Anesthesia Techniques for EP Lab Flashcards
Cardiac Electrophysiology lab began in the late 1960s as a _____ specialty to identify arrhythmogenic foci. It then evolved into ____ for cardiac conduction defects:
- catheter ablations of _______
- device management for bradyarrhythmias (_____) and tachyarrhythmias (________)
It is the fastest growing subspecialty in the field of cardiology. (revenue producing)
diagnostic
treatment
tachyarrhythmias
brady - pacemakers
tachy - ICD implantation for lethal tachyarrythmias
Anesthesia is now involved as procedures are more complex and offsite.
______ duration require patients to remain motionless (complex a-fib cases can be 6-8 hours!)
Patients have more ______ and higher _____.
Arrhythmias are now sought & provoked - mapped/identified to fix the problem.
*Published studies addressing EP & Anesthesia are lacking.
**patients are typically cardiac unstable so can be tense environment.
LONGER duration
comorbidities/higher acuity - they depend on anesthesia to artificially prop up hemodynamically
**every cardiologist wants a different anesthetic setup - this lecture is just the basics.
Review Pacemaker AP vs. Ventricular AP on slide 5:
Remember that ____ and ____ have a lot to due w/ APs and that nodal tissue is very different than ventricular tissue.
Electrophysiologists can fix nodal, ventricular, or both.
K+, Ca++
Autonomic Neurohormonal Influences:
1) ______ is sensitive to autonomic NTs (which effect autonomic tone). _____ tissue is MOST affected. Changes in autonomic tone affect cardiac _____ and impacts ____.
2) PSNS: _____ directly impacts nodal tissue - _____ rate, contractility, and propagation of electrical impulse. _______ can also affect this (tell surgeon before you give).
3) Sympathetic: ______ directly impacts nodal tissue via ___ __ - _____ rate, contractility, and propagation of electrical impulses. If the patient is too light, this may come into play.
1 - Calcium - nodal tissue - conduction, rhythm
2 - acetylcholine - decreased - antimuscarinics
3 - norepinephrine via beta 1 - increases
There are 3 primary mechanisms of arrhythmias:
1) ______ most common cause of _______ (the current jumps to an accessory pathway and then back).
2) Abnormal _______ less common (i.e. cells spontaneously firing)
3) ______ activity
1 - reentry - tachyarrhythmias (electrical signal comes down the normal path, hits ischemic tissue/block, and jumps to alternate path)
2 - automaticity
3 - triggered activity
Reentry Mechanisms:
1) Circuit pathways are initiated between different connected tissues within regions of myocardium.
- Normal current enters refractory tissue and then jumps to an ______ pathway then enters refractory tissue and jumps BACK into normal conduction pathway.
- The abnormal routing of electrical signals in endocardial tissue are near ____ and ____ walls.
- The GOAL is to stimulate a foci ____/_____ node and work ____ tissue until duplicated in a process of elimination to identify problematic tissue.
2) Newly created _____ pathways or _____ pathways (WPW)
3) Different conduction _____ and _____ times.
1 - accessory pathway
atrial and ventricular walls
above/around node - working down
2 - micro-circuit pathways, anatomical
3 - velocities, refractory times
_____ and ____ ______ are 2 common treatments in the EP lab.
ablations of tachyarrhythmias
device implantation
Ablations for tachyarrhythmias can include:
1) _____: normal QRS: AVNRT (atrial ventricular nodal reentry tachycardia), A-flutter, SVT, WPW
2) _____: normal QRS: a-fib, MAT (multiple atrial tach)
3) _____ ____: Vtach, SVT w/ BBB or aberrant conduction pathway
regular
irregular (*ablation for A-fib is about 50% effective)
wide QRS
Device implantations can include:
1) Cardiac _____ _____: cardiomyopathy (RV or LV) & poor LV function
2) ____ ______: symptomatic bradyarrhythmias & heart block
3) ____: prevent lethal arrhythmias in patients w/ severely reduced LV function
4) Implantation of ____ _____ in left atrial appendage
1) cardiac resynchronization therapy (CRT) - heart is out of sync, leads to low EF, low BP
2) permanent pacemaker (PPM)
3) ICD
4) Watchman Device - used in patients who can’t take blood thinners - stops up the appendage to keep blood from clotting
EP Lab Setup:
1) Multiple fluoroscopy arms & multiple large screen displays - HIGH levels of _____ exposure.
2) ______ mapping screens
3) ___ lead EKG (EGM) screens
4) Intra-cardiac ______ (ICE) screens
5) Computer and electrical ____ wires & machines
1 - radiation 2 - electroanatomic mapping **can change w/ varying respirations/coughing/bucking - makes surgeon mad (have to remap to avoid ablating wrong area) 3 - 12 lead 4 - echocardiography 5 - mapping
The EP lab is a _______ _____ anesthesia location. There is not as much access to the patient, and we may not have our normal equipment.
Slide 13 for more info.
non-operating room
Pre-procedure Evaluation:
1) Most have damaged conduction systems from a damaged heart. The patient will have a 12-lead EKG _____ and _____ assessment.
2) ______ results including ___ ____ and ___ function.
3) _____ studies (many are _____)
4) Use of anti-hypertensive agents including ___ ____ that may affect rhythm.
1 - conduction, arrhythmias
2 - echocardiographic - EF and valve
3 - coagulation (anticoagulated)
4 - beta-blockers
Anesthesia Monitoring in EP Lab (Similar to Typical Anesthesia Monitoring)
1) _____, ____ ___, ______, and ____-______ ____ (4)
2) ____ ____ if hemodynamically instability is expected (& for frequent blood draws).
3) ____ if frequent blood draw & secure access is required (used less frequently).
4) Esophageal temperature monitoring for ____ ablations - may require frequent adjustment of probe.
1 - 5-lead EKG, pulse ox, capnography, non-invasive BP
2 - art line
3 - CVL
4 - a-fib
EP Procedure:
1) Access via ____, ____, _____, or ____ VEIN to RIGHT side of heart.
2) Access via _____ ARTERY to LEFT heart or _____ VEIN to RIGHT heart.
- _____ access across aortic valve
- _____ puncture from right to left atrium using fluoroscopic guidance
3) ______required d/t prothrombotic nature of procedure.
- _____ infusions & frequent activated clotting times (ACT) > ____ seconds preferred.
- We may or may not be performing the ACTs
4) Separate ______ catheter probe inserted to identify chambers.
5) Various catheters positioned to identify ablation targets for mapping.
1 - femoral (*most common), SC, brachial, IJ veins
2 - femoral artery for LEFT heart, femoral vein for RIGHT heart
- retrograde access
- transseptal puncture
3 - anticoagulation
- heparin
> 300 seconds
4 - ultrasound
Ablation Electrode Catheter Location & Placement:
1) _____ identifies catheter position inside of cardiac chambers.
2) _____ provides intra-cardiac chamber view for precise location. It can capture right to left transeptal puncture * detect entrance of intra-chamber ____.
3) _____ _____ _____ (ACL): 3 ____ on chest/back forms a matrix surrounding cardiac chambers & uses electrical impedance for location. Catheter location can be pinpointed to w/in __mm of accuracy. This prevents having to use fluoroscopy.
4) ____ _____ image of the heart chamber.
1 - fluoroscopy
2 - ICE (intra-cardiac echo) - AIR
3 - advanced cardiac location: magnets - 1 mm (new w/in 5 years - being used more now b/c way less radiation)
4 - 3D mapping
Mapping points are aligned using computer coordinates from heart ___ or ____.
Red is ____ to electrical activity (see picture on slide 21)
CT or MRI
red is dead (ablated points)
purple (slower conduction)
Inducing arrhythmias is also known as _______.
