P1161Pre-implantation MRI identification of late-mechanical activation segments with dedicated software platform to guide the cardiac resynchronization therapy
Authors: Muca M , Bastian D , Walascheck J , Buia V , Schmidtbauer E , Gmeinwieser J , Rittger H , Vitali Serdoz L 
Published: June 2020

Abstract

Introduction
The Cardiac Resynchronization Therapy (CRT) is a well-established treatment for patients with electromechanical dyssynchrony of the left ventricle (LV) and drug-refractory heart failure (HF). Despite technical improvement and accurate selection, still a 30% of implanted patients are non-responder to CRT. Suboptimal LV lead placement in areas of early mechanical activation is one of the major reasons of poor response rate.

Objectives
To evaluate and test the performance of an integrated and highly automated software platform used for processing and analyzing standard preoperative Cardiac Magnetic Resonance (CMR) data and overlaying this data with real-time fluoroscopic images.

Methods
Using a dedicated software for post-hoc analysis of CMR data, segments of late mechanical activation (LMA) in the 16 segments model before CRT implant were identified and used as target segments for the coronary sinus (CS) lead implant. All patients underwent CRT implantation after performing a standard CMR. A real time match between the selected segments and the fluoroscopic images (AP and at least one LAO or RAO projection with ≥30° angle difference) was obtained for each case during the procedure (Figure 1). In two patients who underwent to Cardiac-CT (CCT), a postprocessing analysis with a dedicated software was performed to obtain a 3D CS anatomy model before implant, which was used as a guide for the CS catheter during procedure. The 3D CS model was merged with the 3D-LV Model. Patients were enrolled during a period from 30th November 2017 to 30th July 2019 and where divided in two groups, Group A if the CS lead was placed in the target segment and Group B if the lead didn´t reach the target.

Results
Considering all patients (21 patients, 24% females and 76% males, age 69 ± 10.7 years; NYHA class: 3 ± 0.4; 62% with Late-gadolinium-enhancement and 38% without Late-gadolinium-enhancement; EF 30 ± 5.6%; QRS 174.9 ± 29 ms; 81% with left bundle block), in 57% the placement of the CS lead to the pre-procedurally defined LMA target segments and an effective pacing was obtained. In the Group A we documented a trend in shorter paced QRS duration (QRS pre 173.2 ± 31.9, QRS post 138.3 ± 26) and a trend in EF increase during short-term follow up (EF from 29.4 ± 3% to 41.9 ± 3%) compared with Group B (QRS pre 177.2 ± 26, QRS post 147 ± 33.6 and EF from 36 ± 7.5% to 41 ± 5%).

Conclusions
The pre-implantation planning of CRT implant, in patients candidate to a resynchronization treatment, focusing on identification of the LMA segments, is an emerging tool. Real-time fluoroscopic images and CMR-guided LV CS lead placement provide preferential sites for lead placement and preliminary data demonstrated a trend in increase of treatment response. A successful implant in the preselected target segment was achieved in 57% of cases in our study and a trend in a concomitant better electrical response of resynchronization was observed.
Abstract Figure 1. CS lead in target segments