title: Prediction of interatrial and interventricular electromechanical delays from P/QRS measurements: value for pacemaker timing optimization.
abstract: Cardiac pacing creates spurious delays between and within the cardiac chambers. These are: 1. Left atrial (LA) transport delay (ATD) either sensed (s) or paced (p), (time from right atrial P-wave to the end of LA transport (mitral Doppler A-wave)). 2. Interventricular delay (IVD), (time from onsets of right (RV) to left ventricular (LV) contractions). 3. P-sense offset (PSO), (time from P-onset to P-detection). Thus, restoration of left heart atrioventricular (AV) synchrony can be accomplished by compensating above delays, according to a previously published equation: RAV = ATD-IVD-PSO, where RAV = right heart AV.
  
  
  OBJECTIVE
  To test the hypothesis that ATD could be predicted from Ps and Pp, and that interventricular delay (IVD) could be predicted from QRSp, using three-lead surface electrocardiograms (ECGs).
  
  
  METHODS
  Thirty-six patients aged 63.5 +/- 15.5 years, 64% males, all with previously implanted DDD pacemakers, were studied by echo-Doppler and surface ECG obtained with a pacemaker programmer. Measurements included Ps; Pp; intrinsic QRSs; and paced QRSp, ATDs, ATDp, and IVD (difference between RVp and RVs left preejection intervals, PEI). Regressions between ECG and echo-Doppler intervals were calculated.
  
  
  RESULTS
  Regressions and correlation coefficients: ATD (s+p) = 0.96*P + 55 (R = 0.94, P < 0.0001); PEIp = 0.75 * QRSp + 34.8 (R = 0.89, P< 0.0001); IVD = 0.39 *QRSp - 7.9 ms (R = 0.87, P = 0.002).
  
  
  CONCLUSIONS
  Inter-atrial and inter-ventricular electromechanical delays can be predicted from P-wave and QRS durations. These measurements allow AV delay optimization in DDD and cardiac resynchronization therapy devices with no need of Doppler echocardiography.
authors.affiliation: Hospital Fernandez, Buenos Aires, Argentina. rchirife@fibertel.com.ar
authors.forename: Raul
authors.initials: R
authors.lastname: Chirife
authors.forename: Julio
authors.initials: J
authors.lastname: Pastori
authors.forename: Hugo
authors.initials: H
authors.lastname: Mosto
authors.forename: Mónica
authors.initials: M
authors.lastname: Arrascaite
authors.forename: Aleksandre
authors.initials: A
authors.lastname: Sambelashvili
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000592:standards*; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012044:Regression Analysis