The major ECG rhythms classified as bradycardia include:
- -Sinus Bradycardia
- -First-degree AV block
- -Second-degree AV block
- -Type I —Wenckebach/Mobitz I
- -Type II —Mobitz II
- -Third-degree AV block complete block
Bradycardia vs. Symptomatic Bradycardia
Bradycardia is defined as any rhythm disorder with a heart rate less than 60 beats per minute. (Usually less than 60)
Symptomatic bradycardia, however, is defined as a heart rate less than 60/min that elicits signs and symptoms, but the heart rate is typically 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.
Relative bradycardia occurs when a patient may have a heart rate within normal sinus range, but the heart rate is insufficient for the patient’s condition. An example would be a patient with a 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 is reviewed following this page.
- The single dose administration of atropine was increased from 0.5 mg to 1 mg. Now give 1 mg for the first dose and then repeat every 3-5 minutes at the 1 mg dose.
- Also, the dopamine infusion rate for chemical pacing was changed to 5-20 mcg/kg/min.
The previous rate from the 2015 guidelines was 2-20 mcg/kg/min. - The demand rate may be set at a range from 60-80/min. 2015 guidelines had the start demand rate to start at only 60/min.
2015 AHA Update: For symptomatic bradycardia or unstable bradycardia IV infusion a chronotropic agent (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. The dose in the bradycardia ACLS algorithm is 1 mg IV push and may repeat every 3-5 minutes up to a total dose of 3 mg.
Dopamine: Second-line drug for symptomatic bradycardia when atropine is not effective. Dosage is 5-20 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, observe and monitor the patient. 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 finished, click again to close the diagram.
Bradycardia Algorithm Diagram
or Download the High Resolution PDF Here. (This will open in another window.)
Transcutaneous pacing (TCP)
Preparation for TCP takes place as atropine is being given. If atropine fails to alleviate symptomatic bradycardia, TCP is initiated. Ideally, the patient receives 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. The starting rate for TCP is 60-80/min and adjust up or down based on the patient’s clinical response. The dose for pacing is set at 2mA (milliamperes) above the dose that produces observed capture.
TCP is contraindicated in the patient with hypothermia and is not a recommended treatment for asystole.
Do not use a carotid pulse check for the 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 protocol since reversing of the cause will likely return the patient to a state of adequate perfusion.
Top Questions Asked on This Page
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Q: Should I use atropine in all cases of symptomatic bradycardia regardless of the level of block? The prep test for AHA ACLS seems to support giving atropine initially in symptomatic second-degree block type II, but not for complete block.
A: There are a couple of things to mention here. First, atropine may be used for any type of block but may negatively affect outcomes if the bradycardia is being caused by myocardial infarction.
This negative effect may occur because atropine increases the heart rate and myocardial oxygen demand. In the case of bradycardia caused by MI, it would be safer to transcutaneous pace (TCP) at a rate of 60 and move toward some type of cardiac intervention. You should use the 12 lead ECG to help determine MI. This will help determine if atropine may exacerbate the patient’s condition. If the patient has severe symptoms, you should not delay transcutaneous pacing (TCP).
You will usually have time to try atropine as you prepare for TCP.
Second, AHA states “For Mobitz II and complete block (3rd Degree block), atropine should not be relied upon.” This does not mean that it is contraindicated. It just means that it should not be relied upon because there is a good chance that it will not work.
It may not work because atropine blocks the action of the vagus nerve. Atropine works at the SA and AV node through its effect on the vagus nerve, and since conduction abnormalities associated with 2nd-degree block type II and 3rd-degree heart block are below (distal) the site of action for atropine, the drug will typically have an insignificant effect.
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Q: Why is pacing contraindicated in hypothermia?
A: Bradycardia may be physiologic in the hypothermic patient. This type of bradycardia is an appropriate response to the decreased metabolic rate that normally occurs with hypothermia.
Also the hypothermic ventricle is more prone to fibrillation with any sort of irritation. Thus the irritation of TCP could induce VF. Once the hypothermic ventricle begins to fibrillate, it is more resistant to defibrillation. Warm the patient and then treat any remaining arrhythmias.
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Q: What is TCP?
A: TCP means transcutaneous pacing.
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Q: What is chemical pacing?
A: Chemical pacing is when IV medications (epinephrine or dopamine) are used to increase the heart rate rather than the transcutaneous pacing which uses electricity to increase the heart rate.
abosuyonov says
Thank you very much .
Just a question.
A pt with symptomatic Functional or relative bradycardia with HR of 80 do we or not use the bradycardia algorithm ?
Jeff with admin. says
In this situation, you would not necessarily follow the algorithm. Clinical discretion would be warranted because there are some comorbidities that could be made worse by interventions within the algorithm particularly the use of atropine. If you cannot get immediate expert consultation, best option for symptomatic bradycardia with a rate greater than 80 would be the cautious use of TCP. Also, the cautious use of pressers to maintain blood pressure should be considered.
Kind regards,
Jeff
1989 says
Hi Jeff, Is it OK to give Epinephrine and Dopamine infusion simultaneously?
