Which feature is most characteristic of a wide complex tachycardia that supports VT diagnosis?

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Multiple Choice

Which feature is most characteristic of a wide complex tachycardia that supports VT diagnosis?

Captures and fusions are tells for ventricular tachycardia. A capture beat happens when a sinus or atrial impulse momentarily conducts to the ventricles during VT, producing a normal-looking QRS on that beat despite ongoing VT. A fusion beat occurs when a ventricular beat from the VT and a conduction from the atria mix, giving a hybrid QRS morphology. These patterns reflect that the ventricles are being activated by a separate ventricular focus, with intermittent intact atrial conduction, which is characteristic of VT. In SVT with aberrant conduction, you don’t typically see clear capture or fusion beats because the wide QRSs are due to slowed conduction through an abnormal pathway, not simultaneous ventricular pacing by two different wavefronts. Other statements aren’t reliable: P waves preceding QRS aren’t required in VT (AV dissociation can occur), and the PR interval isn’t a defining feature of VT. There are reliable clues distinguishing VT from SVT, with capture or fusion beats being a strong one.

Captures and fusions are tells for ventricular tachycardia. A capture beat happens when a sinus or atrial impulse momentarily conducts to the ventricles during VT, producing a normal-looking QRS on that beat despite ongoing VT. A fusion beat occurs when a ventricular beat from the VT and a conduction from the atria mix, giving a hybrid QRS morphology. These patterns reflect that the ventricles are being activated by a separate ventricular focus, with intermittent intact atrial conduction, which is characteristic of VT.

In SVT with aberrant conduction, you don’t typically see clear capture or fusion beats because the wide QRSs are due to slowed conduction through an abnormal pathway, not simultaneous ventricular pacing by two different wavefronts. Other statements aren’t reliable: P waves preceding QRS aren’t required in VT (AV dissociation can occur), and the PR interval isn’t a defining feature of VT. There are reliable clues distinguishing VT from SVT, with capture or fusion beats being a strong one.

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