causes (4 H’s & 4 T’s)

• 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