Unstable Tachycardias




God Knows
God Knows
Heart Rate Fast = tachycardia rate > 150 bpm. Technically any HR > 100 is tachycardia. And just like the bradycardia algorithm, when we see symptoms in patients is different than the technical definition. Most patients will show signs of poor perfusion with a HR > 150 bpm. Be aware that any heart rate > 90 bpm meets one of the SIRS criteria (Systemic Inflammatory Response Syndrome), AND finding the cause of the increase heart rate is very important. (Treat the patient, not the monitor).

Primary Assessment
Identify and treat underlying cause:
  -Consider causes (Differential Diagnosis-see PEA for Hs and Ts for 
    some possibilities and treatments)

Ask these questions, does the patient have:
             1. Hypotension? (decreased blood pressure SBP < 90 
             2. Altered mental status?
             3. Signs of shock?
             4. Ischemic chest discomfort?
             5. Acute heart failure?
If yes to any of these, then the patient is considered unstable.  It doesn't matter whether it is wide or narrow complex tachycardia, prepare for immediate cardioversion (hit the sync button on the defibrillator).  This will allow the defibrillator to synchronize with the pt's QRS complex so as not to shock during the vulnerable repolarization phase (on the T-wave).  This is known as synchronized cardioversion.

1.  Monitor O2 saturation
2.  Prepare suction device
3.  Make sure intubation equipment is available
4.  Make sure IV line is patent
5.  Premedicate whenever possible:  Midazolam or 
      for sedation with an analgesic unless patient is 

Synchronized Cardioversion Procedure  
Note:  I'm calling the machine that does this procedure a defibrillator.  The difference between cardioversion and defibrillation is that the sync button is on for cardioversion and off for defibrillation.  The machine will still be called a defibrillator, but defibrillation and cardioversion are different procedures as described.

Narrow QRS (< 0.12), regular rhythm -     50 - 100 
   Joules - SVT/A. Flutter

Narrow QRS (< 0.12), irregular rhythm - 120 - 200 J 
   Biphasic or  200 J monophasic - A.Fib

Wide QRS (> 0.12), regular rhythm -              100 J
   - V. Tach monomorphic

Wide QRS (> 0.12), irregular rhythm -  V.Tach 
   polymorphic defibrillation dose (NOT 
   syncronized) - 360 J monphasic
Turn on defibrillator

Attach monitor leads to pt (White to right shoulder, Red to left ribs, what's 
      Left Over goes over to the left shoulder)

Hit SYNC button 

Look for markers on the R waves on the defibrillator's monitor indicating 
      sync mode (increase the gain if necessary so each R wave has a marker)

Select energy level, start at 100 Joules, then increase in above increments with 
      each shock

Place pads on pt as marked (Sternum-Apex) or paddles with gel

Announce charging defibrillator- "Stand Clear!"

Press the charge button on the defibrillator or on the apex paddle

State:  I'm clear! - make sure you are clear
          You're clear! - make sure your helpers are clear
          Everybody's clear! - make sure everyone is clear of the patient

If using paddles, apply at least 25 lbs of pressure on the chest. Also if using paddles, you need a water soluble lubricant placed on the paddles.

Press the discharge button on the defibrillator or discharge buttons simultaneously on each paddle.  

Check the monitor for the rhythm

Each time shocking, you must reset the sync button to continue to shock using cardioversion.
If no is the rhythm wide QRS > 0.12 sec. or narrow QRS < 0.12 sec.?

If Wide, then:

If Narrow, then: