title: Acute effects of right ventricular pacing on cardiac haemodynamics and transvalvular impedance.
abstract: OBJECTIVE
  To assess the acute side-effects of right ventricular (RV) stimulation applied in apex and mid-septum, in order to establish the optimal lead location in clinical practice.
  
  
  METHODS
  During pacemaker implantation, the ventricular lead was temporarily fixed in the apex and then moved to mid-septum. In both positions, surface and endocardial electrograms and transvalvular impedance (32 cases), left ventricular (LV) pressure (23), and transthoracic echocardiography (10) were acquired with intrinsic activity and VDD pacing.
  
  
  RESULTS
  A larger increase in QRS duration was noticed with apical than septal pacing (65±25 vs. 45±29 ms; P<10(-4)). The proportion of cases where RV stimulation affected the transvalvular impedance waveform was higher with apical lead location (56% vs. 20%; P<0.02). VDD pacing at either site reduced the maximum dP/dt by 6% with respect to intrinsic AV conduction (IAVC; P<0.005). The maximum pressure drop taking place in 100 ms was reduced by 6 and 8%, respectively, with apical and septal pacing (P<0.01 vs. IAVC). Apical VDD decreased mitral annulus velocity in early diastole (E') from 7.5±1.4 to 5.9±0.9 cm/s (P<0.02) and prolonged the E-wave deceleration time (DT) from 156±33 to 199±54 ms (P<0.02), while septal pacing induced non-significant modifications in E' and DT.
  
  
  CONCLUSIONS
  Ventricular stimulation acutely impairs LV systolic and diastolic performance, independent of the pacing site. Septal lead location preserves RV contraction mechanics and reduces the electrical interventricular delay.
authors: Department of Internal Medicine I - Cardiology, University Hospital Olomouc, Czech Republic.
authors: Milos
authors: M
authors: Taborsky
authors: Marian
authors: M
authors: Fedorco
authors: Tomas
authors: T
authors: Skala
authors: Eva
authors: E
authors: Kocianova
authors: Dalibor
authors: D
authors: Pastucha
authors: David
authors: D
authors: Richter
authors: Jana
authors: J
authors: Petrkova
authors: Franco
authors: F
authors: Di Gregorio
authors: Alberto
authors: A
authors: Barbetta
authors: Jan
authors: J
authors: Vaclavik
mesh_terms: D002304:Cardiac Pacing, Artificial / Q000009:adverse effects / Q000379:methods*; D004452:Echocardiography; D017097:Electric Impedance / Q000009:adverse effects / Q000627:therapeutic use*; D004562:Electrocardiography; D006352:Heart Ventricles / Q000503:physiopathology*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D013318:Stroke Volume; D016276:Ventricular Function / Q000502:physiology*