Friday, December 8, 2023

ECG Video Blog #407 (292): Why the Patient Died?

 CLICK HERE — for a Video presentation of this case! (22:30 min.)

  • Below are slides used in my video presentation.
  • For full discussion of this case — See ECG Blog #292 


The 2 ECGs shown in Figure-1 were obtained from a man in his 30s — who presented to the ED (Emergency Department) with chest pain that began several hours earlier. ECG #2 was recorded 1 hour after ECG #1. Initial troponin was negative.

Cardiac cath was advised — but the patient refused. Instead, he left the hospital — only to be found dead at home 36 hours later
  • How would YOU interpret the serial ECGs shown in Figure-1?
  • WHY did the patient die? 

Figure-1: The 2 ECGs in today's case (See text).

ADDENDUM: Some additional material on ECG diagnosis of OMI.

ECG Media PEARL #39a (4:50 minutes Audio) — Reviews the concept of Dynamic ST-T Wave Changes (and how this ECG finding can assist in determining if acute cardiac cath is indicated).



ECG Media PEARL #46a (6:35 minutes Audio) — Reviews HOW to compare Serial ECGs (ie, Are you comparing "Apples with Apples" — or — with Oranges?).

Related ECG Blog Posts to Today’s Case: 

  • ECG Blog #205 — Reviews my Systematic Approach to 12-lead ECG Interpretation. 
  • ECG Blog #183 — Reviews the concept of deWinter T-Waves (with reproduction of the illustrative Figure from the original deWinter NEJM manuscript). 
  • ECG Blog #222 — Reviews the concept of Dynamic ST-T wave changes, in the context of a detailed clinical case. 
  • ECG Blog #260 — Reviews another case that illustrates the concept of "dynamic" ST-T wave changes.

  • ECG Blog #218 — Reviews HOW to define a T wave as being Hyperacute? 
  • ECG Blog #230 — Reviews HOW to compare Serial ECGs (ie, "Are you comparing Apples with Apples or Oranges?"). 

  • ECG Blog #193 — Reviews the concept of why the term “OMI” ( = Occlusion-based MI) should replace the more familiar term STEMI — and — reviews the basics on how to predict the "culpritartery.

  • ECG Blog #194 — Reviews how to tell IF the “culprit” (ie, acutely occluded) artery has reperfused using clinical and ECG data.

  • ECG Blog #115 — Shows an example of how drastically the ECG may change in as little as 8 minutes.
  • The January 9, 2019 post in Dr. Smith's ECG Blog (Please scroll down to the bottom of the page to see My Comment). This case is remarkable for the dynamic ST-wave changes that are seen. It's helpful to appreciate: i) That acute ischemia/infarction is not the only potential cause of such changes (cardiac cath was normal); ii) That changes in heart rate, frontal plane axis and/or patient positioning can not always explain such changes; andiii) That entities such as repolariztion variants, LVH and/or acute myopericarditis may all contribute on occasion to produce an evolution of challenging dynamic ST-T wave changes on serial ECGs.

  • The August 22, 2020 post in Dr. Smith's ECG Blog — which illustrates another case of dynamic ST-T wave changes that resulted from a repolarization variant

  • The July 31, 2018 post in Dr. Smith's ECG Blog (Please scroll down to the bottom of the page to see My Comment). This case provides an excellent example of dynamic ST-T wave changes on serial tracings (that I illustrate in My Comment) in a patient with an ongoing acutely evolving infarction.

Saturday, December 2, 2023

ECG Video Blog #406 — To Do Additional Leads?

 CLICK HERE — for a Video presentation of this case! (19:40 min.)

  • Below are slides used in my video presentation.
  • For full discussion of this case — See ECG Blog #351 


The ECG in Figure-1 — was obtained from a previously healthy older man who contacted EMS (Emergency Medical Services) because of "chest tightness" that began ~1 hour earlier. Given this history:

  • How would YOU interpret the ECG in Figure-1?
  • Should you activate the cath lab ?

Figure-1: The initial ECG in today's case — obtained by EMS at the scene, from an older man with ~1-hour of chest "tightness". (To improve visualization — I've digitized the original ECG using PMcardio).

Figure-4: ECG findings to look for when your patient with new-onset cardiac symptoms does not manifest STEMI-criteria ST elevation on ECG. For more on this subject — SEE the September 3, 2020 post in Dr. Smith’s ECG Blog with 20-minute video talk by Dr. Meyers on The OMI Manifesto. For my clarifying Figure illustrating T-QRS-D (2nd bullet) — See My Comment at the bottom of the page in Dr. Smith’s November 14, 2019 post.


ECG Blog #205 = The Systematic Approach I favor ...


