Tag Archives: cardiac device

Introduction T-wave oversensing (TWOS) is a well-recognised phenomenon encountered in cardiac implantable electronic devices (CIEDs), particularly in high-energy platforms.1 TWOS occurs when the ventricular repolarisation signal, corresponding to the surface ECG T-wave, is mistakenly identified as a de novo depolarisation by the device. The principal effect of this is to ‘double count’ the heart rate. This may lead the device to mistakenly register a ventricular rate high enough to reach the threshold for detection of a tachycardic episode, which may in turn precipitate the CIED to inappropriately discharge. TWOS may be seen for a number