Answer for November 5, 2013
Note the “m” shaped P waves in 1,2, and aVF, and the deep terminal component of the P wave in V1. The Pwaves are at least 3 boxes wide in the limb leads, making the EKG diagnosis of left atrial abnormality (in this case “P mitrale”, because in the past, this was often due to rheumatic mitral stenosis). The most common cause for this in the United States is left ventricular hypertrophy, and this is usually from hypertension.
The deep S wave in V3 suggests that LVH is likely present, but we are missing V4-V6. Key findings for left atrial abnormality are wide P waves (3 boxes) in the limb leads, and a deep negative component of the P wave in V1 (the left atrium is located to the left and posterior to the right atrium and lead V1). Key findings for right atrial enlargement were discussed in last week's EKG and include TALL and pointy P waves in 2,3, and F, and a TALL initial component of the P wave in V1.
NOTE: EKG's are for internal educational purposes of the University of Massachusetts Department of Family Medicine. Please do not forward without permission from Dr. Golding!