Induction, identification, and mapping of the arrhythmia is the goal. This is accomplished by:
1) ____ _____ at various fixed cycle lengths
2) _____ _____ ______:
- 8 beat heart rate at 100 bpm followed by premature beats
- premature beats move closer to refractory period until arrythmia is stimulated
- induces both supraventricular and ventricular beats
- electrical impulse signal can identify alternative conduction pathway
3) _____ infusion: ______ is the most commonly used. It is a is a CNS ______ that _____ MAC and _____ BIS score
arrhythmogenesis
1 - burst pacing
2 - programmed electrical stimulation
3 - catecholamine - isoproterenol (CNS simulant - increased MAC, and elevates BIS)
Thermoablation (HEAT) Procedure:
______ energy is the treatment of choice. It is delivered to the identified tissue. The electrode contacts tissue forming a _____. They then heat tissue around the ____ ____ creating a circular scar (to prevent afferent impulses). The lesions stop irregular beats by creating a __-____ _____ in tissues with abnormal electrical activity.
These catheter electrodes are _______ - the damaged tissue can ____.
Lesion size is controlled by power, _____, and _____ of RF.
radiofrequency (RF) lesion pulmonary vein non-conductive barrier prothrombotic - clot power, temp, duration
Heat Ablation Catheter Specifics:
1) Monitor for electrical _____ of blood & tissue. Assess adequacy of electrode-tissue contact. Monitoring is deficient in its ability to accurately assess lesion ____.
2) The catheter tip electrode is cooled w/ saline to decrease tissue damage:
- ____ cc for every ___ dot burn made
- reduces _____ and _____ formation on tip
- may require ____ at end of procedure if a lot is given
- _____ can be caused by temps exceeding ___F at electrode-tissue interface
- A rise in electrical impedance inhibits the ability to ____ tissue.
1 - impedance (tissue may stick to catheter and cause impedance/false reading)
- DEPTH (can burn a hole straight through the chamber - can cause pericardial effusion)
2 - 14 cc for every blue dot
- impedance and coagulum
- Lasix (may use up to 1500 cc - may cause overload)
- thrombus - 100 F
- ablate
- tip also needs to be cool to decrease likelihood of puncturing chamber.
______ uses cold (lower than ___degree) temps w/ ____ lesions created.
It is considered SAFER than heat b/d heat can burn and injure the ____ _____ transmission to the point where it is unrecoverable.
There are normally ___ pulmonary veins feeding the heart. Sometimes accessory branches feeding the heart may also requiring ablating.
cryoablation - <30 degrees - larger
phrenic nerve
*can be easy to hit on accident - must monitor - damage can result in diaphragm injury (can’t extubate)
4 pulm veins
Cryoablation Procedure:
1) Catheter tip w/ _____ _____ is inserted into each pulmonary vein ONE at a time.
2) The balloon is inflated w/ refrigerant to “freeze” tissue which causes the tissue to stop ______.
3) Cryo balloon makes contact w/ pulm. vein creating a _____ _____.
4) _____ of the pulmonary vein does occur when the balloon is inflated.
inflatable balloon
conducting
circular scar
occlusion
Pacing the Phrenic Nerve During Cryoablation:
- Testing of phrenic nerve when ____ pulm. veins are cryoablated.
- Almost CONTINUOUS phrenic nerve pacing when _____ pulm. vein.
- Pacing assesses phrenic nerve function _____ pulm. vein.
- _____ to _____ indicates phrenic nerve is stunned. Nerve transmission reoccurs after nerve rewarms. It can take minutes to hours for transmission to return to pre-cryo function.
- Phrenic pacing is NOT necessary w/ ___ pulm. veins as they are away from the phrenic nerve.
**May be asked to reverse NMBA so they can find where it is to pace.
RIGHT
ABOVE
BELOW
failure to capture
LEFT
Implications for Cryoablation:
1) ___ _____ to allow for continuous phrenic nerve testing
2) will have to ____ anesthetic to keep patient motionless. This may require ___ support w/ Neo, vasopressin, Epi to maintain acceptable ___.
