Subcutaneous or Transvenous Defibrillator Therapy

To the Editor: We inquire about the adjudication of shocks in the Prospective Randomized Comparison of Subcutaneous and Transvenous Implantable Cardioverter Defibrillator Therapy (PRAETORIAN) trial conducted by Knops and colleagues (Aug. 6 issue). 1 Of the 83 patients in the subcutaneous implantable cardioverter–defibrillator (ICD) group who had shocks labeled as “appropriate,” 11 had shocks for ventricular tachycardia below the cutoff of 180 beats per minute solely because of oversensing of cardiac signals. For example, ventricular tachycardia at a rate of 150 beats per minute could be sensed as 300 beats per minute. Although the device ultimately terminated an arrhythmia in these . . .