TACHYCARDIAS

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TACHYCARDIAS

• Steven R. Lowenstein, MD, MPH
• ACLS May 5, 2009

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3 Critical Concepts

• Sinus tachycardia is most common
• Most irregularly irregular rhythms are atrial
  fibrillation
• Alternatives
• Atrial flutter
• MAT
• Most wide, regular tachycardias are VT

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Approach Clinical EKG

• Is the patient stable?
• Is the rhythm regular?
• Are the QRS complexes narrow?

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Monitor shows
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• The Diagnosis
• Sinus Tachycardia
• What defines sinus tachycardia?
• Tachycardia (gt 100 beats per minute)
• P-wave before every QRS
• P-wave is UPRIGHT in II and negative in AVR

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Is it a tachycardia?
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AVR
AVL
?
I
III
II
AVF
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SINUS TACHYCARDIA

• A sign of physiologic stress
• Hypoxia, acidosis, sepsis
• Fever
• Hypotension
• Heart failure
• Catecholamines, adrenergic drugs
• Thyrotoxicosis
• Cardioversion, adenosine Futile
• Beta-blockers?
• Not a rhythm to be treated

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Approach to the patient

• A 58 year-old man presents with continuing chest
  pressure. He is alert, diaphoretic. BP is 86/68.
  Pulse Ox 87. Rales are heard.

What is this? What should I do?
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Our approach

• Is the patient stable?
• Blood pressure (86/68)
• Mentation
• Skin moist, chest pain, rales, ? 02
• Is the rhythm regular?
• Are the QRS complexes narrow?

Cardiovert
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Our approach

• Is the rhythm regular? Are QRS complexes narrow?
• Diagnosis? Treatment? Cant figure it out?
• CHECK THE PATIENT
• Is the patient stable?
• Diagnosis Artifact

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• 40 year-old female was relaxing in the hot tub
  and felt the sudden onset of palpitations and a
  pounding in her neck. Mentation and vital
  signs are normal.

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Our approach

• Is the patient stable?
• Is the rhythm regular?
• Are the QRS complexes narrow?
• Is it sinus?

• Diagnosis
• Stable patient
• Regular
• Narrow
• No visible p-waves
• AVNRT
• AV Nodal Re-entry Tachycardia

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AVNRT
PAC
Slow
Fast

• ? VAGAL
• ADENOSINE
• CARDIO-VERSION

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Narrow, fast regular (and no p-waves)
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AVNRT (PSVT) Stable

• TRY VAGAL MANEUVERS (Valsalva, CSM)
• Slows AV nodal conduction
• Interrupt re-entry circuit
• Effective 20 OF TIME
• ADENOSINE
• Endogenous purine nucleoside
• Dose 6 mg IV (Repeat 6 - 12 mg)
• Slows AV nodal conduction
• Interrupts re-entry circuit

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ADENOSINE

• The Good
• Lasts 6-10 secs
• Converts 90 of tachycardias with
• Re-entry within AV node
• Slows ventricular rate in AF or flutter but
  cannot convert
• Preferable to beta blockers and calcium blockers
• Shorter half life
• No negative inotropy

• The Bad
• Could provoke wheezing
• Rare in asthma/COPD
• Brief side effects
• Prolonged asystole if heart transplant
• Can precipitate AF
• Drug interactions
• ? effects if tegretol, persantine
• ? effect if theophylline or caffeine
• Dont use if wide-complex

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Adenosine in AVNRT
Chest pain, SOB, dizziness
Adenosine
Not in patients with carotid artery disease
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70 YEAR OLD MAN WITH COPD, PRESENTS WITH 2 DAYS
OF FEVER, CP, ?COUGH, SPUTUM AND SOB temp was
39.8? C. Alert. BP 148/90, RR 20, unlabored
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Our approach

• Is the patient stable?
• Is the rhythm regular?
• Are the QRS complexes narrow?

• Diagnosis
• Stable patient
• Irregularly irregular
• Narrow complex
• No visible p-waves
• Atrial fibrillation

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Consequences of AF

• Hemodynamic compromise if rapid
• Impaired left ventricular filling and ? CO
• Rapid rate (shortened diastole)
• Absent atrial contractions
• Pump failure-hypotension or pulmonary edema
• If prolonged ? tachycardia-induced cardiomyopathy
• Atrial clot

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Management of Rapid AF

• Slow ventricular rate
• Anticoagulation
• Convert to normal sinus rhythm

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Management of AF

• If unstable Synchronized cardioversion
• If stable
• Slow ventricular response
• Calcium channel blocking drugs (diltiazem 15-20
  mg IV)
• Digoxin (.25 - .5 mg I.V.)
• Treat underlying CHF, hypoxia, electrolyte
  disturbance
• Beta blocking drugs
• Restore sinus rhythm?
• If lt 48 hours, use drugs or electricity
• Amiodarone or ibutalide
• If gt 48 hours, must provide anticoagulation first

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Irregularly irregular Mimics
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Atrial Fibrillation
Atrial Flutter
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Irregularly irregular Mimics
Multi-focal Atrial Tachycardia

• Clinical Settings
• Hypoxia, respiratory failure
• Congestive heart failure
• Theophylline toxicity

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Multi-focal atrial tachycardia
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• A 71 year old man presents with dizziness and
  fatigue, and mild chest pressure for 6 hours.
  Prior history includes MI and CHF.
• BP 150/88. He is alert and in no distress.

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What is it?

• Diagnosis
• Stable patient
• Regular
• Wide complex tachycardia (gt.12 sec)
• Almost always VT
• 85 in most series
• gt 95 if
• Prior CAD
• Prior CHF
• Cardiomegally
• Age gt 60

• Stable?
• Regular?
• Narrow?

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• Why does it happen?
• Why is it wide?

• Monomorphic
• Single focus
• Regular rate and QRS form
• Often stable

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Ventricular tachycardia

• Monomorphic
• Single re-entry focus arises in ventricle
• Regular rate and QRS size and shape
• Often, patient is hemodynamically stable

• Polymorphic
• Arises from multiple sites in ventricle
• Varying rate, size and shape of QRS
• Overlaps with VF and is always unstable

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How to manage monomorphic VT

• UNSTABLE (VS, mentation, signs, sx)
• No pulses Defibrillation
• Pulses Synchronized Cardioversion
• STABLE
• Amiodarone (150 mg I.V. over 10 minutes)
• If indicated
• IV magnesium (2 g)
• IV beta-blockers

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• Polymorphic VT
• Varying rate and QRS shape
• Hard to synchronize
• Often hemodynamically unstable
• Rapid deterioration to VF is frequent (ALWAYS
  ELECTRICALLY UNSTABLE)
• Treatment Defibrillation

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Torsades de pointes

• A special variety of polymorphic VT
• QT interval is long during sinus beats
• Treatment a) Defibrillation then b) Magnesium
• Often underlying hypokalemia or hypomagnesemia
• Offending agents that ? QT
• Antibiotics (macrolides)
• Antihistamines (Seldane)
• Anti-arrhythmic drugs
• Alcohol (via hypo-magnesemia or hypokalemia)

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Polymorphic VT vs VF
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Synchronized cardioversion

• Energy synchronized to QRS
• Timed to R-wave
• Avoids vulnerable period (T-wave)
• Lower energy levels
• Interrupts re-entry circuits
• VT (mono-morphic)
• PSVT (AVNRT)
• Atrial fibrillation or flutter

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Synchronized cardioversion

• NOT for arrest rhythms
• Ventricular fibrillation
• Pulseless VT
• Polymorphic VT
• NOT effective in automatic tachycardias
• Sinus tachycardia
• MAT
• Ectopic atrial rhythms

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Synchronized cardioversion

• For unstable tachycardia
• With pulses
• With organized, upright QRS
• Eyeball test
• If your eye cannot synchronize to each QRS
  complex, neither can the machine
• So, not reliable for polymorphic VT or VF arrest
• Sedation and analgesia are mandatory

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Energy levels

• Atrial fibrillation
• 100-200 J (monophasic)
• 100-120 J (biphasic)
• Atrial flutter and SVT
• 50-100 J (monophasic)
• ? ? For biphasic

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Tachycardias Summary

• Most common Sinus tachycardia
• If irregularly irregular Atrial fibrillation
• Wide complex tachycardia VT
• Narrow and regular, no P-waves PSVT (AVNRT)

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The Approach Summary

• Is the patient stable?
• Is the rhythm regular?
• Are the QRS complexes narrow?
• Is it sinus?

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REVIEW TRACINGS
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Bonus Tracing