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.
zhik says
is there any situation that we start adrenaline as 1st line instead of atropine?
Jeff with admin. says
No there is no situation within the bradycardia algorithm that you would start epinephrine before you give atropine.
Atropine is the first line drug for the bradycardia algorithm.
Kind regards,
Jeff
Mardith says
Hi Jeff,
Why TCP is not use with hypothermia?
Jeff with admin. says
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.
Kind regards,
Jeff
Adrie34 says
Hi Jeff, your site was of great help to me, due to your site, I took my ACLS last week and pass my test, I think your site is great. God bless you.
Kamal Kishore says
great site for those preparing for ACLS certification. thanks.
Kamal Kishore
Lucilleholloman says
Jeff do we check h’s and t’s on all of these rhythm ?
Jeff with admin. says
It is wise to consider the H’s and T’s any time there is an emergency whether dealing with bradycardia, tachycardia, PEA, VT/VF, or asystole.
Finding the cause and treating it is produce the best outcome.
Kind regards, Jeff
sazima says
I’m a little confused about unstable bradycardia treatment. Is TCP the first treatment or atropine or are they to be used simultaneously? I thought TCP was used only if atropine doesn’t work. Which one is the first treatment of choice?
Jeff with admin. says
For symptomatic bradycardia, the first treatment of choice is usually atropine. However, there are a couple of things you must be aware of. AHA states “For Mobitz II and Complete block, atropine should not be relied upon.” Also, if the patient shows signs of poor perfusion and you have the capability to TCP, the TCP should not be delayed. If giving atropine will delay TCP, in any way, you should just move straight to TCP. Also, a patient with ongoing myocardial ischemia should not be given atropine since atropine increases heart rate and thus increases myocardial oxygen demand which can worsen ischemia. In a situation where there is myocardial ischemia, you should TCP at a rate no greater than 60 and prepare the patient for PCI (heart cath.)
I would not use atropine simultaneously. If you can try atropine (no ischemia) without delaying TCP do it. If atropine would delay TCP then move to TCP without delay. Usually the physician will say get TCP ready now and give atropine stat. Depending on what the atropine does, you are ready to TCP if needed.
Kind regards,
Jeff
sazima says
Hello,
I thought I had understood the treatment for unstable bradycardia but apparently I’m still not clear. I was taking my pre-assessment questions for ACLS and one of the questions is: -You are monitoring the pt and a Second degree AV block type 2 appears on the monitor with HR 50, the pt is c/o dizziness with a BP 80/40. She has an IV in place. What is your next action? The multiple choice answers are 1) Start Transcutneous pacing. 2) Give Atropine 0.5 mg IV. My answer was TCP because pt is unstable due to poor perfusion ( hypotensive). My answer was WRONG. .The correct answer was # 2. Can you please let me know why? I thought as you stated above on my last question that for this type of rhythm Atropine should not be relied upon. This made sense to me now I’m confused again. Please clarify. Thanks 🙂
Jeff with admin. says
The HR is still at 50. The pt. does have hypotension, but if the IV was in place then it would be appropriate to attempt atropine as you are preparing for TCP. If the Atropine does not work then you would proceed with TCP.
Atropine should not to be relied upon does not mean don’t give atropine.
Kind regards,
Jeff
Shokoufeh says
Thank you so much! That was so well explained. I’m clear now!
nicole says
Thanks. This site has really helped.
ranwan51 says
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jincy renjith says
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daiprz says
and thanks
daiprz says
just to be clear Atropine still contraindicated for High degree blocks? Here everybody is confusing me they said you can use it now for all type of degrees and when I looked at the outlines doesn’t specify it either, only in that page that i mentioned before. sorry I just want to be very clear.
charles100000 says
I would also enjoy the clarification of whether to initially use atropine in all cases of symptomatic bradycardia regardless 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. thank you in advance for your help.
Jeff with admin. says
Atropine may be used for any type of block but may worsen bradycardia caused by myocardial infarction due to atropine’s increasing the heart rate. In this case it would be safer to TCP at a rate of 60 and move toward some type of cardiac intervention. You should use the 12 lead ekg which is going to help determine MI and let you know whether atropine might be a problem.
If the patient has severe symptoms, you should not delay TCP.
Kind regards,
Jeff
daiprz says
Im confused with atropine vs Tcp. Before we couldn’t use atropine for symptomatic mobit II second degree and 3rd degree A V blocks. The book says use atropine for unstable, symtomatic bradycaridas, but in page 111 states ” Do no rely on atropine in high degrees Av Blocks.and mentioned all of them. My questiion is do we use Atropine in all of them or not?
daiprz says
ok i think i got it the only diferent now is i can use epinephrine or dopamine instead of TCP as my first choice but the rule still the same as before for high degree blocks. Please let me know if im incorrect
Thanks
Jeff with admin. says
You are correct. And now also you can use dopamine and epinephrine drip as an alternative when TCP is not available. Kind regards, Jeff
jo says
I am concerned with the thought that I can not use dopamine if I am attempting pacing. In the event of an AMI and cardiogenic shock. The heart may not be responsive to the pacer by not capturing and dopamine may increase contractility.
Jeff with admin. says
Upon on the page in the second red box down it states this: “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.”
A dopamine or epinephrine infusion would be appropriate. Also, AHA clearly states in their guidelines that a clinician can tailor the interventions to the scenario at hand even if the AHA guidelines are deviated from. The AHA ACLS Guidelines are just “guidelines.”
Also, the discussion that you commented on was in reference to atropine. I do apologize for the misunderstanding.
Kind regards,
Jeff
lnelson07 says
Lori Nelson;
what do you have medication wise if you are pulseless bradycardia? if monitor shows brady @ 40 but patient has no pulse?
Jeff with admin. says
You would treat this as PEA. You would start CPR and given epinephrine. Regards, Jeff
Logan Kysar says
What does the AHA recommend for stocking Atropine? Should it be .1mg/ml (1mg/10ml) or is it okay to stock .4mg/ml vials?
Jeff with admin. says
The AHA has no recommendations for stocking of one over the other as far as I know. In my personal experience, I have always seen 0.1mg/ml (10 ml vials), and I really like this. It makes administration of the medications simple in an emergency situation. Nice whole numbers are good. 5ml=0.5mg. This is what I would recommend. Regards, Jeff
emre says
i didn’t understand that when we treat the patients?only are they unstable?mean that poor perfusion?
Jeff with admin. says
You should treat them before they are unstable. This would involve basic nursing and medical skills. If they get to the point of instability, you would use ACLS. This site only address the point at which they are unstable. I hope this makes sense.—regards, Jeff