Personalised Biophysical Model to Optimise Left Ventricle Pacing Location for Cardiac Resynchronisation Therapy Over Time

Abstract

Cardiac Resynchronisation Therapy (CRT) causes changes in cardiac anatomy, electrophysiology and mechanics of the heart after 3-6 months of treatment. Multi-pole pacing (MPP) and multi-vein pacing (MVP) (AHR). After sustained CRT treatment the heart remodels and the models predict that the optimal region for pacing the LV would expand by 46% after this remodeling. The expansion in the optimal LV pacing region after remodeling predicts that if LV lead location was placed within the optimal region prior to CRT treatment, it will remain within the optimal region after sustained pacing. IntroductionCardiac Resynchronisation Therapy (CRT) is one of the few effective treatments for patients with drug refractory dyssynchronous heart failure, however 30% of patients fail to respond to this treatment [1]. Many factors can lead to non-response, including suboptimal LV pacing lead location [2].In CRT, the heart is implanted with pacing leads in the right and left ventricles with the aim to resynchronise the ventricular contraction of the heart [3]. The left ventricular (LV) lead is typically implanted via the venous branches of the coronary sinus to electrically stimulate the LV epicardium. To improve the response rate of patients, the optimal location from which to pace the LV free wall has therefore received some interest. In earlier studies, it was found that the optimal location from which to pace the LV is in the non-ischemic, non-apical, postero-lateral/lateral regions of the LV epicardium, or the latest point of mechanical or electrical activation [4][5][6].The heart remodels in response to sustained pacing with regards to the anatomy, mechanics and electrophysiology properties [7,8]. New pacing catheter technologies such as multipole pacing (MPP) and multi-vein pacing (MVP) allow for the LV lead position to be altered post implant without further surgery. The long term benefits of MVP and MPP depend on whether the optimal location for LV pacing changes after remodeling due to CRT. MethodsA male patient with standard indication for CRT (NYHA class III, QRSd≥120ms, LBBB on surface ECG, LV EF≤35%) was recruited and clinical data was acquired before and after six months of sustained CRT. The heart was implanted with three leads, one at the high right atria to regulate the heart rate, one at the RV apex and with a MPP LV lead in the posterior/lateral regions of the heart to synchronize ventricular contraction.Prior to CRT implantation, 3D whole heart MR images were acquired and after device implantation, the heart anatomy was captured using 2D and 3D echocardiography. Gadolinium enhanced MR images were also acquired prior to implantation to determine the regions of infarcted tissues in the heart. Electrical activation of the heart was measured using 12-lead ECG and invasive electroanatomical mapping of the left ventricle. At time of implant and after at least six months of sustained pacing, invasive pressure measurements were taken from the left ventricle cavity under biventricular pacing (DDD-BiV) and with ...