An ECG of an elderly lady who collapsed in the emergency department shows rapid ventricular rate of 220bpm, QRS 140ms. What is the most probable diagnosis?

The key is B. Ventricular tachycardia. [To diagnose ventricular tachycardia we consider: i) history (if

IHD/MI likelihood of a ventricular arrhythmia is > 95%), ii) 12 lead ECG, and iii) lack of response to IV

adenosine). ECG findings in favour of VT:

• Positive QRS concordance in chest leads

• Marked left axis deviation

• AV dissociation (occurs in 25%) or 2:1 or 3:1 AV block

• Fusion beats or capture beats

OHCM 9th edition, page 816]. [In the given case collapse, ventricular rate of 220 and broad QRS

of 140ms ( The normal duration of the QRS complex is between 80 and 100 milliseconds) points towards VT].