A wide-complex tachycardia in a stable patient; which feature helps differentiate VT from SVT with aberrancy?

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Multiple Choice

A wide-complex tachycardia in a stable patient; which feature helps differentiate VT from SVT with aberrancy?

In a wide-complex tachycardia, telling VT apart from SVT with aberrancy hinges on clues that point to a ventricular origin rather than supraventricular conduction with abnormal pathways. AV dissociation is a powerful sign: the atria and ventricles beat independently, so you’ll see P waves marching at a different rate than the QRS complexes. That separation strongly suggests the rhythm is driven from the ventricles. Capture or fusion beats are also highly specific for VT. A capture beat occurs when an atrial impulse briefly conduces to the ventricle and produces a normal-looking QRS, while a fusion beat is a hybrid QRS morphology created by simultaneous supraventricular and ventricular activation. Neither phenomenon typically occurs with SVT with aberrancy, where the ventricular rhythm is driven by the atrial impulse through the usual conduction system. The presence of a wide QRS complex is common in VT, but width alone isn’t diagnostic. It’s the combination with AV dissociation or capture/fusion beats that makes VT the most likely diagnosis. The other features listed—regular narrow QRS tachycardia, short PR interval, or P waves hidden in QRS—don’t provide as strong or specific a distinction in this scenario.

In a wide-complex tachycardia, telling VT apart from SVT with aberrancy hinges on clues that point to a ventricular origin rather than supraventricular conduction with abnormal pathways. AV dissociation is a powerful sign: the atria and ventricles beat independently, so you’ll see P waves marching at a different rate than the QRS complexes. That separation strongly suggests the rhythm is driven from the ventricles.

Capture or fusion beats are also highly specific for VT. A capture beat occurs when an atrial impulse briefly conduces to the ventricle and produces a normal-looking QRS, while a fusion beat is a hybrid QRS morphology created by simultaneous supraventricular and ventricular activation. Neither phenomenon typically occurs with SVT with aberrancy, where the ventricular rhythm is driven by the atrial impulse through the usual conduction system.

The presence of a wide QRS complex is common in VT, but width alone isn’t diagnostic. It’s the combination with AV dissociation or capture/fusion beats that makes VT the most likely diagnosis. The other features listed—regular narrow QRS tachycardia, short PR interval, or P waves hidden in QRS—don’t provide as strong or specific a distinction in this scenario.

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