A 79-year-old man with known ischemic cardiomyopathy has sudden onset of palpitation and severe dyspnea:

• Ventricular tachycardia, 170/min

Strongly favouring the diagnosis of ventricular tachycardia:

• The clinical history (sudden onset of wide QRS tachycardia and severe symptoms in a patient with ischemic cardiomyopathy)
• The very wide QRS complex (188 msec)
• The positive concordance in the chest leads (positive QRS complex from V1 to V6)

The patient underwent successful DC cardioversion:

• Sinus rhythm, 78/min,  with sinus arrhythmia
• Nonspecific T wave abnormality
• Prolonged QT