3) _____ and ____ will be affected when balloon is INFALTED.
4) Pacing phrenic nerve can interfere significantly w/ ______. It can also move ____ and cause _____ which can alter EP ____.
1 - NO paralytic
2 - deepen, BP, BP (**freezing is painful/stimulating)
3 - ETCO2 & BP
4 - ventilation, ETT, coughing, map
External Epicardial Ablation Procedure:
1) 2 fly swatter paddles are used and applied to ______ region outside of heart. They enter through the ______ area.
2) ____ moves to inside of heart.
Long-term ____ can be correct.
epicardial
subxiphoid
ablation
A-fib
Post-Ablation Procedure/Testing:
This is a trial to induce arrhythmias using: (3)
burst pacing
programmed electrical stimulation
catecholamine infusion (Isopril)
**same as before
There is very little research regarding anesthesia’s effect on arrhythmogenicity.
Patients w/ _____ conditions w/ potential _____ _____ can affect our choice of anesthetic agent. They may require artificial support of the CV system.
GOAL: ____ anesthesia footprint BUT prevent moving, coughing, bucking.
comorbid - hemodynamic instability
small
SUPRAVENTRICULAR tachyarrhythmias ablations require/prefer as _____ an anesthetic footprint as possible at the START of the procedure for:
- induction/identification of arrhythmia
- theorized that a deeper level of anesthetic impairs induction of arrhythmia
- some cardiologists prefer ____ _____ over GA.
Then a _____ level of anesthesia after arrhythmia induction.
- NO movement preferred during ____ and _____ of arrhythmias.
- coughing/bucking can lose map and require remapping.
LIGHT at start
- some may want moderate sedation
- deep anesthesia CAN impair SVT/arrhythmias from coming forward - esp. volatiles)
DEEP
mapping, ablation
V-TACH ablations require ____ anesthetic at the START during induction of arrhythmias. The patient may not even be able to tolerate _____ anesthesia. Avoid ______ at beginning for phrenic nerve identification to avoid ablating.
Many w/ V-tach dysrhythmias have significant ____ _____: ischemic/non-ischemic cardiomyopathies, LV dysfunction, decompensated cardiac function w/ hemodynamic instability. Symptomatic ventricular ectopy may not be tolerated.
**There are varying opinions regarding GA effect on inducibility of V-TACH arrhythmias. One source says GA does NOT affect inducibility of VT.
lighter at start
deeper
paralytic
heart disease
V-TACH ablations:
- _____ ARTERY access up to left side of heart
- _______ access is more painful requiring deeper sedation
- GREATER risks of myocardial ______, ______, and _____. An art line is preferred when unstable and for frequent blood sampling.
- femoral
- pericardial
- perforation, effusion, tamponade
ATRIAL FIB ablations are _____ and more _____ procedures (6-8 hours) - these require greater time for catheter placement, mapping, and ablation procedure.
A-fib is 90% ____ side while a-flutter is mostly ____ side but could be both.
A ____ is performed prior to procedure to identify ____.
____ _____ is REQUIRED.
__-__ weeks of ______ required prior to cardioversion OR ablation.
longer and more complex
FIB: left
FLUTTER: right (flutter is in a continuous loop)
TEE - clots (*if clots found, ablation is postponed so pt. can start anticoagulation therapy)
tracheal intubation
3-4 anticoagulation
ATRIAL FIB Ablation:
1) _____ must be timed based on phrenic nerve identification.
2) The ablation of the posterior wall of the atria is in close proximity to the ______ wall - ____ _____ REQUIRED even if LMA is used & can be monitored by cardiologist. Excessive heat can perforate!
3) _____ has been successful - minimizes cardiac movement. However, _____ is required d/t unreliability of volatile anesthetics.
1 - paralytic
2 - esophageal - esophageal temp probe (can cause atrio-esophageal fistula & food/contents can get directly in heart)
3 - high frequency jet ventilation (HFJV) - short bursts of breaths; PROPOFOL required
Biosense electrophysiology catheter w/ auto ID technology allows for precision movement of _____ ____ ____ and allows the cardiologist to watch where it is at all times. **NO fluoroscopy is necessary.
esophageal temp probe
Device Implantation:
BIVENTRICULAR pacemakers have a ____ generator and ___ leads: ___, ____, and ____ (which allows for pacing of LV).
The coronary sinus is in close proximity to the ____ ____. It is _____/_____ aspect of the LV. Too high voltage on LV pacer lead will stimulate the phrenic nerve causing diaphragmatic ______. Initially, NMBs should NOT be used to allow for phrenic assessment.
- 3-lead procedure more lengthy than 2-lead procedure.
- Population usually display significant heart failure w/ low EF.
pulse, 3 leads: RA, RV, coronary sinus
phrenic nerve - posterior/lateral aspect of LV - hiccup
don’t want them hiccupping when they are walking around being paced later lol
ICD implantation requires _____ anesthesia d/t testing of device - ____ w/ LMA or ETT is preferred.
3rd ____ ____ pacer lead is inserted near the ____ _____ (can have ____ ____ pacing via the 3rd lead).
Testing involves R on T using ventricular lead to induce ____ and ____. The ICD is triggered to deliver a shock which should terminate the arrhythmia. An external pacer is used as backup if the device fails.
deeper - GA
coronary sinus - phrenic nerve - phrenic nerve pacing
V-tach, V-fib
SICD (subcutaneous) can be used if no _____ is needed. The generator is at the ___ area. Electrodes are NOT inserted via the central venous system (fewer complications). The electrode is tunneled from the _____ up to the mid chest region. The current path is from the chest lead down to the generator.
pacing
V5
xiphoid
LMA vs. ETT
Constant ____ ____ & _____ preferred for mapping & ablations. Variable ____ affect intrathoracic pressure & heart movement (cardiac chamber size, catheter contact points may be affect - better catheter/contact under GA).
Cardiologist may ask for temporary _____ in rest. rate and volume (gating). EP will watch thoracic movement during respiration to see catheter movement and variations in mapping points. It also ______ the heart chambers and enhances mapping point precision & accuracy.
**Most prefer ____ Vt and ___ w/ higher ____ b/c it decreases movement w/ respirations.
respiration rate and volume preferred (variations affect precision)
rates -
temp. increase in rate/volume
expands
small Vt/RR w/ higher PEEP
GA vs. MAC
____ ____ w/ MAC can add motion to map.
_____ is shown to reduce procedure time and improve outcomes. It also improves catheter stability and mapping precision.
1 year ablation outcomes for A-fib:
- sedation: 70% freedom from arrhythmia
- GETA: 90% freedom from arrhythmia
airway obstruction
GETA
Effects of OPIOIDS:
- vagotonic produce _____ (esp. _____)
- Ca++ current _____ via K+ channels ______ action potentials
- may ____ QT interval & nodal recovery time
- Remifentanil has a short half-life but ____ SA and AV node conduction (hinders induction of tachyarrhythmias and conduction measurements).
bradycardia - fentanyl
reduction, prolongs
prolong
slows
Effects of DEXMEDATOMIDINE (Precedex):
______ SA & AV node function!!!
______ norepi release (may cause transient _____ OR _____)
Enhanced ____ tone = ______
Anti-arrhythmogenic effects make it _______
Reduced SA/AV node function
decreases - hypo or hypertension
vagal tone = bradycardia
non-preferred!
Effects of KETAMINE:
_______ effects can _____ HR/BP
*little evidence exists on cardiac conduction effects - some centers report successful sedation given in low-dose infusions.
sympathomimetic - increase
no problems w/ inducing arrhythmias
Effects of BENZOS:
Some degree of autonomic _____.
Vaso_____ leads to ____ SVR.
