title: Prospective comparison of echocardiographic atrioventricular delay optimization methods for cardiac resynchronization therapy.
abstract: BACKGROUND
  Atrioventricular (AV) delay optimization can be an important determinant of the response to cardiac resynchronization therapy (CRT) in patients with medically refractory heart failure and a ventricular conduction delay.
  
  
  OBJECTIVE
  The purpose of this study was to compare two Doppler echocardiographic methods of AV delay optimization after CRT.
  
  
  METHODS
  Forty consecutive patients (age 59 +/- 12 years) with severe heart failure, New York Heart Association class 3.1 +/- 0.4, QRS duration 177 +/- 23 ms, and left ventricular ejection fraction 26% +/- 6% referred for CRT were studied using two-dimensional Doppler echocardiography. In each patient, the acute improvement in stroke volume with CRT in response to two methods of AV delay optimization was compared. In the first method, the AV delay that produced the largest increase in the aortic velocity time integral (VTI) derived from continuous-wave Doppler (aortic VTI method) was measured. In the second method, the AV delay that optimized the timing of mitral valve closure to occur simultaneously with the onset of left ventricular systole was calculated from pulsed Doppler mitral waveforms at a short and long AV delay interval (mitral inflow method).
  
  
  RESULTS
  The optimized AV delay determined by the aortic VTI method resulted in an increase in aortic VTI of 19% +/- 13% compared with an increase of 12% +/- 12% by the mitral inflow method (P <.001). The optimized AV delay by the aortic VTI method was significantly longer than the optimized AV delay calculated from the mitral inflow method (119 +/- 34 ms vs 95 +/- 24 ms, P <.001). There was no correlation in the AV delay determined by the two methods (r = 0.03).
  
  
  CONCLUSIONS
  AV delay optimization by Doppler echocardiography for patients with severe heart failure treated with a CRT device yields a greater systolic improvement when guided by the aortic VTI method compared with the mitral inflow method.
authors.affiliation: Cardiovascular Division, Washington University School of Medicine, St. Louis, Missouri 63110, USA. jkerlan@im.wustl.edu
authors.forename: Jeffrey E
authors.initials: JE
authors.lastname: Kerlan
authors.forename: Navinder S
authors.initials: NS
authors.lastname: Sawhney
authors.forename: Alan D
authors.initials: AD
authors.lastname: Waggoner
authors.forename: Mohit K
authors.initials: MK
authors.lastname: Chawla
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Garhwal
authors.forename: Judy L
authors.initials: JL
authors.lastname: Osborn
authors.forename: Mitchell N
authors.initials: MN
authors.lastname: Faddis
mesh_terms: D001283:Atrioventricular Node / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial; D015150:Echocardiography, Doppler; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013318:Stroke Volume; D016896:Treatment Outcome