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Tachycardia Algorithm


Tachycardia and its ACLS Algorithm

Tachycardia/tachyarrhythmia is defined as a rhythm with a heart rate greater than 100 bpm.
An unstable tachycardia exists when cardiac output is reduced to the point of causing serious signs and symptoms.
Serious signs and symptoms commonly seen with unstable tachycardia are: chest pain, signs of shock, SOA, altered mental status, weakness, fatigue, and syncope

One important question you may want to ask is: “Are the symptoms being caused by the tachycardia?” If the symptoms are being caused by the tachycardia treat the tachycardia.

There are many causes of both stable and unstable tachycardia and appropriate treatment within the ACLS framework requires identification of causative factors. Before initiating invasive interventions, reversible causes should be identified and treated.


The most common causes of tachycardia that should be treated outside of the ACLS tachycardia algorithm are dehydration, hypoxia, fever, and sepsis. There may be other contributing causes and review of the H’s and T’s of ACLS should take place as needed.

Administration of OXYGEN and NORMAL SALINE are of primary importance for the treatment of causative factors of sinus tachycardia and should be considered prior to ACLS intervention.

Once these causative factors have been ruled out or treated, invasive treatment using the ACLS tachycardia algorithm should be implemented.

Associated Rhythms

There are several rhythms that are frequently associated with stable and unstable tachycardia these rhythms include:

Visit the links above to learn about each specific rhythm.

ACLS Treatment for Tachycardia

Click below to view the tachycardia algorithm diagram. When done click again to close the diagram. Tachycardia Algorithm Diagram. or Members Download the Hi-Resolution PDF Here

The fist question that should be asked when initiating the ACLS tachycardia algorithm is: “Is the patient stable or unstable?” The answer to this question will determine which path of the tachycardia algorithm is executed.

Patients with unstable tachycardia should be treated immediately with synchronized cardioversion. If a pulseless tachycardia is present patients should be treated using the pulseless arrest algorithm.

Patients with stable tachycardia are treated based upon whether they have a narrow or wide QRS complex. The following flow diagram shows the treatment regimen for stable tachycardia with narrow and wide QRS complex.

  • Stable (narrow QRS complex) → vagal maneuvers → adenosine (if regular) → beta-blocker/calcium channel blocker → get an expert
  • Stable (wide/regular/monomorphic) → adenosine → consider antiarrhythmic infusion → get an expert

  104 Responses to “Tachycardia Algorithm”

  1. The patient has wide irregular tachycardia but with bp of 130/90. Asymptomatic. What will be the intervention? Are we going to give lidocaine or are we going to consider this as unstable wide irregular tachy and give unsynchronized cardioversion?or seek expert consultation?

    • If the patient is asymptomatic and completely stable then expert consultation would be in order. An expert will hopefully be able to determine the root cause of the tachycardia and deal with that. There would be no reason to treat a patient who is clinically stable and completely asymptomatic.

      Kind regards,

  2. Dear sir

    What’s the meaning of vagal menuver? How to do it.


    • A vagal maneuver is a technique by which you attempt to increase intrathroacic pressure which will stimulate the vagus nerve. This can result in slowed conduction of electrical impulses through the AV node of the heart. There are a number of ways to do it here are a couple:

      1. Cough Method: Have the patient cough forcefully. This is a simple form of vagal maneuver. The idea is to increase intrathroacic pressure which will stimulate the vagus nerve. This can result in slowed conduction of electrical impulses through the AV node of the heart.
      2. Straw Method: Have the patient blow forcefully through a straw for 3-5 seconds.
      3. Bear down Method: Have the patient bear down and strain. Kind of like how a person might strain when having a bowel movement.
      4. Syringe Plunger Method: First, show the patient how easy it is to move the plunger by pulling it back and forth in within the syringe and then have the patient. Have the patient place their mouth over the exit end of the syringe and attempt to blow the plunger out of the syringe. Have them blow for 3-5 seconds.
      5. Abdominal Pressure Method: Press into the pts abd while they contract and resist pressing into their abd.
      6. Ice Method: Quote from a healthcare provider: “We had a kid (approximately 12 yrs old) present to our ER in SVT, instead of using drugs and vagal maneuvers we dunked his face in a bucket of ice twice and it immediately & effectively brought the heart rate down. We observed him for a period of time and the kid was fine. Worked wonders! Young army doctor’s idea!”

      Hope this helps. Kind regards, Jeff

  3. realy itis very nice and informative diagrams

  4. According to the algorithm you are supposed to give a beta blocker or CA channel blocker with a narrow QRS complex and I was wondering if for AHA’s ACLS class I would be required to know the different drugs that can be given and the dosing for each.

    • I would stick with putting to memory the information found on the tachycardia algorithm diagram. The diagram does not list the doses or even the names of the beta-blockers or CA channel blockers in the diagram. The last two times that I have taken the AHA ACLS certification, this was not brought up.

      Kind regards,

  5. What is the role of Amiodarone in treating SVT in immediate post delivery period? If Adenosine not available which drug should be used for managing SVT

    • I’m no expert on the use of amiodarone but I will try and answer your questions.

      Amiodarone can be used to treat reentry SVT when the rhythm remains uncontrolled despite vagal maneuvers, adenosine, and longer-acting AV nodal blocking agents.

