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Bradycardia Algorithm


Bradycardia Algorithm Review

(includes 2010 AHA Guideline Update)

The major ECG rhythms classified as bradycardia include:
Sinus Bradycardia
First-degree AV block
Second-degree AV block
Type I —Wenckenbach/Mobitz I
Type II —Mobitz II
Third-degree AV block complete block

(See the ECG Interpretation section for images and more detailed information on rhythms)

Bradycardia vs. Symptomatic Bradycardia

Bradycardia is defined as any rhythm disorder with a heart rate less than 60 beats per minute. (Typically it will be <50/min) This could also be called asymptomatic bradycardia. Bradycardia can be a normal non-emergent rhythm. For instance, well trained athletes may have a normal heart rate that is less than 60 bpm.

Symptomatic bradycardia however is defined as a heart rate less than 60/min that elicits signs and symptoms, but the heart rate will usually be less than 50/min. Symptomatic bradycardia exists when the following 3 criteria are present: 1.) The heart rate is slow; 2.) The patient has symptoms; and 3.) The symptoms are due to the slow heart rate.

Functional or relative bradycardia occurs when a patient may have a heart rate within normal sinus range, but the heart rate is insufficient for the patients condition. An example would be a patient with an heart rate of 80 bpm when they are experiencing septic shock.

Bradycardia Pharmacology

There are 3 medications that are used in the Bradycardia ACLS Algorithm. They are atropine, dopamine (infusion), and epinephrine (infusion). More detailed ACLS pharmacology information can be found here.

2010 AHA Update: For symptomatic bradycardia or unstable bradycardia IV infusion chronotropic agents (dopamine & epinephrine) is now recommended as an equally effective alternative to external pacing when atropine is ineffective.

Atropine: The first drug of choice for symptomatic bradycardia. Dose in the Bradycardia ACLS algorithm is 0.5mg IV push and may repeat up to a total dose of 3mg.

Dopamine: Second-line drug for symptomatic bradycardia when atropine is not effective. Dosage is 2-10 micrograms/kg/min infusion.

Epinephrine: Can be used as an equal alternative to dopamine when atropine is not effective. Dosage is 2-10 micrograms/min.

Bradycardia Algorithm

The decision point for ACLS intervention in the bradycardia algorithm is determination of adequate perfusion. For the patient with adequate perfusion, you should observe and monitor. If the patient has poor perfusion, preparation for transcutaneous pacing should be initiated, and an assessment of contributing causes (H’s and T’s) should be carried out.

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

Transcutaneous pacing (TCP)

Preparation for TCP should be taking place as atropine is being given. If atropine fails to alleviate symptomatic bradycardia, TCP should be initiated. Ideally the patient should receive sedation prior to pacing, but if the patient is deteriorating rapidly, it may be necessary to start TCP prior to sedation.

For the patient with symptomatic bradycardia with signs of poor perfusion, transcutaneous pacing is the treatment of choice.

Do not delay TCP for the patient with symptomatic bradycardia with signs of poor perfusion. TCP rate should use 60/min as a starting rate and adjust up or down based on the patient’s clinical response. The dose for pacing should be set at 2mA (milliamperes) above the dose that produces observed capture.

TCP is contraindicated for the patient with hypothermia and is not a recommended treatment for asystole.

A carotid pulse should not be used for assessment of circulation as TCP can create muscular movements that may feel like a carotid pulse. Assess circulation using the femoral pulse.

Identification of contributing factors for symptomatic bradycardia should be considered throughout the ACLS protocal since reversing of the cause will likely return the patient to a state of adequate perfusion.

  162 Responses to “Bradycardia Algorithm”

  1. Hello Jeff,
    Would you treat a 76 yo m patient with the bradycardia algorithm who initially complained of chest pain and a syncopal episode. Now presenting with mild difficulty breathing, alert and oriented x4, a Bp 112/68, feeling of impending doom ECG showing second degree type 1 av block at a rate of 60?

    Since 60bpm is not Brady and he is normotensive….inspite of impending doom (not unstable, but symptomatic)……?
    O2, IV, monitor, 12 lead. Reassure, Keep pacer pads on in case he deteriorates or become symptomatic. I get a little hung when the ranges are right there…. What are your thoughts?

    • I would first treat the patient with the Acute Coronary Syndrome Algorithm. This scenario sounds like a possible MI. I would not treat with the bradycardia algorithm at this time.
      The patient should be admitted to a telemetry unit. Provide O2 if needed. Q 8 hour troponin levels and 12 Lead ECG. Monitor for increased pain, syncope, or other symptoms. Observe for 24 hours and perform a stress test if the patient has any further symptoms.
      If the patient develops bradycardia treat per the bradycardia algorithm. You would not need to leave the patient attached to a pacemaker if the heart rate is normal and the patient is stable. Those are my thoughts.
      Kind regards,

  2. This is a silly question but what is chemical pacing? And ifa patient in bradycardia why give IV fluid?

    • Chemical pacing is when IV medications (epinephrine or dopamine) are used to increase the heart rate rather than the pacemaker which uses electricity to increase the heart rate.
      Kind regards,

  3. I thought the maximum dose of atropine was 6mg, not 3mg as stated?

  4. I had a patient, symptomatic bradycardia. Fully conscious and alert,talking,not in respiratory distress BP 100/80 (he known hypertensive). And had complete heart block. He presented with multiple syncopal attack.he had 2 episodes of syncope and near syncope in ED (witnessed). My question is, between chemical pacing and TCP, which is superior /preferred . Can we do simultaneous pacing? (Both chemical and tcp). Thank you

    • P/s .patient 3rd degree block. Rate 30.
      Is there any studies conducted for chemical pacing vs TCP? (Couldnt find online)

      • PubMed would be the place to look for these types of studies. You would be wading through a lot of literature to get your answers. This is why AHA does a lot of this work for us, and then develops guidelines. AHA makes their guidelines after a regular and thorough review of the medical literature. The AHA now states that chemical pacing is just as effective as an alternative to TCP. Personally, I like electrical pacing. It seems to me like it can be more closely regulated and easily discontinued. However, their literature review seems to indicate that chemical pacing is just as good.

