Bradycardia

1.     If possible, in any patient in whom you are worried about symptomatic bradycardia, try to have atropine and Zoll? pads at the bedside before the patient gets unstable.  Always ask yourself the following two questions in the bradycardic patient

  • Is the patient symptomatic or hemodynamically unstable? If so, place the patient in Trendelenberg and follow ACLS protocols (See ACLS: Bradycardia).
  • Does the ECG show either type II 2nd-degree or 3rd-degree AV block?  If so, consider trans-cutaneously pacing the patient and prepare for possible transvenous pacer (consult Cardiology).

2.     If the patient is relatively stable hemodynamically and symptomatically and there is no sign of a dangerous form of AV block, you have some time to do a quick chart biopsy and look for clues from the patient?s med list and admitting diagnoses. Causes of bradycardia:

Category

Examples

Meds

blockers, calcium channel blockers, digoxin, amiodarone, clonidine (look at the MAR and remember to consider any eye drops?e.g. timolol)

Cardiac

Sick sinus, inferior MI, vasovagal, 2nd or 3rd degree heart block, junctional rhythm

Instrinsic causes

Idiopathic degeneration (aging), infiltrative diseases (sarcoid, amyloid), collagen vascular disease, surgical trauma, endocarditis

Autonomically mediated

Neurocardiogenic syncope, carotid-sinus hypersensitivity, situational: coughing, micturition, defecation, vomiting

Other

Hypothyroidism, hypothermia, increased intracranial pressure (Cushing's reflex), hyperkalemia, hypokalemia, obstructive sleep apnea, normal variant

3.     In general if the patient is not symptomatic and this is not a significant change from prior days/nights, then an exhaustive workup is unnecessary at night. However, have a low threshold to get an ECG in bradycardic patients and consider ischemia in any patient at risk.

4.     Take a focused H&P. Focus on signs and symptoms to distinguish the above (chest pain, prior MI, straining or other maneuvers prior to bradycardia, altered mental status, hypothermia, BP, etc.).

5.     If you believe the bradycardia is secondary to medications, be careful discontinuing them. Remember, treat the patient, not the numbers. Stopping rate control meds could cause a rebound tachycardia and precipitate myocardial ischemia (a bad thing).

6.     Transcutaneous pacing can be quite uncomfortable.  If there's time, short-acting analgesics and/or sedatives may be worthwhile considering.

7.     In asymptomatic patients with bradycardia, the class I indications for pacemakers are as follows:

  • 3rd-degree AV block with asystole lasting > 3 seconds or with escape rates < 40 while awake
  • 3rd-degree or 2nd-degree type II AV block in patients with chronic bifascicular or trifascicular block

Mangrum JM, DiMarco JP. The evaluation and management of bradycardia. N Engl J Med 2000; 342:703-9.