All of the following features can differentiate between ventricular tachycardia and supraventricular tachycardia except:
Answer is B (Ventricular rate > 160/min) In both ventricular and supraventricular tachycardia the ventricular rate is greater than 100/min, therefore ventricular rate > 160/min cannot be used to differentiate between ventricular & supraventricular tachycardia. Ventricular tachycardia (Broad complex tachycardia) Ventricular rate > 100 bpm QRS duration > 0.12 sec. (>.14 sec.- Harrison)Q Cannot be relieved by carotid sinus massage. Q Supraventricular tachycardia (Narrow complex tachycardia) Ventricular rates > 100 bpm QRS duration < 0.12 sec. Can be relieved by carotid sinus message Q 100 bpm * QRS duration > 0.12 sec. (>.14 sec.- Harrison)Q * Cannot be relieved by carotid sinus massage. Q " align="left" height="74" width="277"> 100 bpm * QRS duration < 0.12 sec. * Can be relieved by carotid sinus message Q " align="left" height="74" width="314"> Other features can be used to distinguish ventricular and supraventricular tachycardia. Variable First hea sound is a features of ventricular tachycardia only. In ventricular tachycardia QRS duration is greater then 0.14 Sec, while in supra ventricular tachycardia it is less than 0.14 Sec. Supraventricular tachycardia can be relieved by carotid sinus massage while ventricular tachycardia cannot.
QRs < 0.14 seconds
Ventricular rate > 160/min
Variable first hea sound
Relieved by carotid sinus massage