1. Acute Management of Stable Narrow Complex Tachycardia
Mini Lecture
2013

2. 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

3. 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
Answer E intern should ask the nurse these questions on the phone so the nurse can start getting the information that you need if he or she doesn’t have it already. Then go see the patient asap.

4. 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
Answer E,

5. Narrow Complex Tachycardia
Rate >100 (often )
QRS <120 msec
Regular
Sinus tachycardia (usually <150)
AVNRT
AVRT
Atrial Tachycardia
Atrial Flutter with regular block (150, 100, 75)
Irregular
Atrial Fibrillation
MAT
Be aware of they types of narrow complex tachycardia or “SVT”
We will only talk more about AVNRT, AVRT, ATRIAL TACHYCARDIA in more detail

6. Initial Assessment for Tachycardia
Questions
Symptomatic?
Hypotensive?
12 lead EKG
IV access
Stable or Unstable?
Altered Mental Status
Hypotension
Chest Pain
Acute SOB
Hypoxia
Back to the initial assessment when you are called by the nurse- it is Important to first decide if this is an unstable or stable situation

7. Unstable? Crash Cart ACLS Call for backup Senior resident
Cardiology fellow
Nocturnist
Code blue
ACLS review: DC cardioversion Narrow regular J, Narrow Irregular J, Adenosine

8. Stable? Initial Assessment
Focused H&P
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
Run through the following in your evaluation
4H’s: Hypovolemia, Hypoxia, Hyperthermia, Hyper/Hypokalemia,
4T’s: Tamponade, Tension PTX, Thromboembolism, Toxins,

9. EKG shows..

10. 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

11. Vagal maneuvers Adenosine 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
Sensation that the heart has stopped, chest pain, shortness of breath
Crash Cart Should Be available in the event that the patient becomes unstable i.e. you may need atropine for a long pause or urgent cardioversion
Don’t forget to obtain frequent vital signs while you are at the bedside
Tachyarrythmias and WPW- AV nodal blocking agents are contraindicated

12. AVNRT Cause DX Rate 150-250 Inverted p or “psuedo S” Tx Vagal
Dual AV nodal pathways with differing refractory periods
Often initiated by a PAC
60% SVT DX
Rate
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
Since it is a nodal rhythm, adenosine/vagal/BB.CCB can terminate the rhythm

13. AVNRT
PSUEDO S WAVES
V4 p wave at the end QRS, and characteristic “pseudo S wave”

14. AVRT Cause Dx: Rate 150-250 Retrograde P inferior leads Tx: Vagal
Adenosine
BB: Metoprolol 5mg min q5 x 3
CCB: Diltiazem 10mg IV, repeat 10-30mg IV in 5-10 min
Cause
Re-entrant tachycardic circuit with conduction down AV node and back up a bypass tract (i.e. WPW)
30% SVT
WPW is an example of AVRT, use caution with AV nodal agents which can stimulate the bypass tract causing degeneration to vfib because AV nodal blocking agents can speed up the bypass tract (you can try to look at an ekg taken prior to event to look for pre-exitation, you should discuss with cardioology fellow)

15. AVRT Narrow complex rate ~ 150
Retrograde p waves seen in ST segment (unlike AVNRT where p is usually burried)

16. Atrial Tachycardia Cause Dx P wave precedes each QRS
Enhanced Automaticity of atrial tissue or ectopic atrial pacemaker
10% SVT Dx
P wave precedes each QRS
Unusual p wave axis
Adenosine may show continued atrial beats, without AV conduction
Tx:
BB: metoprolol 5mg q5 x 3
CCB: Diltiazem 10mg IV, repeat 10-30mg IV in 5-10 min
Adenosine will not terminate this rhythm, but it can help with the dx

17. Atrial Tachycardia ADENOSINE Unusual p wave axis
Continued atrial automaticity
Initally you can see tachycardia with unusual p wave axis
This is a rhythm strip with adenosine administration showing continued atrial beats when AV node is blocked indicating atrial tachycardia rather than AVNRT, AVRT
This is a MKSAP question

18. 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!

19. 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..

20. References UpToDate Med Res UCLA http://medres.med.ucla.edu/
FP Notebook
Images sited previously