Wednesday, March 16, 2016

Chest Tightness and Asthma in a Young Man

A male in his 20's presented with chest tightness and dyspnea.  He had wheezing.  An ECG was recorded:
There is sinus bradycardia.  There is an rsr' in V1 and normal T-wave inversion.  There is also a subtle Rsr' in V2, with some ST elevation and a bit of a saddleback.
Saddlebacks are rarely ischemia.
Are you worried about this ECG?

There is no suggestion of ischemia.
However, the r' in V1 is wider than normal.  There is a saddleback in V2.
These two features suggest type 2 Brugada pattern.

This is NOT type 1 Brugada pattern (which is far more likely to actually represent Brugada syndrome) because the wide r'-wave returns to the baseline, then flattens out before having an inverted T-wave.  Here is a more typical type 1 Brugada.

The wide beta angle makes type 2 Brugada pattern much more likely.

Here is the way the beta angle is measured; this image is from this consensus paper, annotated by me:
1. Draw a horizontal line from top of r' wave (black line 1)
2. Draw a horizontal line 5 mm below this (green line 2)
3. Extend the downsloping r'-ST segment (black line 3) until it intersects the green line
4. Measure the base.  

If greater than 3.5 mm, then meets criteria (this is equivalent to a 35 degree beta angle)

Here I apply this to this case:
Obviously, the beta angle is very wide
The bottom horizontal line is 15 mm and it need only be 3.5 mm.

Criteria for Type 2 Brugada:

In this consensus paper, types 2 and 3 Brugada have been merged into one type called type 2. They specify the criteria to be used (below).

First, there must be:
a) An RSr' with a typical saddleback pattern in V1 and/or V2.  This case meets this.
b) V1 may have either an upright, flat, or inverted T-wave.  It is upright here.
c) T-wave in V2 is usually but not always positive.  It is positive here.
d) Minimum ST segment ascent of 0.5 mm.  There could be no saddle without an ascent.  It is 1.5 mm here.

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 greater than 2 mm).   The r'-wave is thus not distinct, as it is in benign causes of rSr'.  It is exactly 2 mm here.

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.  Here is it 130 ms in lead V1 and 90 ms in lead V6

3. The base of the triangle outlined should be longer than 3.5 mm.  This confirms that the slope of the ST segment is flat enough for the diagnosis.  This is clearly the case here.

4. As with Type 1, the peak of the r'-wave comes slightly before the J-point in other leads.  The J-point is at the end of the J-wave.  See explanation and figure below:

Jani Tikkanen, who does a lot of research on early repolarization, says that "I personally do not like the term "J-point" when discussing J waves (or haissaguerre pattern etc), as people really get confused with terms and points. I'd still say that the J-point is when it hits the baseline, but J wave amplitude should be measured from the highest point, usually in the middle of the J-wave.

This diagram by my EKG colleague and friend, Ken Grauer, shows the peak of the J-wave.  The end of the J-wave is slightly farther right.

So, as I interpret Jani's statement, the J-point would be at the end of the J-wave, which would be farther to the right than these lines are drawn.  The peak of the r'-wave does indeed come slightly before the J-point.    

So, this ECG does seem to meet this criterion.

So this ECG meets all criteria for type 2 Brugada pattern (morphology).

You can read all about type 2 Brugada at this article:

Case continued

The clinicians were looking for ischemia and correctly interpreted the ECG as non-ischemic.  He was discharged with treatment for asthma.  But there was no comment on the possible Brugada morphology.

At a later date he presented to another hospital with syncope.  He was admitted and had multiple episodes of syncope, especially associated with emotion.  None were recorded on cardiac monitor, but in at least some of the cases, he was found to be bradycardic down to the 30's afterward.  Further history revealed that he father had sudden cardiac death at a young age, as did a younger sibling.  He was also taking a prescription cough medication which can prolong the QTc and increase the risk of dysrhythmias related to Brugada syndrome.  After a nondiagnostic EP study, a loop recorded was implanted for further diagnostic clarity.  Cardiac MRI ruled out RV dysplasia.  An echocardiogram was normal.

As far as I can tell, he did later get an implanted cardioverter-defibrillator.  Exactly what tipped the electrophysiologist over the edge to implant it is unclear, but must have been a recording from the implanted loop recorder.

He presented again with syncope which sounded vasovagal, and his ICD was interrogated but did not reveal any dysrhythmia.

Here was his ECG at that visit:

Learning Points:

1. If you see an ECG that looks like type 2 Brugada, take a good history of syncope and ask about a family history of sudden death.

2. Refer the patient to an electrophysiologist if there is h/o syncope or family history of sudden death.

3. In my opinion, there is no need to admit unless the patient presents with syncope.

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