6. EP Flashcards
(397 cards)
1
Q
What % of pregnancies have fetal arrythmias?
A
1-2
2
Q
What is the most common type of arrhythmia in fetal life?
A
PACs
80-90%
3
Q
What % of fetal arrhythmias are sustained?
A
10%
4
Q
What can fetal SVT lead to?
A
- Hydrops
- Reduced ventricular function
(Limits diastolic filling time)
5
Q
When is treatment indicated in fetal SVT?
A
- Sustained arrhythmia (>50% SVT burden)
2. Hydrops
6
Q
What is the first line drug for fetal SVT if there is no evidence of hydrops?
A
Digoxin
7
Q
What % of patients respond to digoxin for fetal SVT?
A
60-80%
8
Q
What digoxin level do you need to have adequate fetal transfer?
A
2 (high)
This results in 60% fetal transfer
9
Q
What happens to the fetal transfer rate of medications if the baby has hydrops?
A
Decreases by 50%
10
Q
What are medication options for fetal SVT that is refractory to digoxin or if the baby is hydropic?
A
- Flecainide
- Sotalol
- Amiodarone
11
Q
What are treatment options for fetal atrial flutter?
A
- Flecainide
- Sotalol
- Amiodarone
12
Q
Which 2 drugs used for fetal arrhythmias have an excellent fetal transfer?
A
Flecainide and sotalol (80-100%)
13
Q
What the fetal transfer of amiodarone
A
Poor, 10-30%
? role for this in infants with more severe hydrops
14
Q
How early can a fetus with sustained tachycardia develop hydrops?
A
48 hours
15
Q
Can adenosine be used in fetal SVT?
A
Yes, as an injection into umbilical vein
High risk to the fetus
16
Q
Do isolated PACs require restriction from sports?
A
No
17
Q
First line therapy for long QT?
A
Beta blockers
18
Q
Risk factors for SCD in LQTS?
A
- Length of QT interval (>500 greatest risk)
2. Prior syncope
19
Q
Can amiodarone be used in LQTS?
A
Relative contraindicated (prolongs QT)
20
Q
Is a prophylactic ICD recommended in LQTS?
A
No
21
Q
Best way to break flutter?
A
DC cardioversion
22
Q
What effect does digoxin have on flutter?
A
Can slow ventricular response, but won’t often terminate the tachycardia
23
Q
What are 3 drugs that can be used for flutter, but take time for effect and may not convert the rhythm?
A
- Sotalol
- B-blocker
- Amiodarone
24
Q
What does a vagal maneuver do to flutter?
A
Slow ventricular rate so flutter becomes more visible
25
True or False: In infants, flutter has a low incidence of recurrence and won't require short/long term anti-arrhythmics?
True
26
Strongest risk markers for sudden death in patients with HCM?
1. FHx premature sudden death
2. Septal thickness >30mm
Other RF:
1. Non-sustained V-tach
2. Syncope (not neurally mediated)
3. BP decrease or inadequate increase during exercise testing
4. LGE on MRI
27
What drugs does amiodarone increase effect/level/toxicity of any may need to have a decreased dose once starting amiodarone?
1. Coumadin
2. Digoxin
3. Phenytoin
4. Class I anti-arrhythmic
28
How is digoxin excreted?
Kidneys
29
True or false: Patients with WPW can have intermittent pre-excitation?
True
30
What are patients with WPW at risk for?
SVT
31
What % of patients with Lyme disease have cardiac involvement?
8%
32
When does cardiac involvement from Lyme disease usually present?
Within a few weeks of illness onset
33
What is the most common feature of Lyme carditis?
AV block
34
True or False: Most cases of Lyme carditis with AV block require pacemaker?
False- most resolve gradually with normalization of PR in 1-2 weeks... persistence needing pacemaker is unusual
35
Drug of choice for Lyme carditis?
Doxycycline
| -Can also consider cephalosporin or amoxicillin
36
What may you need to due in Lyme carditis with AV block if the HR is too slow?
Temporary pacing
37
First step in neurocardiogenic syncope?
Increased fluids
38
Can an athlete with LVH and T-wave inversions on ECG still play?
Not until an echo is done
| Worry about HCM
39
T wave inversions in which leads is almost always an abnormal finding?
V5
V6
I
aVL
40
Chronic opthalmoplegia, pigmentary retinal degeneration and at least 1 of ataxia/heart block/high protein in CSF
Kearns-Sayre syndrome
41
When does Kearns-Sayre usually present
Before 20
42
Cardiac issues in Kearns-Sayre?
BBB and prolonged QT often progressing to complete heart block
43
What should be done for a patient with Kearns-Sayre and bifasicular block on ECG?
Pacemaker (can rapidly progress to complete AV block)
44
Should all patients with Kearns-Sayre syndrome get a pacemaker?
Not necessarily... only if bifascicular block
45
What is % mortality in infancy for patients with LQTS with 2:1 AV block?
50
46
What is recommended therapy for an infant with bradycardia due to LQTS with 2:1 AV block?
Pacemaker and B-blocker (the B-blocker will enhance AV block, but decreases chance of ventricular arrhythmia)
47
Relationship of the conduction system to the VSD in patients with an AV canal?
Posterior/inferior to VSD
48
Why is there LAD in AC canal defects?
- Initial QRS forces inferior/rightward
| - QRS loop moves counterclockwise... superior/left causing LAD
49
Normal baseline HR of fetus?
120-160
50
Normal short term HR variability in a fetus?
2-3bpm around baseline
51
Normal long term HR variability in a fetus?
Baseline HR occurring 3-5 times per minute with an amplitude of 5-20bpm
52
What normally happens to HR when there is an increase in fetal BP?
Bradycardia (initiates vagal nerve reflex)
53
What effect can fetal hypoxemia have on HR?
Bradycardia or loss of HR variability
| Hypoxia has a direct depressing effect on function of CNS and fetal myocardium
54
List predictors of poor long-term survival after ToF repair
1. Older age at operation
2. Significant residual hemodynamic abnormalities
3. Use of outflow tract patch
4. QRS >180msec
5. Elevated LVEDP
6. Poor LV function
55
True or False: Do PVCs increase risk of SCD in ToF patients?
