Key result
Electrocardiographic mapping-guided optimization cuts bulk ventricular activation time an additional ~20% vs. echo optimization.
Why the study?
Optimal CRT delays are set using echocardiographic indices, but acute studies show reductions in bulk ventricular activation time correlate with improved acute haemodynamics, leaving the link between echo optimisation and activation time unclear.
Does electrocardiographic mapping-guided optimization improve ventricular activation times compared to echocardiographic optimization in heart failure patients receiving cardiac resynchronization therapy?
Cohort (n=21)
No
Does electrocardiographic mapping-guided optimization improve ventricular activation times compared to echocardiographic optimization in heart failure patients receiving cardiac resynchronization therapy?
Noninvasive electrocardiographic mapping enables more rapid biventricular activation than standard echocardiographic optimization, potentially translating to superior acute hemodynamic responses in CRT patients.
Mapping-guided CRT optimization was associated with faster activation; hypothesis-generating and should not yet change practice pending randomized trials.
Study hypothesis . We sought to investigate the association between echocardiographic optimisation and ventricular activation time in cardiac resynchronisation therapy (CRT) patients, obtained through the use of electrocardiographic mapping (ECM). We hypothesised that echocardiographic optimisation of the pacing delay between the atrial and ventricular leads—atrioventricular delay (AVD)—and the delay between ventricular leads—interventricular pacing interval (VVD)—would correlate with reductions in ventricular activation time. Background . Optimisation of AVD and VVD may improve CRT patient outcome. Optimal delays are currently set based on echocardiographic indices; however, acute studies have found that reductions in bulk ventricular activation time correlate with improvements in acute haemodynamic performance. Materials and methods . Twenty-one patients with established CRT criteria were recruited. After implantation, patients underwent echo-guided optimisation of the AVD and VVD. During this procedure, the participants also underwent noninvasive ECM. ECM maps were constructed for each AVD and VVD. ECM maps were analysed offline. Total ventricular activation time (TVaT) and a ventricular activation time index (VaT 10-90 ) were calculated to identify the optimal AVD and VVD timings that gave the minimal TVaT and VaT 10-90 values. We correlated cardiac output with these electrical timings. Results . Echocardiographic programming optimisation was not associated with the greatest reductions in biventricular activation time (VaT 10-90 and TVaT). Instead, bulk activation times were reduced by a further 20% when optimised with ECM. A significant inverse correlation was identified between reductions in bulk ventricular activation time and improvements in LVOT VTI (p<0.001), suggesting that improved ventricular haemodynamics are a sequelae of more rapid ventricular activation. Conclusions . EAM-guided programming optimisation may achieve superior fusion of activation wave fronts leading to improvements in CRT response.
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Pereira et al. (2019) conducted a cohort in Heart failure with CRT indication (n=21). Electrocardiographic mapping (ECM)-guided CRT optimization vs. Echocardiographic CRT optimization was evaluated on Reductions in total ventricular activation time (TVaT) and ventricular activation time 10-90 index (VaT 10-90) (20% further reduction in bulk activation times, p=<0.001). Electrocardiographic mapping-guided optimization reduced bulk ventricular activation times by an additional 20% compared to standard echocardiographic optimization, with reductions correlating with improved LVOT VTI (p<0.001).
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