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Distinct impacts of heart rate and right atrial-pacing on left atrial mechanical activation and optimal AV delay in CRT

Kyriacou, A; Rajkumar, CA; Pabari, PA; Sohaib, SA; Willson, K; Peters, NS; Lim, PB; ... Francis, DP; + view all (2018) Distinct impacts of heart rate and right atrial-pacing on left atrial mechanical activation and optimal AV delay in CRT. Pacing and Clinical Electrophysiology , 41 (8) pp. 959-966. 10.1111/pace.13401. Green open access

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Abstract

BACKGROUND: Controversy exists regarding how atrial activation mode and heart rate affect optimal AV delay in cardiac resynchronisation therapy. We studied these questions using high-reproducibility haemodynamic and echocardiographic measurements. METHODS: 20 patients were hemodynamically optimized using non-invasive beat-to-beat blood pressure at rest (62±11 bpm), during exercise (80±6 bpm) and at 3 atrially-paced rates: 5, 25 and 45 bpm above rest, denoted Apaced,r+5 , Apaced,r+25 and Apaced,r+45 respectively. Left atrial myocardial motion and transmitral flow were timed echocardiographically. RESULTS: During atrial-sensing, raising heart rate shortened optimal AV delay by 25±6 ms (p < 0.001). During atrial pacing, raising heart rate from Apaced,r+5 to Apaced,r+25 shortened it by 16±6 ms; Apaced,r+45 shortened it 17±6 ms further (p < 0.001). In comparison to atrial-sensed activation, atrial pacing lengthened optimal AV delay by 76±6 ms (p < 0.0001) at rest, and at ∼20 bpm faster, by 85±7 ms (p < 0.0001), 9±4 ms more (p = 0.017). Mechanically, atrial pacing delayed left atrial contraction by 63±5 ms at rest and by 73±5 ms (i.e. by 10±5 ms more, p < 0.05) at ∼20 bpm faster. Raising atrial rate by exercise advanced left atrial contraction by 7±2 ms (p = 0.001). Raising it by atrial pacing did not (p = 0.2). CONCLUSIONS: Hemodynamic optimal AV delay shortens with elevation of heart rate. It lengthens on switching from atrial-sensed to atrial-paced at the same rate, and echocardiography shows this sensed-paced difference in optima results from a sensed-paced difference in atrial electromechanical delay. The reason for the widening of the sensed-paced difference in AV optimum may be physiological stimuli (e.g. adrenergic drive) advancing left atrial contraction during exercise but not with fast atrial pacing.

Type: Article
Title: Distinct impacts of heart rate and right atrial-pacing on left atrial mechanical activation and optimal AV delay in CRT
Location: United States
Open access status: An open access version is available from UCL Discovery
DOI: 10.1111/pace.13401
Publisher version: http://doi.org/10.1111/pace.13401
Language: English
Additional information: Copyright © 2018 The Authors. Pacing and Clinical Electrophysiology published by Wiley Periodicals, Inc. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Keywords: atrioventricular delay, cardiac resynchronisation therapy, electrophysiology-clinical, heart failure, optimization
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Cardiovascular Science
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Cardiovascular Science > Population Science and Experimental Medicine
URI: https://discovery.ucl.ac.uk/id/eprint/10049963
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