title: Analyses of the redistribution of work following cardiac resynchronisation therapy in a patient specific model.
abstract: Regulation of regional work is essential for efficient cardiac function. In patients with heart failure and electrical dysfunction such as left branch bundle block regional work is often depressed in the septum. Following cardiac resynchronisation therapy (CRT) this heterogeneous distribution of work can be rebalanced by altering the pattern of electrical activation. To investigate the changes in regional work in these patients and the mechanisms underpinning the improved function following CRT we have developed a personalised computational model. Simulations of electromechanical cardiac function in the model estimate the regional stress, strain and work pre- and post-CRT. These simulations predict that the increase in observed work performed by the septum following CRT is not due to an increase in the volume of myocardial tissue recruited during contraction but rather that the volume of recruited myocardium remains the same and the average peak work rate per unit volume increases. These increases in the peak average rate of work is is attributed to slower and more effective contraction in the septum, as opposed to a change in active tension. Model results predict that this improved septal work rate following CRT is a result of resistance to septal contraction provided by the LV free wall. This resistance results in septal shortening over a longer period which, in turn, allows the septum to contract while generating higher levels of active tension to produce a higher work rate.
authors.affiliation: Imaging Sciences & Biomedical Engineering Division, King's College London, London, United Kingdom.
authors.forename: Steven Alexander
authors.initials: SA
authors.lastname: Niederer
authors.forename: Pablo
authors.initials: P
authors.lastname: Lamata
authors.forename: Gernot
authors.initials: G
authors.lastname: Plank
authors.forename: Phani
authors.initials: P
authors.lastname: Chinchapatnam
authors.forename: Matt
authors.initials: M
authors.lastname: Ginks
authors.forename: Kawal
authors.initials: K
authors.lastname: Rhode
authors.forename: Christopher Aldo
authors.initials: CA
authors.lastname: Rinaldi
authors.forename: Reza
authors.initials: R
authors.lastname: Razavi
authors.forename: Nicolas Peter
authors.initials: NP
authors.lastname: Smith
mesh_terms: D002037:Bundle-Branch Block / Q000503:physiopathology; D002304:Cardiac Pacing, Artificial / Q000379:methods; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D003198:Computer Simulation; D004594:Electrophysiology / Q000379:methods; D005260:Female; D006333:Heart Failure / Q000628:therapy*; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D008875:Middle Aged; D008953:Models, Anatomic; D010101:Oxygen Consumption; D013314:Stress, Mechanical; D020257:Ventricular Remodeling