Rhythms and Management (Chapter 3) Flashcards
1
Q
Blockage of which coronary a. can result in MI and/or AV nodal block
A
RCA
2
Q
Blockage of this coronary artery often leads to sudden cardiac death, earning it’s name as the “widowmaker”
A
LCA
3
Q
Blockage of what artery leads to lateral wall infarct
A
Left circumflex a.
4
Q
Blockage of what artery leads to posterior wall MI
A
RCA (most common) or left circumflex (if pt has a left dominant heart)
5
Q
What is responsible for the ability of the cardiac myocytes to propagate impulses (i.e. what is responsible for conductivity)
A
Intercalated disks
6
Q
Why can you not get tetanic contractions in myocardial cells
A
Absolute refractory period
7
Q
The absolute refractory period last until about what point on an ECG
A
Midway through the T wave
8
Q
When is the relative refractory period on an ECG
A
From the top of the T-wave to the end of the T-wave (i.e. the downslope)
9
Q
What is the supranormal period?
A
Period right after the relative refractory period where the myocytes are more sensitive stimuli than normal
10
Q
When is the supranormal period on the ECG
A
Right after the end of the T-wave (i.e. after the end of the RRP)
11
Q
Intrinsic rate of the SA node
A
60-100 beats
12
Q
What does the AV junction consist of
A
AV node and the non-branching portion of the Bundle of His
13
Q
Intrinsic rate of the bundle of His
A
40-60
14
Q
Intrinsic rate of the Purkinje fibers
A
20-40
15
Q
What is the record of electrical activity b/w 2 electrodes
A
A lead
16
Q
What leads make up the frontal plane
A
I, II, III (standard leads)
aVR, aVL, and aVF are called augmented leads
17
Q
Lead that is right arm to left arm
A
Lead I (only one “L”)
18
Q
Lead that is right arm to left leg
A
Lead II (2 “L’s”)
19
Q
Lead that is left arm to left leg
A
Lead III (3 L’s)
20
Q
Which frontal plane lead most closely follows the normal pathway of current in the heart
A
Lead II
21
Q
General rule for which limb the + electrode is on in a lead
A
Whichever lead has the most L’s (e.g. III is left arm to left leg, so the + node is on the left leg (2 L’s))
22
Q
Heart surface viewed by lead I
A
Lateral
23
Q
Heart surface viewed by leads II and III
A
Inferior
24
Q
Heart surface viewed by aVR
A
NONE
25
Heart surface viewed by aVL
Lateral
26
Heart surface viewed by aVF
Inferior
27
What horizontal leads monitor the interventricular septum
V1 and V2
28
What horizontal leads monitor the anterior heart surface
V3 and 4
29
What horizontal leads monitor the lateral heart surface
V5 and 6
30
What surface of the heart is not directly viewed by any leads on a standard 12 lead ECG
Posterior surface
31
15 lead EKG has what additional leads
V4R, V8 and V9
32
In a normally conducted beat, QRS complex mainly represents electrical activity of what
LV
33
What leads monitor the inferior heart wall
II, III, aVF
34
What leads monitor the septum
V1 and 2
35
What leads monitor the anterior wall
V3 and 4
36
What leads monitor the lateral wall
I, aVL, V5, V6
37
What is one horizontal unit on ECG a measure of
0.04 seconds
38
What is measure by the thicker horizontal lines on the ECG
.2 seconds (made up of 5 single unit intervals)
39
What does one vertical unit on an ECG measure
.1 mV
40
What does a thick line on the vertical axis measure
.5 mV (5 single unit intervals)
41
Normal Q wave is how long?
.04 second (one small box)
42
About how much vertical distance on the Q wave is considered abnormal
>1/3 the height of the R wave
43
Normal duration of QRS complex
.11 s or less
44
QRS duration in an incomplete bundle branch block
B/w .10 and .12
45
Duration of QRS complex in a complete BBB
Greater than or equal to .12
46
From which lead should you measure the QRS complex width
Whichever has the longest duration and the most clear onset and end.
47
Wider QRS complexes mean what
Delay in conduction through ventricles
48
What does the U wave represent and where is it on an ECG
Represents Purkinje fiber repolarization and is after the T wave
49
What conditions may cause deviation in ST-segment
MI, myocardial injury, or infarction
50
ST depression in a pt with acute coronary syndrome (ACS) represents what
Myocardial ischemia
51
ST elevation in a pt w/ ACS represents what
Myocardial damage
52
What part of the ST segment are we most interested in looking at when looking for ST elevation or depression
Early portion next to the J-joint
53
Normal duration of PR interval
.12-.20
54
What does the QT interval represent
Total ventricular activity (Depol and repol)
55
What happens to the QT interval as the HR increases
QT interval decreases
56
Corrected QT intervals more than what time are considered high risk for life-threatening arrhythmias
>0.5 s
57
What normal physiological event can mess with sinus rhythm
Breathing (can cause a respiratory sinus arrhythmia)
58
What happens to HR during inspiration
Increases
59
What happens to HR during expiration
Decreases
60
How can you tell if a sinus arrhythmia is due to breathing or not?
