Cardiac resynchronisation therapy optimisation of interventricular delay by the systolic dyssynchrony index: A comparative,randomised, 12-month follow-up study

BackgroundThe aim of our study was to compare the effect of interventricular (VV) delay optimisation in CRT recipients on the basis of systolic dyssynchrony index (SDI) derived from the three-dimensional echocardiography (3DE) versus QRS width assessment on left ventricle volume reduction at the 12-month follow-up.MethodsWe included 63 patients with recently implanted CRT in this randomised, open-label trial. Patients were randomised to VV delay optimisation according to QRS complex width measurement in group 1 (n = 31) to obtain the narrowest QRS complex and SDI in group 2 (n = 32) to achieve its lowest possible value. We evaluated left ventricular end-systolic volume (LVESv), left ventricular ejection fraction (LVEF) and SDI by 3DE before CRT implantation and at a 12-month follow-up in all the patients. We also obtained the New York Heart Association functional class, the 6-minute walk test, the quality of life questionnaire and the level of NT-proBNP.ResultsThe number of volumetric responders was similar in both groups (17 vs. 20, P = 0.786). There were also no significant differences in the reduction of LVESv (−41 ± 55 mL vs. - 61 ± 51 mL, P = 0.111), improvement in LVEF (+10.1 ± 10.6% vs. + 13.0 ± 9.9%, P = 0.213) or differences in clinical outcomes between both groups at the 12-month follow-up.ConclusionCRT optimisation of interventricular delay using SDI compared with QRS width assessment did not reveal any significant difference in terms of volumetric and clinical response at the 12-month follow-up.