Complete Heart Block Medical Slides

Present nodal block (narrow QRS escape at 40-60 bpm, often from increased vagal tone or AV nodal-acting drugs, responsive to atropine, may be transient) versus infranodal block (wide QRS escape <40 bpm, from structural His-Purkinje disease, atropine-unresponsive, unreliable escape rhythm requiring urgent pacing). This distinction drives both acute management and the urgency of permanent pacemaker implantation.

Step 1: Assess hemodynamic stability. Step 2: If unstable, immediate transcutaneous pacing (do not delay for atropine in wide-complex escape). Step 3: Atropine 0.5 mg IV may temporize narrow-complex escape rhythms only. Step 4: Dopamine or epinephrine infusion as bridge. Step 5: Transvenous pacing wire placement. Emphasize that atropine can paradoxically worsen infranodal block by increasing atrial rate without improving conduction.

Present DDD as the standard for complete heart block (preserves AV synchrony), VVI as acceptable in permanent atrial fibrillation with slow ventricular response, and CRT-P/D when LVEF ≤35% requiring pacing >40% of the time. Discuss the emerging role of conduction system pacing (His bundle or left bundle branch area pacing) as a physiological alternative to RV apical pacing, referencing the 2023 HRS guidelines.