False
56
What % of patients can have atrial tachycardia after ToF repair?
20-30% (may predispose to sudden death)
57
What ECG findings is a minor Jones criteria for acute rheumatic fever?
PR interval prolongation
58
How many major/minor Jones criteria for acute rheumatic fever?
2 major
| 1 major, 2 minor
59
Acute rheumatic fever follows an infection with that?
Group A strep
| -After latency period of 3 weeks
60
What systems does rheumatic fever affect?
1. Heart
2. Joints
3. Brain
4. Cutaneous/subcutaneous tissues
61
What % of patients with RF have carditis?
50%
62
True or false, complete heart block usually isn't seen in rheumatic carditis?
True
63
What is an early sign of myocarditis?
Tachycardia
64
What disease does Choreiform movements go with?
Rheumatic fever (rapid jerking movements of hands, face, feet)
65
Coronary artery aneurysms
Kawasaki
66
Dilated ascending aorta
Marfan
67
Bifid Uvula
Loeys-Dietz
68
True or False: SLE and scleroderma may be associated with a prolonged PR interval
True
69
True or False: PACs are common in fetal life and don't warrant therapy
True
70
In a fetus with PACs, what can cause temporary decreases in HR?
Blocked PACs
71
What intervention is needed for blocked PACs in fetal life?
None if fetus has good ventricular function and no hydrops
72
What is the incidence of premature beats detected in utero?
2%
73
What % of fetuses with premature beats in utero have arrhythmias that persist in the newborn?
<10%
74
What % of premature beats in fetuses are PACs?
80-90%
75
First line therapy for SVT in WPW?
Propranolol
76
What 2 drugs are relatively contraindicated for SVT in presence of WPW?
Digoxin and verapamil
77
What is a second line agent for SVT in WPW if the patietn does respond to beta blocker?
Flecainide
78
What anti-arrhythmic class does mexiletine fall into?
IB
79
What causes the + T wave in V1 in a neonate?
Early appearance of repolarization in LV and late termination of depolarization in RV (overall LV to RV sequence)
-Change to negative T waves happens during 1st week of life
80
What happens to P waves in episode of PJRT?
Deeply negative in II, III, aVF
81
What is an accessory pathway mediated tachycardia due to a slowly conducting accessory pathway typically located in the right posterior septum?
PJRT
82
Due to the position of the pathway in PJRT, the P-wave axis is usually what?
-90 degrees... negative P-waves in II, III, aVF
83
True or False: P waves are usually easily visible on ECG in PJRT
True
84
True or False: PJRT often has 1:1 relationship of ventricles to atria
True
85
Describe PJRT
- Incessant form of tachycardia
- May cause a cardiomyopathy
- Rates tend to be slower (150-200bpm)
- Harder to detect clinically
86
What happens to ECG with K of 5.5-6.5?
T waves become tall and peaked
87
What happens to ECG with K >6.6?
QRS widening with ST segment elevation
88
What happens to ECG with K >8.5?
P waves disappear
89
Above what K level do you typically see arrhythmias?
9
*AV block, v-tach, v-fib
90
What are Q waves often indicative of?
Infarction
91
Most common arrhythmia in the acute post-op period following surgery?
JET
92
What is a focal tachycardia with gradual warm-up/cool down and rate variability?
JET
93
Where are P-waves in JET?
- Terminal portion or shortly after QRS
| - Can be completely dissociated
94
Describe the rate in JET
Constant or fluctuate with increases/decreases in catecholamine state
95
True or False: JET has VA dissociation with ventricular rate being faster than atrial rate
True
*Know it's not flutter/EAT because ventricular rate is faster than atrial rate
96
Describe relationship between atria/ventricles in re-entrant SVT
1:1
97
How to distinguish between tachycardia with V-A dissociation?
Narrow QRS: JET
| Wide QRS: V-tach
98
Most common coronary anomaly?
Left circumflex from right main (1/3 of all)
*Usually incidental finding with no clinical significance
99
Name a coronary anomaly that is often of greater clinical significance
Left main from right sinus of Valsalva
100
What are the 4 pathways a left coronary artery from the right sinus of Valsalva can take?
1. Posterior to aorta
2. Anterior to RVOT
3. Within ventricular septum beneath RV infundibulum
4. Between aorta and pulmonary artery
101
What type of coronary anomaly most commonly causes sudden cardiac death?
Left main coronary artery from right sinus of Valsalva passing between aorta and PA
102
Most likely result of maternal treatment with amiodarone during pregnancy?
Neonatal hypothyroidism
*No significant impact to neonatal liver, lungs, eyes or kidneys
103
What defect should you consider with LAD on ECG?
Primum ASD
| -80 degrees
104
Common findings on ECG with primum ASD?
LAD, RVH, RAE
105
What type of ASD has a prolonged PR?
All
106
Which ASD types have a normal to right axis?
Secundum, sinus venosus, unroofed CS
*Can have an rSR' pattern in V1
107
What % of the population has a PFO?
20-30%
108
True or False: Erythromycin is associated with QT prolongation
True
*Others include some anti-arrhythmic, tricyclic antidepressants, erythromycin, ondansetron, chloral
109
Half life of adenosine?
2-10 seconds
110
What drug is excellent for acute termination of re-entrant SVT or diagnosis of flutter?
Adenosine
111
What is done for SVT if patient is hemodynamically unstable?
DC cardioversion
112
What anti-arrhythmics are relatively contraindicated under 1 year?
CCB- Verapamil
113
First line therapy for neonatal atrial flutter?
DC cardioversion
* 0.5-1 J/kg
* High doses often needed in neonates due to the energy not being delivered as efficiently via neonatal pads
* If 1J/kg unsuccessful, increase energy and cardiovert again
114
What type of cardioversion if there is a stable rhythm with a pulse?
Synchronized
*Unsynchronized can cause shock on T-wave = V-fib
115
What may be needed if flutter cardioversion is successful, but re-starts immediately after?
