Monday, September 19, 2016

Non-Vagal Syncope and Saddleback Morphology in V2

This is another case provided by Mustafa Alwan, an internist from Jordan and very talented ECG enthusiast.  He posted it on Facebook EKG Club, and I am reposting with his permission.

Case
This is a 26 year old male who presented after having had 2 episodes of syncope in 1 day.  Both episodes started with palpitations, then dizziness.  He had no family history of sudden death.    

Vital signs: normal 

Initial ECG :
This is suggestive of Type 2 Brugada morphology because of the Saddleback in lead V2
At first glance, the beta angle looks wide.
 
See this post for a review of Type 2 Brugada.
The method is to draw a line from the peak of the R'-wave down along the downslope of the R'-wave, as shown.  At a point which is 5 mm below the peak, you draw a line across and if the distance to the S-wave is greater than 3.5 mm, it is a wide beta angle.   This is equivalent to a 35 degree angle, or 0.61 radians (calculated as the inverse tangent of 3.5/5, or 0.7).


Dr. Ken Grauer, the ECG master who runs this site: http://ecg-interpretation.blogspot.com/, measured the beta angle here: 

So the beta angle is not wide enough to meet type 2 Brugada morphology criteria


For those wanting more — go to minute 21:19 in Ken's ECG Video on Brugada Syndrome. Here is the link to this specific point in the video — https://youtu.be/h1MhtLMF-7M?t=21m19s 

Type 2 Brugada morphology (in contrast to syndrome) is really quite common, and if you rely on the morphology alone, without the other criteria for syndrome (see below), you will have a lot of false positives.


Diagnosis of Brugada Syndrome requires both:

1. Brugada pattern ECG (either Brugada Type 1, or the newly defined Brugada Type 2 morphology)
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.


This patient only had (c), and no other criteria.

So this ECG did not even meet the criteria for Type 2 Brugada morphology (because the beta angle was too small).  These criteria were developed in a comparison of Brugada syndrome patients with athletes who have an Rsr' saddleback, and they were about 90% sensitive and 90% specific, so they weren't perfect.  

Presumably because this patient had 2 episodes of non-vagal syncope, he was admitted for observation and the admitting cardiologist referred him for Ajmaline challenge test (a sodium channel blocker) in the electrophysiology (EP) lab.

Here is the resulting ECG:
Now there is clearly Brugada morphology.


Commentary

Does this establish Brugada syndrome?  

One cannot clearly state that there is, or is not, Brugada syndrome due to response to Ajmaline or other Na channel blockers.  One can only risk stratify for future arrhythmic events.

The considerations for ICD implantation are far beyond the scope of this article and all such patients should be evaulated by an electrophysiologist.

Not all emergency and primary care physicians, and even some general cardiologists, recognize these important issues:

This paper (full text) discusses the risk of arrhythmia in patients who have spontaneous vs. drug induced (e.g. ajmaline) type 1 morphology.  If the patient only has a history of syncope (like our patient), the risk of future arrhythmic events is 0.6%-1.9%.  If the patient with only drug-induced Brugada morphology is asymptomatic (unlike this patient), the risk of future arrhythmia is extremely low.

They reference this paper which shows that ICD implantation has a high rate of inappropriate shock and that the ICD's record a low annual rate of dysrhythmia.  

Moreover, the authors of this study, (Outcome After Implantation of a Cardioverter-Defibrillator in Patients With Brugada Syndrome) found that the best cutoff for the beta angle is wider than 35 degrees.  It is 58 degrees, which corresponds to a triangle base width of 8 mm (not 3.5 mm!!).

Here are the latest recommendations from this 2014 publication (full text: HRS/EHRA/APHRS Expert Consensus Statement on the Diagnosis and Management of Patients with Inherited Primary Arrhythmia Syndromes): 

Unfortunately, the situation of our patient is not reflected here:
Symptomatic with drug induced Type 1 ECG, but no family history

Here are the full recommendations:
Class I
  • 1.
    The following lifestyle changes are recommended in all patients with diagnosis of BrS:
    • (a)
      Avoidance of drugs that may induce or aggravate ST-segment elevation in right precordial leads (for example, visit Brugadadrugs.org),
    • (b)
      Avoidance of excessive alcohol intake.
    • (c)
      Immediate treatment of fever with antipyretic drugs.
  • 2.
    ICD implantation is recommended in patients with a diagnosis of BrS who:
    • (a)
      Are survivors of a cardiac arrest and/or
    • (b)
      Have documented spontaneous sustained VT with or without syncope.
Class IIa
  • 3.
    ICD implantation can be useful in patients with a spontaneous diagnostic type I ECG who have a history of syncope judged to be likely caused by ventricular arrhythmias.
  • 4.
    Quinidine can be useful in patients with a diagnosis of BrS and history of arrhythmic storms defined as more than two episodes of VT/VF in 24 hours.
  • 5.
    Quinidine can be useful in patients with a diagnosis of BrS:
    • (a)
      Who qualify for an ICD but present a contraindication to the ICD or refuse it and/or
    • (b)
      Have a history of documented supraventricular arrhythmias that require treatment.
  • 6.
    Isoproterenol infusion can be useful in suppressing arrhythmic storms in BrS patients.
Class IIb
  • 7.
    ICD implantation may be considered in patients with a diagnosis of BrS who develop VF during programmed electrical stimulation (inducible patients).
  • 8.
    Quinidine may be considered in asymptomatic patients with a diagnosis of BrS with a spontaneous type 1 ECG.
  • 9.
    Catheter ablation may be considered in patients with a diagnosis of BrS and history of arrhythmic storms or repeated appropriate ICD shocks.
Class III
  • 10.
    ICD implantation is not indicated in asymptomatic BrS patients with a drug-induced type 1 ECG and on the basis of a family history of SCD alone.
     But what about symptomatic patients with drug-induced type 1 ECG??




1 comment:

  1. Steve...

    Very interesting. I read the articles, also. I just have a problem with any recommendation that requires that I be successfully resuscitated from a cardiac arrest caused by a KNOWN entity that I am KNOWN to have and that is KNOWN to cause cardiac arrest before an ICD should be recommended. In this case, it is a fact that around 3% of these people with confirmed Brugada Type 1 are going to arrest. What I really have a problem with is the rather strange assumption that these people are going to be in a place where they can be immediately resuscitated and, even if they are, that the resuscitation attempt will be successful. I really believe there are ethical issues here.

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