High-grade A-V block (HA-VB) from inferior MI is usually due to ischemia proximal to the bundle of His. This rhythm has a narrow QRS, and many patients tolerate this rhythm without hemodynamic compromise. How does HA-VB from anterior MI differ?
HA-VB from anterior MI is usually due to a larger infarct causing ischemia to the trifascicular conduction system distal to the A-V node. The rhythm tends to be slow with a wide QRS and a greater risk of hemodynamic compromise.