2020 Bradycardia algorithm review | ACLS-Algorithms.com

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  1. Khadidja says

    I had a case of a medically free pt , post cs. In recovery she developed sinus bradycardia. Hr was between 48/49 when she move it goes up to 60 and down again to 48/45 completely asymptomatic therefore i chosed to monitor rather than giving atropine. After 8h hr dropped tob37 always asymptomatic. 1mg of atropine was given and her hr raised to 107 with high bp and headache. Every thing went back to normal she remained bradycardic 35/38 asymptomatic no atropine giver. 48h laiter her hr went back to normal gradually. Can you coment the case. What could have caused the brady? Was it wise not to give atropine at first? Is it true that asymptomatic brady 37 can cause sudden arrest? Are pst cs pt more exposed to benign brady?
    Can you please

    • ACLS says

      Hi Khadidja,

      This case of asymptomatic bradycardia post-cesarean section (CS) reflects a pattern that is documented but not very common, and your conservative management was consistent with current recommendations except in the setting of symptoms or hemodynamic instability[1][2][3].

      Causes of Bradycardia after Cesarean Section

      – Postpartum bradycardia has been linked to increased vagal tone as the body readjusts after pregnancy, the influence of anesthesia (especially spinal or epidural), medication effects (e.g., oxytocics, ergot alkaloids), underlying conduction abnormalities, electrolyte disturbances, and preeclampsia[1][4][5][6][7][8].
      – In many documented cases, including large case series, transient hypervagotonic sinus node dysfunction (excessive vagal influence) is suspected, often in entirely healthy patients and typically resolves without intervention[1][9][8].
      – Bradycardia is also relatively more common after anesthesia for CS, but is usually benign and self-limited, especially in the absence of hemodynamic compromise or symptoms[5][7][10].

      Atropine Use: Was Withholding Initially Appropriate?

      – Leading guidelines (e.g., ACLS, StatPearls) specify that atropine is indicated for symptomatic bradycardia—manifested by hypotension, altered mental status, ischemic chest pain, or signs of shock—not for isolated low heart rates without symptoms[3].
      – Asymptomatic bradycardia, even down to the 30s, can be observed in certain populations (particularly postpartum, athletes, or after spinal anesthesia) so long as the patient remains stable and well-perfused[1][2].
      – Administering atropine in an asymptomatic patient can cause unwanted side effects, including tachycardia, hypertension, and sometimes headache, as occurred in your patient[3].

      Risk of Sudden Arrest in Asymptomatic Bradycardia of 37 bpm

      – Major studies show that asymptomatic sinus bradycardia—even at rates approaching 30 bpm—rarely results in sudden arrest unless there are underlying conduction abnormalities, structural heart disease, or concurrent conditions affecting perfusion[2][11].
      – Routine treatment with atropine is not indicated if there are no symptoms; the course is usually benign, but secondary causes (electrolytes, thyroid dysfunction, medications) should be ruled out[2].
      – Extremely rare cases of sudden arrest in completely stable, asymptomatic individuals have been described, but these often involve other comorbidities or unrecognized cardiac disease.

      Are Post-CS Patients More Exposed to Benign Bradycardia?

      – Incidence of benign (usually transient) bradycardia is higher following CS, especially with regional anesthesia, and is frequently linked to a hypervagotonic state or drug effects[5][6][7][10].
      – Most such episodes resolve over hours to a few days, as seen in your patient. Only persistent, symptomatic, or hemodynamically significant bradycardia warrants aggressive intervention[1][4][5].

      In summary, the approach of monitoring an asymptomatic post-CS patient with bradycardia was consistent with evidence-based practice; atropine is indicated only if bradycardia becomes symptomatic or there is hemodynamic compromise. The risk of sudden arrest from asymptomatic bradycardia at 37 bpm is exceedingly low in otherwise healthy individuals. Post-CS patients, particularly those who received regional anesthesia, are at a somewhat higher risk for benign, self-limiting bradycardia[1][2][3][5].

      Sources
      [1] Asymptomatic Postpartum Bradycardia: A Case of Spontaneous … https://pmc.ncbi.nlm.nih.gov/articles/PMC12035969/
      [2] Evaluation and Management of Asymptomatic Bradyarrhythmias https://pmc.ncbi.nlm.nih.gov/articles/PMC8142361/
      [3] Atropine – StatPearls – NCBI Bookshelf https://www.ncbi.nlm.nih.gov/books/NBK470551/
      [4] Post-partum maternal bradycardia: A case series and literature review https://pmc.ncbi.nlm.nih.gov/articles/PMC11110741/
      [5] Post-partum maternal bradycardia – Sage Journals https://journals.sagepub.com/doi/pdf/10.1177/1753495X231178407
      [6] [PDF] Postpartum Maternal Bradycardia Overview http://www.library.wmuh.nhs.uk/wp/library/wp-content/uploads/sites/2/2017/01/Maternal-Bradycardia.pdf
      [7] An Observational Study on Arrhythmia During Cesarean Section … https://www.cureus.com/articles/65316-an-observational-study-on-arrhythmia-during-cesarean-section-under-spinal-anesthesia-incidence-risk-factors-and-effects-on-immediate-post-delivery-neonatal-outcome
      [8] Postpartum Transient Hypervagotonic Sinus Node Dysfunction … https://www.cureus.com/articles/36687-postpartum-transient-hypervagotonic-sinus-node-dysfunction-leading-to-sinus-bradycardia-a-case-report
      [9] [PDF] Transient Sinus Node Dysfunction in a Postpartum Female with … https://scholarworks.utrgv.edu/cgi/viewcontent.cgi?article=1493&context=somrs
      [10] Arrhythmias following spinal anesthesia for cesarean delivery https://pmc.ncbi.nlm.nih.gov/articles/PMC3214565/
      [11] Sinus Bradycardia – StatPearls – NCBI Bookshelf https://www.ncbi.nlm.nih.gov/books/NBK493201/

      My response was aggregated with the help of perplexity

      Kind Regards,
      Jeff
      https://acls-algorithms.com/member-login/

  2. marc david simmons says

    I cannot find anywhere why atropine was increased to 1mg from .5mg. Is it detrimental to give .5 mg? I have been giving .5 since 2005. I have never had an issue and do not see why I should change this practice.

    • ACLS says

      The increase in the recommended atropine dose from 0.5 mg to 1 mg in the 2020 ACLS guidelines was based on updated evidence and expert consensus.
      The key points for the changes were:
      Efficacy: The 1 mg dose is believed to be more consistently effective in treating symptomatic bradycardia.
      Safety: The 1 mg dose is still considered safe for most patients. The maximum total dose remains 3 mg.
      Simplification: Using a standard 1 mg dose simplifies the protocol and reduces potential dosing errors.
      Avoiding paradoxical effects: Very low doses of atropine (less than 0.5 mg) can potentially cause paradoxical bradycardia. The 1 mg dose helps ensure this is avoided.
      Not detrimental: Giving 0.5 mg is not considered detrimental or harmful. It may still be effective in many cases.
      Clinical judgment: While guidelines recommend 1 mg, clinicians can still use their judgment based on individual patient factors.

      If the 0.5 mg dose has been effective in your experience, it’s understandable to be hesitant about changing. It may be worth discussing with your colleagues and institution about adopting the new recommendation. Remember that guidelines are meant to inform clinical practice, but individual patient factors and clinician judgment always play a crucial role in decision-making.

      Kind regards,
      Jeff

    • ACLS says

      It is not necessary to give the full 3 mg maximum amount of atropine before moving on to a dopamine or epinephrine drip.

      Kind regards, Jeff

  3. MM says

    If a patient is unstable and has known third-degree heart block, is atropine still given first-line or is isoprenaline given as this is more effective in such situations?

    Thank you :))

    • ACLS says

      The American heart association gives no guidance with regard to the use of isoprenaline.

      The following quote is from the American Heart Association Circulation Journal. “Avoid relying on atropine in type II second-degree or third-degree AV block with a new wide-QRS complex. These patients require immediate pacing.”

      It also states, “atropine administration should not delay implementation of external pacing for patients with poor perfusion.”

      Kind regards,
      Jeff

  4. Mustafa says

    Hi Jiff
    When will say patient with bradycardia is symptomatic ( unstable) , if he has one symptom or more than two symptoms….??
    As I know unstable of bradycardia with symptoms ( hypotension, altered mental status, chest discomfort , sign of shock, acute heart failure) ..
    Thx u

    • ACLS says

      A patient can be symptomatic without being unstable. Any one of the symptoms that you listed would indicate that the patient is (unstable hypotension, altered mental status, chest discomfort, signs of shock, acute heart failure.)

      Kind regards,
      Jeff

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