Correction of dyssynchrony by conduction system pacing: results of LEVEL-AT trial

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: Public Institution(s). Main funding source(s): Catalan Society of Cardiology; Asociación del Ritmo Cardiaco (Spanish Society of Cardiology). BACKGROUND: Correction of dyssynchrony measured with echo strain, in conduction system pacing (CSP) vs biventricular pacing (BIVP) has not been reported. OBJECTIVES: Our purpose was to compare echocardiographic dyssynchrony correction and strain improvement during follow-up between CSP and BIVP. METHODS: A treatment received analysis was performed in patients (n=29 CSP; BIVP 40). Patients were evaluated at baseline (ON and OFF programming) and at 6 and 12 months. All echocardiograms were completed by operators blinded to the type of device implanted. Intraventricular (septal flash), interventricular (difference between left and right ventricular outflow times), and auriculoventricular (diastolic filling time) dyssynchrony, as well as strain parameters (septal rebound, global longitudinal strain (GLS), and Risum pattern (typical left bundle branch block contraction pattern)) were analyzed. RESULTS: 32% (22/69) were women; baseline LVEF was 27.5% (7% SD) and left ventricular end-systolic volume (LVESV) 138ml (77ml SD) without differences between groups. At the 12-month follow-up, there were no differences in CSP vs. BIVP in LVEF (45.8% (10% SD) vs. 42.7% (12% SD), p=0.25) and LVESV (81.5 ml (41 ml SD) vs. 101.7 ml (56 ml SD), p=0.08). Longitudinal analyses showed that the improvement of all echocardiographic dyssynchrony parameters over time was similar between groups (p<0.001) (Table 1 and Fig 1A). GLS acute correction significantly correlated with LVEF and LVESV at the 12-month follow-up (Fig 1B). CONCLUSIONS: CSP and BIVP provided a similar dyssynchrony and strain correction over time. Acute strain correction predicted ventricular remodeling at 12 months follow-up. [Figure: see text] [Figure: see text]