R-on-T Run of Non-sustained VT

Report:

Sinus tachycardia 144/min

Ventricular tachycardia 280-305/min, 6-beat run

(Accelerated) junctional escape beats

Comment:

There are 8 ectopic beats. At some stage during the short run, retrograde conduction found its way into the atria and reset the sinus node, stunning it sufficiently for two junctional beats to occur after the VT. The speed of these escape beats reflects the hyperadrenergic state causing the sinus tachycardia and the VT itself in this shocked patient.

The R-on-T onset and the monophasic R morphology (except for the initial qR complex) constitute evidence for the ventricular origin of the run. Its brief duration, too, is more in keeping with non-sustained VT than with atrial flutter with 1:1 conduction + RBBB.

Non-sustained VT rates over 300/min are uncommon, but not rare; at times they resemble ventricular flutter or even VF. Not so in this strip – the QRS-T differentiation is surprisingly well preserved.

The patient’s VT was not treated and he died several days later – from multi-organ failure.

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