ventricular and arrest rhythms Flashcards
dysrhythmias originating in the ventricles
- ventricular escape complexes and rhythms
- accelerated idioventricular rhythm
- premature ventricular contractions
- ventricular tachycardia
- torsades de pointes
- ventricular fibrillation
- asystole
- artificial pacemaker rhythm
ventricular escape complexes and idioventricular rhythms
- rate- 15-40
- rhythm- escape complex=irregular; escape rhythm= regular
- pacemaker site- ventricle
- p waves- none
- PRI- none
- QRS- >.12 seconds -> bizarre
ventricular escape complex and rhythms (idioventricular rhythm): etiology, clinical significance, treatment
- etiology- safety mechanism to prevent cardiac standstill
- results from failure of other foci or high degree AV block
- clinical significance- decrease CO, possibly to life threatening levels
- treatment- for perfusing rhythms, administer atropine and/or TCP (preferred)
accelerated idioventricular rhythm: etiology, clinical significance, treatment
- etiology- a subtype of ventricular escape rhythm that frequently occurs with MI
- ventricular escape rhythm with a rate of 60-100
- clinical significance- may cause decreased cardiac output if the rate slows
- treatment- does not usually require treatment unless the patient becomes hemodynamically unstable
- primary goal is to treat the underling MI
premature ventricular contractions
- rate is underlying rhythm
- rhythm interrupts regular underlying rhythm
- pacemaker site is the ventricle
- P waves- none
- PRI- none
- QRS: > .12 s -> bizarre
ventricular is the third choice
- sinus- 60-100
- atrial- 40-60
- ventricles- less then 40
premature ventricular contractions: Etiology
- single ectopic impulse resulting from an irritable focus in either ventricle
- causes may include myocardial ischemia, increased sympathetic tone, hypoxia, idiopathic causes, acid-base disturbances, electrolyte imbalances, or as normal variation of the ECG
- may occur in patterns:
- bigeminy* (every other is a PVC), trigeminy (two normal beats than a PVC -> every three), or quadrigeminy (three normal beats than a PVC -> every 4)
- couplet (two in a row) and triplets (3 PVCs in a row -> really just called ventricular tachycardia)
premature ventricular contractions: clinical significance
- malignant PVCs
- significant when there are a lot of them
- more than 6/minute
- R on T phenomenon- r wave of the next complex lands on the T wave before it -> can throw you into ventricular fibrillation
- couplets or runs of ventricular tachycardia,
- multifocal PVCs- PVCs that look different from each other
- PVCs associated with chest pain
- ventricles do not adequately fill, causing decrease cardiac output (CO)
ventricular tachycardia
- rate- 101-250+
- rhythm- usually regular
- pacemaker site- ventricle
- p waves- if present, not associated with QRS
- PRI- none
- QRS- >.12 s -> bizarre
ventricular tachycardia: etiology and clinical significance
ETIOLOGY
-3 or more ventricular complexes in succession at a rate of > 100
-causes include myocardial ischemia, increased sympathetic tone, hypoxia, idiopathic causes, acid-base disturbances, or electrolyte imbalances
-VT may appear monomorphic (all look alike) or polymorphic (look different)
CLINICAL SIGNIFICANCE
-decreased cardiac output, possibly life threatening levels
-may deteriorate into ventricular fibrillation
torsades de pointes
-Polymorphic VT.
-Caused by the use of certain antidysrhythmic
drugs.
-Exacerbated by coadministration of antihistamines; azole antifungal agents and macrolide antibiotics; erythromycin, azithromycin, and clarithromycin
-caused by hypomagnesemia - not enough magnesium
-typical occurs in non-sustained bursts
-prolonged QT interval during “breaks”
-QRS rates from 166-300
-RR interval highly variable
ventricular fibrillation
- rate- no organized rhythm
- rhythm- no organized rhythm
- pacemaker site- numerous ventricular foci
- p waves- usually absent
- PRI- none
- QRS- none
- bunch of different cells are all trying to initiate rhythm
- lethal -> no CO
ventricular fibrillation: etiology and clinical significance
- Etiology- Wide variety of causes, often resulting from advanced coronary artery disease.
- Clinical Significance- Lethal dysrhythmia with no cardiac output and no organized electrical pattern
asystole
- rate- no electrical activity
- rhythm- no electrical activity
- pacemaker- no electrical activity
- p waves- none
- PRI- none
- QRS- none
ventricular fib vs asystole
-much more likely to be revived from ventricular fib than asystole
