Cardiac Rhythm Monitors & Equipment Flashcards
1
Q
Which pathway depolarizes the left atrium?
A
Bachmann bundle
2
Q
Anterior internodal tract gives rise to the
A
Bachmann bundle
3
Q
Middle internodal tract is also called the
A
Wenckebach tract
4
Q
Posterior internodal tract is also called the
A
Thorel tract
5
Q
What bundle is a pathologic accessory pathway responsible for WPW syndrome?
A
Kent’s bundle
6
Q
What fiber goes from the Atrium to AV node?
A
James fiber
7
Q
What fiber goes from the Atrium to His bundle
A
Atrio-hisian fiber
8
Q
What fiber goes from the Atrium to ventricle
A
Kent’s bundle
9
Q
What fiber goes from the AV node to ventricle
A
Mahaim bundle
10
Q
Phase 0 of the ventricular action potential corresponds to what EKG part?
A
QRS complex
11
Q
Phase 2 of the ventricular action potential corresponds to what EKG part?
A
QT interval
12
Q
Phase 3 of the ventricular action potential corresponds to what EKG part?
A
T wave
13
Q
What ion moves out of the cell in 4 of the 5 phases of the ventricular action potential?
A
Potassium
14
Q
What portion of the ventricular action potential occurs during the ST segment?
A
End of ventricular depolarization
15
Q
Pericarditis and EKG abnormality
A
PR interval depression
16
Q
Hypokalemia and EKG abnormality
A
U wave
17
Q
Intracranial hemorrhage and EKG abnormality
A
Peaked T wave
18
Q
Wolff-Parkinson-White syndrome and EKG abnormality
A
Delta wave
19
Q
Normal PR interval
A
0.12 - 0.20 secs
20
Q
Normal QTC
A
< 0.45 secs
21
Q
Normal QRS complex secs
A
< 0.10 secs
22
Q
What is the J point on the EKG?
A
where the QRS complex ends and the ST segment begins
23
Q
What is considered a significant ST change?
A
J point greater than +1.0 (ST elevation) or less than - 1.0 (ST depression) relative to the PR segment
24
Q
What segment of the EKG is considered isoelectric?
A
PR interval
25
PR interval with hyperkalemia
Wide
26
T wave with hyperkalemia
Narrow, peaked T wave
27
QRS with hyperkalemia
Wide
28
T wave with hypokalemia
Flat
29
ST with hypokalemia
depression
30
QT interval with hypokalemia
Long QT interval
31
What is the mean electrical vector?
The average current flow of all the action potentials at a given point in time.
32
Name 3 bipolar leads.
Lead I, II, III
33
Name 3 limb leads.
aVR, aVL, aVF
34
Vector of Depolarization
Base → Apex
Endocardium → Epicardium
35
Vector of Repolarization
Epicardium to endocardium
Apex → Base
36
Normal mean electrical vector
between -30 degrees and +90 degrees
37
Extreme right axis deviation (lead I, aVF changes)
Neg, neg
38
Left axis deviation
(lead I, aVF changes)
pos, neg
39
Normal axis (lead I, aVF changes)
pos, pos
40
Right axis deviation
(lead I, aVF changes)
neg, pos
41
During sinus arrhythmia, heart rate increases during: (inspiration or expiration)
Inhalation → ↓intrathoracic pressure → ↑venous return → ↑heart rate
42
What reflex may initiate sinus arrhythmia?
Bainbridge reflex. Increased venous return stretches the right atrium and SA node causing the heart rate to increase.
43
What is the minimal dose of atropine to treat bradycardia in an adult?
0.5 mg IV. Underdosing can cause paradoxical bradycardia.
44
What is the initial shock treatment (in joules) for an acute episode of atrial fibrillation?
Cardioversion at 100 joules
45
Second degree heart block Mobitz type 2
Some P's conduct to the ventricles, while others don't (there is usually a set ratio 2:1 or 3:1). After the dropped QRS, the next P arrives right on time.
46
Recite the heart block rhyme.
If "R" is far from "P" then you have a First Degree.
Longer, longer, longer, drop than you have a Wenckebach.
If some "P"s don't get through then you have a Mobitz 2.
If "P"s and "Q"s don't agree then you have a Third Degree.
47
What inotrope best treats third degree heart block?
Isoproterenol
48
Class 1 Antiarrhythmic drugs MOA
inhibit fast sodium channels
49
Class 2 Antiarrhythmic drugs MOA
decrease the rate of depolarization
50
Class 3 Antiarrhythmic drugs MOA
inhibit potassium ion channels
51
Class 4 Antiarrhythmic drugs MOA
inhibit slow calcium channels
52
Wolff-Parkinson-White syndrome is associated with which reentry type
atrial-ventricular reentry.
53
What are 2 ways to disrupt a reentry circuit?
Slow the conduction velocity through the circuit.
Increase the refractory period of the cells at the location of the unidirectional block.
54
What is the most common cause of tachyarrhythmias?
Reentry pathway
55
How can mitral stenosis cause a reentry pathway?
Conduction must occur over a longer distance.
56
How can ischemia cause a reentry pathway?
Conduction velocity through the affected region is too slow.
57
How can epinephrine cause a reentry pathway?
It shortens the duration of the refractory period.
