1
Q
What is the primary purpose of an electrophysiology (EP) procedure?
A
To diagnose and treat electrical activity issues in the heart.
2
Q
What is the purpose of a temperature monitoring system during an ablation procedure?
A
To prevent overheating of heart tissue.
3
Q
What role does the software play in an EP mapping system?
A
It processes and analyzes electrical signals to create visual maps.
4
Q
True or False: A normal intracardiac electrogram shows consistent and regular waveforms.
A
True.
5
Q
What does the P wave represent in an intracardiac electrogram?
A
Atrial depolarization.
6
Q
True or False: The T wave represents ventricular repolarization.
A
True.
7
Q
What is the significance of the isoelectric line in an electrogram?
A
It indicates the baseline electrical activity of the heart.
8
Q
Fill in the blank: The distance between two successive R waves is known as the _____ interval.
A
RR.
9
Q
True or False: The atrioventricular node is responsible for the delay in conduction between atria and ventricles.
A
True.
10
Q
What does a negative deflection in the electrogram typically indicate?
A
Repolarization of the heart muscle.
11
Q
Fill in the blank: The _____ interval is measured from the start of the P wave to the start of the QRS complex.
A
PR.
12
Q
What can cause variations in the baseline of an intracardiac electrogram?
A
Electrode placement and patient movement.
13
Q
What does the term ‘depolarization’ refer to?
A
The process of heart muscle cells becoming electrically activated.
14
Q
Fill in the blank: The _____ wave is the first deflection seen in a normal electrogram.
A
P.
15
Q
What is the expected morphology of a normal T wave?
A
Asymmetric and usually upright in most leads.
16
Q
What does a biphasic T wave indicate?
A
Possible repolarization abnormalities.
17
Q
What is the primary purpose of baseline measurements in an EP study?
A
To establish a reference point for comparison during the study.
18
Q
True or False: Baseline measurements should be taken before any pharmacological agents are administered.
A
True
19
Q
What does the term ‘conduction velocity’ refer to in EP studies?
A
The speed at which electrical impulses travel through the heart.
20
Q
What is the role of sinus node recovery time in baseline measurements?
A
It assesses how quickly the heart’s natural pacemaker can resume pacing after a period of stimulation.
21
Q
What is the importance of measuring the QRS duration at baseline?
A
It helps in assessing the conduction time through the ventricles.
22
Q
What does a prolonged PR interval indicate in baseline measurements?
A
Potential atrioventricular block.
23
Q
What does the term ‘threshold’ refer to in the context of pacing during baseline measurements?
A
The minimum current required to induce a contraction.
24
Q
Fill in the blank: The __________ interval is a key measurement for assessing the risk of sudden cardiac events.
A
QT
25
What is incremental pacing?
Incremental pacing is a method where the pacing rate is gradually increased over time.
26
What is extrastimulus pacing?
Extrastimulus pacing involves introducing additional stimuli to assess the heart's response.
27
Multiple Choice: Which method is typically used to assess the refractory period?
Extrastimulus pacing
28
Fill in the blank: In extrastimulus pacing, a _______ stimulus is introduced to test the heart's response.
premature
29
What is a key difference between incremental and extrastimulus pacing?
Incremental pacing gradually increases the pacing rate, while extrastimulus pacing introduces additional stimuli.
30
What does the term 'stimulus coupling interval' refer to?
The time between the extrastimulus and the preceding beat in extrastimulus pacing.
31
True or False: Ventricular incremental pacing is used to evaluate ventricular response to pacing stimuli.
True
32
Fill in the blank: Incremental pacing helps determine the _______ of conduction pathways during an EP study.
threshold
33
How does incremental pacing contribute to understanding arrhythmias?
It helps to induce arrhythmias to study their mechanisms and characteristics.
34
What is one key indicator of effective atrial pacing?
Consistent capture of the atrium.
35
Name one potential outcome of ventricular incremental pacing.
Induction of ventricular tachycardia.
36
What is the role of pacing intervals in incremental pacing?
To gradually increase the pacing rate to assess the heart's response.
37
What is a common complication to monitor for during incremental pacing?
Arrhythmias or hemodynamic instability.
38
What type of pacing is used to evaluate the refractory period of the atrium?
39
Fill in the blank: Incremental pacing can help determine the _______ of arrhythmias.
mechanism
40
What can be inferred if the threshold for ventricular pacing is significantly higher than expected?
