MODULE 1 Flashcards
Name the three layers of the heart wall tissue from inside out…
Endocardium
Myocardium
Epicardium
How many papillary muscles does the normal left venticle have?
TWO
Antero-lateral
Postero-medial
Blood supply for the anterolateral papillary muscle in the left ventricle…
Anterolateral muscle blood supply: left anterior descending artery (LAD) and left circumflex artery (LCX)
Posteromedial muscle blood supply provided by what vessel?
Posteromedial muscle blood supply: right coronary artery (RCA)
The posteromedial muscle ruptures more frequently because it only has one source of blood supply.[3]
Typical atrial flutter is abbreviated as:
Cavo-tricuspid Isthmus Dependent Flutter (CTI)
What are the 3 EGMs that read on a HIS catheter?
A H V
List the Catheters that make up a typical study along with the colors typically used to denote them.
HRA - red
HIS - Yellow
CS - Green
RVA - Magenta
When troubleshooting displays, what’s the first thing to consider?
“Connectology”
Beginning with the catheter …describe the connections required to get a signal on the system…
Catheter connector cables Blocks or pods Amp Recording System Monitors
Define gain:
Increases amplitude of the signal
Define clipping:
Constrains the size of a signal to a geographic location on the monitor such that two adjacent signals don’t overlap
Explain high pass filters:
Allow signals higher than the preset frequency to pass through to the monitor. This means that it STOPS lows frequency signals (wandering baseline) from getting through
Explain low-pass filters
Allows signals whose frequency are less than the preset to be passed through to the monitor. This means it STOPS high frequency signals. For example, any signal with a freq lower than 500hz will be allowed to pass through and above 500hz it will be blocked.
The notch pass filter is a special filter for what frequency?
60hz
NSR Signal Sequence
HRA A HIS A CS A H RVA V HIS V / CS V
What does the PA interval mark?
How long is it normally?
What two signals are used to measure it?
SA Node to AV Node
35-45ms
Surface P wave to A wave on HIS
What does he AH Interval Mark?
What signals are used to measure it?
Average times?
Time for the signal to travel through he AV node
HIS channel
70-80ms
HV Interval marks what?
Average times?
Signals used to measure it?
HIS to ventricles time
35-45ms
HIS deflection to earliest V activation on any channel
What three measurements make up the PR Interval?
P-A + A-H + H-V
What does a long HV Interval suggest?
Distal His-Purkinje disease
Define the AV Node’s ERP.
The longest atrial extra stimulus (A1-A2) that FAILS to conduct to the His Bundle at the extra-stimuli are gradually decremented (brought closer to the last beat of an 8 beat drive cycle).
Define Wenckebach Cycle length.
Longest cycle that blocks down the AV Node. A short BCL indicates tissue capable of sustaining rapid rates during a tachycardia.
Establishing the retrograde Wenckebach cycle length answers 4 questions:
- Did the pacing capture the ventricle?
- Is there VA conduction?
- What is the pattern of the retrograde atrial activation?
- Does the VA time stay constant or is it prolonged (decrements) as we increase the pacing rate?
Retrograde patterns of conduction defined.
- Central or concentric: via the AV NODE. The yellow HIS A being the first A seen following the large V. CS A’s follow in this order: 7-8, 5-6, 3-4, 1-2.
- Eccentric: the earliest A signal is not at the HIS A…suggesting an AP.
Does the VA time stay constant or prolonged (decrements) as we increase the pacing rate?
We expect the AV Node to start slowing at higher pacing rates.
APs do not decrement at higher rates.
Therefore, if there is no decrement during higher rates…suggests an AP.
While conducting VA Retrograde Pacing BCL testing, no AV Decrement is noted…this could suggest what condition?
WPW
While conducting Ventricular Extra Stimulus pacing…you note a “jump” in the VA Conduction…what 3 things could this jump suggest?
- Block of the fast AV nodal pathway switching to the slow AV nodal pathway
- Block in the AP switching to the AV node or vice versa.