Have the pt hold their breath (if due to breathing it disappears)
61
Do sinus arrhythmias usually need treatment?
No, but if hemodynamic compromise is present (due to a slow rhythm) atropine may be indicated
62
When do tachycardias start to cause problems
When ventricular rate is >150 beat/min
63
When is a tachycardia considered unstable
Serious signs and symptoms w/ HR usually >150
64
What should you do in an unstable pt w/ a pulse and serious S&S due to tachycardia
Cardiovert!
65
What is considered tachycardia in an infant
>200 beats/min
66
What is considered tachycardia in children >5
>160 BPM
67
Sinus tachycardia
B/w 101-180
68
What is sinus tachycardia normally caused by
Normal response to demand for an increased CO
69
How do you treat a sinus tachycardia?
Treat the underlying cause, give fluid replacement, and relieve pain.
NEVER SHOCK A SINUS TACHYCARDIA
70
Irritable site in the atria fires automatically at a rapid rate
Atrial tachycardia
71
Fast and slow pathways in the AV node form an electrical circuit or loop
AV nodal reentrant tachycardia (AVNRT)
72
Impulse begins above the ventricles but travels via a pathway other than the AV node and bundle of His
AV reentrant tachycardia (AVRT)
73
What kind of tachycardia is Wolff-Parkinson-White
AVRT
74
Which SVT need the AV node to continue the tachycardia
AVNRT and AVRT
75
What SVT use the AV node only to conduct the rhythm to the ventricles
atach, aflutter, afib
76
Conduction of atrial impulses to the ventricles in atach (ratio)
1:1
One P wave for every QRS
77
Atach with a small cluster of cells with altered automaticity and often involves a "warm up" and "cool-down" period
ectopic atach
78
What is considered a "sustained rhythm"
Rhythm >30 seconds
79
If vagal maneuvers fail to terminate an atrial tachycardia, what do?
Antiarrhythmic medications; adenosine is the DOC
80
When is adenosine contraindicated
Asthmatics
81
What can you use to slow ventricular rhythm in an atrial tachycardia
BB or CCBs
82
When is cardioversion considered in atrial tachycardias (ATs)?
Drug-resistant arrhythmias
83
Dihydropyridine CCBs
Amlodipine and nifedipine
84
Nondihydropyridine CCBs
Verapamil and diltiazem
85
Major AEs of CCBs
Hypotension, HF, bradycardia, AV block
86
When should you avoid doing a carotid sinus massage
Older patients, pts w/ hx of stroke, known carotid stenosis, carotid bruit on auscultation
87
Cold water as a vagal maneuver is useful in what kinds of patients
Infants and young children
88
What is an AVNRT usually caused by
premature atrial complex
89
If pt is stable and has an AVNRT, what do you do
O2, IV access and vagal maneuvers
If those fail, first antiarrhythmic tried is adenosine
90
Tx for unstable pt w/ AVNRT
O2, IV access, sedation, synchronized cardioversion
91
A narrow QRS tachycardia that starts and/or ends suddenly
Paroxysmal supraventricular tachycardia
92
What kind of ST segment changes do you usually see with an SVT
Usually depression
93
Rhythm that originates above the ventricles but the impulse travels a pathway other than the AV node/bundle of His
Pre-excitation
94
What is the accessory pathway in WPW
Kent bundle (connects atria directly to ventricles
95
Accessory pathway in LGL
James bundle (connects the atria directly to the lower portion of the AV node)
96
Most common tachycardias WPW predisposes you to
Afib, aflutter, or PVST
97
Why should you not give drugs that slow AV node conduction in someone with a pre-excitation syndrome
This will actually speed up conduction through the accessory pathway and INCREASE the HR
98
Ectopic rhythm that begins in cells in the bundle of His
Junctional tachycardia
99
Usually rate for nonparoxysmal junctional tachycardia
101-140
100
What will the P wave look like in leads II, III and aVF if the AV node paces the heart?
Upside down because the impulse is traveling away from the + electrode
101
Common causes of junctional tachycardia
ACS, HF, theophylline, or digitalis
102
What constitutes a "wide-QRS" tachycardia
QRS >.12 s
103
DOC if pt is stable, QRS is wide, rhythm is regular, and QRS complexes are of similar shape
Adenosine
104
Drugs used to terminate wide-QRS tachycardia due to VT
Procainamide, amiodarone, sotalol
Lidocaine is 2nd line
105
Dosage for procainamide
20-50 mg/min IV
106
Dosage of amiodarone
300 mg IV bolus, can be followed by 150 mg
107
Dosage for Sotalol
1.5 mg/kg IV
108
2 conditions that must be met for BBB
1. QRS complex must have an abnormal duration
| 2. QRS must arise as a result of supraventricular activity
109
QRS complex duration in an incomplete BBB
.10-.12
110
Accelerated idioventricular rhythms are common after what
Successful reperfusion therapy
111
Typical rate of monomorphic VT
100-250
112
A rapid, wide-QRS rhythm w/ pulselessness, shock, or HF should be presumed to be what?
