62 yom CC: chest discomfort

EMS is dispatched to a 62 year old male with a chief complaint of chest discomfort. On arrival, the patient is found sitting at the dinner table. He appears acutely ill.

Onset: Fairly sudden after sitting down for dinner 20-30 minutes ago
Provoke: Nothing makes the pain feel better or worse
Quality: Dull pressure/ache
Radiation: The pain does not radiate
Severity: 8/10 "feels like a 747 is sitting on his chest"
Time: Feels slightly better since the onset

Skin: cool, pale, diaphoretic

Vital signs:

Resp: 20
Pulse: 62
BP: 84/48
SpO2: 99 on RA

The cardiac monitor is attached.


A 12 lead ECG is captured.


The paramedic trouble-shoots the loose electrode. The data quality looks good to me, but the computer disagrees!


Three's a charm!


Now what? You're 5 minutes into the call...

*** Update ***

The paramedic in charge of the call elected to perform an additional 12 lead ECG using modified leads V4R and V5R.

Here is the result.


Here are some charts from my series on right ventricular infarction for reference. I don't remember where the first chart came from, but it shows the ramifications of various ST/T configurations in lead V4R.


Also consider Eskola et al. How to Use ECG for Decision Support in the Catheterization Laboratory - Cases With Inferior ST Elevation Myocardial Infarction. Journal of Electrocardiography Vol 37 No. 4 October 2004.


Question: Does this change anything? Why or why not?

35 yom CC: palpitations

35 year old male (on vacation) presents to the fire station complaining of an irregular heart beat.

History of present illness: Patient states he walked up to the top of the lighthouse earlier in the day and started to feel palpitations.

PMH: Healthy
Meds: None

Vital signs are assessed.

Resp: 18
Pulse: 54 (irregular)
BP: 130/84
SpO2: 99 RA

The cardiac monitor is attached.

A 12 lead ECG is captured.


The patient is adamant that he does not want to be transported to the hospital. He states that he just wants a printout of the 12 lead ECG to show his private physician.

What is your interpretation of this ECG?

How would you explain to this patient the risk of refusing care/transport?

Right bundle branch block - Part III

Let's take another look at the ECG from Part II.


I asked you to look carefully at this ECG, and then using the concept of appropriate T-wave discordance, see if anything bothers you.

Does anything stand out?

How about lead V4?


Here you can see the terminal deflection (blue arrow) is positive, and so is the T-wave (inappropriate T-wave concordance). There is also at least 1 mm of ST segment elevation. That's definitely abnormal!

Now let's look in the inferior leads. They all look abnormal, but I'm going to use lead aVF as the example.


The terminal deflection is negative (blue arrow) and the T wave is also negative (inappropriately concordant T-wave). The inferior leads are reciprocal to the anterior leads. Could this represent reciprocal changes? Absolutely!

It is sometimes said that reciprocal changes are of no value in the presence of bundle branch blocks. That's not entirely true! You just have to interpret them within the context of appropriate T-wave discordance.

In other words, in the presence of bundle branch block, if the terminal deflection of the QRS complex is negative in lead III and positive in lead aVL, then you will have pseudo reciprocal changes (positive in lead III and negative in lead aVL). This is a normal finding in left bundle branch block, for example.

If, however, the terminal deflection of the QRS complex is negative in lead III (as in this ECG) and the same lead is showing inappropriately concordant ST-segment depression or T-wave inversion, then it's probably not a pseudo reciprocal change. Why? Because it's opposite the expected pattern.

I'd also like to point out that leads V2 and V3 look really strange in this ECG. Why? Because there's a merging together of the S-wave and T-wave (sometimes seen in severe hyperkalemia). This is a really ugly T-wave abnormality, especially since we would normally expect a terminal R wave in lead V2 with right bundle branch block.

Something's going on here!

Let's look at some serial ECGs. This one was taken just 4 minutes later.


Now what do you see?

*** Update 07/13/09 ***

Here's the final ECG in the series, recorded as the ambulance arrived at the hospital.


Quite a difference! Once again, it's easy to see the value of serial ECGs.

Let's take a look at lead V2 and see how it changed from the first ECG to the last.


The problem (or perhaps the challenge) is that this final piece of the puzzle wasn't present until arrival at the hospital. Fortunately, it was one of 17 PCI hospitals in the State of South Carolina!

This is why paramedics need to be able to interpret a 12 lead ECG at a high level. Every Patient Counts! We need to make sure that STEMI patients are delivered to the right hospital!

QRS confounders like right and left bundle branch block can make the ECG diagnosis of STEMI more difficult, but these are the patients who receive the most benefit from reperfusion therapy, and prompt, expertly performed primary PCI is the preferred strategy!

We shouldn't delay a high risk patient's care because we can't read their ECG. Unfortunately, it happens every day all over the country.

That's assuming the EMS system has 12 lead ECG monitors in the first place.

See also:

Right bundle branch block - Part I

Right bundle branch block - Part II

82 yom CC: chest pain

"Funky Troubling Looking" -- Right Bundle Branch Block and MI

Right bundle branch block - Part II

Once you've identified a RBBB on the 12 lead ECG, the next thing you want to do is determine whether or not you're dealing with a normal RBBB or an abnormal RBBB (or new RBBB).

You may remember this graph from my previous post: Who benefits the most from reperfusion therapy?


It shows that patients with "new BBB" receive the most benefit in terms of lives saved per 1000 treated with fibrinolytics (based on the FTT Collaborate Group). We often here it claimed that patients with "new LBBB" receive the highest benefit from prompt reperfusion therapy, but it's worth pointing out that the FTT Collaborative Group did not distinguish between LBBB and RBBB.

