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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.

  146 Responses to “Bradycardia Algorithm”

  1. 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,

  2. 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,

  3. 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,

  4. 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,

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

  6. 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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