Review Question - QID 104056

Temporary pacemaker placement and work-up for potential underlying etiology. This patient is symptomatic and hemodynamically unstable due to complete heart block (3rd degree atrioventricular block). Immediate temporary pacing is required to stabilize the patient while reversible etiologies are assessed.

The patient's symptoms of dizziness, syncope, and "fluttering sensation" in the chest, along with the ECG findings, confirm complete heart block. Immediate intervention is necessary to prevent further hemodynamic compromise. Temporary pacing can be achieved through transcutaneous or transvenous methods. Transcutaneous pacing is quicker to initiate, but is generally less comfortable for the patient and less reliable for long-term use. Transvenous pacing, although requiring more time and expertise to set up, provides more reliable pacing and is better tolerated by the patient. Both methods serve as a bridge to permanent pacemaker placement, which is considered after a thorough work-up to identify any reversible causes.

Denay and Johansen discuss indications for pacemaker placement. They recommend management with pacemaker for the following: symptomatic bradyarrhythmia due to sinus node dysfunction, frequent & lengthy sinus pauses, complete (3rd degree) heart block, and type II second degree AV heart block (due to risk of progression to complete atrioventricular block).

Barra et al. review complete heart block in middle-aged adults. The most common causes of complete heart block in this age group include: coronary artery disease, lupus, rheumatoid arthritis, myocarditis, infiltrative processes, hypothyroidism, and congenital cardiac disease.

Figure A is an electrocardiogram showing complete heart block. Illustration A shows a chart listing some of the medications that may induce complete heart block. Illustration B summarizes ACLS guidelines for emergent management of complete heart block.

Incorrect Answers:
Answer 1: Digoxin may exacerbate complete heart block and is contraindicated in this situation. Digoxin would be considered in atrial fibrillation with rapid ventricular response, but not in complete heart block.
Answer 2: This patient is symptomatic and hemodynamically unstable, requiring immediate intervention. No intervention would be appropriate for asymptomatic 1st-degree heart block.
Answer 3: Permanent pacemaker placement is generally the definitive treatment, but should only be considered after reversible causes have been ruled out.
Answer 4: Verapamil, a calcium channel blocker, can worsen complete heart block and is contraindicated in this case. It is used for supraventricular tachycardias, but not in complete heart block.

Bullet Summary:
In symptomatic and hemodynamically unstable patients with complete heart block, immediate temporary pacemaker placement via transcutaneous or transvenous methods is essential for stabilization while reversible causes are investigated.