Elias B Hanna, MD LSU New Orleans, Cardiology Morning report ECG Elias B Hanna, MD LSU New Orleans, Cardiology

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Look for P waves, deflections falling over ST/T or TP segments of consistent morphology and timing. You can march those P waves out 3

Sinus rhythm rate of 84 bpm with 2:1 AV block Non-specific intra-ventricular conduction delay Is this second-degree AV block type 1 (Mobitz 1) or type 2 (Mobitz 2)?

P drops, preceded by progressive PR prolongation

P drops without progressive PR prolongation P drops without progressive PR prolongation. Rate~60, but is ominous because it is Mobitz 2. Mobitz 1 is benign.

Location of AV block Mobitz 1 is usually a nodal blockthe QRS is often narrow. Mobitz 1 rarely progresses to complete AV block and is often asymptomatic Mobitz 2 is an infranodal blockthe QRS is often wide. Mobitz 2 is ominous even if asymptomatic, it can progress to a bad complete AV block with slow ventricular escape In this case, this is Mobitz 2. We went from saying sinus bradycardia to Mobitz type 2

In 2:1 AV block, there is only one conducted QRS before the dropped QRS, thus you cannot tell if the dropped QRS is preceded by progressive PR prolongation or not, i.e. Mobitz 1 or 2. In order to say Mobitz 1 or 2 in case of 2:1 AV block, rely on the width of QRS. If QRS is wide, it is an infranodal block, i.e. Mobitz 2; if QRS is narrow, it is Mobitz 1. The 2:1 AV block on the current ECG is therefore Mobitz 2 AV block. 8