Investigation of a novel algorithm for synchronized left-ventricular pacing and ambulatory optimization of cardiac resynchronization therapy: results of the adaptive CRT trial.
BACKGROUND
In patients with sinus rhythm and normal atrioventricular conduction, pacing only the left ventricle with appropriate atrioventricular delays can result in superior left ventricular and right ventricular function compared with standard biventricular (BiV) pacing.


OBJECTIVE
To evaluate a novel adaptive cardiac resynchronization therapy ((aCRT) algorithm for CRT pacing that provides automatic ambulatory selection between synchronized left ventricular or BiV pacing with dynamic optimization of atrioventricular and interventricular delays.


METHODS
Patients (n = 522) indicated for a CRT-defibrillator were randomized to aCRT vs echo-optimized BiV pacing (Echo) in a 2:1 ratio and followed at 1-, 3-, and 6-month postrandomization.


RESULTS
The study met all 3 noninferiority primary objectives: (1) the percentage of aCRT patients who improved in their clinical composite score at 6 months was at least as high in the aCRT arm as in the Echo arm (73.6% vs 72.5%, with a noninferiority margin of 12%; P = .0007); (2) aCRT and echo-optimized settings resulted in similar cardiac performance, as demonstrated by a high concordance correlation coefficient between aortic velocity time integrals at aCRT and Echo settings at randomization (concordance correlation coefficient = 0.93; 95% confidence interval 0.91-0.94) and at 6-month postrandomization (concordance correlation coefficient = 0.90; 95% confidence interval 0.87-0.92); and (3) aCRT did not result in inappropriate device settings. There were no significant differences between the arms with respect to heart failure events or ventricular arrhythmia episodes. Secondary end points showed similar benefit, and right-ventricular pacing was reduced by 44% in the aCRT arm.


CONCLUSIONS
The aCRT algorithm is safe and at least as effective as BiV pacing with comprehensive echocardiographic optimization.
Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio 44195, USA. martind3@ccf.org
David O
DO
Martin
Bernd
B
Lemke
David
D
Birnie
Henry
H
Krum
Kathy Lai-Fun
KL
Lee
Kazutaka
K
Aonuma
Maurizio
M
Gasparini
Randall C
RC
Starling
Goran
G
Milasinovic
Tyson
T
Rogers
Alex
A
Sambelashvili
John
J
Gorcsan
Mahmoud
M
Houmsse
D000368:Aged; D000465:Algorithms; D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D017147:Defibrillators, Implantable; D004311:Double-Blind Method; D004452:Echocardiography; D023381:Endpoint Determination; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial / Q000592:standards*; D011446:Prospective Studies; D011788:Quality of Life; D015996:Survival Rate; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology