THE CONTEXT
Clinical history, electrocardiographic findings and lack of response to certain interventions can favour ventricular tachycardia.
History and diagnostic findings
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A history of myocardial infarction favours ventricular tachycardia.
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Atrioventricular dissociation and capture or fusion beats are identified as pathognomonic features.
QRS morphology and axis
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Very broad QRS complexes lasting more than 140 milliseconds favour ventricular tachycardia.
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Extreme left or right axis deviation also favours the diagnosis.
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With atrioventricular dissociation, some P waves may be visible while others are buried within QRS complexes.
Response to interventions
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Lack of response to carotid sinus massage or intravenous adenosine favours ventricular tachycardia.