Elisha says
Hi Jeff
I was told by a senior trauma nurse during a resuscitation (initial bradycardia leading to PEA post polytrauma) to administer 1 mg atropine and 1 mg epinephrine at the same time as soon as possible. Having done the ACLS course a year ago my understanding was that one would use one or the other at 4 minute intervals. What is the effect of atropine and concurrent adrenaline administration in a pulseless patient? Should I be concerned?
Jeff with admin. says
The use of atropine for PEA is not recommended because there has been no evidence that it improves outcomes.
There are some physicians that continue to use this treatment along with epinephrine, and this would be per their own discretion.
I don’t think you would have anything to be concerned about with regard to malpractice. Physiologically speaking, atropine would potentially increase the heart rate and epinephrine would increase heart rate and vasoconstrict. There would be no contraindication with this, but it is just not recommended per the American Heart Association guidelines.
Kind regards,
Jeff
Sara says
In treating reflex bradycardia caused by phenylephrine, would atropine still be the drug of choice? In this case, I was also wondering if an alpha blocker such as phentolamine be effective.
Jeff with admin. says
I was not sure on this question since I don’t deal much with phenylephrine. I spoke with my younger brother who is a nurse anesthetist and asked him how he would handle the situation. This is what he says :
“I don’t treat the bradycardia unless it gets really low. The half-life of phenylephrine is short. If it does get to low I usually use glycopyrrolate first if it still stays low then I use atropine. If I give glycopyrrolate I usually start at .1 mg.”
Hope that helps.
Kind regards,
Jeff
Prem says
Hi Jeff,
Can you explain me more what is TCP?
Jeff with admin. says
Transcutaneous pacing (TCP) is performed by placing pads on top of the skin (transcutaneous). These pads conduct an electrical current that stimulate the heart to contract. TCP is used when sever bradycardia leads to decreased circulation which is the same as poor blood perfusion.
The following link is just as good an explanation as any on the web: Transcutaneous pacing.
Kind regards, Jeff
brendamcginnity says
In the 2016 ACLS manual , on Bradycardia it lists Dopamine dosages from2-20 mcg/kg/min. Is this now correct? your course lists dopamine 2-10 mcg/kg/min. It is confusing. Brenda
Jeff with admin. says
Over the past several months revisions have been made to the site to reflect the new 2015-2020 AHA ACLS Guidelines. 2-20 mcg/kg/min for the dopamine infusion is the correct dosing according to the new guidelines. Kind regards, Jeff
jlaroza says
Hi Jeff,
Great site, its very informative. I did not see much information on Heart block, Is it a topic that is not discussed in detail for ACLS?
Thanks,
Jlaroza
Jeff with admin. says
You can find all of the major blocks including complete heat block covered here:
https://acls-algorithms.com/rhythms/
Also here is a video review of the bradycardia algorithm if you have not watched it yet.
https://acls-algorithms.com/acls-video-review/bradycardia-review/
Also the interactive course guide covers all of this step by step.
https://acls-algorithms.com/lessons/bradycardia-algorithm/
Kind regards,
Jeff
michaelgv says
I’m unclear about the dopamine solution 200mg in 100ml= 2000mcg/ml. Please check my math but it seems to me that if I’m treating a 70 kg person 2mcg/kg/min would then be 140mcg/min and 10mcg/ml/min would be 1400mcg/min. Even at the higher dose the drip is only running at about 0.7ml/min, while at the lower dose the rate would be 0.07ml/min. The latter rate seems like a difficult rate to monitor, even with an infusion pump. Wouldn’t a larger initial volume be better?
Thanks.
Jeff with admin. says
Dopamine is usually prepared by mixing 800mg dopamine in 500ml of NS for a concentration of 1600 mcg/ml. This can also be done by mixing 400mg dopamine in 250ml of NS. At least this is how I have always seen it mixed.
However, I will look at it your way for the math. 200mg in 100ml = 2mg/ml = 2000 mcg/ml. A 70kg person receiving 2 mcg/kg/min would receive 140 mcg/min. The same 70 Kg person receiving 10mcg/kg/min would receive 700 mcg/min.
Now first, convert mcg/min to mg/hr. 700mcg/min=42,000mcg/hr=42mg/hr
Now second, convert mg/hr to ml/hr. dose ordered/dose available x volume avaliable 42mg/200mg x 100= 21 ml/hr (The rate would be 21 ml/hour).
I’m not sure where you went wrong on the math, but this is how I would calculate it. You can also use the calculator found here: infusion calculator
Kind regards,
Jeff
jinhomc says
Both of you have the same calculation, but Jeff, unfortunately, your reply is not answering his question…
Jeff with admin. says
Michael,
If you are infusing 0.7ml/min this would work out to 42ml/hr. I don’t see why you think that it would be a problem to control/monitor this rate. We do it all of the time. Small dose/min dose not equate to small effectiveness. Dopamine is very effective in minute doses/min. and fairly easy to monitor if you have an arterial line to determine second by second blood pressure. Even if you have an automatic BP cuff, you can perform minute to minute BP’s to titrate the dopamine for effect. Kind regards, Jeff
Dacite says
Hey!