Possible underlying conduction system disease.
41
Fill in the blank: Ventricular extrastimulus pacing is typically performed to assess _____ in the ventricular conduction system.
reentrant circuits
42
What is the significance of the coupling interval in extrastimulus pacing?
It determines the timing of the extrastimulus in relation to the preceding heartbeat.
43
Fill in the blank: The technique of extrastimulus pacing can help differentiate between _____ and _____ arrhythmias.
reentrant; non-reentrant
44
Multiple Choice: What does a short coupling interval in extrastimulus pacing indicate? A) Increased chance of arrhythmia induction B) Decreased heart rate C) Normal conduction D) None of the above
A) Increased chance of arrhythmia induction
45
What is the typical pacing site for atrial extrastimulus pacing?
The right atrium
46
Fill in the blank: Extrastimulus pacing is often used in conjunction with _____ to provide a comprehensive assessment of the heart's electrical activity.
mapping techniques
47
What does the term 'extrastimulus' refer to?
An additional electrical impulse delivered to the heart.
48
True or False: The goal of extrastimulus pacing is to induce an arrhythmia for diagnostic purposes.
True
49
What is the main difference between atrial and ventricular extrastimulus pacing?
The site of stimulation and the type of arrhythmias assessed.
50
Fill in the blank: During an EP study, the pacing threshold is determined by gradually decreasing the _____ of the extrastimulus.
interval
51
True or False: The absolute refractory period is when a cell cannot respond to any stimulus, no matter how strong.
True
52
Fill in the blank: The relative refractory period follows the _____ refractory period.
absolute
53
Short Answer: How is the refractory period measured during an electrophysiology study?
By delivering a series of stimuli and observing the timing of action potentials.
54
What is the significance of the refractory period in arrhythmia management?
It helps to determine the susceptibility of the heart to reentrant circuits.
55
Short Answer: What role does the autonomic nervous system play in refractory periods?
It modulates heart rate and can alter refractory periods through sympathetic and parasympathetic activity.
56
What is the relationship between the refractory period and the action potential duration?
The refractory period is closely related to the duration of the action potential; longer action potentials generally result in longer refractory periods.
57
Multiple Choice: Which drug class can prolong the refractory period?
Class III antiarrhythmics
58
What type of refractory period occurs immediately after depolarization?
Absolute refractory period.
59
True or False: The refractory period can be measured using pacing protocols during an EP study.
True
60
Fill in the blank: The refractory period can be affected by changes in _____ concentration.
potassium
61
Short Answer: Why is it important to accurately measure refractory periods during an EP study?
To evaluate the risk of arrhythmias and guide treatment strategies.
62
What is the main difference between the absolute and relative refractory periods?
The absolute refractory period is when no action potential can be generated, while the relative refractory period allows for a potential if the stimulus is strong enough.
63
What are the two phases of the refractory period?
The absolute refractory period and the relative refractory period.
64
Fill in the blank: The absolute refractory period occurs during the ________ phase of the action potential.
depolarization
65
How long does the absolute refractory period typically last?
Approximately 1-2 milliseconds.
66
Multiple choice: Which of the following best describes the relative refractory period?
A period where a stronger stimulus can initiate an action potential.
67
What is the primary ion responsible for the depolarization phase during the action potential?
Sodium (Na+)
68
Fill in the blank: The ________ period is when no action potential can be generated, regardless of stimulus strength.
absolute refractory
69
What role do potassium ions (K+) play during the refractory period?
They are involved in repolarization, contributing to the relative refractory period.
70
What is the relationship between refractory periods and the conduction velocity of action potentials?
Longer refractory periods can lead to slower conduction velocities.
71
True or False: Refractory periods can be influenced by pharmacological agents.
True
72
How can the refractory period be clinically significant?
It can affect the treatment of arrhythmias and other cardiac conditions.
73
True or False: The normal PR interval range is 120 to 200 milliseconds.
True
74
What is the normal QT interval corrected for heart rate known as?
QTc
75
What is the normal range for the QT interval in milliseconds?
Less than 440 milliseconds for men and less than 460 milliseconds for women
76
True or False: A prolonged PR interval can indicate first-degree heart block.
True
77
Multiple choice: Which interval is primarily evaluated to assess atrial conduction?
A) QRS interval
B) PR interval
C) QT interval
D) RR interval
B) PR interval
78
What is the average duration of a normal QRS complex?