        In the situation you experienced something like demand pacing for a heart rate less than 50 or 60 many have been the right way to go especially with complete block.

        If you were to attempt chemical pacing, you would probably want to infuse to maintain a HR greater than 60 or 70 and keep the patient free of symptoms until a pacemaker could be placed.

        I’m not an expert in this area, and I imagine that even most internal med residents and such would get with a cardiologist rather quickly on cases like this.

        Hope this helps.

        Kind regards,

  5. i had a patient with blackout,airway n breathing was clear, BP 90/60,HR 40x,what should i do first?sugestion please..i decided to iv line loading RL n epineprine 0,5 im is that correct?


    • Considering that the Heart rate was 40 and the patient was symptomatic AHA ACLS guidelines would have directed toward IV, EKG, atropine 0.5mg IV push. You would also want to immediately start looking for the cause of the bradycardia and also ensure that the bradycardia was the cause of the blackout.

      Kind regards,

  6. If pt fails with atropine n T C P which is first choice dopamine
    or adrenaline

  7. Today we witnessed a cardiac arrest where the patient was experiencing a palpable beat centrally at an irregular rate of approximately 6 per minute; for a sustained period of approximately 25 minutes. Could you please tell me if there is a minimum heart rate for atropine to be successful in raising the heart rate?

    Thank you!

    • You cannot have cardiac arrest and bradycardia at the same time. Most likely, this irregular beat was chaotic and should not be considered a perfusion generating pulse.
      If the patient was in cardiac arrest then atropine would not be appropriate. By definition cardiac arrest means that the heart is no longer providing effective perfusion to the vital organs. CPR would be the appropriate action in this case. It is not uncommon to think that a pulse if felt or to feel a random pulse. The fall back would be to obtain a peripheral blood pressure. If you cannot obtain a blood pressure then you have no effective perfusion. In this case, CPR Should be performed and the pulseless arrest algorithm should be used.
      You also would need to look for the cause of this arrest. Understanding why the arrest is very important so that any reversible causes can be addressed.
      Kind regards,

  8. is there any limit for the heart rate in asymptomatic sinus bradicardiab that should given atropine 0,5 mg? thx

    • If a patient is asymptomatic with a heart rate of 30 and they are not an athlete, it would be surprising. Atropine should be used when a pt. has symptoms. If the HR is low and there is no reason and the patient is asymptomatic, they should probably should have a cardiology evaluation. Also, they probably would become symptomatic with activity.

      Anyway, if they are severely bradycardic but asymptomatic, they should be evaluated by a cardiologist. I do not think it would be recommended to use atropine unless they are symptomatic.

      Kind regards,

  9. We were wondering if pacing is less invasive than IO atropine. As in you can not get an IV not serious signs and systems but deteriorating. Would it be better to pace or IO atropine.

    • IO is really only used in emergencies. If the above scenario occurred in an ER, I think that most ER physicians would get a quick central line in if possible. If this were not possible, I think that most ER physicians would go with TCP and then get a line once pacing was initiated. Pacing is very non-invasive with minimal complications, and it can be discontinued easily.

      Kind regards,

  10. I see since the last time I took ACLS that Isuprel is no longer on the bradycardia algorithm. Has it been removed?

    • Also I was looking for something on transplanted hearts. Are there any exceptions to the algorithms for transplanted hearts?

      • I could not find anything stating that the treatment of patients with heart transplants would be any differently during cardiac arrest.
        I did find this article that speaks specifically to CPR and this issue.

        I have sent an e-mail to my brother who has more experience in this area. If I find out any other information, I will let you know.

        Kind regards,

    • Although Isoprel is no longer a first-line medication in the ACLS bradycardia algorithm, it is still can be used. Here is a quote from AHA 2010 guidelines on this issue:
      “Although not first-line agents for treatment of symptomatic bradycardia, dopamine, epinephrine, and isoproterenol are alternatives when a bradyarrhythmia is unresponsive to or inappropriate for treatment with atropine, or as a temporizing measure while awaiting the availability of a pacemaker. Alternative drugs may also be appropriate in special circumstances such as the overdose of a β-blocker or calcium channel blocker.” Here is the link to the AHA article.

      Kind regards,

  11. I have such a hard time differentiate between a complete blocks ,Sinus exit block and sinus pause Cant get them straight…..please help!

    • The easiest why I explain it is as follows.
      In a 3rd degree heart block is a persistent rhythm having P waves and QRS complexes that are not associated with one another. Further, the P waves march out with one another as do the QRS complexes.

      Sinus Arrest/Pause is not a persistent rhythm/ It’s intermittent. P waves and QRSs are associated with one another. i.e you have a PR interval except for when you have sinus arrest, then you just have no electrical impulse for a beat.

      Does that make since. Here is a great sight to view and study 12 lead ECGs
      Hope this helps.
      Kind regards,

  12. I have such a hard time with the blocks! Cant get them straight…..please help!

  13. There are some statement said, we cannot give IV atropine less than 0.5mg. it may cause paradoxically result in further slowing the heart rate. Can you elaborate more thank you

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