Impact of left ventricular lead position on echocardiographic response after upgrading from right to biventricular pacing - Insights from the BUDAPEST CRT Upgrade Trial

Abstract Introduction Left ventricular (LV) lead position is strongly associated with the long-term outcome of patients undergoing de novo cardiac resynchronization therapy (CRT) implantation. However, data is scarce about patients who undergo upgrade CRT from right ventricular (RV) pacing. Aims To investigate the impact of the LV lead location on the primary outcome of heart failure (HF) hospitalization, all-cause mortality, or echocardiographic reverse remodelling in the BUDAPEST CRT Upgrade trial cohort. Methods Heart failure patients with reduced ejection fraction (HFrEF), with previously implanted pacemaker (PM) or implantable cardioverter defibrillator (ICD) and intermittent or permanent RV pacing, who were randomly assigned to the CRT-D arm (n=215) and those who were cross-overs from the ICD arm (n=27) were investigated. Short-axis position (anterior / posterior / lateral) of the LV lead was assessed. Primary endpoint encompassed HF hospitalization, all-cause mortality, and the end-systolic volume (ESV) decrease less than 15% from baseline to 12 months follow-up. Echocardiographic response was evaluated by percent change of ESV and LVEF. Results LV lead location was available for 223 patients (age 72.8 ± 8 years, 14% female, 38% diabetic, 49% with prior myocardial infarction, 30% with prior ICD) with a median follow-up time of 12.4 months. There was no difference in the occurrence of the primary endpoint by the lead positions (anterior vs. lateral OR 0.33; 95%CI 0.09-1.22, p=0.10, anterior vs. posterior OR 0.58; 95%CI 0.14-2.50, p=0.47). However, LVEF change was more pronounced in those with lateral LV lead location compared with anterior position (adjusted LVEF difference 7.43%, 95%CI 1.25 – 13.62; p=0.02), while those with posterior leads did not differ from the anterior ones (adjusted LVEF difference 3.00%, 95%CI -3.92 – 9.93; p=0.39). Decrease in ESV was also more remarkable with a lateral position as compared to the other locations (lateral vs. anterior adjusted ESV difference -0.17 mL, 95%CI -0.32 – (-0.01); p=0.03, posterior vs. anterior adjusted ESV difference -0.09 mL, 95%CI -0.26– 0.08; p=0.31). Conclusion Upgrade CRT results in better outcomes as compared to ICD alone; however, lateral LV lead position is associated with the most beneficial mid-term echocardiographic response as compared to other short-axis locations. This finding may translate into better clinical outcomes in the long term.