Generally speaking, RBBB does not mimic or obscure the ECG diagnosis of acute STEMI the way LBBB does. However, sometimes it can (remember the update to Funky Trouble-Looking RBBB with AMI).

So how do we know what's "normal" for right bundle branch block? We use the concept of "appropriate T wave discordance". This concept usually comes up in the context of discussing LBBB, but it's also useful for RBBB (and paced rhythms, ventricular rhythms, non-specific IVCD, and so on).

For RBBB, the concept is that when the terminal deflection of the QRS complex is positive, the T wave should be negative. Likewise, when the terminal deflection is negative, the T wave should be positive.

You may recall this graph from my previous post: Identifying AMI in the presence of LBBB - Sgarbossa's Criteria - Part II.


The blue and red arrows show the expected relationship between the terminal deflection and the T wave with RBBB.

Remember, the terminal deflection is the last deflection in the QRS complex.

Consider the following case.

EMS is contacted for a 77 year old male complaining of chest pain. On arrival, you find the patient lying supine on the couch. He is ashen in color and diaphoretic with absent radial pulses. He responds sluggishly but appropriately and states that he is having severe sub-sternal chest pain.

His shirt is cut off and the combo-pads are applied, revealing the following heart rhythm.


It appears to be sinus rhythm with wide QRS complexes and occasional PVCs.

A 12 lead ECG is captured.


Using the concept of "appropriate T wave discordance" is there anything about this ECG that bothers you?

See also:

Right bundle branch block - Part I

Right bundle branch block - Part III

Happy 4th of July weekend

Sorry I haven't posted anything in a while, but I've been away at my parents beautiful log home on Lake Huron. It's been nice to get away for a while and enjoy some crisp northern air!

I've been power washing, painting, and digging all week (the artesian well sprang a leak -- who knew trench rescue would have real-world applications?)

Here is a video I shot the other morning with my Canon PowerShot A450 (cheap little point and shoot camera I purchased at Walmart that takes surprisingly good video).


The sun finally came out yesterday!

I may add more photos later tonight. I hope you're having a great 4th of July weekend!

Be safe. See you soon!

*** Update 07/10/09 ***

Restoration of the "bear tree"

Before


After

Right bundle branch block - Part I

How do you identify RBBB on the 12 lead ECG?

Forget about turn signals and bunny ears! They do more harm than good.

All you need for the ECG diagnosis of RBBB are the following:

• A supraventricular rhythm
• QRS duration equal or greater than 120 ms (0.12 s)
• Terminal R wave in lead V1
• S wave in lead I

It's that easy!

Let's look at an example.


What's the rhythm?

Borderline sinus bradycardia with 1°AVB and occasional PACs.

Is that a supraventricular rhythm? Yes!

Let's move on.

Is the QRS duration equal to or greater than 120 ms (o.12 s)?

In other words, are the QRS complexes "wide"?

Be careful! It's easy to fixate on the tight R wave and discount the S wave with RBBB. If this was a tachycardia at a rate of 150, it might appear to be a narrow complex tachycardia, when in fact, it would be a wide complex tachycardia!

The QRS duration is > 120 ms. Just barely, but it's like being pregnant. It either is or it isn't!

So we have a supraventricular rhythm with wide QRS complexes. This process is important because one of the most important and basic rules of electrocardiography is:

Wide complex rhythms are ventricular until proven otherwise!

Once you have determined that a supraventricular rhythm is wide, you can examine QRS moprhology to figure out what kind of intraventricular conduction delay is present.

Let's look at the 12 lead ECG.


Is there a terminal R wave in lead V1?

Yes!

What do we mean by "terminal R wave"?


The last wave of a QRS complex is the terminal wave, or terminal deflection. If a QRS complex ends in an R wave, then it has a terminal R wave. It can also be said that the terminal deflection is positive.

I would call the QRS complex in this 12 lead ECG an rsR' complex. Compare it to the rsR' complex in this PowerPoint slide.

It's important to think in terms of the terminal deflection (or terminal R wave) in lead V1 with RBBB because the QRS morphology can be quite variable!

Consider these examples.


All of these QRS complexes are different. Most are positively deflected but some are negatively deflected. Most start with an R wave, but a few start with a Q wave. However, they all share one important feature.

They all have a terminal R wave!

Why?

Ask yourself a question. If the right bundle branch is blocked, which ventricle depolarizes first?

The left ventricle!

So which ventricle depolarizes last?

The right ventricle!

What is the only precordial lead on the right side of the chest?

Lead V1!

A terminal R wave in lead V1 represents late right ventricular depolarization.

The terminal S wave in lead I represents the same thing, because the positive electrode for lead I is on the left shoulder. So, late left-to-right ventricular depolarization moves away from the positive electrode for lead I and toward the positive electrode for lead V1.

Remember when I said that the first step was to establish that you were dealing with a supraventricular rhythm?

The QRS complex in the top row, far right, was cropped from a run of VT (lead MCL-1 which is a surrogate for lead V1). The QRS complex in the bottom row, far right, was also taken from a run of VT.

So, you have a supraventricular rhythm, with wide QRS complexes, and a terminal R wave in lead V1. You're 99% of the way toward calling this a RBBB.

All we have to do now is search lead I for a terminal S wave.

Does lead I show a terminal S wave?

Yes!

ECG diagnosis: Borderline sinus bradycardia with 1°AVB and RBBB, occasional PACs.

See also:

Right bundle branch block - Part II

Right bundle branch block - Part III

Incredible video of soccer player saved by ICD

In this amazing video, 20 year old Belgian soccer player Anthony Van Loo is saved by his implantable cardioverter-defibrillator (ICD).



Are these cool times we live in, or what?

h/t Dr. Wes.