A Real‐Time Three‐Dimensional Echocardiographic Validation of an Intracardiac Electrogram‐Based Method for Optimizing Cardiac Resynchronization Therapy

Abstract

Introduction: Although optimization of atrioventricular and interventricular delays has been demonstrated to improve hemodynamics in patients with cardiac resynchronization therapy (CRT), segments (Tmsv 16-SD), six basal and six mid segments (Tmsv 12-SD), and the six basal segments (Tmsv 6-SD) were assessed as a asynchrony indexes. LV end-diastolic and endsystolic volumes (EDV, ESV), stroke volume (SV), ejection fraction (EF), myocardial performance index (MPI), ejection time (ET), and filling time (FT), corrected by R-R interval, were also evaluated. After IEGM optimization, as compared with baseline Tmsv 12-SD and Tmsv 16-SD decreased (P = 0.01, P< 0.001, respectively), EF and SV improved (P < 0.001, P = 0.01 respectively), FT/RR and ET/RR increased (P = 0.02 for both), and MPI improved (P < 0.001). Tmsv 6-SD, EDV and ESV did not change.Conclusion: A simple IEGM-based method of CRT optimization decreased LV dyssynchrony and improved systolic function. (PACE 2008; 31:56-63) cardiac resynchronization therapy optimization, real-time 3D echocardiography, atrioventricular, interventricular delay Introduction Cardiac resynchronization therapy (CRT) is effective in the management of moderate-to-severe heart failure (HF) due to systolic dysfunction and associated cardiac asynchrony. A wide variety of studies have shown that CRT improves cardiac function, quality of life, and exercise capacity; alleviates symptoms; shortens hospitalizations; and lowers mortality. 1-3 These advantages conferred by CRT are currently thought to be mainly related

Echocardiography versus intracardiac electrocardiography-based optimization for cardiac resynchronization therapy

“…In concordance with these observations are the results of Porciani et al who demonstrated that a significant improvement in ejection fraction and stroke volume assessed by real-time three-dimensional echocardiography can be achieved with the IEGMbased approach [25]. Data from these studies suggest that IEGM-based optimization is equivalent at least with respect to acute hemodynamic changes.…”

Atrioventricular dyssynchrony from empiric device settings is common in cardiac resynchronization therapy and adversely impacts left ventricular morphology and function

“…The landmark, industry‐driven trials that spearheaded the paradigm shift away from echocardiography Doppler‐guided AVO toward automated IEGM‐based optimization algorithms included the SMART‐AV trial (Smart‐AV algorithm; Boston Scientific), the FREEDOM trial (QuickOpt algorithm; St. Jude), and Medtronic's AdaptiveCRT investigation yielded inconsistent results that are open for interpretation . Automated device algorithms have been studied in several smaller prospective clinical trials, but most were underpowered for hard clinical outcomes, included heterogenous patient populations and AVO methods, and offered conflicting results . In the present study, patients were implanted with CRT devices from each of the major device manufacturers whose programming algorithms were associated with post implantation AV dyssynchrony in a substantial group of patients who may have benefited from additional echocardiographic Doppler‐guided AVO.…”

Strategies for pacemaker programming in acute heart failure

“…Two small studies showed that the IEGM method correlated closely with A-V and V-V optimization determined by Doppler measured aortic valve VTI [49,50]. The IEGM method also was found to result in a higher degree of LV resynchronization and greater improvement in LV ejection fraction based on real-time three-dimensional echocardiographic assessment [28]. Though large-scale trials have yet to validate routine use of V-V optimization either by echocardiographic guidance or by automated electrogram measurements, this technique remains available and is worth consideration in acute heart failure patients implanted with devices that have such capabilities.…”

“…Doppler echocardiography may also be used to assess mitral inflow velocities (utilizing the Iterative or Ritter method, described below) as well as aortic and left ventricular outflow tract (LVOT) outflow velocities across several AV intervals to find the one that maximizes cardiac output. Invasive techniques involve direct endovascular intracardiac hemodynamic measurements (LV dP/dt or pulse pressure) [21][22][23][24][25][26][27][28][29][30]. The majority of the landmark CRT trials that utilized AV optimization employed either the Ritter [31,32] or Iterative [33] techniques.…”