This strip shows the onset of atrial fibrillation. A fib can be "paroxysmal," meaning that it has a sudden onset, but then stops spontaneously, usually within 24 hours to a week. A fib can also be classified as "persistent", meaninging that the a fib lasts more than a week. It can stop spontaneously, or be halted with medical treatment. "Permanent" a fib is a fib that is resistent to treatment.
This ECG rhythm strip has all the hallmarks of atrial fibrillation: the rhythm is irregularly irregular and there are no P waves. The rate is about 150 beats per minute. There is no P wave because the atria are being irregularly depolarized by many ectopic pacemakers at once, causing the atria to "quiver". This patient has new-onset atrial fib, and has been medicated with a calcium channel blocker. The rate shows signs of slowing, but has not reached the target rate for this patient of less than 80 bpm.
This rhythm strip is recorded in two simultaneous leads, which is always preferable to one single lead. It is a good example of atrial fibrillation with a rapid ventricular response. Atrial fib that has not been treated will usually have a rapid ventricular rate. This reflects the ability of the AV node to conduct a tachycardia, within limits. The natural slow conduction of the AV node allows it to act as a "filter", preventing the huge numbers of impulses generated by the atrial fibrillation from reaching the ventricles.
This is a good rhythm strip to use to illustrate how atrial fibrillation can almost look regular when the rate is fast. Students should be taught how to "march out" the rhythm for regularity. It is always a good idea with atrial fib to take a longer strip, looking for the inevitable "gaps" in the R-to-R intervals. Also, as your students progress, a 12-lead ECG is invaluable to really search for P waves. Even two or three simultaneous leads are better than just one.
Atrial fibrillation with a controlled ventricular response is often considered to be atrial fib that has been controlled with medication. While this is often true, it is possible to see atrial fib with a ventricular rate between 50 and 100 bpm in a patient who has not been treated. The hallmark signs of atrial fib are: no P waves and irregularly-irregular rhythm.
This ECG was kindly donated to the ECG Guru website by Dr. Ahmed for open discussion among our members. The patient was a 70+ year-old man who presented with a complaint of dizziness. His serum potassium level was found to be 6.5 (normal is 3.5 - 5.0). Upon correction of his K levels, his rhythm was atrial fibrillation at 130 / min.
WHAT DO YOU THINK ABOUT THIS INITIAL ECG? What is causing the slow rate? Is there atrial activity? Do you see QRS morphology changes? What about the anterior ST and T wave changes?
This is a good basic rhythm strip example of atrial fibrillation with a rapid ventricular response showing the identifying characteristics of atrial fibrillation: no P waves, an irregularly-irregular rhythm, and a "fibrillatory" baseline. The wavy baseline will not be seen in all leads in all patients, so it is best to use the first two findings as diagnostic criteria. Atrial fib often appears initially as a rapid rhythm, as the AV node is being bombarded by many impulses from multiple foci (pacemakers) in the atria.
A good teaching ECG, showing clearly elevated ST segments in V1 through V4. This patient had an LAD occlusion. In addition, he has new-onset atrial fib at a rate of about 120/min. Atrial fib has decreased cardiac output because of the loss of P waves prior to the QRS complexes, and a resultant decreased ventricular filling pressure. In addition, this fast rate contributes to increased myocardial oxygen demand and damage. An early priority, along with getting this patient to PCI, is slowing the rate.
This is a good example of atrial fibrillation with a rapid ventricular response. The rate is around 150 per minute, and the rhythm is almost regular. Show your students how to "march out" the QRS complexes so they can see the irregularity. When the rate is around 150, also check for atrial flutter with 2:1 conduction. In this case, none of the 12 leads shows strong evidence of flutter waves, but it is a possibility when the rhythm is almost regular. Fortunately, the initial treatment for both AFib and AFlutter with rapid response are the same.
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