3.1 Ventricular Dysrhythmias and Asystole Flashcards
Premature Ventricular Contractions
- Contractions that do not originate from the SA node
- Arises from irritable, ectopic focus (foci) in ventricles
- Wide and distorted QRS that often goes the opposite way from normal beats
DIFFERENCE BETWEEN NORMAL HEARTBEAT
- Normal heartbeats start in SA node and move throughout the heart
- PVC’s ventricles contract first which reverses the impulse
Types of PVC
Unifocal - Originate from 1 single spot (all look alike)
Multifocal - Arise from multiple spots (look different from one another and is a worse issue)
Bigeminy - Every other beat is a PVC
Trigeminy - Every third beat is a PVC
Couplets - 2 PVC’s occur together
Triplets - 3 PVC’s occur together
Ventricular Tachycardia - 4+ PVC’s occurring together
R on T Phenomenon - R wave of PVC occurs on the T wave prior. This puts patients at risk because it is during the refractory period where heart is at risk of depolarizing early. This can cause V-Tach
PVC Causes
- Stimulants (caffeine, alcohol, nicotine)
- Electrolyte imbalances
- Hypoxia
- Fever
- MI, HF, CAD
- Mitral Valve Prolapse
- THROMBOLYTIC/REPURFUSION THERAPY (may cause reperfusion dysrhythmias) - REQUIRES MONITORING
Medications
- Aminophylline (used for COPD)
- Epinephrine
- Isoproterenol
- Digoxin
Significance of PVC
- Normally they are not an issue if they are rare and the patient does not have heart disease
(May just feel a skipped beat) - In patients with HF, it can decrease cardiac output and cause angina or worsening of HF
- MONITOR PATIENTS RESPONSE TO PVC
- Causes apical-radial deficit
(apical pulse heart rate is higher than radial pulse heartrate) - This is because ventricular contractions aren’t strong enough to reach peripheral pulses.
PVC Treatment
- Treat underlying cause
- Give oxygen if patient is hypoxic
- Treat electrolyte imbalances
Medications
- Beta-blockers
- Procainamide
- Amiodarone
- Lidocaine
Ventricular Tachycardia
- Ventricular rhythm greater than 40
- Usually a regular rate and greater than 180
ECG
- Wide QRS and no P wave (atria still contracts but it is hidden in the QRS)
- LIFE THREATENING (CARDIAC OUTPUT SIGNIFICANTLY DECREASED)
Associations
- MI
- CAD
- Electrolyte imbalances
- Digoxin toxicity
- CNS disorders
Types of V-Tach
Non-Sustained - Short Bursts
Sustained - Shows nothing but V-tach configurations
Pulse/No Pulse - NO PULSE MEANS NO CO. CPR REQUIRED
Stable/Unstable - Hemodynamic Stability (BP, Pulse, LOC)
Monomorphic - All beats look the same
Polymorphic - Intervals are regular but looks very irregular
Torsade De Pointes (Twisting of Points) - Crescendo/De-crescendo pattern but still regular
Significance of V-Tach
- Patient may be stable but potential for deterioration is significant
- NURSE MUST GET HELP AND GET CRASH CART READY
Treatment V-Tach
- Treat underlying causes
Monomorphic with Pulse
- Stable - provide amiodarone
- Unstable - shock for cardioversion
Monomorphic without pulse
- Shock
- CPR
- Epinephrine
Polymorphic (Torsades de Pointe)
- Give magnesium
V-Fib
- Ventricles are just quivering instead of contracting
- No cardiac output
- ECG is completely irregular
Associations
- MI, CAD
- Can occur during cardiac catherization, cardiac pacing, fibrinolytic therapy, after reperfusion
- Can occur after accidental electric shocks
Treatment
- SUPPORT CARDIAC OUTPUT (CPR)
- Rapid initiation of defibrillator
Asystole
- Absence of any atrial/ventricular electrical activity (ZERO CARDIAC OUTPUT)
TREATMENT
- FIRST SHAKE PATIENT AND ASK IF THEY ARE OKAY
- After determining patient is pulseless, apneic and no heart rhythm START CPR
- Epinephrine
- THIS IS NOT A SHOCKABLE RHYTHM
Associations
- End-stage HF
- Advance Cardiac Disease
- Complete Heart Block
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