Antiarrhythmic (like amiodarone)
116
Class I recommendations for permanent pacing in children, adolescents and patients with congenital heart disease?
1. Advanced second or third degree AV block associated with symptomatic bradycardia, ventricular dysfunction, or low CO
2. Sinus node dysfunction with correlation of symptoms during age-inappropriate bradycardia. The definition of bradycardia varies with the patient’s age and expected HR
3. Post-operative advanced 2nd or 3rd degree AV block that isn’t expected to resolve or persists at least 7 days after cardiac surgery
4. Congenital 3rd degree AV block with a wide QRS escape rhythm, complex ventricular ectopy or ventricular dysfunction
5. Congenital 3rd degree AV block in the infant with a ventricular rate <50-55bpm or with congenital heart disease and a ventricular rate <70bpm
6. Sustained pause-dependent VT, with or without prolonged QT, in which the efficacy of pacing is thoroughly documented
117
True or False: Complex ventricular ectopy is an indication for pacemaker placement
True
118
What type long QT presents as syncope or arrhythmia with exercise?
1
119
What is the most common form of long QT
Long QT 1
120
Genetic testing can reveal a cause in what % of patients with high index of suspicion for long QT?
75%
121
What is the gene mutation in Long QT 1?
KCNQ1
122
True or False: There is often no conduction disease of AV node (no abnormalities of AH or HV intervals) in long QT
True
123
What testing can be helpful in bringing out Brugada?
Procainamide challenge
124
True or False: Proxainamide can prolong the QT
True
125
In order for reentry to occur in cardiac muscle and to result in dysrhythmia, what must also be present?
Area of conduction delay
126
What is needed for SVT to occur?
2 pathways with difference in conduction properties and refractory periods separated by an area of nonconduction
127
What is entrainment?
Form of mapping reentry tachycardias
128
Name 2 properties of focal tachycardias
1. Triggered activity
| 2. Increased automaticity
129
True or False: Patient can develop AV block years after heart surgery
True
* More common in patients who had temporary AV block in immediate post-operative period
* Late development of AV block may play a role in sudden cardiac death
130
Which patients with 2nd degree heart block need a pacemaker?
- Mobitz I (Wenckebach): Only if slow underlying rate or symptoms
- Mobitz II: All patients, there is conduction system disease and patient is at risk even without symptoms and with good underling HR
131
What is a macro re-entrant arrhythmia with atrial rates between 240-400bpm?
Atrial flutter
132
ECG with regular rhythm and saw-tooth P-waves?
Atrial flutter
* AV node can’t conduct at the same rate as the atrial activity
* Typically some type of conduction block (2:1 or 4:1)
* Block can be variable and cause flutter to appear as an irregular rhythm
133
True or False: Flutter is common in patients who have undergone atrial surgery
True
134
What is the most effective way to terminate flutter?
DC cardioversion
*Especially if hemodynamic instability
135
What is an alternative to DC cardioversion for hemodynamically stable flutter?
Atrial overdrive pacing
*With atrial pacing wires post-op
136
Temporary overdrive pacing can work to terminate what type of tachycardias?
Re-entrant
- Flutter
- SVT
137
For temporary overdrive pacing, what do you typically set the pacing rate at?
10-20bpm faster than tachycardia
*Can try progressively faster rates, but there is a risk of inducing a-fib
138
What is the effect of adenosine and digoxin on flutter?
Blocks the ventricular response, but doesn't terminate rhythm
139
What is elective replacement indicator or ERI?
- Set when the battery voltage drops below a certain limit on pacemaker
- Paces at a rate lower than the set rate
- Pacemaker may change from dual chamber to a single chamber pacing mode as well to conserve battery life
140
How long will a pacemaker operate on ERI conditions from the point the ERI is set?
At least 3 months
141
What happens after 3 months in ERI for a pacemaker?
- End of life mode
- Erratic pacing
- Pacemaker further conserves battery life by disabling all pacemaker features except pacing
142
When should a patient be scheduled for pacemaker replacement due to battery?
When ERI first reached
143
What is rate-responsive pacing?
Increases the pacing rate in response to increased patient activity
*Can also set pacemaker to decrease rate at night during sleep and pace at set rate otherwise
144
What dysrhythmia occurs in 10-15% of patients with hyperthyroidism?
A-fib
145
How does thyroid hormone contribute to arrhythmogenic activity?
Alters the EP characteristics of atrial myocytes by shortening the AP duration and enhancing automaticity and triggered activity in the pulmonary vein cardiac tissue
146
What does hypothyroidism due to ECG voltages?
Decreases them
147
True or False: Hyperthyroidism can cause heart block
False- Typically doesn't affect conduction
148
In peds, sick sinus syndrome is most likely associated with what?
Surgery for CHD
149
What type of surgery can cause damage to sinus node?
Anything within the atrium
*Risk for sinus node dysfunction is directly related to the extent of surgery in the atrium
150
Which two surgical patients are at the highest risk for sinus node dysfunction?
1. Atrial switch
| 2. Fontan
151
Name 3 conditions associated with AV block
1. Lyme
2. Maternal SLE
3. Myocarditis
152
Most common arrhythmia after sinus venosus ASD repair?
Sinus node dysfunction
153
Why do sinus venosus ASDs have a higher incidence of sinus node dysfunction?
Proximity to the sinus node with the potential for direct damage or injury to the sinus node artery during repair
154
What do the 3 letters represent in pacemakers?
1. Chamber paced
2. Chamber sensed
3. Response to sensed event
155
What is inhibit mode for a pacemaker?
- When pacemaker senses an intrinsic cardiac event, it inhibits pacing
- Allows intrinsic cardiac events to happen without pacing
156
What is triggered mode for a pacemaker?
-Pacemaker actively paces in response to sensed event -Senses an intrinsic atrial contraction then paces ventricle in response
157
What does DDD pacemaker setting do?
- Paces both atrium and ventricle
- Senses both atrium and ventricle
- Inhibits and tracks in response to sensed event
158
If a person with a DDD pacemaker has a higher HR than the set rate, what is happening?