_____ myocardial contractility.
Effect on cardiac conduction is NOT known
*Typically stay away from these - it can have synergistic effects with volatiles on diminishing hemodynamics in a population that’s has a fragile hemodynamic state
suppression
dilation - decreased
reduced
Effects of Volatile Inhalational Anesthetics:
There is conflicting evidence regarding AEs - clinical significance is minimal.
Cardiac conduction is _____, _____ QT, _____ contractility and automaticity of secondary atrial pacer is ______.
Using gas can cause more difficult cases & poorer outcomes than using TIVA - general consensus is that volatiles should not be used for these cases.
- _______ suppression of SVT re-entrant tachycardia
- _________ shortens atrial action potential and refractory
- ________ minimal effect on conduction of AV, SA, & accessory pathway; causes autonomic suppression, prolongs QT and action potential which may affect arrhythmogenicity.
altered, prolonged, reduced
enhanced
Isoflurane
Desflurane
Sevoflurane
Effects of PROPOFOL:
Sympathetic nervous system ______ may cause _______.
May cause _____ OR _____.
No measurable effect on accessory, SA, or AV nodal pathway.
Rapid onset and recovery.
inhibition - hypotension
bradycardia, tachycardia
*rapid recovery unless for prolonged duration
Effects of NMBAs:
Mild indirect effects on _____ via ____ & ____
_____-induced vasodilation is a transient effect (_____)
Rocuronium can be utilized w/out directly effecting _____.
_______ is recommended when phrenic nerve assessment is required. Stimulation allows nerve ID - maintain spontaneous ventilation to monitor nerve.
conduction via PSNS, SNS
histamine (atricurium)
conduction
Succs
Complications CAN occur!
1) Transient hemodynamic _____ during arrhythmia induction
2) Cardiac ______ results in _____ w/ _____ (1-2%) - confirm w/ fluoroscopy or US catheter
3) ____ from vascular site or vascular damage, _____ (3-4%)
4) ______ heart ____ formation (1-2%)
5) Atrioesophageal fistula (0.01-0.2%) - may go undetected for ___ days (100% mortality)
6) ____ ___ injury!
7) Valvular or septal injury from catheter
8) ___ embolism w/ transeptal communication to L side of heart
9) ______ vein damage & stenosis
10) Hematoma & bleeding at vascular access (femoral/subclavian) sites
11) ______ at device pocket site
12) ______ stroke is rare but most often w/ ____ side catheters.
1 - instability 2 - perforation - effusion w/ tamponade 3 - bleeding, hematoma 4 - complete heart block 5 - 3 days 6 - phrenic nerve 8 - AIR 9 - pulmonary (may increase BPs) 11 - pneumothorax 12 - thromboembolic stroke
Anesthesia Implications:
1) Expect to _____ w/ cardiologist & make collaborative changes. Sometimes they are busy ablating and unaware of problems developing - most important thing is ______ well w/ cardiologist & know expectations.
2) Sustained ______ unresponsive to ______ can indicate cardiac ______ w/ _______ requiring pericardiocentesis.
3) ______ is a class IB antiarrhythmic and in theory may impede arrhythmogenesis.
4) Airway access is LIMITED d/t multiple fluoroscopy arms.
5) Diligent ____ monitoring during A-fib ablations.
6) Strick measurement of fluid _____ including catheter tip saline irrigation.
7) Purge ALL IV air for patient’s undergoing _____ puncture.
8) Cardiac compromised patients w/ low EFs need LESS anesthesia - do not allow coughing or bucking or re-mapping will be necessary.
9) Keep _____ consistent to avoid intrathoracic pressure changes.
10) Know specific events in each procedure to tailor your anesthetic.
11) Anesthesia depth & other drugs can hinder arrhythmogenicity - manipulation of ___ and ___ has been considered to aid in arrhythmia induction.
1 -COMMUNICATE 2 - hypotension, vasopressors, perforation w/ tamponade 3 - lidocaine 5 - temperature 6 - intake 7 - transeptal puncture 9 - respirations (rate, Vt) 11 - Ca++ & K+
