Case 2 it happened to me

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Case 2it happened to me

• Robert C. Bosack, DDS

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Assumptions

• Only lead II with extremity clips
• No chest leads
• blind to gt60 of all possible ST changes
• Rarely will you see a classic tracing
• Variability in the origin of the dysrhythmia
• Underlying cardiac anatomy is different
• Pre-existing ECG abnormalities may exist
• Most patients without overt cardiac disease

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When trouble looms.Think

• Severity duration ability to tolerate
• May make you glad you only Tx ASA 1 and 2
• Stable no anticipated change
• Unstable things may change
• For the better OR worse
• Blood pressure ???
• Focus on what the ventricle is doing
• What is the hemodynamic insult (BP, perfusion)
• Think about hypoxia, xs cats, possibility of
  electrolyte imbalance

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Case 2

• Hysterical 16 y/o ? for elective extraction K,
  T, 20 and 29
• 120, 50
• ASA 1
• BMI 19
• Mallampati 1
• 10 METS

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• PMH negative
• What does this really mean?
• 22g angiocath to left dorsal hand
• LR running
• OBVIOUSLY TACYCARDIC, BUT
• did you notice???

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Induction

• .4mg ATR ????
• 5mg Versed
• 25 µg fentanyl
• 40mg propofol
• 4 carpules 2 carbocaine with 120,OOO
  levonordefrin

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Suddenly

• Heart rate gt 220bpm
• BP machine taking reading for 1st time no
  baseline
• What happened ?
• What will you do ?

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Quid nunc?

• Signs / Sx
• Awake or asleep
• Once the drugs pass the IV, its your gig
• Hypotension is what youre lookin at
• MAP lt 50mmHg

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Arrhythmias Whats so bad?

• Cause ? CO, hypotension, ? organ perfusion
• They can ? O2 demand leading to imbalance and
  myocardial deterioration furthering the risk of
  dysrhythmias.
• They can interfere with coronary perfusion by 25
• Can degenerate to worse rhythms

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Sinus tachycardia gradualphysiologic response
to stressorcan cause or be a result of ?BP

• Rates gt 100, identical p waves
• P (if seen) and QRS are normal, 11 ratio
• Palpitations (awareness of heart beat)
• Lightheadedness, SOB, chest pain
• Max rate 220 - age

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Precipitating Factors

• Anemia
• Hypovolemia -
• Fever
• prolonged fast
• hot day
• Drugs
• Methohexital
• Naloxone
• Ketamine
• Vasoconstrictors //// TCA

• ? ? circulating cats
• Anxiety pain fight/flight
• Light anesthesia
• Hypoxia
• PE
• Airway obstruction,
• Lspasm
• Bspasm
• Hypoventilation
• Hypercarbia

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PSVT - suddenpathologic, 120-250bpm, regular

• Activation above bifurcation always produces a
  narrow complex QRS ( 120msec)
• Episodic, abrupt in onset and termination
• It is important to establish width of QRS
• As treatment for narrow complex tachycardias
• Vagal maneuvers
• Adenosine
• CCB
• ß blockers
• can cause lethal deterioration of V tach

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Abnormal circuit
Re-entry
Slow conduction Fast recovery
Fast conduction Slow recovery
slow
fast
slow
fast
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PSVT

• Etiology
• Unlucky re-entry circuit present
• ? symp tone drugs, stress, pain, hypoxia
• Light anesthesia
• Crucially timed PAC, PVC, change in rate
• Symptoms
• None, SOB, hypotension, diaphoresis
• Where is the pathway located???

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In the node - AVNRTAV Nodal Re-entrant
Tachycardia

• Is paroxysmal (abrupt)
• Dual pathways within the AV node
• Can occur in normal hearts
• Triggers
• PAC
• Stimulants, exercise,
• Surge in vagal tone
• Sx
• Palpitations, lightheadedness, dyspnea, angina,
  fatigue, syncope
• Starts in early 20s, peak at 32

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Outside the node??

• WPW
• Others

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AVNRT AVRTreentry
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WPW
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Treat narrow complex tachycardia

• Remove cause, BP OK?
• Vagal maneuver - ? parasympathetic tone, slows
  conduction at or above the AV node
• Valsalva bear down against closed glottis x 15
  sec
• Carotid sinus massage (CSM)
• Adenosine
• Esmolol
• Cardioversion only to prevent irreversible
  complications of hypoperfusion (stroke, MI)
• If wide or in doubt
• V-tach, WPW, amiodarone, procainamide

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Vagal maneuvers affects nodes only

• Slows rate of impulse formation in SA node
• Slows conduction and lengthen refractory period
  in AV node
• Atria and ventricles not affected

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Carotid sinus massage

• Press on carotid sinus
• Stimulate glossopharyngeal (IX), which stimulates
  medullary centers vagus
• R side SA node, L side AV node??
• Never in stroke patients or with bruits

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Carotid sinus massage

• Contraindications
• Absolute
• MI
• TIA/CVA within 3 months
• Hx Vfib or Vtach
• Relative
• Carotid bruit
• Monitoring
• Continuous EKG, BP

• Precautions
• Never massage bilaterally
• Ascertain bilateral carotid pulses
• Have defibrillator nearby

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Carotid sinus massage

• Technique monitors on
• Supine / -10o trendelenburg x 5 minutes
• Eliminates sympathetic tone
• Extend the neck
• ID bifurcation high in the neck, just below
  angle (mistake is applying pressure too low)
• Start on R side, turn to left firm, circular
  massage or steady pressure to indent a tennis
  ball for 5 10 sec,
• Can retry on left side, or after drug therapy

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Carotid sinus massage

• Complications
• Asystole if gt 3 seconds ? thump
• Sinus arrest
• Syncope
• Stroke dislodgement of carotid plaque

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Drug choices

• Adenosine chemical valsalva
• Hyperpolarizes nodal tissue by activating K
  channels
• Esmolol
• ß blocker
• Do not use either with any wide complex!!!!!!!!!

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Adenosinefirst line, 90 effective for AVNRT,
AVRT

• Depress SA node frequency and AV node conduction
• Peak affect in 15 30 sec
• T ½ 8 seconds
• 6mg IV, 10-30ml NS flush, followed by 2 - 12mg
  doses if needed - 6 12 12
• Potent vasodilator, short acting
• Do not use with heart blocks

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Adenosine

• ? dose with dipyramadole or tegretol
• Side effects
• Facial flushing
• Angina
• Dyspnea
• Dizziness
• Transient asystole
• Bronchospasm in asthmatic patients (caution)

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Verapamil ???

• 2nd line choice with adenosine failure
• Blocks Ca channels during depolarization
• Slows SA node and AV conduction
• 2 - 10 mg, IV over 2 -3 minutes
• See results in 1 2 minutes, peak in 1015 min.
• Can accelerate a WPW

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Verapamil

• Side effects
• Hypotension
• Bolus fluids before use, Trendelenburg
• Bradycardia
• High degree AV block
• Do not use with 2o and 3o heart blocks

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B blockersincrease AV refractory period

• Rapid-acting
• Esmolol 20 30mg (.5 1 mg/kg) over 1 min
• Onset is 1 minute, duration is 15 minutes
• B1 selective at lower doses

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Esmolol

• Brevibloc - ß1 selective antagonist
• Loses selectivity at higher doses
• Be careful with bronchospastic disease
• Rapid onset, short duration (T ½ 9 minutes)
• Metabolized by esterases in RBCs (just like remi)
• Side effects
• Heart block, pulmonary edema

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Cardioversion 50 100j (deep circuits)

• Energy synchronized to the QRS
• Depolarizes all the tissues around the re-entrant
  circuit makes tissue refractory
• Circuit cannot propagate or sustain
• Complications
• Non-sustained VT (5)
• Bradycardias (25)
• Hypotension (several hours)
• VF (rare)

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Have you ever treated an arrhythmia with IV meds
during office sedation / anesthesia?

• Yes
• No

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What drug?

• Lidocaine
• Amiodarone
• Procainamide
• Adenosine

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Drugs for Tachycardias
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Summary

• Which arrhythmias are dangerous?
• Do they all need treatment or just more close
  observation?

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Thanks for your attention

• r.bosack_at_comcast.net