Device is sensing native higher atrial rate and triggering the ventricle to pace at same rate
159
What type of patients would DDI be a helpful pacemaker setting?
- Atrial arrhythmias
- Avoid pacemaker tracking rapid atrial rates with subsequent rapid pacing in the ventricles
-Sense/pace in both atrial ventricles, but only inhibits...can't track an atrial rate above the lower rate limit of the pacemaker
160
What is DOO pacing?
Pace the atrial and ventricle at lower rate limit with no sensing (pace atria and ventricles without regard to intrinsic cardiac activity)
161
3 most common side effects of B-blockers in children?
1. Behavioral changes
2. Depression
3. Mood swings
162
Less common side effects of beta blockers in children (besides behavioral changes, depression and mood swings)?
1. Lightheadedness
2. Tiredness
3. Headache
4. Nightmares
5. Difficulty sleeping
6. Heartburn
7. Diarrhea
8. Constipation
*Rarely can cause rash or hypoglycemia
163
What underlying condition can beta-blockers exacerbate?
Asthma
164
Why do beta-blockers need to be used cautiously in patients with diabetes?
Can block hypoglycemia symptoms
165
ECG findings in Pompe?
- Marked ventricular hypertrophy (QRS complexes off the page)
- Short PR interval
- Strain with ST segment changes and T-wave inversion in limb leads
166
What results from an inherited deficiency of lysosomal enzyme alpha-glucosidase (responsible for breakdown of glycogen to glucose)?
Pompe disease- Glycogen storage disease type II
167
Glycogen storage disease type II
Pompe
168
What results in intralysosomal accumulation of glycogen (primarily in muscle cells) which leads to progressive loss of muscle function?
Pompe
169
What is one of the most severe/lethal forms of HCM with death in the 1st 2 years of life?
Pompe
170
Baby clinically well at birth, but within 6 months starts
to develop hypotonia, severe cardiomegaly, hepatomegaly, poor weight gain, difficulty sucking, enlarged protruding tongue...?
Pompe
171
What EP issue is a patient with unrepaired L-TGA most at risk for?
Complete AV block
- 10% may present with heart block
- Occurs at a rate of up to 2% per year
172
Why is there an increased risk for AV block in L-TGA?
Displacement of AV node and abnormal course of conduction tissue which runs very superifical
173
What 2 EP issues are patients with L-TGA at risk for?
- Complete heart block (highest risk)
| - WPW
174
True or False: Patients with L-TGA are not at high risk for atrial flutter, sinus node dysfunction, junctional tachycardia or torsades
True
175
A normal HV interval is usually between what?
35-55msec
176
A shorter HV interval is seen in what?
Ventricular preexcitation (WPW)
177
A longer HV interval is seen in what?
AV node or His-Purkinje disease (BBB)
178
What should happen during an EP study if you deliver a premature atrial stimuli after a pacing train?
Small decremental change in AH interval
179
What is an AH jump?
When there is a large change (>50msec) in the AH interval with a 10msec change in premature atrial stimulus
180
What does an AH jump suggest?
Dual AV node pathways (fast and slow)
*This may be a substrate for AV nodal re-entry tachycardia
181
What is it called during an EP study when you deliver a premature atrial stimuli after a pacing train and it captures the atrium, but doesn't conduct to the ventricles?
AV node effective refractory period
182
What is it called during an EP study when you deliver a premature atrial stimuli after a pacing train and it fails to capture the atrium?
Atrial effective refractory period
183
True or False: Wenckebach is demonstrated during an extrastimulus protocol?
False- During atrial pacing
184
True or False: The lengthening of the AV conduction time represented by the AH interval is a normal finding (decremental property of the AV node) and doesn’t indicate AV conduction disease
True
185
What is it called during an EP study when you deliver a premature ventricular stimuli after a pacing train and it fails to capture the ventricle (pacing spike, but no QRS)?
Ventricular effective refractory period
*Failure of output if there was no pacing spike
186
What is it called during an EP study when you deliver a premature ventricular stimuli after a pacing train and is captured the ventricular beat, but blocked going to the atria (ventricular signal on ventricular catheter and QRS on surface ECG, but no atrial conduction)?
AV node retrograde effective refractory period
187
True or False: VA Wenckebach occurs during ventricular pacing and not during a ventricular extrastimulus protocol?
True
188
Paced ECG with P waves that have no relationship to the QRS complex (completely dissociated)... what modes are possible?
VOO or VVI
189
What mode represents asynchronous dual chamber pacing?
DOO
190
Electrogram with complete AV dissociation and ventricular rate faster than atrial?
Ventricular tachycardia
191
In an accessory pathway mediated tachycardia, what is the relationship between the atria and ventricle?
1:1
192
In a wide complex rhythm with rapid ventricular rate, how do you diagnose antegrade complete AV block?
The atrial rate would have to be faster than ventricular
193
What is the AV relationship in AVNRT?
1:1
194
What form of CHD should you consider with RVH and ST segment elevations consistent with ischemia in V1/V2?
PA + IVS
195
What causes RVH and RV ischemia seen in PA + IVS?
RV dependent coronary circulation
*High pressure in the RV creates sinusoidal connections between the RV and coronary artery circulation that can predispose to ischemia
196
What is typically seen on ECG in ToF and Truncus?
RVH
197
What is typically seen on ECG in TAPVR?
RVH + RA enlargement
198
What pacemaker settings would have atrial sensing followed by ventricular tracking and resultant ventricular pacing?
Dual chamber
DDD or VDD
199
What is a VDD pacemaker setting?
Can sense in the atria, but not pace
200
True or False: Most patients have atrial and ventricular leads placed with a dual chamber pacemaker?
True
*There are leads which have the capability in a single lead to sense both atrium and ventricle as well as pace the ventricle achieving AV synchrony using a single lead set VDD
201
If a pacemaker was set VVI or VOO, how would it pace?
At the lower rate limit set
202
How does DOO pacing work?
