Abstract
BackgroundPost-implantation therapies to optimize cardiac resynchronization therapy (CRT) focus on adjustments of the atrio-ventricular (AV) delay and ventricular-to-ventricular (VV) interval. However, there is little consensus on how to achieve best resynchronization with these parameters. The aim of this study was to examine a novel combination of doppler echocardiography (DE) and three-dimensional echocardiography (3DE) for individualized optimization of device based AV delays and VV intervals compared to empiric programming.Methods25 recipients of CRT (male: 56%, mean age: 67 years) were included in this study. Ejection fraction (EF), the primary outcome parameter, and left ventricular (LV) dimensions were evaluated by 3DE before CRT (baseline), after AV delay optimization while pacing the ventricles simultaneously (empiric VV interval programming) and after individualized VV interval optimization. For AV delay optimization aortic velocity time integral (AoVTI) was examined in eight different AV delays, and the AV delay with the highest AoVTI was programmed. For individualized VV interval optimization 3DE full-volume datasets of the left ventricle were obtained and analyzed to derive a systolic dyssynchrony index (SDI), calculated from the dispersion of time to minimal regional volume for all 16 LV segments. Consecutively, SDI was evaluated in six different VV intervals (including LV or right ventricular preactivation), and the VV interval with the lowest SDI was programmed (individualized optimization).ResultsEF increased from baseline 23±7% to 30±8 (p<0.001) after AV delay optimization and to 32±8% (p<0.05) after individualized optimization with an associated decrease of end-systolic volume from a baseline of 138±60 ml to 115±42 ml (p<0.001). Moreover, individualized optimization significantly reduced SDI from a baseline of 14.3±5.5% to 6.1±2.6% (p<0.001).ConclusionsCompared with empiric programming of biventricular pacemakers, individualized echocardiographic optimization with the integration of 3-dimensional indices into the optimization protocol acutely improved LV systolic function and decreased ESV and can be used to select the optimal AV delay and VV interval in CRT.
Highlights
Despite progress in the treatment of heart failure the five year mortality still remains over 50% [1]
Aortic flow increased from baseline 2467 cm to 2769 cm after AV delay optimization (p,0.05)
The systolic dyssynchrony index (SDI) improved significantly from 14.365.5% to 9.064.6%, as well as the Ejection fraction (EF), which rose from a baseline value of 2367% to 3068% after AV delay optimization (Table 2, Figure 2)
Summary
Despite progress in the treatment of heart failure the five year mortality still remains over 50% [1]. About one third of patients with heart failure show a widened QRS complex ($120 ms) as a sign of conduction system disease [2],[3]. Cardiac resynchronization therapy (CRT) has evolved as the treatment of choice for patients with symptomatic heart failure, left bundle branch block/ QRS widening ($120 ms) and severely reduced systolic left ventricular (LV) function despite optimal medical therapy. Large studies showed that CRT improves quality of life and LV systolic function [4,5,6] and leads to a reduction in mortality [7]. Post-implantation therapies to optimize cardiac resynchronization therapy (CRT) focus on adjustments of the atrio-ventricular (AV) delay and ventricular-to-ventricular (VV) interval. The aim of this study was to examine a novel combination of doppler echocardiography (DE) and three-dimensional echocardiography (3DE) for individualized optimization of device based AV delays and VV intervals compared to empiric programming
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