This ECG was obtained from a patient who had a serum potassium level of 7.4 mEq/L. It shows some of the earliest ECG signs of hyperkalemia. There are tall, sharply-peaked T waves in many leads. The P waves have not yet widened and lost amplitude, but they will soon flatten out and disappear.
First-degree AV block
This ECG is from a man with left ventricular hypertrophy. LVH causes taller-than-normal QRS complexes in leads oriented toward the left side of the heart, such as Leads I, II, aVL, V4, V5, and V6. Leads on the opposite side, such as V1, V2, and V3, will have deeper-than-normal S waves.
TODAY, we are starting a new feature on the ECG GURU. ECG BASICS will provide rhythm strips and 12-leads for your beginner or refresher students. It can be discouraging to the entry-level student to see only intermediate or advanced material and not understand it. We must remember to start at the most elementary concepts, and then build on them, just as we do with any other subject. Even more advanced students sometimes benefit from a return to the "basics". In this weekly feature, you will find downloadable content that is, like all ECG Guru content, FREE for
This is a good ECG for demonstrating sinus brady and first-degree AV block. It shows the sinus node in the process of slowing down. For your more advanced students, there is left axis deviation due to left anterior fascicular block (left anterior hemiblock). The ST segments are flat, suggesting coronary artery disease. The fourth (bottom) channel is a good rhythm strip. Just crop the image. Please refer to Dr. Grauer's interesting post on teaching hemiblocks on our Ask The Expert page.
Inferior wall MI: ST elevation in II, III, and aVF. Reciprocal ST depressions. Sinus bradycardia and first-degree AV block suggests sinus node and AV node ischemia. This is a good "classic" inferior wall M.I. It is good for teaching inferior-posterior injury, and the effects of RCA occlusion on the sinus and AV nodes. The low voltage in the limb leads may also be due to acute M.I., but in this case, we do not know the patient's body size.
This patient was seen by his primary care provider (PCP) on an outpatient basis. The PCP decided to send her patient over to me to perform a routine ECG and establish a baseline, hince the computer's statement below of "No previous ECGs available". I printed out the above 12-lead ECG and became slightly concerned with the rhythm I was seeing. Consequently, I also recorded six full pages of continuous rhythm (not shown here). I don’t ordinarily resort to doing this
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