Left ventricular performance during triggered left ventricular pacing in patients with cardiac resynchronization therapy and left bundle branch block.
OBJECTIVE
To assess the acute effect of triggered left ventricular pacing (tLVp) on left ventricular performance and contraction pattern in patients with heart failure, left bundle branch block (LBBB), and cardiac resynchronization therapy (CRT).


METHODS
Twenty-three patients with pre-implant QRS complex >150 ms, QRS complex narrowing under CRT, and sinus rhythm were included ≥3 months after CRT implantation. Echocardiographic assessment of left ventricular ejection fraction (LVEF), global peak systolic longitudinal strain (GLS), and contraction pattern by 2D strain was performed during intrinsic conduction, tLVp, and BiV pacing and compared as paired data. Echocardiographic analysis was done blinded with respect to pacing mode.


RESULTS
LVEF was significantly higher during BiV pacing (47 ± 11 %) compared with intrinsic conduction (43 ± 13 %, P = 0.001) and tLVp (44 ± 13 %, P = 0.001), while there was no difference between intrinsic conduction and tLVp (P = 0.28). GLS was higher during BiV (14 ± 3) than during intrinsic conduction (13 ± 3, P = 0.01) and tLVp (13 ± 3, P = 0.03). Difference in time-to-peak contraction between the basal septal and lateral walls was shorter during BiV pacing (-3 ± 44 ms) than during intrinsic conduction (129 ± 66, P < 0.001) and tLVp (118 ± 118 ms, P < 0.001), with no difference between tLVp and intrinsic conduction (P = 0.56). The electrocardiogram showed change in frontal axis from intrinsic conduction in only 2 (9 %) patients during tLVp and in 20 (87 %) patients during BiV pacing.


CONCLUSIONS
The acute effect of tLVp on LV systolic function and contraction pattern is significantly lower than the effect of BiV pacing and not different from intrinsic conduction in patients with LBBB and CRT.
Department of Cardiology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark. CTWI@clin.au.dk.
Christoffer Tobias
CT
Witt
Department of Cardiology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark.
Mads Brix
MB
Kronborg
Institute of Clinical Research, University of Southern Denmark, Winslowparken 19, 5000, Odense, Denmark.
Ellen Aagaard
EA
Nohr
Department of Cardiology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark.
Jens Cosedis
JC
Nielsen
D000368:Aged; D002037:Bundle-Branch Block / Q000150:complications / Q000175:diagnosis / Q000517:prevention & control*; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D017147:Defibrillators, Implantable; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000000981:diagnostic imaging / Q000517:prevention & control*; D006801:Humans; D008297:Male; D013318:Stroke Volume; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000209:etiology / Q000517:prevention & control*
Cardiac resynchronization therapy; Echocardiography; Speckle tracking; Triggered left ventricular pacing