VT
113
Tx of a pt w/ stable but symptomatic VT
O2, IV access, and ventricular antiarrhythmics (amiodarone, sotalol, procainamide)
114
Avoid what antiarrhythmics if VT is due to prolonged QT interval
Sotalol and procainamide
115
Tx of unstable pts w/ VT
O2, IV access, sedation (if awake) and cardioversion
116
Venricular rate >100, size, shape, and direction of P-waves change from beat to beat
Multifocal atrial tachycardia (MAT)
117
When is afib/aflutter described as "uncontrolled"
Ventricular rate > 100
118
Polymorphic VT in the presence of long QT interval
Torsades de pointes
119
Dosing for Mg Sulfate
1-2 g IV
120
What is "absolute" bradycardia
HR < 60 BPM
121
If someone has a bradycardia but no symptoms, should you treat?
No, but you should observe them
122
1st line drug for symptomatic bradycardia
Atropine
123
What do if atropine doesn't work in symptomatic bradycardia
Epi, dopamine, or isoproterenol
124
Dosing for atropine
.5 mg every 3-5 minutes for a total dose of 3 mg
125
Sinus bradycardia is HR < what?
60
126
Tx for symptomatic sinus bradycardia
O2, start an IV, give atropine
127
Is the QRS complex wide or narrow in a junctional escape rhythm
Narrow (b/c it starts from above the ventricles)
128
Epi dosage for symptomatic bradycardia
2-10 mcg/min
129
Dosing for dopamine
2-10 mcg/kg/min
130
Dosing for isoproterenol
IV 2-10 mcg/min
131
What happens when SA node and AV junction fail to initiate an electrical impulse
Ventricular escape rhythm
132
Tx for ventricular escape rhythm
Try atropine first, but it's unlikely to be effective
If atropine doesn't work try dopamine, epinephrine, isoproterenol or transcutaneous pacing
AVOID lidocaine b/c it may stop ventricular activity
133
What the main purpose of give Epi in pulseless VT/VF
vasoconstriction, even though it can increase HR and other beneficial effects
134
These drugs can be given via trachea
Naloxone, atropine, vasopressin, epinephrine, lidocaine
135
Dose of vasopressin
40 U IV/IO; may be used in place of 1st or 2nd dose of epi in cardiac arrest
136
When doyou give antiarrhythmics in cardiac arrest (pulseless VT/VF)
If pulseless VT/VF continues despite CPR, defib, and vasopressors
137
1st antiarrhythmic to give during cardiac arrest
Amiodarone, then lidocaine if amiodarone isn't working
138
Dosing for lidocaine
1-1.5 mg/kg IV, consider repeat dose in 5-10 minutes
139
Total absence of ventricular activity
Asystole
140
What does PATCH-4-MD's a mnemonic for and what do the letters stand for
```
Reversible causes of cardiac arrest
PE
Acidosis
Tension pneumothorax
Cardiac Tamponade
Hyperkalemia
Hypokalemia
Hypoxia
Hypovolemia
MI
Drugs
Shiver (low body temp)
```
141
Tx for asystole and PEA
CPR, IV access, consider treatable causes, epi, advanced airway
142
Goals of resuscitation team
Restore breathing/circulation, preserve organ function
143
Resuscitation effort requires coordination of 4 critical tasks
1. chest compressions
2. Airway management
3. ECG monitoring and defib
4. Vascular access and drug administration
144
Phase I of the "Phase Response" in code organization
Anticipation
145
Phase II of the "Phase Response" in code organization
Entry
146
Phase III of the "Phase Response" in code organization
Resuscitation
147
2 most important priorities in cardiac arrest
CPR and defibrillation (if shockable rhythm)
148
Why is a pulse-ox helpful in cardiac arrest situations
May be able to indicate a return to spontaneous circulation
149
Preferred sites for IV access in cardiac arrest
External jugular vein or antecubital
150
Phase IV of the "Phase Response" in code organization
Maintenance phase (pt has stabilized)
151
Is having family members in the room during the resuscitation beneficial to the patient and family
Yes; it comforts the pt and helps with the grieving of the pts family.
152
Phase V of the "Phase Response" in code organization
Family notification
153
Phase VI of the "Phase Response" in code organization
Transfer
154
Phase VII of the "Phase Response" in code organization
Critique
155
Immediate postarrest phase
1st 20 mins after ROSC
156
Early postarrest phase
20 minutes to 6-12 hours after ROSC
157
Intermediate phase
6-12 hours to 72 hours after ROSC
158
Recovery phase
Beyond 3 days
159
What should you do immediately after primary survey
Repeat primary survey
160
Elevating the head of the bed 30 degrees does what
Reduce incidence of cerebral edema, aspiration, and ventilatory-associated pneumonia
161
IVs should contain what fluids
Saline or lactated ringers
162
Hypotonic solutions increase the risk of what if given IV
Edema (including cerebral edema)
163
Therapeutic hypothermia should be part of a standardized tx of what kind of patients
Comatose survivors of cardiac arrest