- Pace atria/ventricles without sensing
| - Atrial and ventricular pacing spikes would be present and pace without any regard to existing P waves or QRS complexes
203
AV conduction block is a complication of what % of surgical operations for CHD?
1-3%
204
Unless treated with an implanted pacemaker, post-op complete heart block is associated with what % mortality?
28-50%
205
True or False: Permanent placement implantation is a class I indication for surgically induced complete AV block regardless of the ventricular escape rate and condition of the patient
True
206
How long should wait to determine whether AV nodal conduction will return following post-op heart block?
At least 7 days
* Usually resolves after 7-10 days if it will resolve
* Patients need long-term monitoring for conduction abnormalities
207
Progressive PR prolongation, usually due to changes in AH interval (AV node delay) with eventual failure of conduction to ventricle
Mobitz type I 2nd degree AV block (Wenckebach)
208
Abrupt failure of AV conduction of 1 or more atrial impulses without prior PR prolongation
Mobitz type II 2nd degree AV block
209
Where does Mobitz type II 2nd degree AV block usually occur?
Below AV node
210
Why is Mobitz type II 2nd degree AV block an indication for a pacemaker even in the absence of symptoms?
May abruptly progress to 3rd degree heart block without an adequate escape rhythm
211
When would you place a pacemaker in the setting of sinus bradycardia, Wenckebach or prolonged PR interval?
If there are significant symptoms associated with the rhythm
212
True or False: LBBB is an indication for a pacemaker?
False
*Not an indication, regardless of QRS duration
213
What should you consider with bidirectional v-tach with QRS changing in every other beat during VT?
CPVT
214
What should you consider with ventricular tachyarrhythmias which occur with exercise or emotion?
CPVT
215
True or False: The resting ECG in CPVT can be normal?
True
*Heart often structurally normal as well
216
What mutations cause CPVT?
1. RYR2 (ryanodine receptor)
2. CASQ2 (calsequestrin 2)
+ many more
217
What often triggers dysrhythmias in long QT or Brugada?
Early afterdepolarization with a PVC at the end of the T-wave leading to torsades
218
What tachydysrhythmia is often seen with long QT or Brugada?
Torsades
219
What kind of rhythm issues are seen in ARVC?
VT from RV
220
True or False: HCM patients are at increased risk of VT?
True
221
Intermittent capture of the ventricles by a pacemaker is consistent with what issue in the lead?
Partial fracture of ventricular lead
222
What measure on interrogation would be a clue that there is a partial lead fracture of a ventricular pacemaker lead?
Lead impedance abnormal
223
Inability of a pacemaker to sense spontaneous myocardial depolarization… get paced complexes in presence of intrinsic rhythm
Undersensing
224
What does undersensing lead to?
Inappropriate pacing complexes after native QRS beats
225
What can happen when native ventricular escape beats don't reset the pacemaker timing cycle?
Pacemaker continues to pace at lower rate limit- Undersensing
226
True or False: Undersensing can be a marker that something is wrong with a pacing lead?
True
227
Pacemaker sensing artifact and not pacing when indicated
Oversensing
228
Point in pacemaker battery life where replacement is needed, but pacemaker will continue to operate and will result in ventricular capture
ERI
*At end of life when battery voltage extremely low, pacemaker may not be able to generate enough energy to capture the heart
229
What happens if you put a magnet over a pacemaker?
Causes it to pace asynchronously
*Shouldn't lose capture
230
List adverse effects of amiodarone
1. Photosensitivity
2. Thyroid dysfunction
3. Weakness
4. Peripheral neuropathy
5. Corneal microdeposits
6. Elevated hepatic enzymes
*Less common: Proarrythmic, pulmonary fibrosis
231
What tests need followed with someone on amiodarone?
TFTs, PFTs, LFTs
| Yearly optho visits (corneal microdeposits)
232
What side effect is common when starting amiodarone, but usually resolves with time?
Nausea
233
What do you need to counsel patients about regarding sun exposure when starting amiodarone?
Photosensitivity common
234
What should an ECG with marked RAE, RBBB and pre-excitation make you consider?
Ebstein
235
Ebstein, HCM and cc-TGA are associated with what?
WPW
236
True or False: 30% of patients with Ebstein have pre-excitation, 50% of those with an accessory pathway will have more than 1 accessory pathway
True
237
What dysrhythmias are patients with Ebstein at risk for?
1. Re-entrant SVT (accessory pathway)
2. Atrial tachycardia/flutter (dilated atrium)
3. Atrial fibrillation
238
True or False: Isolated PS often results in RAE on ECG?
False
239
What are 1st steps in treatment of neurocardiogenic or vasovagal syncope?
1. Fluids
| 2. Behavior modifications- exercise, etc.
240
When should tilt-table testing be used in the diagnosis of neurocardiogenic syncope?
Only if diagnosis can't be made by history alone
241
When does digoxin toxicity commonly occur?
Acute or chronic renal failure
242
What electrolyte imbalance increases the cardiac sensitivity to digoxin?
Hypokalemia and hypomagnesemia
*Can become cardiotoxic even with therapeutic digoxin levels
243
Management of digoxin toxicity?
- ICU
- Hydration
- O2
- Temporary transvenous pacemaker (severe bradycardia)
- Dig immune Fab
- Lidocaine
244
What is a big problem with digoxin toxicity?
Arrhythmias
245
How should beta-blocker be used in digoxin toxicity?
- Can be helpful for supraventricular tachycardias with rapid ventricular rates
- Cautious if sinus node suppression or AV block, can cause further bradycardia
- Use shorter acting like esmolol
246
What anti-arrhythmics can help with ventricular arrhythmias in digoxin toxicity?
1. Lidocaine
| 2. Phenytoin
247
What causes ventricular arrhythmias from digoxin?
Result from early afterdepolarization (depolarization of the ventricular myocardium during early repolarization)
*Same as long QT
248
What is Dig immune Fab made from?
Immunoglobulin fragments from sheep which have been exposed to a digoxin derivative
249
How does Dig immune Fab work?
