Dual-chamber discrimination and discrimination error due to inappropriate programming of the correlation percentage

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Patient

• 79-year-old male with ischemic cardiomyopathy implanted with a Resonate triple-chamber defibrillator

Summary 1

• tachycardia episode with atrial rate equal to the ventricular frequency (V>A: False)
• initially, Rhythm ID correlation: True; inhibition of therapies
• in a second step, Rhythm ID: False; AF: true + stable rhythm (threshold value programmed at 20 ms)
• a burst of ATP is delivered

Trace 1 EGM

1. onset of regular 1/1 tachycardia; first rapid cycle originates in the atrium
2. after 8 consecutive VT or VF cycles, V-Epsd marker; ventricular complexes are correlated
3. end of duration; for the device, the rhythm is stable with a diagnosis of AF; therapies not delivered because RID+ (at least 3 correlated ventricular complexes out of 10).
4. cycle-by-cycle discrimination continues, still with RID+.
5. RID- (less than 3 correlated cycles out of the last 10); stable rhythm with diagnosis of AF: suspicion of dual tachycardia and a burst of ATP is delivered
6. arrhythmia termination