      If you mean treating prophylactically with amiodarone after adenosine coverts SVT, there is some supportive evidence that suggest amiodarone can be used to treat and prevent reoccurrence of SVT. However, because of the significant side effects and the slow onset of action, it is not highly recommended. There are other safer medications that can be used. These agents should be used in conjunction with expert consultation.
      Here is a reference.

      Pharmacologic agents commonly used in the long-term management of SVT include amiodarone, procainamide, calcium channel blockers (eg, diltiazem and verapamil), and beta-blockers (eg, metoprolol or atenolol). – See more at:
      Here is a reference.

      If adenosine is not available you could use verapamil. Verapamil has a high success rate for converting SVT as well. Here is a reference.

      Kind regards,

  6. Very very informative sir,please tell me which fluid is preferred during resuscitation

  7. Very very informative sir

  8. I’m a little confused about monomorphic VT- it looks like it is treated under the tachycardia algorithm- why isn’t it treated under the VF/VT algorithm? Is it just the polymorphic that is treated under the VF/VT algorithm?

    • If it is monomorphic with a pulse then it would be treated using the tachycardia algorithm. If there is no pulse, the monomorphic VT would be treated using the pulseless arrest algorithm (Pulseless VT/VF algorithm).

      Kind regards,

  9. A question regarding a-flutter and adenosine in a case of a stable patient: Should I use it or no?

  10. Following this algorithm, where would A.fib fall if the pt. is stable? (I understand that unstable would be treated with immediate synchronized cardioversion)….but since a fib is narrow qrs it says attempt vagal maneuvers, then give adenosine (only if REGULAR) and to my understanding a fib is a highly irregular, chaotic rhythm? So you wouldn’t give adenosine? would you still attempt vagal maneuvers? Thanks for any clarification you can offer!!

    • Atrial fibrillation would not be treated using the tachycardia algorithm unless the patient has a rapid ventricular rate and is unstable. This is why you first obtain an ECG. If the patient has stable atrial fibrillation with an RVR, the patient would be admitted to the hospital and worked up to identify the cause of the afib and then treat (Cardiology work-up). The patient would be admitted, placed on anticoagulant therapy and the RVR could be treated in a number of ways.

      If the afib with RVR is unstable, then the patient would be treated using the AHA ACLS tachycardia algorithm. Vagal maneuvers would not be indicated. Synchronized cardioversion would be indicated (120-200 J)

      Kind regards,

  11. Please help me understand the two terminologies; Monophasic and Polymonophasic tachycadia. why use adenosimne in regular narrow complex and regular wide complex tachycadia.

  12. Very informative site. Thanks!

  13. Excelent website.
    It’s amazing what I have learned today
    Thank you.

  14. Can you please confirm the syncronized cardioversion doses in the above algorithm? I am confused as to which rhythms go in each category. I was reading on the AFlutter page that it is a lower dose 20-50J I think it said…. Do I have these right?

    Narrow Regular 50-100 – SVT
    Narrow Irregular 120-200 – Afib, Aflutter
    Wide Regular 100 – VTach
    Wide Irregular Defibrilation -Torsades

    Are there others I am missing?

    • For Cardioversion here is what you should remember for dosing sequences:
      (narrow complex regular) 50-100-200-300-360 (a-flutter is usually has a regular rate. The starting shock dose can be 20-50J)
      (narrow irregular) 120-200-300-360
      (wide complex regular) 100-200-300-360
      (wide irregular) defibrillation same as VT/VF

      Kind regards, Jeff

  15. Your site is excellent help!

    I you please simplify unstable and stable Tachycardia and shocks in joules given.
    How can it be analyzed quickly and acted upon.

    Thanks, you are great help.

    • The easiest way to simplify the stable and unstable tachycardia is through a diagram shown in the article above. If you click on the text link labeled “Tachycardia Algorithm Diagram” this should be helpful. Hopefully, this diagram makes the tachycardia algorithm a little easier to understand.
      I have also tried to make the algorithm as easy as possible to understand through this web page above. I’m not sure if it can be simplified much further. The tachycardia algorithm is probably the most complex algorithm. This is why expert consultation should be considered if the pt. is not to unstable.

      Kind regards,

  16. While resuscitating a patient , do you give the patient iv fluids or do you wait until the patient is post arrest before giving I’ve fluids

    • IV fluids may be started during resuscitation if it does not delay the basic ACLS interventions that should be taking place. If there is a person designated specifically for giving IV medications, they can start IV fluids while waiting to give the next dose of epinephrine. Fluids can play a vital role in several types of cardiac arrest.
      Post resuscitation IV fluids can also play a major role in the patient recovery after ROSC.

      Kind regards,

  17. Hello..been your comments and it really is very informative. In a patient that supraventricular tachycardia, Would you consider a patient unstable if the bp down to palpatory 80 from 100/60 with good o2sats even after giving the patient adenosine 6 mg? In short should I manage the patient as stable and give subsequent dose of amiodarone 12 mg or just do cardioviorsion.?

    Would really appreciate you reply, thanks…

    • This blood pressure is not to good. However, I have seen patients stable with a SBP of 80. I would say that you should also look at other signs/symptoms. LOC, chest pain, signs of poor perfusion, short of breath, mottled skin.
      A patient is unstable if they display signs of poor perfusion. Blood pressure is just one indicator. If the patient is unstable, you will have other indicators.
      I would be ready to use synchronized cardioversion on this patient, but I would say you would be ok to give the 2nd dose of adenosine.

      Kind regards,

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