@article{Kyriacou:2018:10.1111/pace.13401,
author = {Kyriacou, A and Rajkumar, CA and Pabari, P and Sohaib, SMA and Willson, K and Peters, N and Lim, P and Kanagaratnam, P and Hughes, A and Mayet, J and Whinnett, Z and Francis, D},
doi = {10.1111/pace.13401},
journal = {Pacing and Clinical Electrophysiology},
pages = {959--966},
title = {Distinct impacts of heart rate and right atrial-pacing on left atrial mechanical activation and optimal AV delay in CRT},
url = {http://dx.doi.org/10.1111/pace.13401},
volume = {41},
year = {2018}
}

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TY  - JOUR
AB  - AbstractBackgroundControversy exists regarding how atrial activation mode and heart rate affect optimal AV delay in cardiac resynchronisation therapy. We studied these questions using highreproducibility haemodynamic and echocardiographic measurements.Methods20 patients were hemodynamically optimized using noninvasive beattobeat blood pressure at rest (62±11 bpm), during exercise (80±6 bpm) and at 3 atriallypaced 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.ResultsDuring atrialsensing, 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 atrialsensed 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).ConclusionsHemodynamic optimal AV delay shortens with elevation of heart rate. It lengthens on switching from atrialsensed to atrialpaced at the same rate, and echocardiography shows this sensedpaced difference in optima results from a sensedpaced difference in atrial electromechanical delay.The reason for the widening of the sensedpaced difference in AV optimum may be physiological stimuli (e.g. adrenergic drive) advancing left atrial contraction during exercise but not with fast atrial pacing.
AU  - Kyriacou,A
AU  - Rajkumar,CA
AU  - Pabari,P
AU  - Sohaib,SMA
AU  - Willson,K
AU  - Peters,N
AU  - Lim,P
AU  - Kanagaratnam,P
AU  - Hughes,A
AU  - Mayet,J
AU  - Whinnett,Z
AU  - Francis,D
DO  - 10.1111/pace.13401
EP  - 966
PY  - 2018///
SN  - 0147-8389
SP  - 959
TI  - Distinct impacts of heart rate and right atrial-pacing on left atrial mechanical activation and optimal AV delay in CRT
T2  - Pacing and Clinical Electrophysiology
UR  - http://dx.doi.org/10.1111/pace.13401
UR  - http://hdl.handle.net/10044/1/60257
VL  - 41
ER  - 

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