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 ...

ECG Challenge Jerry W. Jones, MD FACEP FAAEM Which coronary artery is occluded? Where is the occlusion? Let's have some responses! If you get it right, that means you are very accomplished at interpreting ECGs. If you are wrong, that means you have a great opportunity to become very accomplished at interpreting ECGs! I'll post my response in a few days. Check out my website at: https://medicusofhouston.com Come join us and be a PARTICIPANT... never just an audience!

  Aberrancy and a Complete LBBB That Isn’t! Jerry W. Jones, MD FACEP FAEM This post is about aberrancy, retrograde P′ waves and disease of the conducting system. This ECG was recorded in 2011, so the patient is an 80 year old female who presented to the emergency room for an unknown complaint. There’s a lot to learn on this 12-lead ECG… First, the patient is in sinus rhythm and therein lies our first problem. We see obvious P waves in the inferior leads (II, III, aVF), but not much in Leads I, aVL or aVR. This tells us that the P wave axis is very vertical: the impulse is traveling almost straight down toward the recording electrode on the left foot – which happens to be the positive pole for Leads II, III and aVF. Leads I and aVL are left-sided and Lead aVR is right-sided. They are seeing little to none of the P wave vector, so that tells us that the vector is directed very vertically and downward. There is no suggestion of a P wave in Lead I, which tells us that the P wave vect...

                   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...