ADULT BRADYCARDIA: AN OVERVIEW

Faez BaherinEmergency Physician

ED Hospital Melaka

Outline

• Introduction and definition• Bradycardia algorithm at a glance• Stable vs unstable bradycardia• Drugs in bradycardia• Transcutaneous pacing• Take-home message• New updates 2015

Introduction• heart rate of <60 beats per minute.

• when bradycardia is the cause of symptoms, the rate is generally <50 beats per minute, which is the working definition of bradycardia used in ACLS

• focuses on management of clinically significant bradycardia (ie, bradycardia that is inappropriate for the clinical condition)

Approach to bradycardia• ABC• provide supplementary oxygen if hypoxemia• hypoxemia is a common cause of bradycardia, initial evaluation of any

patient with bradycardia should focus on signs of increased work of breathing and oxyhemoglobin saturation

• Attach a monitor to the patient• evaluate blood pressure• establish IV access• 12-lead ECG to better define the rhythm• Assess stable vs unstable

Stable bradycardia

• asymptomatic or minimally symptomatic patients do not necessarily require treatment

• unless there is suspicion that the rhythm is likely to progress to symptoms or become life-threatening (eg, Mobitz type II second-degree AV block in the setting of acute myocardial infarction)

Unstable bradycardia

• identify signs and symptoms of poor perfusion and determine if those signs are likely to be caused by the bradycardia

• acute altered mental status • ischemic chest discomfort• acute heart failure • hypotension• signs of shock

Drugs in unstable bradycardia :Atropine

• first-line drug, reverses cholinergic-mediated decreases in heart rate• improved heart rate, symptoms, and signs associated with

bradycardia.• considered a temporizing measure while awaiting a transcutaneous

or trans venous pacemaker for patients with symptomatic sinus bradycardia, conduction block at the level of the AV node, or sinus arrest

Drugs in unstable bradycardia :Atropine

• 0.5 mg IV every 3 to 5 minutes, maximum total dose of 3 mg

• Avoid relying on atropine in type II second-degree or third-degree AV block, preferably treated with TCP or β-adrenergic support as temporizing measures while the patient is prepared for transvenous pacing

Drugs in unstable bradycardia :

• dopamine, epinephrine, and isoproterenol are alternatives when a bradyarrhythmia is :• unresponsive to or inappropriate for treatment with atropine, or • as a temporizing measure while awaiting the availability of a pacemaker

Dopamine: 2 to 20 mcg/kg/minOrAdrenaline: 2-10 mcg/min

Transcutaneous pacing

• initiate TCP in unstable patients who do not respond to atropine

• Immediate pacing might be considered in unstable patients with high-degree AV block when IV access is not available

• If the patient does not respond to drugs or TCP, transvenous pacing is probably indicated

Transcutaneous pacing

• Attach pads• Select mode : fixed or demand• Select rate 60-80• Select energy : step up / step down method• Look for electrical capture then feel for mechanical

capture• Increase energy by 5mAmp

• Transcutaneous pacing may be uncomfortable for the patient. Sedation should be considered.

TCP stimulus does not work through the normal cardiac conduction system but by a direct electrical stimulus of the myocardium. Therefore, a “captured" compex will resemble a PVC. Electrical capture is characterized by a wide QRS complex, with the initial deflection and the terminal deflection always in opposite directions

• Attach pads• Select mode : fixed or demand• Select rate 60-80• Select energy : step up / step down method• Look for electrical capture then feel for mechanical

capture• Increase energy by 5mAmp

• Transcutaneous pacing may be uncomfortable for the patient. Sedation should be considered.

New Updates•CPR•ACS•ACLS•Post Arrest Care

Take-home message• Memorize the algorithm • Know your drugs• Know how to operate TCP machine• Early referrals for further management – TCP is only

TEMPORARY