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Inadvertent QRS prolongation by an optimization device-based algorithm in patients with cardiac resynchronization

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The QuickOpt algorithm for cardiac resynchronization therapy (CRT) programming prolongs QRS duration, unlike synchronous pacing. Device algorithms need rigorous pre-clinical testing before clinical use.

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Area of Science:

  • Cardiology
  • Biomedical Engineering
  • Medical Device Technology

Background:

  • Automated optimization of cardiac resynchronization therapy (CRT) using device-based algorithms shows promise.
  • Current clinical adoption of these algorithms lacks standardized pre-clinical and clinical validation.
  • The QuickOpt algorithm's performance for optimizing ventricular-ventricular delay (VVD) requires evaluation against established methods.

Purpose of the Study:

  • To compare the efficacy of the QuickOpt-guided VVD programming against the heuristic of QRS complex shortening in CRT.
  • To assess the impact of QuickOpt-recommended VVD on QRS duration in patients undergoing CRT.

Main Methods:

  • A prospective study involving 37 consecutive patients with CRT across two centers.
  • QRS complex duration (QRSd) was measured manually using electronic calipers during intrinsic conduction, synchronous biventricular pacing, and QuickOpt-guided VVD.
  • Signal-averaged and magnified 12-lead ECGs were used for precise QRSd assessment.

Main Results:

  • Synchronous biventricular pacing significantly shortened native QRSd by 17 ± 27 ms (P = 0.0003).
  • QuickOpt recommended left ventricular preexcitation (VVD of 42 ± 18 ms) in 36/37 patients.
  • QuickOpt-based VVD resulted in significantly longer QRSd (168 ± 25 ms) compared to synchronous pacing (156 ± 20 ms; P <0.00001), correlating with VVD values.

Conclusions:

  • The QuickOpt algorithm systematically promotes left ventricular preexcitation, leading to significant QRSd prolongation.
  • Widening of the QRS complex is physiologically counterproductive for CRT optimization.
  • Device-based CRT optimization algorithms necessitate thorough mechanistic pre-clinical evaluation before large-scale clinical trials.