Would one use atropine i/v undiluted? Or with 5 % glucose? If with glucose, how much? Thank you!
kind regards,
DZ
Jeff with admin. says
When using atropine within the bradycardia algorithm, atropine will be given undiluted and followed with a 20 mL flash of normal saline.
Atropine found on crash carts usually comes in pre-fill ready to administer syringes.
Kind regards,
Jeff
mjcole@shaw.ca says
how would you mix the epi or dopamine to allow an appropriate infusion rate
Jeff with admin. says
Epinephrine IV infusion for bradycardia: Add 1mg epinephrine with 500ml of NS or D5W.
Dopamine IV infusion for bradycardia: Add 200mg of dopamine (5ml) to 95ml of compatible IV fluid (NS, or D5NS) (i.e. 200mg in 100ml)
Kind regards, Jeff
Al says
In ACLS Bradycardia algorithm is it necessary to max out the dose of atropine first (3mg) before proceeding to do TCP or Epi or Dopa?
Jeff with admin. says
No it is not necessary to max out the atropine dose before proceeding on to TCP or chemical pacing. In fact, you are encouraged to not delay pacing for the administration of atropine in unstable patients with poor perfusion. Kind regards, Jeff
Heber Rodriguez says
Inferior MI’s can cause bradycardia. Under this circunstances atropine is contraindicated, and nitroglycerin should be used. We identify these patients using an 12 lead, so does it mean that we always need to do an 12 lead EKG before giving atropine?? Thank you
Jeff with admin. says
Yes, a 12 lead EKG would be indicated prior to give atropine. This is to ensure a proper diagnosis and identify any underlying abnormalities.
Kind regards,
Jeff
seaschelle1 says
Im confused. About the statement above. I thought nitro was contraindicated in right vent infarcts that are most commonly associated with inferior wall MI’s. Could you please clarify. thanks
Jeff with admin. says
Yes, you are correct. In the comment that the user (Heber) made, they mistakenly stated that nitro would be used. This is incorrect. Nitroglycerine would be contraindicated for inferior wall MI until an ECG is performed and right ventricular involvement is ruled out. Morphine would also be contraindicated until RVI is ruled out.
Thank you for pointing this out.
Kind regards,
Jeff
lsedgwick says
Glad someone else picked this up. Inf MI must confirm no RVF prior to administering nitrates as these pts are preload dependent. Look for hypotension with elevated JVD and clear lungs.
Jarod says
A 12-lead should be performed prior to any Rx intervention. Ruling out right side involvement with inferior AMI is extremely important in considering NTG administration. MS is indicated in AMI (excepting right-sided MI) primarily due to it’s vasodilatory effects, not analgesia (this is a latent benefit), therefore fentanyl could be used to help with pain but would not work to the same end as MS and is not generally recommended in my experience. Remember that both MS and fentanyl can result in respiratory depression, so consider the pt.’s status carefully before administration. Bradycardia can often be a natural protective mechanism in AMI to reduce myocardial oxygen demand, and should NEVER be treated solely based on the rate. A pt. who is SYMPTOMATIC for bradycardia related complications should be treated accordingly. This may sometimes require a Rx such as oxygen, fluids, dopamine or dobutamine (both result in relatively minimal myocardial oxygen demand compared with atropine or epinephrine), and possibly TCP.
Ronnie para uk says
Hi, at present Uk paramedics are prohibited from tcp. Is it possible that with a patient presenting Brady due to a type 2 block, giving atropine could worsen the block? For example a type 2 mobitz progressing to complete heart block or a complete block into a systole. Due to the nature of these blocks, the problem lies below the AV node?
Many thanks
Jeff with admin. says
In most cases of Mobitz 2, atropine will not work and can worsen the patient’s condition. Atropine can cause degeneration to 3rd degree block.
Atropine increase firing of the SA node and conduction through the AV node.
In most cases Mobitz 2 is a disease of the distal conduction system (His-Purkinje System). Atropine’s affects are above this and therefore atropine will most likely have no effect on Mobitz 2.
High degree blocks (Mobitz 2 and 3rd degree block) will usually not improve with atropine.
Kind regards,
Jeff
sweetbluesgirl says
So if the patient presented with a heart rate showing high degree block, would the treatment of choice be TCP and/or Epi or dopamine infusion?
Thanks,
Gizelle
Jeff with admin. says
It would depend upon whether the patient had signs of poor perfusion. If she had signs of poor perfusion, TCP, EPI, or dopamine would be indicated and should be administered.
Kind regards,
Jeff
Pmorris4ACLS says
Fentanyl too?
Jeff with admin. says
Yes Fentanyl would be ok. Kind regards, Jeff
goar0701 says
What is the recommended medication for sedation in a patient who will be given with TCP and/or Cardioversion?
Thanks!!!
Jeff with admin. says
There are not specific recommendations for sedation/analgesia. Probably the two most common is morphine and versed.
The object is to titrate an analgesic or sedative to control any major discomfort.
Kind regards,
Jeff
S Microys says
I frequently do sedation for cardio version in a large tertiary Center and all that is needed is very small dose of propofol. It is not painful so narcotics are not necessary and only delay awakening and increase risk.