Less than 100 milliseconds
79
True or False: A normal PR interval suggests proper atrioventricular conduction.
True
80
Fill in the blank: The normal ST segment is typically isoelectric, meaning it is at the same level as the ___ line.
baseline
81
What does a short PR interval indicate?
Possible pre-excitation syndromes like Wolff-Parkinson-White syndrome.
82
What can a prolonged QRS duration suggest?
Ventricular conduction delay or bundle branch block.
83
Fill in the blank: The QT interval varies with the heart rate; it is corrected using the ___ formula.
Bazett's
84
Multiple choice: A normal QTc interval is considered to be less than:
A) 450 ms
B) 460 ms
C) 470 ms
D) 480 ms
B) 460 ms
85
Fill in the blank: The __________ interval is the time from the onset of atrial depolarization to the onset of ventricular depolarization.
PA interval
86
Identify the interval measured from the end of ventricular depolarization to the start of repolarization.
QT interval
87
What does a prolonged A-V interval indicate?
It may suggest a block in the conduction system.
88
What is the relationship between the QT interval and heart rate?
The QT interval shortens as heart rate increases.
89
Fill in the blank: The __________ interval is critical for assessing the timing of ventricular contraction.
QRS
90
What effect does medication have on intracardiac baseline intervals?
Some medications can prolong or shorten these intervals.
91
PA Interval
-Define
-Where to measure
-Normal value
-Time it takes for the electrical signal to travel
from the SA node to the AV node (onset of atrial depolarization and the onset of ventricular depolarization)
-Measure from the onset of the P‑wave on the
surface ECG to the rapid deflection of the A‑wave on the H IS
channel.
-25-55 ms
92
AH Interval
-Define
-Where to measure
-Normal value
-Importance
-Trans-nodal conduction time, or the time it takes for the electrical signal to
travel through the AV node.
- Measure on the HIS channel as the A signal to
the onset of the H deflection.
-55-125ms
-You must know the baseline A-H in order to
recognize subsequent AV nodal decrement and potential
“jumps.”
93
H-V interval
-Define
-Where to measure
-Normal value
-Importance
- Measure from the onset of the H IS deflection to the
earliest onset of ventricular activation on any channel available,
either intracardiac or ECG.
-This is the His to ventricular activation time, that is,
the time it takes for the electrical signal to travel from the His
bundle to the ventricles.
-35-55ms
94
On a surface ECG, these three measurements make up the
PR interval:
PR interval = P-A + A-H + H-V
= 40 + 80 + 40
= 160 msec
95
Signal Sequence in Sinus Rhythm
1st: The HRA earliest since this catheter is closest to the sino-atrial (SA) node.
2nd: HIS A- The wave of atrial depolarization has successfully arrived at the AV node.
3rd: CS A - spreads from the proximal CS distally into the left atrium.
4th: The H deflection on the HIS catheter. This indicates that the wave has propagated over the atrio
5th: The RVA it is near the right bundle branch exit, which is usually the first part of the ventricles to be activated. *Note that it is before the HIS V or CS V signals since the wave of depolarization travels down the bundle branches, past the apex, and arrives at the base of the ventricles last.
6th: The HIS V and CS V are the last signals to occur.
Remember that the HIS and CS catheters are positioned at the base of the ventricles.
96
What is the sinus node recovery time (SNRT)?
The time it takes for the sinus node to recover and be ready to generate another impulse after a heartbeat.
97
True or False: The corrected sinus node recovery time (CSNRT) accounts for the influence of heart rate.
True
98
What does CSNRT stand for?
Corrected Sinus Node Recovery Time
99
Short answer: How is corrected sinus node recovery time calculated?
By adjusting the sinus node recovery time based on the preceding heart rate.
100
True or False: Sinus node dysfunction can lead to arrhythmias.
True
101
What role does autonomic nervous system play in sinus node recovery time?
It modulates heart rate and influences the recovery time of the sinus node.
102
Short answer: Why is it important to correct sinus node recovery time?
To provide a more accurate assessment that is not affected by varying heart rates.
103
SNRT: Catheter paced and pacing maneuver.
SNRT varies with sinus rate, so we correct it.
CSNRT equation
Pace the high right atrium (overdrive pacing) for about 30 seconds, and then stop. The SNRT is the time measured from the last paced beat to the first spontaneous sinus beat that resumes after pacing is terminated.
For a more precise value, the corrected SNRT (CSNRT) is calculated by subtracting the patient's baseline sinus cycle length from the SNRT.
CSNRT= SNRT msec -SCL msec
104
What is anterograde atrial Wenkebach?
It is a type of heart block where there is a progressive lengthening of the PR interval until a beat is dropped.
105
What does the term 'Wenkebach' refer to?
It refers to a specific type of second-degree AV block characterized by progressive PR interval elongation.
106
Fill in the blank: Anterograde atrial Wenkebach is also known as _______ block.
Mobitz type I
107
What is the primary mechanism behind anterograde atrial Wenkebach?
It involves a gradual increase in conduction time through the AV node until a beat is dropped.
108
Multiple Choice: Which of the following is a characteristic of anterograde atrial Wenkebach? A) Constant PR interval B) Progressive PR interval lengthening C) Shortened PR interval
B) Progressive PR interval lengthening
109
Multiple Choice: Anterograde atrial Wenkebach is categorized under which type of AV block? A) First-degree B) Second-degree C) Third-degree
B) Second-degree
110
What is the significance of the PR interval in diagnosing anterograde atrial Wenkebach?
It helps to identify the progressive lengthening pattern characteristic of this condition.
111
Fill in the blank: A normal CSNRT is usually less than _____ seconds.
550
112
What might a significantly reduced SNRT indicate?
Increased automaticity or ectopic pacemaker activity.
113
What role does autonomic nervous system play in sinus node recovery time?
It modulates heart rate and influences the recovery time of the sinus node.
114
What does a prolonged CSNRT suggest about the patient's cardiac health?
It may indicate impaired sinus node function or increased susceptibility to arrhythmias.
115
Short answer: How is corrected sinus node recovery time calculated?
By adjusting the sinus node recovery time based on the preceding heart rate.
116
Fill in the blank: A CSNRT of greater than _____ seconds may be considered abnormal.
550
117
What is the significance of corrected sinus node recovery time?
It provides a standardized measure of sinus node function that is independent of heart rate.
118
What does CSNRT stand for?
Corrected Sinus Node Recovery Time
119
True or False: The corrected sinus node recovery time (CSNRT) accounts for the influence of heart rate.
True
120
What is the sinus node recovery time (SNRT)?
The time it takes for the sinus node to recover and be ready to generate another impulse after a heartbeat.
121
What does **Incremental Atrial Pacing** determine?
The CL at which 1:1 conduction over the AV node ceases
## Footnote
This pacing technique helps assess the conduction properties of the AV node.
122
What is the protocol for **Incremental Atrial Pacing**?
* Atrial pace from HRA/CS at CL 50-100 msec faster than SCL
* Decrement by 10 msec until ventricles no longer capture
## Footnote
This method helps identify the conduction limits of the AV node.
123
What is another name for the **Incremental Atrial Pacing** technique?
Antegrade Wenkebach CL
## Footnote
This term refers to the characteristic pattern observed during pacing.
124
What may be observed during **Incremental Atrial Pacing**? List at least one observation.
* Sudden increase in AH interval suggesting dual AV nodal physiology
* Ventricular pre-excitation via an accessory pathway
* Induction of an arrhythmia
## Footnote
These observations can indicate various underlying cardiac conditions.
125
What indicates where we are **pacing**?
Look for the pacing spike
## Footnote
The pacing spike helps in identifying the pacing location.
126
What is sufficient to assess **capture** during pacing for EPS?
2x pacing threshold
## Footnote
This is considered plenty for effective assessment.
127
True or false: **More mA** always indicates better pacing.
FALSE
## Footnote
More mA usually means a bigger spike, but it is not always good.
128
What is the basic unit of time in **EP (Electrophysiology)** studies?
milliseconds (msec)
## Footnote
Everything in EP studies is measured in milliseconds.
129
What does **Cycle Length (CL)** represent in electrophysiology?
Length of time between each heartbeat
## Footnote
CL is calculated using the formula CL = 60,000 / HR.
130
Calculate a patient's resting **Cycle Length (CL)** if his **Heart Rate (HR)** is 100 bpm.
600 msec
## Footnote
CL is calculated as CL = 60,000 / 100.
131
What is the phenomenon where the conduction velocity through the **AV node** decreases as the coupling interval is decremented?
Decremental conduction
## Footnote
This phenomenon is observed when the drive train is decremented, leading to a progressive lengthening of the AH interval.
