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 |
- 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.
| QRS Complex | P Wave | PR Interval | Rate (bpm) |
|---|---|---|---|
| >0.12s (> 3 small boxes) | Absent | Not Measurable | 20 – 40bpm |
- 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.
| QRS Complex | P Wave | PR Interval | Rate (bpm) |
|---|---|---|---|
| >0.12s (> 3 small boxes) | Absent | Not Measurable | 40 – 100 bpm |
- 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.
| QRS Complex | P Wave | PR Interval | Rate (bpm) |
|---|---|---|---|
| >0.14s (> 3.5 small boxes) | Absent | Not Measurable | 140 – 250 bpm |
- 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.
| QRS Complex | P Wave | PR Interval | Rate (bpm) |
|---|---|---|---|
| >0.14s (> 3.5 small boxes) | Absent | Not Measurable | 140 – 250 bpm |
- 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.
| QRS Complex | P Wave | PR Interval | Rate (bpm) |
|---|---|---|---|
| None | Absent (Coarse or fine wave) | Not Measurable | None |
- 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.
| QRS Complex | P Wave | PR Interval | Rate (bpm) |
|---|---|---|---|
| None | May be present but not sustainable | Not Measurable | None |
- 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
Page contributors:
 | Thanh Bui, AP60825 Event Medic, Emergency Medical Technician & Volunteer Development Officer
|
 | Andrew Moffat, AP16790 |
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