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
-
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.
-
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.
-
Q: What is TCP?
A: TCP means transcutaneous pacing.
-
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.
Pietro Bocchi says
Good Morning Jeff, I have a question.
What is the diluition of dopamine in bradycardia algorithm?
Thank you
Best Regards
Pietro
ACLS says
Standard dilution is 400mg/250ml D5W OR 800mg/250ml in D5W.
Kind regards,
Jeff
Yvette Konemann says
Do you know why the dosing for atropine changed from the 2015 guidelines? Unable to find. Thank you!
ACLS says
I have searched for an answer to that question for quite some time. I have reviewed all of the American heart Association primary literature and I cannot locate a reason and rationale for the change.
They did something similar previously with the dosing of adenosine and I never could find a specific reason for that either.
Sorry I do not have a specific answer for your question.
Kind regards,
Jeff
Jasmine says
Atropine dose equals or less than 0.5mg may cause slower heart rate to bradycardia patient. The resource is from Heartcode ACLS Online Course. They have a question about it in the test.
Kerin says
Hi – I had a question about profound sinus bradycardia hypotension (70/40) with hypothermia (28C) and sepsis. I was trying to find journal articles concerning fluid use. My practice has been to judiciously use fluids due to the bradycardia. Give a fluid boluses and continuous fluids but not reflexive 30cc/kg bolus. I’m having trouble finding any articles discussing evidence based fluid use. Any thoughts?
ACLS says
This question is beyond the scope of my experience and beyond the scope of ACLS. I have dealt very little with sepsis and hypothermia along with the use of fluids in these situations. The more variables you add to situations like this when trying to find research the less likely you’re going to be able to find specifics. What I would recommend is searching keyword subject two word Key word phrases then searching back two or three pages in the search. You often times will stumble upon what you’re looking for when you do this. Kind regards, Jeff
breeana says
Hi if I have a first degree heart block or even a second degree type 1 with poor perfusion do I TCP or always atropine first even if the vitals are unstable?
ACLS says
Atropine should be attempted while setting up TCP. Atropine is the first-line medication for the treatment of symptomatic bradycardia.
If atropine fails then move directly to TCP.
If for some reason you already would have had TCP attaches to the patient then it would be appropriate to begin TCP ASAP.
Kind regards,
Jeff
jeffrey kasbohm says
Hi Jeff — regarding the first degree heart block: if that alone , that wouldn’t require pacing — unless of course a symptomatic rate. correct? What say you
ACLS says
This is correct. First-degree heart block alone is not an indication for pacing.
Kind regards,
Jeff
Kaes says
I had a patient presented with sonis bradycardia heart rate 30 BPM, he is alert and conscious, no dyspnea or chest pain, BP 124/85 mmHg, looks unaffected.., he is using beta blockers, I choosed to stop net blockers and observe patient with no intervention… is it OK..
ACLS says
Sounds like a wise conservative choice. The patient was stable and this was most likely related to the beta blocker.
How did things turn out?
Kind regards, Jeff
Rubén says
Hi Jeff,
completely agree in the management but just one doubt: we still use isoproterenol in patientes with brady without HDN compromise with good results (24-48 hours), while waiting pacemaker implant . Any place nowadays…
regards
metwally says
I AM A PSYCHIATRIST,,
KINDLY WHAT ARE THE PSYCOTROPICS WHICH ARE CONTRA INDICATED W BRADYCARDIA ,, ASYMPTOMATIC,, LESS THAN 60/MIT
ACLS says
Although there is no exclusive data on the extent of cardiac effects and interaction of psychotropic medication with drugs used in treating cardiovascular conditions, The following article has a good review.
Psychotropics and Arrhythmias
Kind regards, Jeff
Gavin Grant says
Why is dopamine used instead of norepinephrine? yes norepinephrine on its own causes reflex bradycardia but if you use atropine before it, which blocks the activation of the vagal nerve then your good. I’ve read many studies that have said dopamine causes more arrhythmias than norepinephrine so why is dopamine preferred?
Thank you , Gavin
ACLS says
Norepinephrine has less of an effect on the heart rate and has a greater effect on vasoconstriction. Dopamine is the choice for bradycardia because it’s effects on heart rate are more profound than its affects on vasoconstriction.
Kind regards,
Jeff
Eleni says
I have observed that noradrenaline increases HR and many times when we have an unstable , tachycardic , intubated pt, an increase in e.g Levophed in order to raise BP almost always requires an increase in dose of e.g. Brevibloc (esmolol) . I have almost never experienced bradycardia after higher noradrenaline doses. Anybody else agree?