Irreversibly binds to digoxin and makes it unable to act on its target cells
250
What do you have to monitor for closely when giving Dig immune Fab?
Anaphylaxis
251
What is the timeframe for onset of action and complete response with Dig immune Fab?
- Onset of action: 20-90 minutes
| - Complete response: 4 hours
252
Ventricular tachycardia with varying QRS morphology?
Torsades de Pointes
253
What is the treatment for Torsades de Pointes?
Mg Sulfate
*5-10mg/kg IV (1-2g adults) as bolus over 30-60 seconds, repeat dose in 5-15 minutes and start drip at 0.3-1mg/kg/hr
254
True or False: Mg Sulfate can be effective even in patients with normal Mg levels in the setting of Torsades?
True
255
What should be done in patients with sustained torsades (especially is Mg isn't available)?
Defibrillation
*But Mg may prevent further recurrences
256
How does adenosine work?
- Via specific adenosine receptor linked to K channel
| - Results in shortening of AP duration and sinus bradycardia/AV block
257
What is the half-life of adenosine?
1-5 seconds
*Metabolized by erythrocytes and endothelial tissue
258
How should adenosine be given?
- Rapid push
- Large vein close to heart
- Saline flush following to ensure entire dose quickly administered in blood stream
259
True or False: Adenosine should be effective regardless of the duration of tachycardia?
True
260
What is the 4th letter of NBG pacing code represent?
Rate response pacing
261
What is rate response pacing?
- Pacemaker uses some type of sensor to detect activity and increases the lower rate limit of pacing in conjunction with the level of activity
- When activity ceases, pacing returns to set basal rate
262
What does rate response allow for?
Patients pacemaker can vary the HR when the sinus node can't provide appropriate rate for body's demands
263
When is rate-response pacing indicated?
Patients who have chronotropic incompetence (HR can't reach appropriate levels during exercise, etc)
264
What is the 5th letter in NBG code used to signify?
Biventricular pacing
*Pacing both left and right ventricles
265
When would you use AAIR pacemaker settings?
Sinus node dysfunction
266
What does AAIR pacing mean?
It can only sense and pace in the atria
267
AAIR pacing is only indicated when?
Problem with sinus node
*To correct any degree of heart block, a lead in ventricle is needed
268
A patient will get a defibrillation shock if the ventricular rate goes above what rate?
Programmed shock rate or v-fib zone
269
True or False: In the v-fib zone, patients will receive a shock if the ventricular rate is above the set rate, even if the rhythm is sinus?
True
*Separate v-tach zone can be set with discriminators to try to determine if the arrhythmia is a sinus tachycardia or atrial tachycardia and can be programmed to withhold shock therapy if the device determines patient isn’t in v-tach... in v-fib zone, discriminators aren’t available and the device will deliver therapy purely base on the ventricular rate
270
True or False: A patient who is in slow v-tach might not receive a shock?
True- if V-tach occurs at a rate lower than the set shocking rate
271
What is one of the most common reasons for inappropriate shocks in patients with ICD?
Sinus tachycardia in the VT zone
272
Why do you need to be cautious with someone who has a pacemaker and is getting a surgery where electrocautery will be used?
Electrocautery can create inappropriate noise and sensing within the pacemaker thus causing it to oversense and prevent necessary pacing
273
How do you prevent oversensing due to electrocautery from a surgery?
Place a magnet over the pacemaker to cause asynchronous pacing
274
What happens if you place a magnet over a pacemaker/ICD?
- Asynchronous pacing in a programmed mode
- Disables all shock therapy --Avoids inappropriate shocks due to oversening from electrocautery during surgery
- Stops appropriate shock delivery due to v-tach
* Over ICD: Disables shock therapy, but pacing isn't affected
* Over Pacemaker: Asynchronous pacing
275
In the absence of a known reversible or treatable cause of sudden cardiac arrest, what is the treatment of choice?
ICD
*Class I indication
276
Newborn with an ECG showing LAD, LVH, RAE and decreased right sided forces?
Tricuspid atresia
*Can also see short PR w/o preexcitation
277
CAVC, primum ASD, tricuspid atresia and WPW can all cause what on ECG?
LAD
278
True or False: LVH only rarely causes LAD in pediatrics?
True
279
HLHS, truncus and ToF may show what on ECG?
RAD/RVH
*Could be normal in newborn period though
280
What are some potential ECG findings in a baby with truncus?
- RAD/RVH
| - Normal axis, combined ventricular hypertrophy
281
Complete heart block in utero is strongly associated with that?
Maternal antibodies to SSA/SSB
282
What is the common maternal history in a baby with complete heart block?
-Often asymptomatic, but with underlying autoimmune diseases like SLE or Sjogrens
283
How does maternal SLE/Sjogren's cause neonatal heart block?
Unknown... presumed due to transplacental passage of IgG autoantibodies from Mom to baby
284
What screening should be done for Mom and baby when baby has complete heart block?
Anti-SSA
| Anti-SSB
285
True or False: 22q11 deletions are a rarely reported in some patients with complete heart block?
True
286
What can cause a wide complex rhythm with sine wave pattern and no differentiation between QRS and T wave
- Hypoxia
- Acidosis
- Hyperkalemia
287
What happens to the ECG with hyperkalemia?
- Initially tall peaked T-waves
- T waves become more peaked
- Intraventricular conduction delay
- Widened QRS
- PR prolongation
- ECG looks like sine wave or wide v-tach
288
At K concentrations above what does atrial standstill, AV block or v-fib occur?
>9
289
Increased Ca causes what on ECG?
Shortened QT interval
290
What is represented by the HV time on an EP study?
The time it takes for the signal to get through the AV node and bundle of his (His to ventricle time)
291
What is a normal HV time?
35-70msec
292
How is the HV interval calculated?
Measure the distance from His deflection to earliest QRS deflection on any lead on surface ECG
293
What does a short HV (<25-35msec) indicate?
Alternative method of conduction other than the AV node... only possible in presence of an accessory pathway
294
What does it mean if the HV interval is negative?
