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QRS Width: Easily Obtained but Overlooked Parameter in Monitoring Algorithms in Implantable Devices
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  • Arjun K. Aggarwal,
  • Ayana Nanthakumar,
  • Bonnie Daba,
  • Arulalan Veluppillai,
  • Melanie Burg R,
  • Kumaraswamy Nanthakumar
Arjun K. Aggarwal
University Health Network

Corresponding Author:[email protected]

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Ayana Nanthakumar
University Health Network
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Bonnie Daba
University Health Network
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Arulalan Veluppillai
University Health Network
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Melanie Burg R
University Health Network
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Kumaraswamy Nanthakumar
University Health Network
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Abstract

Introduction We describe the progressive increase in the QRS durations (QRSd) and the subsequent decrease in the left ventricular ejection fractions (LVEF) of two patients post pacemaker implantation. We aim to highlight the need for contemporary cardiac implantable electronic devices (CIEDs) to include QRSd monitoring in the standard device data capture. This would ultimately allow for early interventions to be made to prevent chronic heart failure (CHF) hospitalizations. Methods The echocardiographic studies of two patients (pre and post pacemaker implantation) were analyzed, in order to determine changes in QRSd and LVEF data leading up to CHF hospitalization events. Results Patient 1 had a QRSd of 66 msec in June of 2018, one month before pacemaker implantation. Six months after implantation, Patient 1 had an increased QRSd of 156 msec. This was accompanied with a stark decrease in LVEF, from 55% at the time of implantation to below 35% in October of 2020. Patient 2 had a QRSd of 160 msec and a LVEF of 43% prior to the implantation of a pacemaker in 2016. Patient 2 similarly showed a progressive increase in their QRSd and was found to have a significantly decreased LVEF of 17% when hospitalized for decompensated heart failure around 5 years after pacemaker insertion. Conclusion Chronic RV apical pacing can be associated with adverse effects, leading to compromised cardiac function and resulting in pacing-induced cardiomyopathy (PICM). Progressive paced QRS widening can be indicative of CHF development and correlates with a decline in ejection fraction. The addition of device based QRS width monitoring to the current trend toolkit in implantable devices could alert electrophysiologists and patients of the potential for PICM, in the absence of serial 12 lead comparisons. This pre-emptive alert is essential in an era where remedy in the form of cardiac resynchronization and physiological pacing therapy is readily available.