DYSRHYTHMIA FINAL EXAM
QUESTIONS WITH COMPLETE
ANSWERS
First Degree Atrioventricular Heart Block - Answer-prolonged PR interval-measures the
time required for an impulse to travel from the SA to the AV node. PRI longer than 0.20
Second degree AV block Type I - Answer-progressive prolongation of PRI, gradual
shortening of R to R intervals
P wave not followed by a QRS wave
a pause with an R to R interval less than the sum of two P to P intervals
first conducted atrial impulse after the pause shows a shorter or normal PRI
Second Degree AV Block Type 2 - Answer-Rhythm: ventricular irregular; atrial regular
Rate: atrial rate > ventricular rate
P waves: P waves may not be followed by QRS
PRI: WNL or prolonged ; PRI before and after a blocked P waves are constant.
QRS duration: WNL; greater than 0.11 sec block occurs below the bundle.
characteristics of first degree AV block - Answer-rhythm: regular
Rate: usually WNL
P waves: one positive before each QRS complex
PRI: prolonged
QRS: normal
causes of first degree AV block - Answer-- normal in hx of cardiac disease especially
athletes
- Acute MI
- acute mydocarditis or endocarditis
- cardiomyopathy
- degenerative fibrosis and sclarosis
- drugs
- hyperkalemia
- increased vagal tone
- ischemia or injury to the AV node or AV bundle
- rheumatic heart disease
- valvular heart disease
what causes second degree AV block type I - Answer-RCA, athletes, aortic valve
disease, atrial septal defects, meds, mitral valve prolapse, rheumatic heart disease.
,what do i do about second degree AV block type I - Answer-atropine for bradycardia.
second degree AV block type II causes - Answer-MI is related to conduction effects,
acute myocarditis, aortic valve disease, cardiomyopathy, fibrosis of the conduction
system, rheumatic heart disease
second degree AV block type II s/s - Answer-depends on the ventricular rate: if normal it
is asymptomatic. could progress to third degree, pacemakers, ECG, pulse ox, obtain
VS, administed oxygen, est IV access
temporary or permanent pacing
third degree heart block - Answer-Rhythm: ventricular regular; atrial regular, no
relationship is present
Rate: the atrial rate is greater than the ventricular and the ventricular rate is determined
by the escape
P waves: normal in size and shape; not followed by a QRS complex
PRI: no PRI bc they are not related
QRS: narrow or wide depending on the location of the pacemaker
hypokalemia T waves - Answer-depressed T waves
hyperkalemia T waves - Answer-elevated T waves
causes of third degree heart block - Answer-acute MI
acute myocarditis
congenital heart disease
drug effect
fibrosis of the conduction system
increased parasympathetic tone
capture - Answer-The successful conduction of an artificial pacemaker's impulse
through the myocardium, resulting in depolarization
demand pacemaker - Answer-Pacemaker that discharges only when the patient's heart
rate drops below the preset rate for the pacemaker; also known as a synchronous or
noncompetitive pacemaker.
dual chamber pacemaker - Answer-Pacemaker that stimulates the atrium and ventricle;
dual-chamber pacing is also called physiologic pacing. They must get counseling
because it hurts
, Fixed rate pacemaker - Answer-Pacemaker that continuously discharges at a preset
rate regardless of the patient's intrinsic activity; also known as an asynchronous
pacemaker
Sensitivity - Answer-the extent to which an artificial pacemaker recognizes intrinsic
cardiac electrical activity.
Temporary Pacemaker's - Answer-transcutaneous: pads that go on the body
transvenous: introduced into a central vein like the subclavian, femoral, brachial,
internal or external jugular vein
complications of pacemaker: - Answer-bleeding, infection, MI, PE, dysrhythmias, wires
can come loose, battery changes, no MRI, cannot do electromagnetic
for transcutaneous: hold pressure for 20 minutes and tell the patient not to bend their
legs.
12 lead ECG - Answer-Limb leads: I, II, II, AVR, AVL, AVF
Chest leads: V₁ , V₂ , V₃ , V₄ , V₅ , V₆
Where are the 12 lead ECG's placed - Answer-Lead I: receives information from R and
L arms; dipolar views top of the heart
Lead II: receives information from R arm and L foot
lead III: receives information from Left leg and arm
avR: on the Right arm
avF: on the right foot
avL: on the Left arm
Normal Sinus Rhythm - Answer-rhythm: R-R and P-P intervals are regular
rate: 60-100 bpm
P waves: positive (upright) in lead II; one precedes each QRS complex, P waves look
alike
PR Interval: 0.12-0.20 seconds and constant from beat to beat
QRS duration: 0.11 seconds or less unless abnormally conducted