Wednesday, August 10, 2016

A Patient with Syncope

A young man had sudden syncope without a prodrome, after which he was aysmptomatic.  He presented to an ED and had this ECG recorded:
What do you see?

















There is an abnormal rSr' in V1, with the r'-wave not falling quickly back to baseline.  The T-wave is inverted, but this is also a normal finding in V1.  The whole morphology is suggestive of Brugada morphology, but by no means "diagnostic" because the r'-wave is not 2 mm.

Here are the criteria for ECG Brugada morphology.  This comes from the paper entitled (with full text link): Current electrocardiographic criteria for diagnosis of Brugada pattern: a consensus report

Criteria for Type 1 Morphology:
1. R'-wave at least 2 mm in V1 or V2
2. But no distinct R'-wave because the ST segment takes off at an angle from the peak
3. The ST segment is convex upward ("coved"). [They use terminology of "concave downward"]
4. The peak at the high takeoff does not correspond with the J-point.  It is BEFORE the J-point, as measured in other leads (such as lead II across the bottom).
5. Gradual downsloping of ST segment such that at 40 ms after the takeoff, the decrease in amplitude is less than 4 mm.  In normal RBBB, the decrease in amplitude is much greater (see this example).
6. ST is followed by a symmetrically negative T-wave
7. "The duration of QRS is longer than in RBBB," and "there is a mismatch between V1 and V6." This criterion is perplexing and not well explained.
8. The downsloping should be such that the Corrado index is greater than 1.0.
This is the ratio: [ST elevation at the J-point] divided by [ST elevation at 80 ms after the J-point]. 



Diagnosis of Brugada Syndrome requires both:

1. Brugada pattern ECG (either Brugada Type 1, or the newly defined Brugada Type 2)
Findings may be dynamic and are sometimes concealed; findings may be observed only in certain circumstances such as fever, intoxication, electrolyte imbalance, presence of sodium channel medications/drugs, or vagal stimulation.
2. At least one of the following:
(a) survivor of cardiac arrest,
(b) witnessed/recorded polymorphic ventricular tachycardia (VT),
(c) history of nonvagal syncope,
(d) familial antecedents of sudden death in patients younger than 45 years without acute coronary
syndrome
(e) Type 1 Brugada pattern in relatives.


Criteria for Type 2 Brugada morphology:
First, there must be:
a) An RSr' with a typical saddleback pattern in V1 and/or V2. 
b) V1 may have either an upright, flat, or inverted T-wave (in our case above it is inverted).
c) T-wave in V2 is usually but not always positive.
d) Minimum ST segment ascent of 0.5 mm.  There could be no saddle without an ascent.
Once these are fulfilled, there should be, in lead V2:
1.  High take-off of the descending limb of the r' at least 2 mm above the isoelectric line (in our case, it is less than 2 mm, so this does not meet criteria for Type 2 Brugada).   The r'-wave is thus not distinct, as it is in benign causes of rSr'
2.  Mismatch between QRS duration in leads V1 and V6 (longer in lead V1).  This helps to distinguish from RBBB, in which the QRS duration is equal in V1 and V6.
3. As with Type 1, the peak of the r'-wave does not correspond to the J-point in other leads.
4. A large Beta angle.  Go to this post to learn about the beta angle.




So this ECG cannot be said to fulfill the criteria for either type 1 or type 2 Brugada, but it is suggestive, and the patient had non-vagal syncope.

Case continued: 
The patient presented with syncope and fever 3 years later.  Here is the ECG:
Now the ECG, in the presence of fever, is diagnostic of Brugada morphology



The patient underwent an EP study and had a ICD implanted.

Learning Point:

The patient and doctor dodged a bullet here.  He could have died in the intervening 3 years.  This sort of cardiac syncope is death that terminates with awakening.

The first ECG is nonspecific but suggestive of Brugada, and in the context of non-vagal syncope the patient should at least get early referral to a cardiologist, preferably an electrophysiologist, for EP testing or for challenge with a sodium channel blocker.

Read more about Type 1 and Type 2 Brugada syndrome here:

Is this Type 2 Brugada syndrome/ECG pattern?


Here are many articles on Fever unmasking Brugada syndrome:

https://scholar.google.com/scholar?hl=en&q=brugada+fever&btnG=&as_sdt=1%2C24&as_sdtp=



9 comments:

  1. That first ECG offers a nice way of comparing a normal and abnormal rSr' with aVR and V1 side-by-side. aVR has a distinct, narrow r' wave, which would be normal to see in V1, but the actual r' in V1 is indistinct with a wide beta angle(as you note).

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  2. Subtle but important case in which this ECG is NOT “normal”. The finding of an rSr’ in lead V1 and/or V2 is common in otherwise healthy young adults. Although some such individuals may have incomplete RBBB — in many, there is no conduction defect, but simply relative delay in terminal RV depolarization that produces a terminal r’ in right-sided lead V1. That said, there are 2 important difference between these common normal variants and the initial tracing in this case: i) This young patient presented with non-vagal syncope (and on close questioning also had an episode of non-vagal syncope 3 years earlier!); and ii) The r’ deflection, even though tiny — has a surprisingly wide angle (ß-angle), whereas with normal variants the r’ (which may be sometimes be taller than that seen here) has a very steep decline from its peak. Comparison with the prior ECG turned out to be diagnostic. It is indeed lucky that the patient did not have a lethal episode during the 3 years since his initial episode.

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  3. First thing i saw was the ST elevation in V2. With history of syncope, isn't that at least suggestive of type 2? But three years later in fever the ecg shows type I? So can it be, that the changes in V2 in the first ecg don't have anything to do underlying brugada syndrome

    ReplyDelete
    Replies
    1. Types I and II are only ECG morphologies. But the syndrome is one with a few genetic variants.

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  4. Agree ajmaline would have been good the first time around.

    However given 2nd non-vagal syncope with clear Brugada pattern the 2nd time, how did the EP study change management? Surely an ICD was indicated regardless?

    ReplyDelete
    Replies
    1. There is a lot of judgment in these cases. Nothing is entirely straightforward.

      Delete
    2. I appreciate the judgement call but I'm trying to get at what in the EPS would have persuaded the clinician to *not* implant an ICD? Or was there something that convinced them to do so when they otherwise were not going to?

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  5. Alan,
    I don't know enough about this specific case to really comment or criticize the management.
    Steve

    ReplyDelete
    Replies
    1. OK thanks, definitely not trying to criticise, was just interested :)

      Delete

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