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.
In regards to Dopamine; In one of the previous ACLS textbooks there was mention of the 2-5 mcg dose was no longer recommended due to lack of data, etc. It advised that the new dose range is 5-20 mcg/kg/min. In the newer texts, I no longer find a reference of this, and the recommended dose continues to be 2-20 mcg, even though we will not be using the 2-5 mcg range.
Any insight of an upcoming change?
Thanks!
Since at least 2008, the dosing recommendation for chemical pacing using bradycardia has been 2-10 mcg/kg/min. I am not aware of any changes from the 2-10 mcg/kg/min dosing.
Kind regards,
Jeff
what is the max milla amp u can go up to in order to try and achieve capture?
There is really no max. You keep going up until you get capture and then if your machine allows, you go up 2 milliamperes.
It is interesting you asked that question. I actually discussed this very thing yesterday with a cardiologist at the Hospital I work at.
Usually capture will occur between 30-50 milliamperes. You can go higher if needed.
Kind regards,
Jeff
What if you had a sinus brady STEMI or a bradycardic rhythm that showed ST elevation on a 3 lead monitor? I have always heard that Pacing a STEMI could actually cause too much stress to the already starving for oxygen heart and put the patient into arrest. Is this true or fallacy?
If you have symptomatic bradycardia with STEMI, you would be ok to pace but keep the rate at around 60 or less. The object would be to keep the rate as low as possible to maintain adequate perfusion. Any intervention may increase oxygen consumption of the heart. This type of patient should receive coronary intervention as soon as possible. You would also start anticoagulation therapy, control pain with nitro and morphine, and provide coronary intervention as soon as possible.
Kind regards,
Jeff
If the TCP is not available, do you keep giving the atropine up to 3 mg or go for the pressors.
If TCP is not available you would attempt chemical pacing with a epinephrine drip or a dopamine drip according to the bradycardia AHA ACLS protocol.
You could continue use of atropine along with the drip if the rate does not improve.
Kind regards,
Jeff
hi
I want to know if you continue with Atropine when it has has failed to alleviate symptomatic bradycardia and TCP has been initiated.
If you have initiated TCP there would be no need to continue with the use of atropine.
Kind regards,
Jeff
When do you pace? do you pace for every kind of bradychardia when the heart rate is low, or only certain ones?
You will use transcutaneous pacing if the patient has symptomatic bradycardia and atropine has not been effective for improving the heart rate and symptoms.
Any am symptomatic bradycardia can be paced.
Kind regards,
Jeff
At what point during severe bradycardia do you start CPR? Is it always once you lose a pulse or would you start it at say 15 or 20 bpm? Just curious because I was told the other day by a nurse it was policy at her hospital to start CPR if atropine is not successful and the HR dropped below 20 BPM until epi or dop drips arrive or TCP arrives. Thank you
AHA has no specific set pulse at which to start CPR for the bradycardia algorithm. Clinical judgment of the situation should dictate what interventions are performed. Of primary importance is adequate perfusion of the vital organs. Signs and symptoms should direct your course of action.
The policy that you mention sounds reasonable. If the patient is having serious symptoms, atropine has failed, and you do not have the means to pace whether with drugs or with electricity then CPR could be warranted.
If you have the means to pace that would be the next appropriate intervention.
Kind regards,
Jeff