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Ventricular Standstill

Submitted by Dawn on Mon, 09/02/2024 - 21:14

The Patient: This 72-year-old woman called EMS because of a sudden onset of breathlessness and anxiety. She had a history of COPD (asthma), CHF, and Type II diabetes. We do not know her medications or any other history. She was found to have bilateral breath sounds with "minimal" expiratory wheezing. She was alert and very anxious. Her initial pulse rate was recorded at around 60 bpm and irregular. A systolic BP was heard at 140 mm Hg, but the paramedic could not hear a pulse after that. She was given oxygen via CPAP (Continuous positive airway pressure). The first ECG at 15:50 was recorded during this assessment. After appearing to improve, she became neurologically altered, and her level of consciousness varied during the call. She was turned over to emergency department staff conscious and able to speak, but had a cardiac arrest subsequently. The paramedics were unable to obtain followup information regarding the outcome. ECG at 1550: The first QRS on the recording has no associated P wave, and is presumed to be an escape beat, probably junctional, with an interventricular conduction delay (QRS .12 sec.). This is a right bundle branch block pattern with left anterior fascicular block (bifascicular block). The second QRS is about the same width, but with a different morphology and discordant T waves, so probably ventricular. The third QRS is very much like the first, except that it appears to be conducted from the preceding P wave. For the next five seconds, there are only P waves, which are regular at about 130 bpm. The three-beat pattern seen at the beginning repeats itself near the end. This ECG shows evidence of severe conduction blocks. The wide QRS complexes indicate interventricular blocks. In this case, some are probably premature ventricular contractions and some are sinus beats with bifascicular block. Even more worrisome is the intermittent loss of AV conduction. This can be called "intermittent trifascicular block", or "intermittent ventricular standstill". This is not a "third-degree AV block", because there are signs of AV conduction, but it is very close. With two of the three main fasicles of the left bundle branch blocked initially, it only takes a block in the remaining fascicle to produce a complete lack of AV conduction. Of course, there are no pulses during the time of ventricular standstill. The really concerning part of this situation is the lack of an ESCAPE RHYTHM. This is a good time for a temporary pacemaker, either transcutaneous or, if available, transvenous. ECG at 1603: This ECG was obtained enroute to the hospital. The patient is once again alert and anxious. There is some artifact which hampers evaluation, but there are two P waves for every QRS complex. The atrial rate is about 120 bpm and the ventricular rate is about 60 bpm. The non-conducted P waves are buried in the T waves of the preceding beats.

Dawn's picture

Inferior-posterior Wall M.I. and AV Dissociation

Submitted by Dawn on Mon, 12/06/2021 - 17:59

At the ECG Guru website, our main goal is to provide quality teaching materials to those who teach ECG interpretation and other cardiac topics.  This ECG offers teaching opportunities for those who teach any level of student.

The patient:   This ECG was obtained in the Emergency Department from a 54-year-old man who was complaining of severe chest pain and nausea.  His BP was 130/68.

Dawn's picture

High-grade AV Block

Submitted by Dawn on Thu, 03/13/2014 - 14:42

To continue on a topic started by Jason Roediger in his February ECG Challenge -

This series of two ECGs was taken from a 71-year-old man who complained of dizziness and near-syncope the day before these ECGs were done.  He was seen in an Emergency Dept., and advised to follow up with a neurologist. On the day of these ECGs, still feeling dizzy and like he would pass out, he called EMS again.  He denied chest pain.  We do not know his past medical history.  The first ECG was taken at 10:22 am.  His BP was 177/76 and SpO2 99%.  It shows a regular sinus rhythm (p waves marked by small asterisks) at a rate of about 75 / min.  There is a high-grade AV block, meaning that some P waves are conducted (beats 2, 4, 7), but most are not.  In addition, he has an escape rhythm, probably ventricular, at a rate of just over 40 / min.  The overall effect of the escape rhythm is to keep the heart rate above 40 beats per minute.

Fifteen minutes later, at 10:37 am, another ECG is taken.  The patient's BP is 154/86.   This ECG shows the high-grade AV block quite well, but this time, most of the QRS complexes on the strip are conducted from P waves.  It is difficult to see all the P waves in every lead, but if you remember that all three channels are run simultaneously, you will find evidence of the P waves in at least one of the three leads represented at any given time.  (Example:  V1, V2, and V3 - V3 shows the P waves well).  The next-to-last QRS on the page is interesting, as it has a different PRI than the normally conducting beats.  Is this a fusion beat or an aberrantly-conducted one?   It probably does not matter to the outcome of the patient. 

The slowing of the rate in the second strip gives us a clue as to why the patient felt dizzy, but the blood pressures recorded did not catch hypotension.  Possibly if the patient had been standing instead of lying on a stretcher, we would have seen more hemodynamic changes.

Unfortunately, we do not know the outcome of this patient, but it seems he is a candidate for an implanted pacemaker.

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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