B-PO03-193 THE MISSING LINK- TIME TO MAXIMAL RATE OF LEFT VENTRICULAR PRESSURE RISE REFLECTS RESYNCHRONIZATION WITH BIVENTRICULAR PACING IN PATIENTS WITH HEART FAILURE AND LEFT BUNDLE BRANCH BLOCK

Abstract

No measures exist that specifically quantifies myocardial resynchronization. We compared the acute differences between BIVP and LVP with regards to the preload dependent maximum rate of the LV pressure rise (dP/dtmax), and time to peak dP/dt (Td) to determine which better reflect dyssynchrony and resynchronization. Twenty-nine patients in heart failure with LBBB underwent CRT implantation with continuous LV pressure registration. The LV lead was first placed in either apical or anterior position followed by a permanent placement in a lateral position. Sequential LVP and BIVP pacing were performed for one minute, at a rate 10% above intrinsic heart rate, before dP/dtmax measurements were recorded. For LVP, BIVP and RVP a patient specific AV delay was used to avoid fusion with intrinsic conduction. Td was defined as the time from pacemaker stimuli to peak dP/dt. Mixed linear models were used for statistics, numbers are estimated marginal means±SEM and are only reported when with significance set at p<0.05. We found no differences in dP/dtmax between BIVP (899±37mmHg/s) and LVP (910±37mmHg/s), while RVP (799±37mmHg/s) was lower. Myocardial synergy was demonstrated as Td was lower with BIVP (165±4ms) than LVP (178±4ms) and RVP (184±4ms). We found no differences in dP/dtmax between lateral (890±35mmHg/s) and anterior (874±38mmHg/s) while apical (824±38mmHg/s) was lower. Td was lower in lateral (171±4ms) than in anterior (179±4ms) and apical (182±4ms) positions. BIVP in lateral position (158±4ms) was lower than any other pacingmode*position, with BIVP*anterior at 173±4ms) and LVP*lateral at 170±2ms. No difference was seen in dP/dtmax between (BIVP+LVP)*(lateral+anterior) that was higher than all other pacingmode*positions. Resynchronization with biventricular pacing translates into a shorter Td and hence links electrical and mechanical events. Td could be the missing link between electrical and mechanical dyssynchrony and may serve as a biomarker for cardiac resynchronization therapy to demonstrate biventricular synergy.