Manual Intracardiac Electrogram Method Is Accurate Alternative to Echocardiography for Atrioventricular and Interventricular Optimization in Cardiac Resynchronization Therapy

Abstract

Some manufacturers do not provide automated intracardiac electrogram method (IEGM) systems for atrioventricular (AV) and interventricular (VV) delay optimization in cardiac resynchronization therapy (CRT). We aimed to evaluate the accuracy of manual IEGM method in 48 patients previously implanted with Medtronic Syncra CRT. All patients underwent standard device interrogation followed by CRT optimization by IEGM method and by echocardiography one month after implantation. The patient mean age was 60.7±11.8 years and there were 33 (68.8%) males. After CRT implantation, the left ventricular ejection fraction increased from 28.0±7.9% to 39.1±11.0% (p<0.001). Optimal aortic flow Velocity Time Integral (aVTI) was obtained when VV was set to 20-50 ms left ventricular pre-activation. There was a strong correlation between VV values determined by echocardiography and IEGM (R=0.823, p<0.001). We found no significant difference in AV, VV and aVTI values between echocardiography and IEGM method. However, IEGM was significantly less time-consuming than echocardiography [20 (10-28) vs. 40 (35-60) minutes, p<0.001]. Manual IEGM method may be good alternative to echocardiography and automated IEGM method. It also emphasizes the need for implementation of automated IEGM systems in as many CRT devices as possible.

Echocardiography‐ versus intracardiac electrocardiogram‐based optimization of cardiac resynchronization therapy: A systematic review

“…Two main factors that determine better outcomes are the optimization of atrial-to-ventricular (AV) and ventricular-to-ventricular (VV) delay (Naqvi et al, 2006). Reviewing the literature on echocardiography versus IEGM-based optimization of CRT, we found out that programming can be performed with the IEGM-based algorithm and the results are comparable with the optimization performed with the echocardiogram (Baker et al, 2007;Giammaria et al, 2016;Hua et al, 2012;Jensen et al, 2011;Kamdar et al, 2010;Pezo Nikolić et al, 2017;Reinsch et al, 2009;Sawhney et al, 2004;Wang et al, 2013;Yan et al, 2018;Zhang et al, 2019). Usually, passive ventricular filling occurs in early and mid-diastolic phases, with the blood flowing from the atrium to the ventricle secondary to AV pressure difference.…”

“…Of these 24 studies, 13 articles were excluded due to multiple reasons (lack of comparison of endpoints, preprints, and no primary outcome). Finally, a total of 11 articles were deemed eligible for review (Baker et al, 2007; Giammaria et al, 2016; Hua et al, 2012; Jensen et al, 2011; Kamdar et al, 2010; Pezo Nikolić et al, 2017; Reinsch et al, 2009; Sawhney et al, 2004; Wang et al, 2013; Yan et al, 2018; Zhang et al, 2019). This is shown in the PRISMA flow diagram in Figure 1.…”

“…The secondary outcome of our review, that is, the time required for optimization, was reported in a total of four studies. The mean time for echocardiography‐based optimization was 60.15 min, while that of IEGM‐based optimization was 6.65 min (Hua et al, 2012; Pezo Nikolić et al, 2017; Wang et al, 2013; Yan et al, 2018). This shows that IEGM‐based optimization is quicker than traditional echocardiography‐based optimization.…”

“…A total of six studies reported echocardiography to be a superior technique to IEGM for improvement in LVOT VTI (Baker et al, 2007;Giammaria et al, 2016;Hua et al, 2012;Kamdar et al, 2010;Reinsch et al, 2009;Wang et al, 2013). One did not improve LVOT VTI significantly in both techniques (Pezo Nikolić et al, 2017). The remaining two studies reported IEGM to be equally efficacious in the improvement of LVOT VTI (Sawhney et al, 2004).…”