title: Simultaneous vs. sequential biventricular pacing in dilated cardiomyopathy: an acute hemodynamic study.
abstract: OBJECTIVE
  Simultaneous biventricular pacing improves left ventricular (LV) systolic performance in patients with dilated cardiomyopathy and intraventricular conduction delay. We tested the hypothesis that further improvements can be obtained using sequential biventricular pacing by optimizing both atrioventricular and interventricular delays.
  
  
  RESULTS
  In 12 patients, LV pressure, right ventricular (RV) pressure and respective rates of change of pressure (dP/dt) were acutely measured during biventricular pacing with different atrioventricular and interventricular (VVi) intervals ranging from -60 to +40 ms. The average increase vs. baseline in maximum LV dP/dt was higher for sequential than for simultaneous biventricular pacing (VDD mode: 35+/-20 vs. 29+/-18%, P<0.01; DDD mode: 38+/-23 vs. 34+/-25%, P<0.01), with a minority of patients accounting for most of the difference. The mean optimal VVi was -25+/-21 ms in VDD mode and -25+/-26 ms in DDD mode. With these settings, RV dP/dt was not significantly different from baseline. QRS shortening was not predictive of LV dP/dt increase.
  
  
  CONCLUSIONS
  A significant increase of LV dP/dt with no change in RV dP/dt can be obtained by sequential biventricular pacing as compared to simultaneous biventricular pacing. The highest LV dP/dt is achieved when LV is stimulated before RV. The hemodynamic advantage might be of clinical significance in selected cases.
authors.affiliation: Istituto Auxologico Italiano, Ospedale S. Luca, Via Spagnoletto 3, 20149 Milan, Italy. perego@auxologico.it
authors.forename: Giovanni B
authors.initials: GB
authors.lastname: Perego
authors.forename: Roberto
authors.initials: R
authors.lastname: Chianca
authors.forename: Mario
authors.initials: M
authors.lastname: Facchini
authors.forename: Alessandra
authors.initials: A
authors.lastname: Frattola
authors.forename: Eva
authors.initials: E
authors.lastname: Balla
authors.forename: Stefania
authors.initials: S
authors.lastname: Zucchi
authors.forename: Sergio
authors.initials: S
authors.lastname: Cavaglià
authors.forename: Ilaria
authors.initials: I
authors.lastname: Vicini
authors.forename: Marco
authors.initials: M
authors.lastname: Negretto
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Osculati
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002304:Cardiac Pacing, Artificial; D002311:Cardiomyopathy, Dilated / Q000503:physiopathology / Q000628:therapy*; D004599:Electric Stimulation Therapy; D004562:Electrocardiography; D004867:Equipment Design; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D013223:Statistics as Topic; D013318:Stroke Volume / Q000502:physiology; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology; D017725:Ventricular Pressure / Q000502:physiology