Accessory pathway with the ventricular myocardium in close proximity to the site of the accessory pathway being activated prior to bundle of His
295
What effect do BBB and infra-Hisian conduction delay have on the HV interval?
Prolongs it
296
What change in the AH interval is seen with 1st degree AV block?
Prolonged
297
What is seen during an atrial extrastimulus protocol which results in prolongation of the AH interval?
Dual AV node physiology
298
What is the classic arrhythmia seen in patients with long QT?
Torsades
299
What characterizes Torsades?
QRS complexes change morphology
300
What effect does erythromycin have on the QTc?
Prolongs it
301
What is the treatment of choice for atrial flutter?
Cardioversion
302
Why should CCB be avoided in newborns?
Newborn heart sensitive to Ca... CCB can result in long pauses and have been associated with sudden death with longer term use
303
True or False: Majority of neonates who present in atrial flutter have no underlying structural heart disease and a low incidence of recurrence
True
* Newborn myocardium has unique properties which allow it to conduct very rapidly
* Rates over 400bpm can be maintained with no structural heart disease
* Need to echo these patients
304
Irregularly irregular rhythm?
A-fib
305
What does a-fib increase the risk of?
Stroke
306
Why does a-fib increase risk of stroke?
- No organized atrial contractions
- Stasis in atria
- Predisposes to thrombi/potential strokes
307
True or False: The risk for stroke can persist for a period of time in a-fib even after sinus rhythm is restored
True
308
Progressive prolongation of the PR interval followed by a dropped beat?
Mobtiz type 1 second degree AV block (Wenckebach)
309
True or False: Mobitz type 1 second degree AV block is not uncommon in teens and older adults while sleeping?
True (rare while awake)
310
What is the management for asymptomatic Mobitz type 1 second degree AV block?
If isolated in an asymptomatic person while sleeping, likely no clinical significance with no therapy or further evaluation
311
What finding on exercise stress testing in someone with pre-excitation indicates an accessory pathway that won't rapidly conduct to the ventricle in a-fib and is low risk for sudden death?
Loss of preexcitation in a single beat (go from a wide/pre-excited QRS to a narrow QRS)
312
True or False: Risk of SVT can be assessed by a baseline ECG in someone with preecitation?
False- Antegrade conduction seen on resting ECG has no definitive relationship with the retrograde conduction that causes SVT
313
What are 2 signs indicative of atrial lead dysfunction?
- Intermittent atrial undersensing
| - Atrial pacing with no evidence of capture
314
What ECG findings are seen in anorexia?
- Sinus bradycardia
- Low voltage QRS
- Low amplitude T-waves
315
What is the body's response to nutritional deprivation?
Decreased HR
316
What is the classic pattern seen in typical AVNRT on an EP study?
Activation via Bundle of His to Atrium followed by ventricle
317
What causes pattern of His deflection, ventricle followed by an atrial activation at least 20-40msec following QRS?
Accessory pathway mediated tachycardia
*Goes down AV node through ventricle up accessory pathway to atrium and back down AV node
318
Atypical AVNRT is what type of tachycardia?
Long RP
319
CAVC, primum ASD and tricuspid atresia all have what in common on ECG?
LAD
320
List forms of CHD which may have a RAD?
Truncus
TAPVR
ToF
CoA
321
Extreme left axis deviation (northwest axis)?
CAVC
322
An ECG with S wave > R wave in I and aVR gives an axis between what?
-90 to -180 (northwest)
323
What are clues to a northwest axis?
- LAD with S wave > R wave in leads I and aVF
- Small Q in I and aVL…. Axis went through a counterclockwise vectorcardiogram loop to get to final axis (If axis went clockwise (through RAD), there would be Q waves in II, III and aVF)
324
What should you consider with extreme biatrial enlargement on ECG?
Restrictive cardiomyopathy
*Patients are at risk for Pulmonary HTN
325
Massive biventricular hypertrophy and short PR interval should make you consider what?
Glycogen storage disorder (type 2- Pompe)
*Patients often present with hepatomegaly
326
RBBB with ST segment elevation in V1/V2?
Brugada
327
What causes Brugada?
Channelopathy affecting Na transport
328
What are the clinical manifestations of Brugada?
- Ventricular tachyarrhythmias
- Recurrent syncope
- SCD
329
What should be done for someone with Brugada and syncope or ventricular arrhythmias?
ICD
330
True or False: Amiodarone can exacerbate ventricular arrhythmia in Brugada?
True
331
True or False: Patients with spontaneous ECG for Brugada are thought to be at risker risk for arrhythmia
True
332
Genetic defect associated with Brugada?
SCN-5A
333
Brugada results from a mutation in what type of electrolyte channel?
Na
334
HERG and KCNQ1?
LQTS
335
What drug can bring out a Brugada pattern on ECG?
Class I- Procainamide
336
Progressive prolongation of the AH interval with PR interval followed by a non-conducted beat?
Wenckebach (Mobitz Type 1 2nd degree AV block)
337
Diffuse ST segment elevation and PR segment depression?
Pericarditis
338
What is one of the most common causes of pericarditis?
Coxsackie
339
What changes can be seen on ECG with cocaine abuse?
ECG changes localized to one segment... appears abnormal without true acute infarction
340
What effect does cocaine have on the heart?
Can cause coronary vasospasm and ischemia
341
Myosin heavy chain mutation?
HCM
342
What can be seen on ECG in HCM?
1. LVH with strain
2. Short PR interval (pre-excitation or pseudo-preexcitation)
*Rapid AV nodal conduction seen in HCM
343
What changes can increased intracranial pressure cause on ECG?
T-wave changes and QT prolongation
344
What effect does erythromycin have on the QT interval?
Prolongs
345
What should you consider with an irregular wide complex tachycardia?
A-fib in the presence of either pre-existing BBB or pre-excitation (WPW)
346
Why is a-fib of concern in someone with WPW?
Patient can have rapid conduction through an accessory pathway and is at risk for v-fib
347
What should be done for someone with an irregular wide complex tachycardia and pulses?
