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Left anterior fascicular block

Teaching Series - Tachycardia and Left Anterior Fascicular Block

Sat, 10/15/2016 - 15:48 -- Dawn

This series of three ECGs is from a 60-year-old man who was brought to the Emergency Department after being involved in a motor vehicle accident.  No injuries were found, but the patient was severely intoxicated by alcohol consumption.  He was conscious but agitated. 

ECG NO. 1     15:07:23

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. 

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.

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.

Right Bundle Branch Block With Left Anterior Fascicular Block

Thu, 02/07/2013 - 23:00 -- Dawn

This is a nice, clear right bundle branch block pattern: wide QRS, supraventricular rhythm (NSR), and rSR' pattern in V1. Wide little s waves in Leads I and V6 are also diagnostic. The left axis deviation indicates a left anterior fascicular block, since there is no other apparent reason for the left axis deviation, such as pathological Q waves or LVH. Left anterior fascicular block is a diagnosis of exclusion, also considering that RBBB and LAFB are often seen together (bifascicular block), since the two fascicles have the same blood supply.

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.

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