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Instructors' Collection ECG: Wide Complex Tachycardia

Fri, 10/09/2020 - 14:30 -- Dawn

The Patient   A 64-year-old woman has called 911 because she has chest discomfort radiating to her left arm, palpitations, weakness, and a headache.  She had a valve replacement (we do not know which valve) two weeks ago and has a healing incision over her sternum.  She is found sitting in a chair, pale, cool, and diaphoretic. Her blood pressure is 94/palp.  Her pulse rate is 196 bpm and weak. She is afebrile.

ECG #1   This ECG shows a wide-complex tachycardia at 196 bpm.  The QRS complexes are .132 seconds in duration, per the ECG machine. The rate is too fast to appreciate whether there are P waves present.  We did not see the onset of the tachycardia, but with a rate this fast and regular, it is most likely a reentrant rhythm, rather than sinus tachycardia.  An abrupt onset of the rhythm would point to a diagnosis of a reentrant rhythm, either ventricular tachycardia (VT) or paroxysmal supraventricular tachycardia (PSVT). 

There is an important rule in emergency medical care:  a wide-complex tachycardia should be treated as VT until and unless it is proven to be something else.  The most likely alternate interpretation is PSVT with aberrant conduction, which usually takes the form of left or right bundle branch block. Fortunately, the paramedics on this call have a protocol for treating WCT that includes electrical cardioversion for the unstable patient, and amiodarone for the stable patient.  This protocol serves both possibilities, VT and PSVT, well.  The patient’s perfusion status and BP made her borderline in this determination, but she was alert and oriented, so the paramedics opted for administering the amiodarone while they prepared to electrically cardiovert.

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Wide Complex Tachycardia

Fri, 05/01/2020 - 16:19 -- Dawn

The Patient:   The details of this patient’s complaints and presentation are lost, but we know he was a 66-year-old man who was being treated in the Emergency Department. His rhythm went from sinus tachycardia with non-respiratory sinus arrhythmia to multi-focal atrial tachycardia (MAT) to wide-complex tachycardia. The WCT lasted a few minutes and spontaneously converted to an irregular sinus rhythm.

Wide-complex tachycardia:  Ventricular tachycardia or aberrantly-conducted supraventricular tachycardia?  When confronted with a wide-complex tachycardia, it can be very difficult to determine whether the rhythm is ventricular or supraventricular with aberrant conduction, such as bundle branch block. The patient’s history and presentation may offer clues.  It is very important, if the patient’s hemodynamic status is at all compromised (they are “symptomatic”), the WCT should be treated as VENTRICULAR TACHYCARDIA until proven otherwise.  

There have been many lists made of the ECG features that favor a diagnosis of ventricular tachycardia. Here are two such lists:  Life In The Fast Lane, and National Institute of Health.

The ECG:  This ECG shows a regular, fast, wide-QRS rhythm.  The rate is 233 bpm.  It had a sudden onset and sudden offset (not shown on this ECG), and the rhythm lasted about 3-5 minutes. The patient felt the change in rate, but did not become hypotensive or unstable.  Some features that relate directly to the most commonly-referenced VT vs. SVT charts are:

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Wide QRS Complex With First-degree AV Block

Fri, 06/07/2019 - 14:48 -- Dawn

The Patient:  This ECG was taken from a 73-year-old man with a history of heart failure with preserved ejection fraction, severe left ventricular hypertrophy, Type II diabetes, and stage 4 chronic kidney disease.  He also suffered deep vein thrombosis and is on anticoagulation.  He has a recent diagnosis of IgA myeloma.  He presented with a complaint of nausea and vomiting and was found to have a worsening of acute kidney infection.  There was suspicion of renal and cardiac amyloidosis, but the patient refused biopsy to confirm this.  He was started on chemotherapy for multiple myeloma and will be followed as an outpatient.

The ECG:  The rhythm is sinus at around 60 bpm, although the rate varies a little at the beginning of the strip.  The QRS complex is wide at .12 seconds, or 120 ms., representing interventricular conduction delay (IVCD).  The PR interval is .32 seconds, or 320 ms. This constitutes first-degree AV block.  There is left axis deviation in the frontal plane and poor R wave progression in the horizontal plane.

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Wide QRS Complex With First-degree AV Block

Fri, 06/07/2019 - 13:40 -- Dawn

The Patient:  This ECG was taken from a 73-year-old man with a history of heart failure with preserved ejection fraction, severe left ventricular hypertrophy, Type II diabetes, and stage 4 chronic kidney disease.  He also suffered deep vein thrombosis and is on anticoagulation.  He has a recent diagnosis of IgA myeloma.

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