Cardiovert
348
What needs done for someone with WPW and a-fib?
Ablation- Eliminate conduction in accessory pathway since it could conduct very rapidly
*If that isn't possible, should be treated with an antiarrhythmic (flecainide or amiodarone) to slow conduction in accessory pathway
349
What rhythm issue is classically associated with Ebstein, cc-TGA and HCM?
WPW
350
Patients with Ebstein are at risk for what rhythm issue?
WPW and a-fib (due to dilated atria)
351
What drug is relatively contraindicated in A-fib + WPW?
Anything that blocks the AV node (adenosine, dig, CBB)
352
Why are AV nodal blockers relatively contraindicated in WPW?
If a-fib, may cause preferential conduction down accessory pathway resulting in rapid conduction to the ventricle and subsequent v-fib
353
No relationship between P waves and QRS complexes?
Complete AV block
354
When is a pacemaker indicated with complete AV block?
- Symptoms
- Wide complex escape rhythm
- Complex ventricular ectop
- HR <50 without CHD
- HR <70 with CHD
355
List conditions associated with complete AV block
1. Chagas
2. cc-TGA
3. Maternal Ro/La antibodies
4. Endocarditis with abscess formation
356
What should you consider for a long RP tachycardia?
PJRT
| Atypical AVNRT
357
Describe the P waves in PJRT or atypical AVNRT?
Deeply negative in II, III and aVF
358
What is PJRT?
-Accessory pathway-mediated tachycardia due to a slowly conducting accessory pathway typically located in the right posterior septum
359
Where is the accessory pathway typically located in PJRT?
Right posterior septum
360
Why is the there a long RP interval in PJRT?
-Accessory pathway conducts slowly so atrial activation is seen a significant time following QRS
361
True or False: PJRT and AVNRT should break with adenosine?
True- But both tend to be incessant and may reinitiate quickly after termination with adenosine
362
What happens after adenosine is given in flutter?
It will continue with the P-waves in a saw-tooth pattern
363
What happens after adenosine is given in sinus tachycardia?
Slows transiently, then speeds back up
364
What might happen after adenosine is given in a sinus or atrial tachycardia in the presence of preexcitation?
QRS may widen transiently as AV node blocks and there is preferential conduction down AV node
365
What is the differential diagnosis of long RP tachycardia:
Atrial tachycardia
PJRT
Atypical AVNRT
*Flutter can also present as a long RP tachycardia
366
Describe a Mahaim fiber
Accessory pathway which conducts only antegrade
367
How does a Mahaim fiber present?
Wide complex tachycardia
368
How to you determine location of an accessory pathway on an EP study?
Look for area of earliest atrial activation once in SVT
369
Where does the CS catheter run in an EP study?
In the CS- so along the AV groove between LA/LV
370
Where would an accessory pathway be located if the earliest atrial activation was in the mid-CS?
Left-sided pathway
371
What ECG finding is a poor prognostic sign in someone with Long QT?
QRS alternans or alternating pattern of the appearance of the T-waves
372
What does an alternating pattern of appearance of the T-waves increase risk for in someone with long QT?
2:1 AV block and sudden death
373
True or False: Methadone does not prolong the QT interval
True
374
What screening needs done with long QT?
Other family members need to be screened... most cases familial
375
The underlying mutation which causes long QT most often involves which channels?
Na or K
376
Ca channel mutations are a common cause of what dysrhythmia?
CPVT
377
What is rate responsiveness on a pacemaker?
- Allows pacemaker to increase pacing rate in response to patient activity
- Denoted by 4th letter of NBG pacing code
378
How does rate responsiveness work in a pacemaker?
Accelerometer which senses motion and increases patient's pacing rate in response
379
True or False: Electromagnetic interference may inhibit rate responsiveness on a pacemaker?
True
*Also can cause it to pace asynchronously
380
How would oversensing affect heart rate?
Decrease- From inhibition of pacing
381
What happens when a magnet is placed over a pacemaker?
Asynchronously paces at a set rate determined by the pacemaker manufacturer (AKA Magnet rate)
382
What are classic ECG findings of Brugada?
ST segment elevation
| RBBB in V1 and V2
383
What type of ECG pattern carries the highest risk for arrhythmias in Brugada?
Spontaneous Brugada ECG pattern
384
True or False: Some patients with Brugada may have a normal ECG at rest?
True
385
What can trigger the ECG findings in Brugada?
Fever... patients can have increased incidence of arrhythmias during febrile illness
386
What adjustment in ECG lead position can bring out ECG findings of Brugada?
"High-lead" placement of V1/V2...Involves moving 2 leads up one or two intercostal spaces in attempt to bring out characteristic changes in J-point ad ST segments of leads V1/V2
387
What drug can be infused to bring out the typical ECG findings of Brugada?
Procainamide
388
What is a typical trigger for LQTS type 2?
Emotional stress
389
What can exacerbate symptoms in patients with HCM?
Dehydration
390
True or False: HTN can cause LVH with strain?
True
391
The majority of events in LQTS type 3 happen when?
Sleep
392
What is the purpose of chronic resynchronization therapy (CRT or biventricular pacing)?
Try to promote ventricular synchrony in patients with HF and a wide QRS
393
What are the indications for CRT?
- LVEF less than or equal to 35%
- Sinus rhythm
- LBBB with QRS duration greater than or equal to 150msec and NYHA class III, III or ambulatory IV symptoms on guideline directed medical therapy (only class I indication)?
394
What is the only class I indication for CRT?
LBBB with QRS duration greater than or equal to 150msec and NYHA class III, III or ambulatory IV symptoms on guideline directed medical therapy (only class I indication)?
395
When is CRT beneficial?
Usually only in EF < 35% and after medical therapy has been optimized
396
True or False: CRT decreases incidence of arrhythmias?
False- CRT only improves symptoms, doesn't decrease incidence of arrhythmias or increase survival
397
True or False: There is some evidence that CRT may be beneficial with narrower QRS duration and in patients with RBBB pattern
True- But tends to have lower success rate in these patients and isn’t a class I indication
