Exam 2
What is Ventricular fibrillation (VF)? - And a chaotic rhythm characterized by a quivering of
the ventricles, which results in total loss of cardiac output and pulse. VF is a life-threatening
emergency, and the more immediate the treatment, the better the survival will be. VF
produces a wavy baseline without a PQRST complex (Figure 7-45, p. 126).
Because a loose lead or electrical interference can produce a waveform similar to VF, it is
always important to immediately assess the patient for pulse and consciousness.
What is Ventricular tachycardia (VT)? - And a rapid, life-threatening dysrhythmia
originating from a single ectopic focus in the ventricles. It is characterized by at least three
PVCs in a row. VT occurs at a rate greater than 100 beats per minute, but the rate is usually
around 150 beats per minute and may be up to 250 beats per minute. Depolarization of the
ventricles is abnormal and produces a widened QRS complex (Figure 7-43, p.126). The patient
may or may not have a pulse.
The wave of depolarization associated with ventricular tachycardia rarely reaches the atria.
Therefore P waves are usually absent. If P waves are present, they have no association with
the QRS complex. The sinus node may continue to depolarize at its normal rate, independent
of the ventricular ectopic focus. P waves may appear to be randomly scattered throughout
the rhythm, but the P waves are actually fired at a consistent rate from the sinus node. This
is called AV dissociation, another clue that the rhythm is VT. Occasionally a P wave will
"capture" the ventricle because of the timing of atrial depolarization, interrupting the VT with
a single capture beat that appears normal and narrow. Then the VT reoccurs. Capture beats
are a diagnostic clue to differentiating wide complex tachycardias.
,VTach rhythm analysis - Ans • Rate: The heart rate is 110 to 250 beats per minute.
• Regularity: The rhythm is regular unless capture beats occur and momentarily interrupt the
VT.
• Interval measurements: There is no PR interval. The QRS complex is greater than 0.12
seconds and often wider than 0.16 seconds
• Shape and sequence: QRS waves are consistent in shape but appear wide and bizarre. The
polarity of the T wave is opposite to that seen in the QRS complex.
• Patient response: If enough cardiac output is generated by the VT, a pulse and blood
pressure are present. If cardiac output is impaired, the patient has signs and symptoms of
low cardiac output; the patient may experience a cardiac arrest.
VFib rhythm analysis - Ans • Rate: Heart rate is not discernible.
• Regularity: Heart rhythm is not discernible.
• Interval measurements: There are no waveforms.
• Shape and sequence: The baseline is wavy and chaotic, with no PQRST complexes.
• Patient response: The patient is in cardiac arrest.
VTach causes - Ans Hypoxemia, acid-base imbalance, exacerbation of heart failure, ischemic
heart disease, cardiomyopathy, hypokalemia, hypomagnesemia, valvular heart disease,
genetic abnormalities, and QT prolongation are all possible causes of VT.
VTach treatment - Ans Determine whether the patient has a pulse.
1. If no pulse is present, provide emergent basic and advanced life support interventions,
including defibrillation.
*2. If a pulse is present and the blood pressure is stable, the patient can be treated with
intravenous amiodarone or lidocaine.
*3. Cardioversion is used as an emergency measure in patients who become
hemodynamically unstable but continue to have a pulse.
,VFib causes - Ans VF can be caused by ischemic and valvular heart disease, electrolyte and
acid-base imbalances, and QT prolongation.
VFib treatment - Ans Immediate BLS and ACLS interventions are required.
* check pulse, CPR, shock(200J), shock(300J), epi(1mg q3-5minuutes), shock, amniodarone
(300mg), shock, amniodarone (150mg), shock, lidocaine
SVT treatment - Ans cardiovert, and give adenosine or vagal maneuver if stable
elective cardioversion (stable) - Ans asymptomatic SVT, VTach:
systolic >90, awake, no complaints
emergent cardioversion (unstable) - Ans symptomatic SVT, VTach:
altered LOC, systolic BP <90
defibrillation - Ans VTach (pulseless), VFib
VTach & VFib (pulseless) - Ans defib (200J)
defib (300J)
defib (360J)
epi (1mg q3-5 minutes)
amniodarone (300mg) then (150mg)
lidocaine
Torsades de pointes ("twisting about the point") - Ans is a type of VT that is caused by a
prolonged QT interval. Unlike VT, where the QRS complex waveforms have similar shapes,
torsades de pointes are characterized by the presence of both positive and negative
complexes that move above and below the isoelectric line.
, Torsades de pointes treatment - Ans This lethal dysrhythmia is treated as pulseless VTach
(defib and CPR). magnesium levels are monitored and corrected with MgSO4 (Mg sulfate)
Torsades de pointes causes - Ans Magnesium deficiency is often a cause of this
dysrhythmia.
Premature ventricular contractions (PVC) - Ans Premature ventricular contractions (PVCs)
are a common ventricular dysrhythmia. PVCs are early beats that interrupt the underlying
rhythm; they can arise from a single ectopic focus or from multiple foci within the ventricles.
Premature ventricular contractions (PVC) causes - Ans Causes: Hypoxemia, ischemic heart
disease, hypokalemia, hypomagnesemia, acid-base imbalances
Premature ventricular contractions (PVC) treatment - Ans may occur in healthy individuals
and usually do not require treatment. The nurse must determine if PVCs are increasing in
number by evaluating the trend. If PVCs are increasing, the nurse should evaluate for
potential causes such as electrolyte imbalances, myocardial ischemia or injury, and
hypoxemia.
*Runs of nonsustained ventricular tachycardia (3 in a row)=ventricular tachycardia.
types of precautions - Ans standard, contact, droplet, airborne
standard precautions - Ans hand hygiene, wear glove when dealing with body fluids, sharps
in sharp-container, biohazard bags for body fluid discard, no artificial nails due to risk for
infection
contact precautions - Ans private room, gloves and gown