- Retrograde block in the RBBB followed by trans-septal conduction and conduction up the LBBB.
Define the Retrograde ERP.
The point at which VA Conduction fails to conduct to the atrium since it has not had sufficient time to recover after conducting the last S1
Define the Ventricular ERP.
The point at which the ventricular myocardium itself can no longer respond to the S2 since it is still refractory from the previous S1
Documented as NC or VERP
NC typically occurs with the S2 interval in the range of 200-250ms
Atrial extra stimulus pacing typically induces the target arrhythmia? T or F
T
Which interval during atrial extra stimulus testing is of particular interest due to its tendency to prolong conduction?
AH interval
Starts around 80ms and stretches to 200ms.
An AH of 210-220ms suggest a second “slow” pathway exists.
Reentrant Tachy
The circuit is facilitated by this zone of ______ conduction. Tachycardia is initiated by an ________ beat that blocks in one zone and “reenters” via the other zone to initiate a circular movement.
Slow
Ectopic
AVNRT
What are different ways to describe the slow / fast pathway phenomenon?
Dual AV Nodal Pathways
Longitudinal Dissociation
A patient with dual pathways is in normal sinus. The signal travels down the fast pathway and conducts. The signal also travels down the slow pathway. What happens to it?
It runs in to the lower common pathway (LCP) and finds it refractory due to the preceding wavefront.
An important practical note for ablation is that the the slow pathway usually enters the AV Node ________ near the __________
Inferiorly
CS Orifice
During the “jump” in extra stimulus testing, we are demonstrating the ____ of the fast pathway.
ERP
A 50ms prolongation in the AH interval with a 10ms shortening of the S1-S2 interval is significant.
AH intervals of ____ to _____ are considered slow pathways.
250 to 700ms
We have been unsuccessful in initiating the target arrhythmia? What can we try?
S2-S3
Isoprotenerol or Atropine
Before tachycardia is induced, we often see an AV Nodal ____. Defined as a beat that returns to its origin and is in actuality a single beat of ________ tachycardia.
Echo
Reentrant
Delta waves represent….
APs conducting directly to the ventricles leading to pre-excitation of the ventricles.
What are the 4 locations for an accessory pathway?
Right sided
Left sided
PeriNodal
Septal
If an AP conducts retrogradely only, we consider it __________ since there is no pre-excitation on the EKG and the presence of a pathway is not present.
Concealed
Define the pathway for an orthodromic AVRT.
Down the Node to the ventricles
Retrograde to the atria through the AP
(Narrow QRS Tachycardia)
Define the pathway for an antedromic AVRT.
Atrium down the AP to the ventricles
Back up AV node to the atria
(Wide QRS tachycardia)
AF ablation to isolate PVs…must be mindful of potentially damaging the ________ esophagus therefore we must use a ___________.
Esophagus
Esophageal Temperature Probe
Tachycardias are caused by one of three underlying mechanisms:
1) reentry
2) enhanced automaticity
3) triggered activity
Give examples of macro-reentry
a flutter
AVNRT
AVRT
Give an example of focal tachycardia
Atrial tachycardia
Macroreentrant rhythms are more readily induced using ___________, whereas triggered or automatic rhythms are less readily induced using _________ maneuvers.
Extra-stimuli pacing
Pacing
The main purpose of entrainment is to determine the __________ of the pacing catheter to the _____________.
Proximity
Tachycardia circuit
Using entrainment to discern between AVRT and AVNRT
PPI-TCL
>115ms AVNRT
<115ms AVRT
Explain the para-Hisian pacing process.
Pace in the vicinity of the HIS at a high output in order to capture the HIS Bundle. Note the V-A time. (Look for a narrow QRS)
Then pace at a low output and make the same measurement (Look for wide QRS)
If there is an AP…then the times will be the same. If not, the low pace output time should be longer since the wave must travel through the myocardium and not the HIS.
