Summary of Heart Blocks 1st Degree Heart Block: • Prolonged PR >200ms (5 small squares). • Narrow & regular rhythm. • No Treatment 2nd Degree, Mobitz I Heart Block (aka Wenckebach): • Prolonged PR then Dropped P • Progressive prolongation of PR culminating in non-conducted P wave. PR longest before dropped beat. PR shorted after dropped beat. Narrow & irregular rhythm. • No Sx? No Treatment. Sx? Brady Management. 2nd Degree, Mobitz II HeartBlock: • Dropped P without PR prolongation • Non-conducted P waves without "warning" of PR prolongation. • PR intervals in conducted beats constant. QRS often wide. • May be no pattern or fixed relationship (2:1 or 3:1 block) • Treatment: Pacemaker 3rd Degree, Complete Heart Block: • No association between P and QRS • Atrial rate > Ventricular Rate. Regular ventricular rate. • Block in AV node: Junctional escape (40-60), narrow QRS • Block infranodal level: Ventricular escape (20-40), wide QRS • Treatment: Pacemaker - Will not respond to atropine if wide QRS (block beyond AV node) - Dr. Sarah Foohey @SarahFoohey #HeartBlocks #Types #Classification #degrees #summary #Diagnosis #EKG #electrocardiogram #ecg #cardiology
