Sunday, August 7, 2011

Young man with syncope while riding a bike [Arrhythmogenic Right Ventricular Dysplasia (ARVD)]

This 31 yo who is otherwise healthy had sudden syncope while riding a bike.  He remembers looking down, then becoming dizzy, then waking up on the ground with his feet still attached to the pedals.  He thought he was unconscious by himself for 45 minutes (!).  Then he awoke and called 911.   He had no prodromal vasovagal symptoms such as flushing, nausea, or diaphoresis. 

He had a several year history of palpitations without syncope, but had one presyncopal epsisode one month prior.  He had been seen by a local cardiologist 3 years prior and had what is described in records as a normal ECG and normal Echo, and had been encouraged to resume exercise.

Here is his presenting ECG in the ED:
Sinus rhythm with some artifact.  QTc may be slightly prolonged; I eyeball it at about 470ms.  This is not long enough to be dangerous.

His symptoms are very alarming.  There are 2 features which are high risk: no prodrome other than dizziness, and onset with exertion.  When a young person who is otherwise healthy presents with high risk syncope, a normal exam, and NSR, it is essential to obtain an ECG not only to look for ischemia, blocks such as LBBB and RBBB, but also for inherited disorders that cause dysrhythmia.  There are 5 that I think of: WPW, HOCM, Brugada, long QT, and Arrhythmogenic Right Ventricular Dysplasia (ARVD), which is a disorder of fatty infiltration of the RV that causes sometimes lethal ventricular tachycardia originating from the RV.  ARVD is quite rare, not often thought of, and very difficult to recognize on the ECG. 

Alas, this young man's presenting ECG shows none of these.

Surprisingly, the first troponin returned at 3.44 ng/ml, the second at 7.48.  Clinicians thought they were dealing with a dysrhythmia due to ACS/NSTEMI, and started heparin and aspirin.  He was admitted to the hospital.

An echo revealed segmental hypokinesis of the apex of the right ventricle only. The contour at this portion of the RV free wall was also unusual, and raised suspicion for ARVD.

MRI of the heart was done; here is the final report:

There is focal dyskinesia involving the RV apex and the anterior wall. On the T2-weighted sequence, there is linear increased signal in the RV myocardium suggesting fatty infiltration. There is no definite delayed enhancement in this area. These findings are suspicious for arrhythmogenic right ventricular dysplasia.

Coronary cath was normal.  Troponins trended down. 

Here is another ECG from 3 days later: 
Now there is abnormal T-wave inversion in III, aVF, and V2.  So the patient only has minor criteria by ECG, and only on the followup ECG (see below).
Case Conclusion:
He had an EP study that induced VT at a rate of 252.  Here is the induced VT:
VT at a rate of 252 bpm.  Short QRS for VT (116 ms).  Not a typical LBBB morphology, but induced VT in ARVD need not be of LBBB morphology.
 
A heart rate like this would stress the heart and lead to troponin release.
An implantable cardioverter defibrillator was placed.


ARVD, also known as arrhythmogenic RV cardiomyopathy, is estimated to have a prevalence of 1 in 5000 adults and is responsible for approximately 11% of sudden death in young adults and 22% in a study of athletes in northern Italy.  The diagnosis is not easy (see below).

Gemayel C, Pelliccia A, Thompson PD.  Arrhythmogenic right ventricular cardiomyopathy.  J Am Coll Cardiol. 2001;38(7):1773.  Full text: http://content.onlinejacc.org/cgi/reprint/38/7/1773.pdf
There is a 2010 publication by the Task Force in Diagnosis of ARVD: Diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia: proposed modification of the task force criteria. 

There are 6 categories of criteria
1) Imaging
2) Pathologic
3) ECG Repolarization
4) ECG Depolarization
5) Arrhythmias
6) Family History.  

ECG and historical Highlights of this publication are (Suspect ARVD with):
1) High risk syncope with no other etiology; Family History
2) Depolarization abnormalities (Major criteria):
        a) Epsilon Waves
        b) Localized prolongation (greater than 110 ms) of the QRS complex in right precordial leads (V1-V3)
3) Repolarization abnormalities in patients of age at least 14 years (because younger patients often have juvenile T-waves)
        a) Minor: Inverted T-waves in right precordial leads V1-V2 
        b) Major: Inverted T-waves in right precordial leads V1-V3 or beyond (major criteria) 
4) Arrhythmias
        a) Major criterion:
                i) VT of LBBB morphology with superior axis (negative or indeterminate QRS in leads II, III, aVF and positive in lead aVL) (major criteria)
        b) Minor criteria:
                i) VT of LBBB morphology with inferior axis (positive QRS in leads II, III, aVF and negative in lead aVL) (minor criteria)
                ii) More than 500 PVCs per hour
5) Finally, it is a progressive disease and patients without ECG abnormalities may develop them over time.



Here is an example of an epsilon wave (image C).  And another example.  Here are some great examples from the post on RV dysplasia (translated by Google translate!) on Pierre Taboulet's great French site#1, #2, #3

Here's a great example on Wave Maven.

Here is an explanation od the importance of leads V1 and V2.

Here is another nice example.  I've taken the liberty of blowing up part of the ECG at this link for better viewing.  Look closely at V1-V2:
There are Epsilon waves (small waves at the end of the QRS) and also a slight prolongation of the QRS at the very end. 

7 comments:

  1. I was very interested in the relatively normal initial ECG given the eventual diagnosis of ARVD! His second ECG definitely looks pathologic though.

    Why the gross change? Was it the ischemic insult to the RV?

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  2. No good answer to that, Christopher.

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  3. Now that the VT has been posted, I'd always thought RVOT-VT was the common VT associated with ARVD. This VT appears to be based in the LV! Do you know where they induced this VT from?

    Very interesting case!

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  4. I do not know. Wasn't in the chart.

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  5. Thank you very much for posting this very interesting case.

    So according to the revised task force criteria for the diagnosis of ARVC, in this patient there a minor criterion for T-wave inversion in V1 and V2 (However that was a dynamic change since in his first ECG there was only TWI in V1). Considering that the patient fulfilled the dimension criteria in addition to the dyskinesia of the RV apex he could also have another minor criterion (or Major depending on the dimensions of the RV). Induced VT during the EP study is not a criterion. So, overall, this patient does not fullfil the diagnostic criteria to be diagnosed with ARVC.

    However, it would be of great value to have a 24 hour Holter monitoring test to see if he has any VES (he could also get another minor criterion from there) and also a signal averaged ECG to look for late potentials (which would contribute as another minor criterion).

    In this case we should also consider myocarditis as a possible diagnosis and would have to exclude during follow up.

    Of note fat seen on MRI in the RV seems to be of no importance, in contrast to delayed enhancement imaging which could be of great value in this disease.

    Additionally, the troponin rise has been documented in some cases of ARVC (http://www.ncbi.nlm.nih.gov/pubmed/21962611)

    Finally, keep in mind that this not always a RV disease, but in many cases there is LV involvement and in some other cases this is a Left-Dominant Disease, and that is the reason that recently its tending to be called ACM (Arrhythmogenic Cardiomyopathy) (http://www.ncbi.nlm.nih.gov/pubmed/19095136, http://www.ncbi.nlm.nih.gov/pubmed/22476658)

    keep up the great work!

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