Figure: The Systematic Approach that I favor. Review of the first 4 parameters in Descriptive Analysis (Rate; Rhythm; Intervals; Axis)NOTE: IF the QRS complex is wide — then STOP and find out WHY the QRS is wide before proceding to assessment of Axis, Chamber Enlargement and QRST Changes. This is because IF the QRS is wide because of BBB (Bundle Branch Block) — criteria for axis, hypertrophy, and ST-T wave changes will be different when there is BBB or IVCD! To emphasize, IF the QRS is wide — this is the ONE time that I depart from the sequence in Figures-2 and -3 (P.S. IF the QRS is wide — Make sure that the rhythm is not VT. If the rhythm is sinus — ECG Blog #204 reviews how to determine if RBBB, LBBB or IVCD is present).


Figure: The Systematic Approach that I favor (Continued). Review of the last 2 parameters in Descriptive Analysis (Chamber Enlargement; Looking for Q-R-S-T Changes) — and then formulating your Clinical Impression.


Figure: I've added the mirror-image of leads V3 and V4 to today's tracing — to illustrate how the initial ECG shows a positive "Mirror" Test suggestive of acute posterior OMI.

Figure: The repeat ECG.


Related ECG Blog Posts to Today’s Case:
  • ECG Blog #205 — Reviews my Systematic Approach to 12-lead ECG Interpretation.

  • ECG Blog #193 — illustrates use of the Mirror Test to facilitate recognition of acute Posterior MI. This blog post reviews the basics for predicting the "Culprit" Artery (as well as reviewing why the term "STEMI" — should replaced by "OMI" = Occlusion-based MI).

  • ECG Blog #285 — for another example of acute Posterior MI (with positive Mirror Test).
  • ECG Blog #246 — for another example of acute Posterior MI (with positive Mirror Test).
  • ECG Blog #80 — reviews prediction of the "culprit" artery (and provides another case illustrating the Mirror Test for diagnosis of acute Posterior MI).
  • ECG Blog #317 — reviews another case regarding use (or not) of Posterior Leads.

  • ECG Blog #184 — illustrates the "magical" mirror-image opposite relationship with acute ischemia between lead III and lead aVL (featured in Audio Pearl #2 in this blog post)
  • ECG Blog #167 — another case of the "magical" mirror-image opposite relationship between lead III and lead aVL that confirmed acute OMI.
  • The February 16, 2019 post in Dr. Smith's ECG Blog — My Comment (at the bottom of the page) emphasizes utility of the Mirror Test for diagnosis of acute Posterior MI. 
  • Diagnosis of an OMI from the initial ECG — Serial tracings with spontaneous reperfusion — then reocclusion! — See My Comment at the bottom of the page in the October 14, 2020 post on Dr. Smith's ECG Blog.
  • Acute OMI that wasn’t accepted by the Attending — See My Comment at the bottom of the page in the November 21, 2020 post on Dr. Smith’s ECG Blog.
  • Another overlooked OMI (Cardiologist limited by STEMI Definition — OMI evident by Mirror Test) — See My Comment at the bottom of the page in the September 21, 2020 post on Dr. Smith’s ECG Blog.
  • Recognizing hyperacute T waves — patterns of leads — an OMI (though not a STEMI) — See My Comment at the bottom of the page in the November 8, 2020 post on Dr. Smith's ECG Blog.

  • ECG Blog #271 — Reviews determination of the ST segment baseline (with discussion of the entity of the entity of diffuse Subendocardial Ischemia).

  • ECG Blog #266 — Reviews distinction between Posterior MI vs deWinter T waves (with anterior terminal T wave positivity reflecting "Reperfusion" T-waves).

  • ECG Blog #258 — How to "Date" an Infarction based on the initial ECG.

  • ECG Blog #294 — Reviews how to tell IF the "culprit" artery has reperfused.
  • ECG Blog #230 — Reviews how to compare Serial ECGs.
  • ECG Blog #115 — Shows how dramatic ST-T changes can occur in as short as an 8-minute period.
  • ECG Blog #268 — Shows an example of reperfusion T waves.

  • ECG Blog #190 — How to diagnose acute RV MI (and use of right-sided leads).

Saturday, November 25, 2023

ECG Video Blog #405 — Is AV Block Complete (vs AV Dissociation)

 CLICK HERE — for a Video presentation of this case! (19:40 min.)

  • Below are slides used in my video presentation.
  • For full discussion of this case — See ECG Blog #191 


The 2-lead rhythm strip shown in Figure-1 was obtained from an elderly woman who presented to the ED following a syncopal episode. On the basis of this rhythm strip — she was diagnosed as being in complete AV Block.

  • Question #1Is there AV Dissociation in Figure-1?
  • Question #2: Do YOU agree that the rhythm shown in this figure represents complete ( = 3rd-degree) AV Block?

Figure-1: Is this complete AV Block

Figure: The Ps, Qs, 3R Approach to Rhythm Interpretation.

Figure: It does not matter in what sequence you assess the 5 Parameters (and I often change the sequence, depending on the rhythm ... ).


Figure: If the AV block is neither 1st-degree nor 3rd-degree — then it will be some type of 2nd-degree AV Block!

