This 56-year-old woman with idiopathic cardiomyopathy presents to the cardiac outpatient clinic for reassessment. Her condition is stable, and she is failure-free:

• Sinus rhythm, ventricular rate 79/min
• Competing accelerated idioventricular rhythm with retrograde atrial conduction

Comment: The T waves following the sinus-originated complexes are negative in II, III and V4-V6. This is a non-specific finding in this patient with idiopathic cardiomypathy: