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What causes PVCs?
- Some part of the ventricle fires because tissues become irritable
- Electrolyte imbalances, hypoxia, not gettings blood, etc.
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Ventricular Dysrythmia causes of decreased CO
Sustained VT, VF, and 6-10 PVCs in one minute
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R on T phenomenon
- PVCs are firing close to T waves; can send someone into VF
- Can be precursor to VT and VF (decreased CO)
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PVC Characteristics
- QRS greater or equal to 0.12sec
- Contraction is premature
- The QRS complex and T waves deflect in opposite directions
- Need K+ levels to be 4.0 or greater
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Multifocal PVCs
multiple positive and negative deflected QRS complexes; different directions
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Unifocal PVCs
PVCs are both in same direction
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PVCs: Bygiminal, Trigiminal, Couplet, and VT
- Bygiminal: PVCs every other beat
- Trygiminal: PVCs every third beat
- Couplet: 2 PVCs together
- VT: 3 or more PVCs together
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Ventricular Tachycardia (VT)
- Wide QRS (greater than 0.12)
- Rate greater than 100bpm
- P wave may be absent (buried in QRS complex)
- Pulse may be absent
- Magnesium can contribute to this
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Ventricular Fibrillation (VF)
- Can not see usual complexes
- No pulse, cannot determine rate, chaotic waveform
- No consciousness, no CO
- Smaller peaks: fine VF
- Bigger peaks: coarse VF
- Most common cause of sudden death
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Asystole
- Straight line
- No electrical impulses
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PVC Treatment
- No treatment is asymptomatic
- Reduce caffeine, ETOH, and stress
- Amiodarone (suppresses PVCs)
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VT Treatment
- Amiodarone
- Magnesium
- Cardioversion
- If no pulse, same treatment as VF
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VF Treatment
- CPR
- Defibrillation
- Epinephrine
- Vasopression
- Amiodarone
- Lidocaine
- Once has pulse and converted, start continuous infusion of last drug used to convert to rythm
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Amiodarone hydrochloride
- Antiarrhythmic agent, depresses conduction, raises threshold for VF
- PO or IV (central line preferred)
- IV loading dose: 150mg over first 10minutes (dilute 150mg in 100ml D5W), then 360mg over next 6hrs, followed by 540mg over next 18hrs
- Adverse effects: H/A, dizziness, hypotension, bradycardia, blue-gray skin color
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