Response to cardiac resynchronization therapy is determined by intrinsic electrical substrate rather than by its modification

Marc Strik*, Sylvain Ploux, Peter R. Huntjens, Uyen Chau Nguyen, Antionio Frontera, Romain Eschalier, Remi Dubois, Philippe Ritter, Nicholas Klotz, Kevin Vernooy, Michel Haissaguerre, Harry J. G. M. Crijns, Frits W. Prinzen, Pierre Bordachar

*Corresponding author for this work

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Abstract

Background: Electrocardiographic mapping (ECM) expresses electrical substrate through magnitude and direction of the activation delay vector (ADV). We investigated to what extent the response to cardiac resynchronization therapy (CRT) is determined by baseline ADV and by ADV modification through CRT and optimization of left ventricular (LV) pacing site. Methods: ECM was performed in 79 heart failure patients (4 RBBB, 12 QRS <120 ms, 23 non-specific conduction delay [NICD] and 40 left bundle branch block [LBBB]). 67 patients (QRS >= 120 ms) underwent CRT implantation and in 26 patients multiple LV pacing site optimization was performed. ADV was calculated from locations/depolarization times of 2000 virtual epicardial electrodes derived from ECM. Acute response was defined as >= 10% LVdP/dt(max) increase, chronic response by composite clinical score at 6 months. Results: During intrinsic conduction, ADV direction was similar in patients with QRS < 120 ms, NICD and LBBB, pointing towards the LV free wall, while ADV magnitude was larger in LBBB (117 +/- 25 ms) than in NICD (70 +/- 29 ms, P < 0.05) and QRS < 120 ms (52 +/- 14 ms, P < 0.05). Intrinsic ADV accurately predicted the acute (AUC = 0.93) and chronic (AUC = 0.90) response to CRT. ADV change by CRT only moderately predicted response (highest AUC = 0.76). LV pacing site optimization had limited effects: +3 +/- 4% LVdP/dt(max) when compared to conventional basolateral LV pacing. Conclusion: The baseline electrical substrate, adequately measured by ADV amplitude, strongly determines acute and chronic CRT response, while the extent of its modification by conventional CRT or by varying LV pacing sites has limited effects. (c) 2018 Elsevier B.V. All rights reserved.
Original languageEnglish
Pages (from-to)143-148
Number of pages6
JournalInternational Journal of Cardiology
Volume270
DOIs
Publication statusPublished - 1 Nov 2018

Keywords

  • Left bundle branch block
  • Cardiac resynchronization therapy
  • Cardiac resynchronization
  • Cardiac mapping
  • Heart failure
  • DYSSYNCHRONOUS CANINE HEART
  • VENTRICULAR PACING SITES
  • PATIENT SELECTION
  • FAILURE PATIENTS
  • TRIAL
  • NONRESPONDERS
  • IMPROVEMENT
  • CONDUCTION

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