Slide 1: Your patient presents for routine follow-up in cardiology clinic. 12-lead EKG shown. What’s the underlying rhythm? Let’s start with the ventricular rhythm.

Slide 2: The rhythm is V-paced. How can you tell from the rhythm? Single pacer spike before each QRS. Wide complex QRS resembling LBBB. Think back to our LBBB post from October 10, 2019. LV activation after RV depol. Deep S wave in V1 equals LBBB appearance. What does this tell you about the location of the pacemaker lead?

Slide 3: Where is the pacemaker lead? With single lead and dual chamber pacers, the ventricular lead sits at the RV apex. Chest x-ray showing the atrial lead and the RV lead. Graphic of the heart with labels showing that the right side depolarizes via conduction system and the left side goes myocyte to myocyte. Appearance of functional LBBB.

Slide 4: What’s the atrial rhythm? Regular “saw-tooth” flutter waves best seen in II, III, and aVF. The rhythm is atrial flutter! What medication adjustments might you make at this visit? Relevant vitals. Heart rate. 60 beats per minute. Blood pressure. 125 over 75. Current medications include lisinopril, metoprolol, aspirin, and statin.

Slide 5: Atrial activity should be assessed in any patient regardless of the presence of a pacemaker. Despite pacing, patients should be evaluated for anticoagulation based on C H A2 D S2 Va Sc (CHAD-Vasc score) if found to have underlying atrial arrhythmia! C is for congestive heart failure. H is for hypertension. A2 is for age (older than 65 years old or older than 75 years old). D is for diabetes mellitus. S2 is for stroke or transient ischemic attack. Va is for vascular disease. Sc is for sex category (female)