CV module 5 Flashcards
Module 5
Electrophysiological Treatment of Cardiac Arrhythmias
Topics
- Abnormal rhythms
- Brugada syndrome
- Troponin levels
- Non-operating room anesthesia “NORA”
- Electrophysiology procedures lab (“EP lab” or “cath lab”)
- Pacemakers & AICDs
- Intra-aortic balloon pumps (IABP)
Abnormal Rhythms in the Operating Room
- _______(1)
- _______(2)
- _______(3)
- Ventricular tachycardia/torsades de pointes (prolonged Q-T interval)
- Excellent review of rhythm strips/descriptions in Barash: appendix 2: “_________(4)”
Answers:
1. Atrial fibrillation
2. Atrial flutter
3. Ventricular tachycardia
4. electrocardiography
Atrial Fibrillation (Afib)
- Most common abnormal rhythm encountered; AF is generally not caused by ischemic heart disease.
- Causes: hyperthyroidism, hypertension, pe, extra electrical connections, valvular heart disease, or muscular sleeves from the la to the pulmonary veins.
- Note: Must be differentiated from atrial flutter:
- (1) absence of flutter waves and presence of fibrillatory line;
- (2) _______(1) usually associated with higher ventricular rates (>150 beats/min).
- Loss of _______(2) reduces cardiac output (10%–20%).
- Mural atrial thrombi may develop. Considered controlled if _______(3) is <100 beats/min.
- Rate: Variable (~150–200 beats/min)
- Rhythm: _______(4)
- PR interval: No P wave; PR interval not discernible
- QT interval: QRS normal
Answers:
1. flutter
2. atrial contraction
3. ventricular rate
4. Irregular
Atrial Flutter
- Atrial flutter usually records a heart rate of 130 - 150 bpm
- The ventricular response is difficult to control.
- Rate: Rapid, atrial usually regular (250–350 beats/min); ventricular usually regular (<100 beats/min)
- Rhythm: Atrial and _______(1) regular
- PR interval: Flutter (F) waves are _______(2). PR interval cannot be measured.
- QT interval: QRS usually normal; ST segment and T waves are not identifiable.
- Note: _______(3) will slow ventricular response, simplifying recognition of the F waves.
Answers:
1. ventricular
2. saw-toothed
3. Vagal maneuvers
Left Bundle Branch Block (LBBB)
- Rate: <100 beats/min
- Rhythm: Regular
- PR interval: Normal
- Note: LBBB does not occur in healthy patients and usually indicates serious heart disease with a poor prognosis. In patients with LBBB, insertion of a _______(1) may lead to complete heart block.
- QT interval: Complete LBBB (QRS > 0.12 sec); incomplete LBBB (QRS = 0.10–0.12 sec);
- lead V1 negative RS complex;
- I, aVL, V6 wide R wave without Q or S component.
- ST segment and T-wave direction opposite direction of the R wave.
Answers:
1. pulmonary artery catheter
Ventricular Tachycardia
- Because medications rarely work to prevent or treat VT as an outpatient, they are not very likely to work in the operating room.
- If you are concerned about VT, the best option is to have _______(1) on the patient prior to anesthetic induction.
- Rate: 100–250 beats/min
- Rhythm: No atrial component seen; ventricular rhythm irregular or regular.
- PR interval: Absent; retrograde P wave may be seen in QRS complex.
- QT interval: Wide, bizarre QRS complex. ST segment and T _______(2) to determine.
- Note: In the presence of hemodynamic compromise, VT with a pulse is treated with immediate _______(3), whereas VT without a pulse is treated with immediate ______(4). If the patient is stable, with short bursts of ventricular tachycardia, pharmacologic management is preferred. Should be differentiated from supraventricular tachycardia with aberrancy (SVT-A). Compensatory pause and atrioventricular dissociation suggest a PVC. P waves and SR’ (V1) and slowing to vagal stimulus also suggest SVT-A.
Answers:
1. external defibrillator pads
2. wave difficult
3. synchronized cardioversion
4. defibrillation
Ventricular Tachycardia/Torsades
- Torsades that begins with a long “short coupling” interval can sometimes be prevented by pacing fast in order to prevent the long “short coupling” interval.
- Torsades that begins without a pause is usually related to increased adrenergic tone and can be treated by beta blockers.
- Rate: ______(1) beats/min
- Rhythm: No atrial component seen; ventricular rhythm regular or irregular.
- PR interval: P wave buried in QRS complex.
- QT interval: QRS complexes usually wide and with phasic variation twisting around a central axis (a few complexes point upward, then a few point downward). ST segments and T waves _______(2) to discern.
- Note: Type of ventricular tachycardia associated with prolonged QT interval. Seen with electrolyte disturbances (e.g., hypokalemia, hypocalcemia, and hypomagnesemia) and bradycardia. Administering standard antiarrhythmics (lidocaine, procainamide, etc.) may worsen torsades de pointes. Prevention includes treatment of _______(3). Treatment includes shortening of the QT interval, pharmacologically or by pacing
- unstable polymorphic VT is treated with immediate a.
Answers:
1. 150–250
2. difficult
3. the electrolyte disturbance
a. defibrillation.
Brugada Syndrome
- Brugada syndrome is an unusual genetic disorder of the heart’s electrical system, in particular, ventricular arrhythmias; associated with torsades and sudden cardiac death.
- Frequently, ______(a) can be the first manifestation of the disease.
- More common in men. (we the boys)
- It is a genetic disease and follows autosomal ______(b) inheritance; estimated at 5 in 10,000 people.
- Although people are born with it, they usually do not know they have it until they reach their 30s or 40s.
- Associated with one of several ECG patterns characterized by incomplete _______(1) in the anterior precordial leads.
- A telltale abnormality — called a type 1 brugada ecg pattern — may be detected.
- Symptoms (may or may not be present):
- Pounding or fluttering in the chest
- Shortness of breath
- Seizure
- Fainting spells (syncope)
- Arrhythmias that occur during sleep (possibly leading to sudden cardiac death)
- Treatable with preventive measures such as avoiding aggravating medications, to include sodium-channel blockers, tricyclic antidepressants, alcohol, cocaine, etc.
- Aggressively treating and reducing fever, when ill
- Implantable cardioverter-defibrillator (ICD).
- If patient were to develop VT/torsade “[electrical] storm,” you would treat with _______(2) (isuprel).
- Most likely, will need to defibrillate as progression to VF is very likely.
Answers:
a. sudden death
b. dominant
1. right bundle-branch block and ST-segment elevations
2. isoproterenol
Troponin Levels
- Troponin elevation can occur from anything which increases release of troponin (injury or stretch) or decreases removal of troponin from the _______(1).
- Decreased removal results from renal insufficiency or renal failure.
- Increased in the presence of
- Ischemia or infarction
- CHF or fluid overload, pneumonias
- Pulmonary embolism, pulmonary HTN
- Pericarditis or myocarditis
- Cardioversion or s/p ablation
- Cardiac surgery
- Cardiac troponins ______(a) are highly sensitive and specific for cardiac damage.
- Serum levels increase within 3 - 12 hours from the onset of chest pain, peak at ______(b) hours, and return to baseline over 5 - 14 days.
- If the troponin value remains level over ______(c) days, it is not cardiac ischemia.
- Ischemia should cause a rise and decrease in the troponin level.
Answers:
1. blood stream
a. T and I
b. 24 - 48
c. 3
EP Lab
- EP labs were originally developed for ______(a) procedures but now are used primarily for ______(b) procedures like treatment of tachyarrhythmias and device implantation, etc.
- Procedures becoming much more complex with a much sicker & less hemodynamically stable patient population
- Soon to be located in ASC’s ???
- Anesthesia used to cover ~20% of cases, but now may staff ~98% of all cases.
- Unfamiliar territory so arrive early to ensure time for fundamental safety checks!
- Anesthesia personnel provide care in both the recovery room and EP labs
- Cases may not be as “complex” in terms of fluid shifts or blood loss, but emphasis must be paid to ensure identical safety standards.
- Regardless of the location or type, you should ALWAYS be prepared for a general anesthetic.
- You are always held to your highest level of education and training (i.e., Licensure)
- All ASA standards must be upheld at all times.
- Equipment check (msmaids or _______(1))
- Anesthesia machine, suction, monitors, airway, IV meds, “special” (jet ventilator, cerebral oximetry) and supplemental oxygen
- Unlike any other anesthetizing location in the hospital, due to the impressive but intrusive amount of equipment
- Space is designed for the often complex work of the cardiologists with the anesthesia provided often an afterthought.
- Lab space is often retrofitted with anesthesia equipment in older facilities.
- Increased number of cases; no longer just for diagnosis and evaluation of heart disease
- EP mapping and ablation of rhythm disturbances
- Implantable devices
- Stenting of abdominal and thoracic aneurysms
- Balloon dilatation and stenting for valvular lesions
- Some labs have a “control room” where an electrophysiologist can monitor advanced imaging, mapping and ablation activities without having to be “hands on”
- During a case, personnel should only enter through the control room
- Headphones may be used to optimize team communication due to increased noise level, obstructed vision between team members and dim lighting
Answers:
a. diagnostic
b. therapeutic
1. soapme
Anesthesia Considerations
- Performed outside of the O.R. Setting in relatively isolated setting
- Bulky equipment and subdued lighting
- Limited access to the patient
- Procedures may be difficult and lengthy
- Surgical team may not be readily available
- Anesthesia support personnel, pharmacy and stat lab may not be immediately available
- Recovery area may be in a distant location
- Moving anesthesia equipment during different parts of a case is often necessary to accommodate the procedure
- Intubation is often performed straddling the lower arm of the x-ray equipment, ducking under the upper arm, and squeezed by the two side arms
- VT and AF ablation are typically performed with _______(1) for patient comfort
- Most other procedures can be done with minimal to moderate sedation
- Generally, prefer minimal sedation when trying to induce SVT or for PVC mapping
Answers:
1. general anesthesia
Pre-operative Assessment
- Standard 12 lead ECG is performed for risk assessment
- Baseline for chronic or acute myocardial ischemia and/or arrhythmias; comparing ECG’s is important
- Both myocardial ischemia and arrhythmias are common following _______(1); post-operative 12 lead ECG is often obtained in high _______(2) patients.
Pre-op Focus
- Airway - identify challenges which may be amplified in _______(3) environment
- Previous anesthetics - review management with focus on sensitivity to _______(4)
- Allergies - focus on shellfish (contrast dye), fish (protamine), _______(5)
- Cardiac hx - note EF, CHF (ability to tolerate supine position), arrhythmia classification, pulmonary HTN (avoid _______(6) and hypoxemia)
- OSA/morbid obesity - important if _______(7) planned
- Positioning - peripheral neuropathy, back pain- peripheral extremity _______(8)/padding
- GERD - important if sedation planned
Answers:
1. CVOR
2. cardiac risk
3. NORA
4. sedatives
5. antibiotics
6. hypercapnia
7. sedation
8. position/padding
A “Typical” Anesthesia Plan
- Airway management
- Intubations performed with a glidescope to decrease chance of airway trauma
- Heparinization during the procedure may lead to airway bleeding -> impacts extubation!
- Mac cases: must be prepared for emergent intubation (with a glidescope)
- Have nasal airways easily accessible
- Induction technique: if EF <40% consider using _______(1) (or etomidate + propofol)
EP Lab Example of Anesthetic Plan
For an EF > 30 %
Fentanyl 250 mcg
Phenylephrine 50 mcg
Lidocaine 100 mg???
Propofol
Consider midazolam, if necessary, to reduce anxiety
For an EF < 30 %
Ketamine 150 mg
Phenylephrine 100 mcg
Lidocaine 100 mg????
Propofol
Consider midazolam, if necessary, to reduce anxiety
High Frequency Jet Ventilation
- Used to minimize respiratory movement during AF ablation
- Decreases atrial motion, promotes intra-cardiac instrument stability
- Should be a joint decision with the electrophysiologist in advance
- Requires GA with ETT and _______(2)
Answers:
1. midazolam
2. TIVA
Anesthetic Plan (con’t)
- The electrophysiologist may prefer to avoid certain anesthetics, as some agents may suppress an arrhythmia. It is important to discuss this at the start of each case.
- Very light anesthetic is desirable when trying to elicit a premature ventricular contraction or ventricular tachycardia in order to determine the focus from which the arrhythmia is arising.
- In most general anesthesia cases, inhalational agents should be avoided because of _______(1) effects
- AVOID ______(a)-acting muscle relaxation to help monitor phrenic nerve activity
- Consider using only remifentanil and no _______(2)
Patient Positioning
- An arterial line should be placed on the opposite side from which the electrophysiologists operate in case adjustment is needed
- A ______(b) should be placed for possible cardioversions/________(3)
- Double check proper position of extremities as arms are typically tucked at sides
- Patients are not paralyzed.
- With cardioversion/defibrillation, there can be significant muscular contracture wrists must be restrained and extremities _______(4)
- Access to the stopcocks, IV lines and monitors will be limited once the patient is draped
Shared-medication Administration
- Cardiology nurses may be assigned to administer various medications
- Heparin, vasoactive inotropes
- Cardiologists may administer drugs directly into cardiac catheters
- Nitroglycerine, calcium channel blockers
- Hemodynamically-acting meds and anesthetics may interact with procedure
- _______(5) IS PARAMOUNT
Answers:
1. anti-arrhythmic
a. long
2. midazolam
b. soft bite block
3. defibrillations
4. padded
5. COMMUNICATION
ISUPREL Challenge
- One of the most difficult times in managing hemodynamics is when the electrophysiologist wishes to evaluate the induction of an arrhythmia using increasing doses of _______(1).
- Normally _______(1) is started at 3 mcg/min by the eps lab _______(2) and titrated to 6, 12, 20, 30 mcg/min, although the dosing is variable.
- This typically produces a significant loss of _______(3) and drop in ______(a)
- The anesthesiologist will likely need to start phenylephrine to support a SBP _______(4)
- Along with the drop in blood pressure, the heart rate will _______(5) to uncomfortably high levels and occasionally ventricular tachycardia or fibrillation will ensue.
- The electrophysiologists are able to treat arrhythmias
- Preventing the severe ______(b) that occurs once the _______(1) is discontinued is a challenge.
- Phenylephrine should be turned off immediately when the _______(1) is discontinued
Answers:
1. isuprel
2. nurses
3. peripheral resistance
a. blood pressure
4. 130-140
5. increase
b. rebound hypertension
Hemodynamic Management
- Patients may become part extremely labile hemodynamically.
- Reactions to these drastic changes at times needs to be tempered (look for underlying cause of vital sign instability) as well as determine when rapid intervention is needed
- Electrophysiologists are very involved in the patient’s hemodynamic management
- When needed, can control the heart rate with pacing or cardioversion
- Communication is critical, particularly when making significant changes to the level of anesthesia
- ______(a) may be caused by tamponade or retroperitoneal bleeding and masking these changes with medication can delay a timely diagnosis.
- In the routine case, the patient will receive a large amount of volume by the electrophysiologist during the ablation process, so fluid management by anesthesia should be conservative
Post-op Considerations
- Pain generators
- Back pain/extremity pain for _______(1) supine for prolonged period
- Foley catheter
- Intravascular catheters in groin, need to hold pressure
- Typical pain medications:
- _______(2) typically given (caution in renal impairment)
- Morphine/dilaudid to be considered
- Ondansetron for PONV
Okay… What are we doing??? Electrophysiologic Procedures (EP) Lab
- Localize the site of origin or pathway of arrhythmias
- Isolate or destroy the tissue
- Improve scar tissue within the conduction pathway
- Apply energy through a catheter using radiofrequency, ultrasound, laser, microwave energy or cryoablation
Answers:
a. Hypotension
1. laying
2. KETOROLAC
