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Atrial Fib To Cardiac Arrest

Submitted by Dawn on Sun, 07/03/2016 - 14:31

A paramedic crew responded to the office of a local physician. A 61-year-old male presented with a one-week history of chest pain and shortness of breath. He had a previously undiagnosed atrial fibrillation with rapid ventricular response and left bundle branch block, but was alert. Shortly after transport commenced, the patient became unresponsive with Torsades de Pointes, which rapidly degenerated into ventricular fibrillation. The paramedic placed pads and defibrillated within one minute.  After two minutes of compressions, the patient had a fairly regular rhythm with return of spontaneous circulation.  Transport time was short.  On catheterization, the patient was found to have severe coronary artery disease, requiring coronary artery bypass graft surgery (CABG) A balloon pump was inserted in an attempt to strengthen him for surgery.

What is the rhythm?   The 12-lead ECG presented here shows atrial fibrillation at a rate of 138 per minute.  The rhythm is irregularly-irregular with no P waves.  Since the patient had not yet been diagnosed with atrial fib, obviously no therapy had been initiated to control the rate. There is a PVC near the end of the strip.

Dawn's picture

ECG Basics: Torsades de Pointes

Submitted by Dawn on Sat, 07/13/2013 - 12:30

Torsades de pointes, or polymorphic ventricular tachycardia, is a ventricular tachycardia precipitated by and associated with long QT Syndrome.  Long QT Syndrome can be congenital or acquired.  Torsades is life-threatening, and can be made worse by many drugs, including some of the drugs used to treat VT.  The rate is usually 150 - 250 / min. and the appearance is of a wide-complex tachycardia with QRS morphology changes.  In some leads, it will appear as if it is "twisting" around the isoelectric line, giving it the French name, Torsades de pointes, a ballet term meaning twisting of the points.  For a thorough discussion of Torsades, check this LINK.

Dawn's picture

Third-degree AV Block and Junctional Escape Rhythm With Right Bundle Branch Block and Prolonged QTc Interval

Submitted by Dawn on Sat, 01/26/2013 - 13:48

This ECG is from a 70 year old woman for which we have, unfortunately, no clinical information.  It shows a sinus rhythm with a rate of about 72 bpm (NSR) with AV dissociation caused by third-degree heart block.  The escape rhythm is junctional at a rate of 38 bpm.  There appears to be a right bundle branch block, based on the QRS duration of 132 ms, and a wide S wave in Leads I and V6.  The precordial leads do not show the usual RBBB pattern of rSR' in V1 and V2, and the r wave progression is poor (non-existent).  This is felt to be due to poor lead placement (a good teaching point).  Of interest, the ECG machine has reported a "severe right axis deviation" based on the tall upright R wave in aVR and the deep S in avF.  In RBBB, the first part of the QRS represents left ventricular depolarization, and the terminal wave represents the delayed right ventricle.  In effect, the two ventricles have their own electrical axes, which we can see because the ventricles are not depolarizing simultaneously.  The axis of the LV appears to be normal in this tracing.

In addition to the above, this patient has a very prolonged QT interval.  The QT is longer in bradycardic rhythms, but when corrected to a standard of 60 bpm (QTc), this patient's QT interval is still prolonged at QTc: 552 ms.  Without clinical data, we cannot speculate  as to why this patient's QTc is prolonged, but it can be a very dangerous situation.  Follow the links for more information on QT prolongation and Torsades de Pointes and Long QT Syndrome.

As always, we welcome comments from our members adding insight to this interesting ECG, and also questions you would like to ask our Guru members.

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