Carrie Miller says
If you immediately start pacing a highly unstable patient in 3rd degree block, how will you then know if the block and instability was caused by a STEMI? Wouldn’t you want to ideally want an EKG first? ACLS says not to delay therapy if the patient is very unstable.
ACLS says
It would be ideal to get a 12 lead EKG prior to starting pacing. If this is not possible, you could begin pacing and then when and EKG is available, momentarily stop pacing to perform the 12 lead EKG.
Kind regards, Jeff
Rani Soi says
Can you please explain How to prepare TCP. If possible video
ACLS says
Here is a video that shows you the set up and procedure of transcutaneous pacing.
TCP Video
Kind regards, Jeff
Karol says
witam, czy w wolnym migotaniu przedsionków można podać Atropinę ? czy ona w ogóle zadziała w takim rytmie ? Przyspiesza rytm zatokowy czyli działa w bradykardii zatokowej ale jeśli mamy wolne AF ? pozdrawiam
ACLS says
Yes, atropine can be given for bradycardia with atrial fibrillation. However, if the patient is unstable, it may be better to use transdermal stimulation or intravenous epinephrine infusion. Kind regards, Jeff
Koh Jiyoon says
Jeff, I hav a qusetion
I met a patient, whose heart rate was 30-40 / min, and Juctional Bradycardia. Initial blood pressure was 60/40mmHg. His mental status was Drowsiness.
We used transcutaeneous pacing, and his rate was controlled, but his blood pressure was not controlled(after pacing, his blood pressure was 70/45mmHg).
In this case, should I use vasoconstricotors like dopamine or epinephrine? Or should I use bolus fluid to maintain blood pressure?
I will wait for your answer. Thank you for your writing.
ACLS says
Depending on the circumstances you would probably use both. If the patient has a history of fluid overload related to heart failure then fluid blouses should be used very cautiously.
A fluid challenge of 500 ml would probably be appropriate, and see how the BP responds. It would be appropriate to use epi or dopamine to help improve and maintain the patient’s BP.
The main caution is not to worsen any ongoing fluid overload related to heart failure.
Kind regards,
Jeff
Martin says
What other type of hypothermias are there? Can you explain? Is it because the heart is not beating fast enough that hypothermia results and makes it different from just being hypothermic because of weather?
Jeff with admin. says
Primary Hypothermia is typically caused by excessive exposure to environmental conditions that cause a reduction in the core temperature of the body.
Secondary hypothermia is a result of disease, trauma, surgery, or drug-induced alteration in heat production and thermoregulation of the body.
When Hypothermia occurs, it results in decreased depolarization of cardiac pacemaker cells which can cause bradycardia.
Kind regards, Jeff
Donald Redford says
Jeff,
In the bradycardia section it states that the infusion dosage of Dopamine is weight dependent and Epinephrine is not weight dependent, and this is the case under dosing on the Bradycardia algorithm, yet on the post-cardiac arrest algorithm under the IV Bolus and IV meds instructions it indicates Epinephrine 0.1 -0.5 mcg/kg/min. Is this an error? Thanks, Don
Jeff with admin. says
Is not an error.
The bradycardia algorithm uses weight dependent dosing for dopamine and not for epinephrine.
The post cardiac arrest algorithm uses weight-based dosing for both epinephrine and dopamine.
Unfortunately, the American heart Association has not developed a consistent dosing method that can match across both algorithms.
Kind regards,
Jeff
Peter Feliciano says
Hi Jeff!
Your site is very helpful to medical professionals. My question is, I’ve read somewhere (I forgot the source/article) that you should never delay electrical therapy for patients who are severely symptomatic. But I read somewhere here from the comments’ section that Atropine, TCP and Dopamine/Epi infusions all have equal effects/possibilities to return the patient’s rhythm to normal. My understanding is that you never delay electrical therapy since using the medication will take more time (absorption and all) compared to electricity which gives you the best possible outcome for the unstable patient.
Sincerely,
Peter Feliciano
Jeff with admin. says
Epi and dopamine are now considered equally effective alternatives to TCP. This is because they are as effective. If TCP is not available or not readily available they may be used.
All of these medications have a rapid onset and a very short half-life. Atropine is the first-line medication for symptomatic bradycardia and should be used if MI is not suspected.
If you have attempted atropine, and it is it effective the best alternative is TCP but Epi and dopamine may be used as equally effective alternatives.
In my humble opinion, if a patient is symptomatic and atropine is not effective use TCP if it is available. Easy to start, easy to stop, minimally invasive.
Kind regards,
Jeff