ECG Guru - Instructor Resources

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Left Anterior Fascicular Block (Hemiblock)

Sun, 09/13/2015 - 22:10 -- Dawn

This ECG provides an example of LEFT ANTERIOR FASCICULAR BLOCK (LAFB).  It is from a 71-year-old woman for whom we have no other history.  She also has first-degree AV block and right bundle branch block.  RBBB and LAFB together are called bifascicular block.  It is not uncommon to see this type of bifascicular block, as the right bundle branch and the  anterior fascicle of the left bundle share a blood supply. 

Acute Anterior-lateral M.I. With Right Bundle Branch Block and Left Posterior Fascicular Block

Thu, 08/21/2014 - 11:45 -- Dawn

This ECG was obtained from a patient who suffered an occlusion of the left main coronary artery.  ST elevation is seen in Leads V1 through V6, as well as I and aVL.  This is an indicator that the circumflex artery is included in this M.I., and the occlusion is above the bifurcation of the LM and the circ.  The patient also has a right bundle branch block and a left posterior fascicular block.

Atrial Pacing With Right Bundle Branch Block

Mon, 05/19/2014 - 12:32 -- Dawn

No instructor's collection should be without an atrial paced rhythm OR a right bundle branch block.  Here, you get both.  First, the atrial pacing.  This patient had a sinus node problem, but his AV conduction system was functional (if not perfect).  At this time, he is able to conduct impulses from the atria to the ventricles.  What he cannot do is reliably produce the impulse in his atria.   So, this pacemaker is currently pacing the right atrium, producing a paced "P" wave, which is then conducted to the ventricles.

Right Bundle Branch Block With Left Posterior Fascicular Block

Mon, 05/13/2013 - 08:09 -- Dawn

This is a good clear example of right bundle branch block with left posterior fascicular block.  The RBBB is diagnosed by the following criteria:  wide QRS (.12 sec), supraventricular rhythm (NSR), an rsR' pattern in V1, and wide little s waves in I and V6.  The LPFB is inferred by the right axis deviation (Lead III QRS is a bit taller than Lead II and Leads I and aVL are negative), and the fact that there is no other obvious cause for right axis shift noted in this patient.  This constitutes a BIFASCICULAR BLOCK.

Right Bundle Branch Block With Atypical QRS in V1 and LAFB or Ventricular Rhythm???

Wed, 03/27/2013 - 19:28 -- Dawn

This is quite an interesting ECG, and the ECG Guru would love to hear what you think about it.  What we do know is that it is a wide-complex bradycardia in a patient for whom we have no clinical data, except that she is a 51 year old female.  The rhythm is probably junctional, as no P waves are seen and the rhythm is regular.  The rate of 63 per minute would be consistent with that.

Sinus Bradycardia With First-Degree AV Block and Left Anterior Fascicular Block

Sun, 03/10/2013 - 01:13 -- Dawn

This is a good ECG for demonstrating sinus brady and first-degree AV block. It shows the sinus node in the process of slowing down. For your more advanced students, there is left axis deviation due to left anterior fascicular block (left anterior hemiblock). The ST segments are flat, suggesting coronary artery disease. The fourth (bottom) channel is a good rhythm strip. Just crop the image. Please refer to Dr. Grauer's interesting post on teaching hemiblocks on our Ask The Expert page.

Sinus Tach vs SVT In An Inebriated Patient

Sat, 12/29/2012 - 15:21 -- Dawn

This series of ECGs was obtained from a 60-year-old man who was involved in a one-car accident.  He sustained no injuries, but his blood alcohol level was far above the legal limit for intoxication at over 300 mmol/L.  ECG No. 1 shows the ECG obtained by paramedics in the field, which they incorrectly interpreted to be atrial fibrillation.  No medication was given.  The ER physician obtained ECG No.

Atrial Fib, Bifascicular Block, Pacemaker

Tue, 04/10/2012 - 12:53 -- Dawn

Lots of information in this ECG! The underlying rhythm is atrial fibrillation with a controlled rate. The QRS is .12 seconds in duration, with an rSR' pattern in V1 and a wide s wave in Leads I and V6, indicating right bundle branch block. In addition, the axis is leftward - Leads I and aVL are upright and Leads II, III, and aVF are negative. There is no other obvious reason for the left axis shift, and therefore, the diagnosis by exclusion is left anterior fascicular block.

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