58
QRS with WPW
Wide
59
PR interval with WPW
Short
60
What is the most common tachydysrhythmia associated with WPW?
Orthodromic AV nodal reentry tachycardia (90%)
61
Is orthodromic AVRNT or antidromic AVRNT more dangerous in the patient with atrial fibrillation?
Antidromic AVRNT. The AV node is bypassed and the ventricular rate can increase dramatically (up to 300 bpm) causing CHF and ventricular fibrillation.
62
Treatment for antidromic AVRNT
Procainamide
63
Treatment for orthodromic AVRNT
Beta-blocker
Vagal maneuvers
Verapamil
Adenosine
64
Hyperventilation's effect on potassium and QT interval
shifts K+ into cells, decreases serum K+, and can prolong the QT interval.
65
A QT interval is defined as prolonged when it is greater than:
(Men/Women)
Men > 0.45 seconds
Women > 0.47 seconds
66
What type of electrical stimulus can initiate torsades de pointes?
A PVC or poorly timed pacer discharge during the second half of the T wave (R on T phenomenon).
67
Name 3 electrolyte disturbances that can prolong the QTc.
Hypokalemia
Hypocalcemia
Hypomagnesemia
68
What are 2 immediate treatments for torsades de pointes?
Magnesium sulfate
Cardiac pacing
69
Position 1 NBG pacemaker function
Chamber paced
70
Position 2 NBG pacemaker function
Chamber sensed
71
Position 3 NBG pacemaker function
Response to sensed event
72
Position 4 NBG pacemaker function
Programmability
73
What information do the first 3 positions of the NBG pacemaker code relay?
What chamber is paced.
What chamber is sensed.
What the response of the pacemaker will be if native cardiac activity is sensed.
74
Describe AOO pacing.
Asynchronous pacing:
The atrium is paced.
The chamber is not sensed.
No response to native cardiac electrical activity
75
Describe VVI pacing.
Single-chamber demand pacing:
The ventricle is paced.
The ventricle is sensed.
Sensed native electrical activity inhibits the pacemaker from firing.
76
What most likely will occur if a magnet is placed over a mechanical pacemaker?
It will convert the pacemaker setting to an asynchronous mode.
77
Hypercalcemia's effect on QT interval
Shorter QT interval
78
Hypocalcemia's effect on QT interval
Longer QT interval
79
Risk of torsades de pointes increases when QT interval is greater than
0.5 seconds
80
Drug used for beta blocker or CCB overdose
Glucagon, increases cAMP -> increases HR
81
Which bipolar limb lead is always positive?
Left leg
82
Which bipolar limb lead is always negative?
Right arm
83
Lead I vector (limbs)
Right arm (-) to Left arm (+)
84
Lead 2 vector (limbs)
Right arm (-) to Left leg (+)
85
Lead 3 vector (limbs)
Left arm (-) to Left leg (+)
86
The mean electrical vector travels away from the
negative pole and towards the positive pole.
87
Left axis deviation in degrees
< -30 degrees
88
Right axis deviation in degrees
> 90 degrees
89
Which dysrhythmia is the MOST common cause of acute myocardial infarction?
Sinus tachycardia
90
Cardioversion dose for atrial flutter
50 joules
91
PVC's can cause ventricular tachycardia if it occurs during what part of the cardiac action cycle?
Relative refractory period (last 2/3's of the T wave)
92
PVC's that occur during the relative refractory period is also called
"R on T" phenomenon
93
What other condition increases risk of R on T?
QT prolongation
94
What does the sync mode during cardioversion prevent?
Prevents shock delivery from occurring during ventricular repolarization
95
BEST drug for the treatment of symptomatic premature ventricular contractions
Lidocaine
96
Drug used to reduce the incidence of torsades de pointes and treats prolonged QT syndrome
Beta blockers
97
Which 2 syndromes are MOST likely to cause prolonged QT syndrome?
Romano-Ward.
Timothy.
98
Wolff-Parkinson-White syndrome is associated with which wave
Delta wave
99
What does a delta wave look like?
short PR interval and an upsloping of the R wave
100
What two anti-arrthymics can cause first degree heart block?
Amiodarone and digoxin
101
2 treatments for third degree heart block
Transcutaneous pacing and isoproterenol
102
Third degree heart block is also known as
Complete heart block
103
Best lead used for monitoring the P wave
Lead II
104
What is the reference point for measuring changes in the ST segment?
PR segment (an isoelectric line)
105
Drug used to treat WPW and supraventricular tachycardia
Adenosine
106
Which 3 methods reduce the risk of inadvertent AICD discharge while using cautery?
Magnets.
Place the return electrode as far as possible from the pulse generator.
Harmonic scalpel instead of a monopolar cautery.
107
Which cautery setting imparts the GREATEST risk of electromagnetic interference in the patient with an AICD?
The coagulation setting on a monopolar cautery
108
What EKG change is associated with intracranial hemorrhage?
Peaked T waves
109
U waves are associated with what electrolyte abnormality
Hypokalemia
110
Which EKG event is consistent with atrial repolarization?
QRS complex
111
Myocardial ischemia should be considered when ST depression exceeds:
1.0 mm.
112
What bundle is affected with second-degree heart block (Mobitz type 2)
His bundle and bundle branches
