Pacemaker optimization guided by echocardiography in cardiac resynchronization therapy

Abstract

Introduction. 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. Outline of Cases. 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. Conclusion. 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.Uvod. Resinhronizaciona terapija (RT) je savremeni oblik lecenja uznapredovalih oblika slabosti srca. Ehokardiografija ima vaznu ulogu u odabiru bolesnika za ovaj vid lecenja, u posmatranju akutnih i hronicnih efekata ove terapije, kao i u optimizaciji rada pejsmejkera za RT. U ovom radu je kroz prikaz dva bolesnika ilustrovana koriste hokardiografije u optimizaciji atrioventrikularnog( AV) i interventrikularnog ( VV) intervala kod bolesnika lecenih RT. Dat je i pregled aktuelne literature o osnovnim principima, ehokardiografskim protokolima i vazecim preporukama za ehokardiografski vodjenu optimizaciju AV i VV intervala kod bolesnika na RT. Prikazi bolesnika. Kod bolesnika sa dilatativnom kardiomiopatijom nakon ugradnje pejsmejkeraza RT uradjena je ehokardiografski vodjena uspesna optimizacija AV intervala. Pulsnim doplerom pracena je promena transmitralnog protoka pri programiranju AV intervala razlicite duzine i pronadjen optimalan profil transmitralnog protoka, koji podrazumeva jasno definisane talase E i A i najvecu vrednost vremenskog integrala brzina (VTI) ovog protoka. Nakon mesec dana kod bolesnika je uoceno klinicko poboljsanje, aehokardiografskije zabelezeno dodatno smanjenje dimenzija leve komore i poboljsanje njene ejekcione frakcije. Kod drugog bolesnika, koji je sest meseci nakon ugradnje aparata za RT i dalje Pripadao NYHA funkcionalnoj klasi III i imao znacajno smanjenu sistolnu funkciju leve komore, uradjena je ehokardiografski vodjena optimizacija VV intervala. Meren je VTI izlaznog trakta levekomore pri programiranju VV intervala razlicite duzine. Na ovaj nacin pronadjen je optimalni VV interval, za koji je VTI izlaznog trakta leve komore najveci. Nakon mesec dana kod bolesnika je uoceno poboljsanje ejekcione frakcije levekomore za oko 50%. Zakljucak. Optimalno nadgledanje bolesnika lecenih sa RT podrazumeva i ehokardiografsko pracenje sa eventualnom optimizacijom AV i VV intervala uz kontrolu na ultrazvuku, cime se pruza mogucnost dodatnog klinickog poboljsanja stanja ovih bolesnika.