Atrioventricular reentrant tachycardia inducing ventricular fibrillation.

I just read a paper published in the latest issue of the Journal entitled ‘A novel mechanism of sudden infant death syndrome during atrioventricular reentrant tachycardia: a case report’ by Dr Mori and coworkers.[1]

Although the diagnosis of atrioventricular reentrant tachycardia (AVRT) at a cycle length of 232 ms has been assumed for explaining the regular narrow QRS tachycardia present on all electrocardiogram tracings available, the authors did not provide the electrophysiologic confirmation of this mechanism. However, they wrote that ventricular fibrillation occurred after 12 min of tachycardia while the rate remained unchanged. Did they have the chance to record any atrial activity during this period of time that could have supported the AVRT mechanism?

It would also be of interest to know if there was any relation between the occurrence of tachycardia and the anaesthesia the baby received or the introduction of the catheters; in addition, what was the patient’s haemodynamic tolerance during the 12 min of tachycardia before ventricular fibrillation occurred?

Finally, was a congenital coronary anomaly ruled out? Was genetic testing considered?

In summary, as reported by others,[2-6] this case confirms that supraventricular tachycardia may exceptionally have a potentially lethal outcome. In addition, in patients with AVRT and manifest WPW syndrome, ventricular fibrillation may develop regardless the antegrade properties of the accessory pathway.