From the Guidelines
If contacted about a patient with complete heart block on their event monitor, immediately assess the patient's clinical status and consider urgent evaluation and possible temporary pacing if symptomatic or hemodynamically unstable, as complete heart block is a serious arrhythmia that often requires permanent pacemaker implantation, especially if symptomatic or if the block is at or below the His bundle, as recommended by the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1.
Clinical Assessment
When evaluating a patient with complete heart block, it is essential to assess their clinical status, including symptoms such as dizziness, syncope, chest pain, or shortness of breath. The patient's heart rate and the presence of escape rhythms should also be evaluated, as these factors can influence the urgency of intervention.
Management
If the patient is symptomatic or hemodynamically unstable, they should be directed to the nearest emergency department for urgent evaluation and possible temporary pacing. For stable patients, same-day evaluation in clinic or emergency department should be arranged. While awaiting evaluation, the patient should be instructed to avoid physical exertion and medications that slow heart rate, such as beta-blockers, calcium channel blockers, and digoxin.
Permanent Pacemaker Implantation
Complete heart block often requires permanent pacemaker implantation, especially if symptomatic or if the block is at or below the His bundle. The decision to implant a pacemaker depends on the presence of symptoms related to bradycardia or ventricular arrhythmias and their prognostic implications, as stated in the ACC/AHA classification 1.
Key Considerations
- Complete heart block is a serious arrhythmia that can progress to dangerous bradycardia or asystole.
- Symptomatic patients or those with hemodynamic instability require urgent evaluation and possible temporary pacing.
- Asymptomatic patients with complete heart block typically need thorough evaluation, as recommended by the 2018 ACC/AHA/HRS guideline 1.
- The urgency of intervention depends on the patient's symptoms, heart rate, and the presence of escape rhythms.
From the FDA Drug Label
Atropine also may lessen the degree of partial heart block when vagal activity is an etiologic factor In some patients with complete heart block, the idioventricular rate may be accelerated by atropine; in others, the rate is stabilized.
Administration of atropine may be considered in patients with complete heart block, as it may accelerate the idioventricular rate or stabilize it in some cases 2.
From the Research
Immediate Response
If contacted regarding a patient with heart monitoring having complete heart block on their event monitor, the following steps should be taken:
- Assess the patient's hemodynamic stability and systemic perfusion 3
- Obtain a complete medical history, including a detailed cardiac history 3
- Perform a detailed physical examination in a patient with cardiac complaints 3
- Investigate the broad differential diagnoses, which include acute coronary syndrome (ACS), electrolyte imbalances, pulmonary embolism, cerebrovascular accident, aortic dissection, and arrhythmias 3
Diagnostic Evaluation
- Obtain and interpret the cardiac monitor rhythm strip to identify complete heart block 3
- Order laboratory and imaging studies to differentiate arrhythmia from other diagnoses, such as:
- Complete blood count
- Comprehensive metabolic panel
- Magnesium level
- EKG
- Troponin level
- Chest radiograph 3
Management
- Administer IV atropine if the patient is hemodynamically unstable 3
- Attempt transcutaneous pacing if the patient is hemodynamically unstable and has a ventricular rate < 40 bpm 3
- Place a transvenous pacemaker if the patient is hemodynamically unstable and has a ventricular rate < 40 bpm 3
- Consider dopamine and epinephrine as bridge therapy while waiting for transfer to a higher level of care if transfer is not feasible 4
- Emergent consultation with interventional cardiology is recommended 3