Advanced ECG Interpretations

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!

  Are you treating myocardial infarctions? Why? That's DEAD tissue! You should be treating myocardial ischemia! What's the difference between ST elevation and ST depression? Does ST depression ALWAYS represent a subendocardial ischemia? Does  ST elevation ALWAYS  represent an acute transmural ischemia? Which blood test do you use to confirm an acute transmural ischemia...         ...troponins, or a CK-MB? If you base you diagnosis of an acute transmural ischemia on the presence of ST elevation according to the STEMI protocol, then you are basing your diagnosis on a CK-MB, because that's the test that was used to "prove" that the ST deviation was or was not a STEMI! The STEMI protocol was based on just ONE article that used CK-MB assays as proof of acute transmural ischemia. Is there a problem with that? Well, no... if you don't mind missing about 25% of acute transmural ischemias that should have gone directly to the cath lab but instead were...

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 ...

  Analyzing an Acute MI “Jones’s Rule” and Primary Repolarization Changes Jerry W. Jones, MD FACEP FAAEM Figure 1 This is another 12-lead ECG randomly selected from my collection. There is a bit of baseline wander, but that’s life! It was recorded on a 68 y/o Hispanic female in the emergency department who was complaining of chest pain. There is no other information about her. First, the absolute basics. We can see by the upright P waves in leads I and II that sinus rhythm is present. The pos/neg biphasic P wave in Lead V1 is also supportive of sinus rhythm. The P wave in Lead V2 is basically isoelectric – but that’s OK, as long as it isn’t inverted or biphasic. There is 1:1 sinoatrial conduction and the P-R intervals are normal and remain the same. The rate is quite variable and may represent a sinus arrhythmia. Also, as we will see in a moment, there is also a good reason for increased parasympathetic influence on the rate. No apparent lethal dysrhythmias and no blocks are not...

  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...