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Instructors' Collection ECG: Regular Really Wide QRS Tachycardia

The Patient:    Unfortunately, this is an old tracing, and we do not have patient information, other than the list of medications the patient has been taking, (Lasix, Capoten, Ntg, and Procardia). Lasix (furosemide) is a potassium – wasting diuretic.  Capoten (captopril) is an ACE inhibitor.  Ntg is presumably sublingual nitroglycerine used for angina. Procardia (nifedipine) is a calcium-channel blocker.  So, we can assume the patient was probably being treated for angina, heart failure, and hypertension.

 The ECGThe first impression is that is a regular WIDE COMPLEX TACHYCARDIA.  The ventricular rate is 100 bpm (Starts a little faster at the beginning at 106, then is 100 by the end).  The QRS duration is about 250 ms (.25 seconds) – VERY WIDE.  There appear to be P waves outside the QRS complexes in V1 and aVL, but probably buried in the ST-T of other leads. 

 We were all taught to treat all wide complex tachycardia (WCT) as VENTRICULAR TACHYCARDIA (VT) until proven otherwise.  This is a very good rule, especially in an emergency setting. It pays to take a moment to consider the possibility of REGULAR REALLY WIDE COMPLEX TACHYCARDIA (RRWCT) before making a treatment decision.

 An extremely wide QRS can occur because of a number of very concerning reasons, most involving blockade of the sodium channels.  Included in this category are:

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An Interesting Holter Strip

Here you can see a long rhythm strip from a Holter ECG, written at 25 mm/s. On the left, a sinus bradyarrhythmia can be seen first, followed by an atrial tachycardia. After a few beats this changes back into a sinus bradyarrhythmia. Then follows a short VT over 3 beats, after 1 sinus node beat then a ventricular couplet. Sinus bradyarrhythmia again at the end.

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Atrial Fibrillation With Rate-related Left Bundle Branch Block

For a better overview, the leads aVL and V2-V4 are not shown in this ECG. The basic rhythm is atrial fibrillation (no P waves or flutter waves visible, but fibrillation waves). When the conduction rate drops, the QRS complexes are narrow. Faster conduction results in wide QRS complexes with LBBB morphology. This is an example of phase 3 (acceleration dependant) LBBB.

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New Book From Dr. Jerry Jones


Pacemaker leads: Atrial and Bi-ventricular

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Pacemaker leads

This original artwork was created by Dawn Altman.  It is free for your use in a non-commercial setting.  For commercial use, contact the artist at [email protected]. All rights reserved. (c) 2023

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ECG Glossary from Dr. Ken Grauer

Are you looking for a comprehensive ECG glossary that goes beyond simply defining words? Dr. Ken Grauer, who is the ECG Guru's Consulting Expert, has a Glossary available on his website that explains the terms.  Instructors and students alike will benefit from having this glossary readily available.  The glossary is exerpted from his e-Publication, "A 1st Book On ECGs - 2014", available on Amazon.

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ECG HISTORY:     ECG was first put into clinical use in the early 1900s.  In 1909, it helped diagnose an arrhythmia.  A year later, indications of a heart attack were noted.



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