title: [Pacemaker optimization guided by echocardiography in cardiac resynchronization therapy].
abstract: BACKGROUND
  Cardiac resynchronization therapy (CRT) or biventricular pacing is a contemporary treatment in the management of advanced heart failure. Echocardiography plays an evolving and important role in patient selection for CRT, follow-up of acute and chronic CRT effects and optimization of device settings after biventricular pacemaker implantation. In this paper we illustrate usefulness of echocardiography for successful AV and VV timing optimization in patients with CRT. A review of up-to-date literature concerning rationale for AV and VV delay optimization, echocardiographic protocols and current recommendations for AV and VV optimization after CRT are also presented.
  
  
  METHODS
  The first case is of successful AV delay optimization guided by echocardiography in a patient with dilated cardiomyopathy treated with CRT is presented. Pulsed blood flow Doppler was used to detect mitral inflow while programming different duration of AV delay. The AV delay with optimal transmittal flow was established. The optimal mitral flow was the one with clearly defined E and A waves and maximal velocity time integral (VTI) of the mitral flow. Improvement in clinical status and reverse left ventricle remodelling with improvement of ejection fraction was registered in our patient after a month. The second case presents a patient with heart failure caused by dilated cardiomyopathy; six months after CRT implantation the patient was still NYHA class III and with a significantly depressed left ventricular ejection fraction. Optimization of VV interval guided by echocardiography was undertaken measuring VTI of the left ventricular outflow tract (LVOT) during programming of different VV intervals. The optimal VV interval was determined using a maximal LVOT VTI. A month after VV optimization our patient showed improvement in LV ejection fraction.
  
  
  CONCLUSIONS
  Optimal management of patients treated with CRT integrate both clinical and echocardiographic follow-up with, if needed, echocardiographically guided optimization of AV and VV delays, which offers the possibility of additional clinical improvement in such patients.
authors.forename: Danijela
authors.initials: D
authors.lastname: Trifunović
authors.forename: Milan
authors.initials: M
authors.lastname: Petrović
authors.forename: Goran
authors.initials: G
authors.lastname: Milasinović
authors.forename: Bosiljka
authors.initials: B
authors.lastname: Vujisić-Tesić
authors.forename: Marija
authors.initials: M
authors.lastname: Boricić
authors.forename: Ivana
authors.initials: I
authors.lastname: Nedeljković
authors.forename: Vera
authors.initials: V
authors.lastname: Jelić
authors.forename: Mirjana
authors.initials: M
authors.lastname: Zivković
authors.forename: Velibor
authors.initials: V
authors.lastname: Jovanović
authors.forename: Olga
authors.initials: O
authors.lastname: Petrović
mesh_terms: D002304:Cardiac Pacing, Artificial / Q000379:methods*; D002311:Cardiomyopathy, Dilated / Q000150:complications; D004452:Echocardiography; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D018084:Ultrasonography, Interventional