Figure: 1st-degree AV Block — is simply a sinus rhythm with a long PR interval (ie, more than 1 large box in duration = >0.20 second). It is EASY to diagnose.

Figure: 3rd-degree AV block with ventricular escape. 3rd-degree AV Block is usually also EASY to diagnose — because most of the time the ventricular "escape" rhythm will be regular (or almost regular) — in contrast to conducted beats that will often occur earlier-than-expected ...

Figure: The 3 types of 2nd-degree AV blockPanel A: Mobitz I 2nd degree AV block with gradual prolongation of the PR interval until a P wave is droppedPanel B: Mobitz II with QRS widening and a fixed PR interval until sudden loss of conduction with successive nonconducted P wavesPanel C: 2nd-degree AV block with 2:1 AV conduction. It is impossible to be certain if 2:1 AV block represents Mobitz I or Mobitz II — because we never see 2 conducted P waves in a row — and, therefore can not tell if the PR interval would progressively lengthen prior to nonconduction IF given a chance to do so ... (That said — 90-95% of 2nd-degree AV Blocks are Mobitz I — and Mobitz I especially likely if the QRS is wide, with 1st-degree, in a patient with acute inferior MI).

Figure: 2nd-degree AV block with 2:1 AV conduction.

Figure: This is high-grade 2nd-degree AV Block — as identified by the finding of at least 2 consecutive on-time P waves that fail to conduct despite adequate opportunity to do so (occurring here between beats #2-3).


Figure: AV dissociation by "default" — because the SA node slows, with result takeover by the AV node. There is not necessarily any degree of AV block with this! 

Figure: AV dissociation by "usurpation" — because either the AV node or the ventricles speed up, and take over the rhythm from the SA node. There is not necessarily any degree of AV block with this! (and the KEY is to figure out WHY the AV node or ventricles have "taken over" the rhythm). 

Figure: Anatomic levels of 3rd-degree AV Block. Panel A: Complete AV Block at the ventricular level. There is a regular atrial rhythm — and the QRS is wide with an idioventricular escape rhythm at a rate between 20-40/minute. Panel B: Complete AV Block at a higher level (probably in the AV node) — as suggested by the presence of a narrow QRS escape rhythm at a rate between 40-60/minute.

NOTE: The KEY criterion for diagnosing complete AV block — is that none of the on-time sinus P waves are being conducted to the ventricles despite having more than adequate opportunity to do so! (which usually requires a long enough rhythm strip at a slow enough rate = <50-55/minute — in order to guarantee that on-time P waves are occurring at all points in the cycle — but still fail to conduct).



Figure: Laddergram of today's rhythm through the Atrial Tier.

Figure: Completed laddergram of today's rhythm. There is AV dissociation for the first 5 beats with ventricular escape (AV dissociation as a result of AV block). Because of underlying sinus arrhythmia — the P wave in front of beat #6 occurs at an opportune time, and is able to conduct to the ventricles. The remaining beats ( = beats #6-thru-9) conduct with 2:1 AV block. Because Mobitz I is some much more common than Mobitz II — and especially because the QRS complex for these conducted beats is narrow — there is almost certainly 2nd-degree AV Block of the Mobitz I Type ( = AV Wenckebach) — here with AV dissociation initially, and 2:1 AV block for the last few beats in the tracing.


Additional Material on Today's CASE:

ECG Media PEARL #4 (4:30 minutes Audio): — takes a brief look at the AV Blocks — and focuses on WHEN to suspect Mobitz I.

ECG Media Pearl #8 (8:20 minutes Video) — ECG Blog #191 — Distinguishing between ADissociation vs Complete AV Block (2/6/2021).

ECG Media Pearl #9 (5:40 minutes Video) — ECG Blog #192 — Reviews the 3 Causes of AV Dissociation (2/9/2021).

  • Section 2F (6 pages = the "short" Answer) from my ECG-2014 Pocket Brain book provides quick written review of the AV Blocks (This is a free download).
  • Section 20 (54 pages = the "long" Answer) from my ACLS-2013-Arrhythmias Expanded Version provides detailed discussion of WHAT the AV Blocks are — and what they are not(This is a free download). 


Related ECG Blog Posts to Today’s Case: 

  • ECG Blog #185 — Review of the Ps, Qs, 3R Approach for systematic rhythm interpretation.
  • ECG Blog #188 — Reviews how to read and draw Laddergrams (with LINKS to more than 50 laddergram cases — many with step-by-step sequential illustration).
  • ECG Blog #164 — Which reviews step-by-step the diagnosis of a Mobitz I 2nd-degree AV block (with sequential laddergram illustration).

  • ECG Blog #168 — A complex dual-level AV Wenckebach (Laddergram).

  • ECG Blog #154 and ECG Blog #55 and ECG Blog #224 and ECG Blog #232 — Acute MI with AV Wenckebach.

  • ECG Blog #63 — Mobitz I with Junctional Escape Beats.