This strip shows a junctional rhythm at a rate of 110 beats per minute. The QRS complexes are slightly wide at .10 seconds (100 ms), and they are within the parameters for supraventricular rhythm. The term, "junctional tachycardia" could be used, also, but this is not likely a "reentrant" junctional tachycardia, which would be fast, regular, and have a sudden onset. That type of junctional tachycardia is a PSVT. In this strip, we can see the underlying sinus rhythm in P waves that appear to pop up randomly.
Normal sinus rhythm
This ECG is nearly completely normal. We say "nearly" because there are VERY subtle changes which may or may not be chronic. Unfortunately, we know nothing about this patient's history or circumstances except age, gender, and race, and the fact that she was an Emergency Department patient. If she presented with chest pain, the ECG might be viewed completely differently than if she presented with a fever.
This patient was diagnosed by the rescue crew as having atrial fibrillation, based on the fact that they thought the rhythm was irregular, and they could not see P waves. They also noted a wavy baseline, and considered it to be fibrillatory waves. In reality, the underlying rhythm is regular, with some PACs (regularly irregular).
This ECG was obtained from a healthy 29-year-old man. It shows "benign early repolarization". It demonstrates the typical pattern of widespread ST elevation with a normal concave upward sloped ST segment. There are also prominent U waves in V2 through V4, and T wave inversions in the inferior wall leads.
This rhythm strip shows normal sinus rhythm, slightly on the fast side of normal at 95 bpm. The baseline undulates up and down with the movements of the patient's chest as she breathes. One way to correct this problem on a monitor strip is to move the limb electrodes away from the chest and onto the limbs.
This is an ECG I performed a couple of years ago on an asymptomatic 83-year old man as an outpatient procedure.
The computer interpreted this as: "Marked sinus bradycardia [with] Frequent Premature ventricular complexes". IS THE COMPUTER CORRECT? Is there more than one plausible interpretation? What is the differential diagnosis?
We try to remember to include some good old "Normal Sinus Rhythm" strips from time to time. Teachers often have large collections of strange and unusual strips that their colleagues have saved for them. But, then they find themselves resorting to electronic rhythm generators for samples of "normal". Here is a strip from a healthy, 23-year-old woman showing NSR. The rate is 65 bpm, QRS duration 76 ms, PRI 136 ms, QTc 410. There are no abnormal ST segments or T wave changes.
Patient data: 54-year old man who recently underwent a major cardiac procedure. At first glance, this ECG may not appear to be particularly unique but a closer inspection reveals something unusual going on here.
This Lead II rhythm strip was taken from a 12-Lead ECG performed on a 66-year-old man who was having an acute inferior wall M.I. The rhythm is normal sinus rhythm at 65 bpm. The QRS complex is slightly wide at 112 ms (.11 seconds). The patient did not have a bundle branch block pattern on his 12-lead ECG. The PR interval is .17 seconds, and the P waves are widened and have a "double peak". This can be a sign of left-sided heart failure, and is called P Mitrale. Your students should be advised not to try to diagnose acute M.I.
Up until now, we have posted basic rhythm strips in this area of the ECG Guru for those of you who are teachers of beginning students. Today, we offer a "normal" 12-Lead ECG for those desiring to introduce students to the 12-Lead format. It is always best to become familiar with normal before venturing into the realm of "abnormal". Encourage your students to find what they know to be normal, then add to their knowledge.
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