132
What is the **AV node ERP (AVNERP)**?
Longest A1A2 interval that fails to conduct to the His bundle
## Footnote
Normal AVNERP ranges from 250-400 msec.
133
What is the typical **drive train** duration mentioned?
600 msec
## Footnote
This duration is used for pacing beats (S1) before decrementing the coupling interval (S2).
134
What does the **Atrial ERP (AERP)** represent?
Longest A1A2 interval that fails to capture the atrium
## Footnote
This interval is crucial for understanding atrial conduction properties.
135
As the coupling interval (S2) is decremented, what happens to the **AH interval**?
It progressively lengthens
## Footnote
This lengthening is a key aspect of decremental conduction through the AV node.
136
What is the **typical drive train** of paced beats followed by a decremental coupling interval?
8 paced beats (S1) followed by a single decremental coupling interval (S2)
## Footnote
This setup is used to study conduction properties in the AV node.
137
As coupling intervals become shorter, what happens to the **retrograde conduction velocity** through the AV node?
Decreases
## Footnote
This results in a progressively lengthening or decrementing VA interval.
138
What does **Ventricular ERP (VERP)** represent?
Longest A1A2 that fails to capture the myocardium
## Footnote
This is a critical measure in assessing conduction properties.
139
What is the **normal range** for Ventricular ERP (VERP)?
180-290 msec
## Footnote
This range indicates normal conduction properties.
140
What is the first step in the **Normal EP Study**?
Baseline surface & intracardiac measurements
## Footnote
This step involves gathering initial data before proceeding with further evaluations.
141
What is the second step in evaluating **Sinus node function**?
SACT
## Footnote
SACT stands for Sinus Node Automaticity and Conduction Time.
142
What is the first step in assessing **AV node function**?
Antegrade Wenckebach CL
## Footnote
This step evaluates the conduction properties of the AV node.
It establishes the antegrade block cycle
length or antegrade Wenckebach point of the AV node. We do this
last since incremental atrial pacing has the greatest potential to
induce A F.
143
What is assessed during **VT inducibility**?
* Single extrastimuli from RVA
* Double extrastimuli from RVA
* Triple extrastimuli from RVA
* 600ms and 400ms drive train
## Footnote
These tests help determine the heart's susceptibility to ventricular tachycardia.
144
What are the **six questions** to ask when analyzing **Intracardiac Electrograms**?
* Where does the impulse originate?
* Is the surface ECG 'normal'?
* Impulse propagation across the A-V Node?
* Does the impulse depolarize the chambers on the other side of the AV node?
* Which catheter should sense the impulse first?
* Which catheter does sense the impulse first?
## Footnote
These questions guide the analysis of intracardiac electrograms to understand cardiac impulses.
145
What does **CS** stand for in the context of EP catheter placement?
Coronary Sinus
## Footnote
CS is an epicardial structure that runs behind the Mitral Valve.
146
Where is the **Coronary Sinus** catheter placed?
In the coronary sinus
## Footnote
It allows recording of signals from the Left Atrium and Left Ventricle.
147
How is the **Coronary Sinus** accessed?
* Via its opening (ostium) on the posterior/septal wall of the right atrium
* From above via the Right Internal Jugular vein
* From below via Inferior Vena Cava using a steerable catheter
## Footnote
Femoral vein sheath access is used from below.
148
Where within the heart are the **EP catheters** positioned?
_______
## Footnote
149
What is the typical pattern of **activation** seen on a normal intracardiac electrogram?
_______
## Footnote
The specific pattern is not mentioned in the provided text.
150
What does **HRA** stand for in the context of EP catheter placement?
High Right Atrium
## Footnote
The catheter is placed at the juncture of the right atrium and the Superior Vena Cava.
151
What does the **HRA** catheter record?
* Electrical potentials from the sinus node
* Signals from the right atria
* Ectopic foci in the RA
* Atrial flutter/fibrillation signals
## Footnote
These recordings are crucial for diagnosing and treating arrhythmias.
152
How many electrodes does a typical **HRA** catheter have?
4 electrodes (quadripolar)
## Footnote
The catheter can be either fixed or steerable.
153
What are the **signals that are not normal** in electrophysiology?
* Fractionation
* Double potentials
* Mid-diastolic potentials
* Low-voltage potentials
## Footnote
These signals can provide clues for possible ablation sites.
