02 Sep 2010

Diffuse ST segment elevation and ventricular fibrillation without structural heart disease

a new electrocardiographic presentation of a channelopathy?

Topics: Syncope
Authors: A. Lebreiro , A. Sousa, R. Lopes, S. Oliveira, A. Correia, M. Paiva, I. Rangel, C. Sousa, A. Silva, M.J. Maciel

Clinical Case:

We report the case of a 52 year-old patient, admitted for syncope. During the previous night he had been febrile (38.7ÂºC), with no other complaints. At admission, lab studies were remarkable for a troponin I (TnI) of 0,16 ng/mL, and c-reactive protein (CRP) of 61mg/L.

The ECG showed marked ST segment elevation in leads V1-6. (Fig.1) It was performed an emergent cardiac catheterization and before the procedure, episodes of non sustained ventricular tachycardia (VT) were registered and followed by fast and polymorphic VT that degenerated in ventricular fibrillation (VF), rapidly reverted with a shock of 150J.
Angiography showed normal coronary arteries, the patient was apyretic, and the ECG repeated immediately after catheterization was similar to the previously described. The transthoracic echocardiogram was normal. During the first 12h of hospital staying the patient had an episode of fever (38ÂºC) without associated electric instability or ECG's modifications.

click to enlarge

Serial biochemical studies evidenced an increased TnI (maximum of 11.7 ng/mL, at 36h) and CRP (maximum of 96mg/L, at 24h); microbiologic studies were negative. A cardiac magnetic resonance (CMR) was carried out at 5th day, and showed no abnormalities (including no late gadolinium enhancement). Serial ECGs demonstrated dynamic changes, with some features suggestive of Brugada pattern.

A provocative test with flecainide was then performed and although the ST changes became more accentuated, an electrocardiographic conversion to a type 1 Brugada pattern didn't occurred. (Fig.2) There was no further recurrence of fever or electric instability.

click to enlarge

Values of TnI and CRP gradually returned to normal without specific interventions. Genotypic screens for SCN5A mutations were negative. In the context of VF without underlying reversible causes or structural heart disease, an automated defibrillator was implanted prior to discharge. Two months after discharge, the patient remained asymptomatic. There was no family history of sudden cardiac death or syncope. The patient's brother, a healthy 47 year-old man, had an electrocardiographic type 2 Brugada pattern and the provocative test with flecainide turned out negative. This case emphasizes the diagnostic difficulties posed by an atypical ECG with diffuse precordial ST segment elevation in face of a structurally normal heart and at the same time points out the need of keeping in mind the diagnosis of electric syndromes in similar cases, since it can completely modify clinical management, namely through the decision of implanting a cardioverter defibrillator. Conclusion
Even though, one can suspect that myocarditis could cause this clinical scenario, we feel that this is unlikely in face of such a potentially lethal clinical presentation and simultaneously, the absence of any cardiac structural or functional anomaly.
Given the findings depicted, an endomyocardial biopsy, which is known to have low sensitivity for the diagnosis of myocarditis and inherent risks, was not performed. In fact it's not possible to establish a definitive etiologic diagnosis, but the exuberant and dynamic features seen on our patient's ECG in the absence of structural cardiac disease or any identifiable precipitating factor, its association with a febrile illness (although VF did not occur during fever) and the presence of a Brugada type 2 ECG in a first degree relative, may point to a genetic aetiology of the condition.

Notes to editor
Submited by Ana Lebreiro (Porto /Portugal), Alexandra Sousa (Porto /Portugal), Ricardo Lopes (Porto /Portugal), Sílvia Oliveira (Porto /Portugal) and Ana Correia (Porto /Portugal), Mariana Paiva (Porto /Portugal), Inês Rangel (Porto /Portugal), Carla Sousa(Porto /Portugal), Anabela Silva (Porto /Portugal), and M.Júlia Maciel.

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.