KEY TEACHING POINTS

•Level of block with 2:1 atrioventricular block poses a challenge. Clues that can suggest His-Purkinje disease versus atrioventricular nodal disease include bundle branch block and normal PR interval. •During lower degree of block (eg, 3:2 or 4:3), the Wenckebach phenomenon can occur even at the His-Purkinje level. •Syncope or sudden death in the setting of bradycardia can be due to torsade de pointes.