Advanced ECG Interpretations

  Notes on a Randomly-Selected ECG Jerry W. Jones, MD FACEP FAAEM Figure 1 What is the rhythm on this ECG? Don’t be too quick to respond because I just asked you a trick question! Which rhythm are we discussing – the atrial rhythm or the ventricular rhythm ? Although this looks like a “single” ECG, it is really two ECGs – an atrial ECG and a ventricular ECG – one superimposed upon the other. Let’s begin with the atrial rhythm. Do you see any P waves? I don’t. That – by definition – is either atrial fibrillation , sinus arrest or third degree SA block . Now let’s consider the ventricular rhythm. It appears irregular . It is always best to assume that a ventricular rhythm that is based on an ectopic junctional or ventricular escape pacemaker will be very regular – even though it may be very slow. That isn’t always the case, but it will be about 99% of the time in my experience. OK… let’s put these two observations together: if the atrial rhythm (or lack of an atrial ...

What To Learn From an Essentially "Normal" ECG Jerry W. Jones, MD FACEP FAAEM  ECG 1 First, I want to say that this is a pretty good ECG for an 88 y/o woman! However, there are a few things to discuss. This post is for the intermediate-level ECG "nerds" but you newbies follow along! First, there is sinus rhythm. We know this because the P waves are upright in both Leads I and II. There is also a POS/NEG biphasic P wave in Lead V1 which is supportive of sinus rhythm. The rate is regular except for one beat near the beginning of the ECG. PEARL: If you want to check the regularity of a rhythm - especially if you suspect that it is subtlety irregular - focus on the T-P intervals and not so much on the R-R intervals. It is often easier to detect rate changes by the T-P segments due to the bordering T and P waves which will make it easier to detect a rate variation. The mean QRS axis (ÂQRS indicates "mean QRS axis") in the frontal plane is normal. We know this ...

                   A Closer Look at Right Bundle Branch Block (RBBB) Jerry W. Jones, MD FACEP FAAEM I once wrote an article about “rabbit ears” and RBBB and posted it on my blog ( https://medicusofhouston.com/dr-joness-ecg-blog/) . To this date it has been the most read article I have produced. So, let’s take a closer look at RBBB.  The  right bundle branch courses down the wall of the interventricular septum on the right ventricular side. Its course is superficial at some points, so it is very susceptible to injury by central venous lines or stretching (dilatation) of the right ventricle. The diagram on the left shows both bundle branches (right – yellow, left – red). With the right bundle branch blocked up high (dotted line), the atrial impulse travels down the left bundle branch into the anterior and posterior fascicles. The left ventricle is depolarized normally and at its usual speed. The first portion of the left vent...