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Acute Management of
Stable
Narrow Complex Tachycardia
Mini Lecture
2013
Objectives
• Review the initial approach to diagnose and
treat narrow complex tachycardia
• Review examples of AVNRT, AVRT, Atrial
Tachycardia
• This is not a comprehensive review of all the
narrow complex tachycardias
• You are not expected to manage these
patients on your own, always ask for back up
Case
• Nurse calls to inform you that bed 10’s heart
rate just went up to 200s on telemetry. Which
of the following information should you obtain
asap?
A. Blood pressure
B. Mental status
C. EKG
D. Focused Physical Exam
E. All of the above
Case
• Nurse calls to inform you that bed 10’s heart
rate just went up to 200s on telemetry. Which
of the following information should you obtain
asap?
A. Blood pressure
B. Mental status
C. EKG
D. Focused Physical Exam
E. All of the above
Narrow Complex Tachycardia
• Rate >100 (often 150-250)
• QRS <120 msec
– Regular
•
•
•
•
•
Sinus tachycardia (usually <150)
AVNRT
AVRT
Atrial Tachycardia
Atrial Flutter with regular block (150, 100, 75)
– Irregular
• Atrial Fibrillation
• MAT
Initial Assessment for
Tachycardia
Questions
• Symptomatic?
• Hypotensive?
• 12 lead EKG
• IV access
Stable or Unstable?
• Altered Mental Status
• Hypotension
• Chest Pain
• Acute SOB
• Hypoxia
Unstable?
• Crash Cart
• ACLS
• Call for backup
– Senior resident
– Cardiology fellow
– Nocturnist
– Code blue
Stable?
Initial Assessment
• Focused H&P
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–
–
–
–
–
–
–
Talk to the patient to assess mental status
Reason for admission (sepsis, ACS)
Cardiac Hx (CAD, HF, Afib, SVT)
Recent electrolytes
Medications (AV nodal agents, digoxin)
Listen to heart and lungs
Volume status
JVD
EKG shows..
Too fast to interpret rhythm?
• Vagal Maneuvers and Adenosine
– Slow down the rhythm
– Terminate certain SVTs which conduct
through the AV node
– If possible obtain 12 lead EKG recording
during intervention
• Vagal maneuvers
–
–
–
–
–
Bearing down
Face in ice cold water
Carotid Massage
Blowing into a folded straw
Cough
• Adenosine
– May avoid if bronchospasm/asthma/COPD?
– Caution if history of pre-exitation/ WPW?*
– Warn them about the symptoms
• 6mg IV push followed by NS flush followed by
• 12mg IV push followed by NS flush
AVNRT
Cause
• Dual AV nodal pathways
with differing refractory
periods
• Often initiated by a PAC
• 60% SVT
DX
• Rate 150-250
• Inverted p or “psuedo S”
Tx
• Vagal
• Adenosine
• BB: Metoprolol 5mg q5min x3
• CCB: Diltiazem 10mg IV,
repeat 10-30mg IV in 5-10
min
AVNRT
PSUEDO S WAVES
AVRT
Cause
Dx:
• Rate 150-250
• Retrograde P inferior leads
• Re-entrant tachycardic
circuit with conduction
down AV node and back up
a bypass tract (i.e. WPW)
Tx:
• 30% SVT
•
•
•
•
Vagal
Adenosine
BB: Metoprolol 5mg min q5 x 3
CCB: Diltiazem 10mg IV, repeat
10-30mg IV in 5-10 min
AVRT
Atrial Tachycardia
Dx
• Enhanced Automaticity of atrial • P wave precedes each
QRS
tissue or ectopic atrial
pacemaker
• Unusual p wave axis
• 10% SVT
• Adenosine may show
continued atrial beats,
without AV conduction
Tx:
• BB: metoprolol 5mg q5
x3
• CCB: Diltiazem 10mg
IV, repeat 10-30mg IV in
5-10 min
Cause
Atrial Tachycardia
ADENOSINE
QuickTime™ and a
decompressor
are needed to see this picture.
Unusual p wave axis
Continued atrial automaticity
General Principles
• Note the common theme: Vagal Maneuvers,
Adenosine, Beta Blockers, Calcium Channel
Blockers, caution in WPW
• Check vitals (BP) frequently during acute
setting to make sure a stable situation does
not become unstable
• Again, this is meant to be a review of the
initial management of SVT you are not
expected to independently manage these
patients- Call for backup!
Case Follow Up
• Nurse calls: “ Bed 10’s heart rate just
went up to 200s”
• You reply:
– What is his blood pressure?
– Is his arousable and oriented?
– Please get a 12 lead EKG now
– Does he have IV access?
– I’ll be right there..
References
• UpToDate
• Med Res UCLA
http://medres.med.ucla.edu/
• FP Notebook
http://www.fpnotebook.com/
• Images sited previously