Heart Failure: Current Concepts

Singh, Charanjit; Sabharwal, JS

doi:10.1016/s0377-1237(03)80135-1

Cited by 1 publication

(1 citation statement)

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“…However, in BBB simulations, due to the different excitation propagation, there was an apparent abnormality of contraction sequences of both ventricles, which affected the ventricular contractile activity and decreased the heart function. During simulation of the LBBB, mechanical delay was evident in the LV free-wall segments (see figure 4), which suggested a severe interventricular dyssynchrony in accordance with clinical results (Grines et al 1989, Liu et al 2002, O'Dell et al 1995, Singh and Sabharwal 2003. The abnormalities may be explained by the asynchronous RV contraction with early activation but delayed activation and contraction of the LV free wall in LBBB.…”

Section: Discussionsupporting

confidence: 78%

Mechanical analysis of congestive heart failure caused by bundle branch block based on an electromechanical canine heart model

Dou¹,

Xia²,

Shou³

et al. 2008

Phys. Med. Biol.

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Asynchronous electrical activation, induced by bundle branch block (BBB), can cause reduced ventricular function. However, the effects of BBB on the mechanical function of heart are difficult to assess experimentally. Many heart models have been developed to investigate cardiac properties during BBB but have mainly focused on the electrophysiological properties. To date, the mechanical function of BBB has not been well investigated. Based on a three-dimensional electromechanical canine heart model, the mechanical properties of complete left and right bundle branch block (LBBB and RBBB) were simulated. The anatomical model as well as the fiber orientations of a dog heart was reconstructed from magnetic resonance imaging (MRI) and diffusion tensor MRI (DT-MRI). Using the solutions of reaction-diffusion equations and with a strategy of parallel computation, the asynchronous excitation propagation and intraventricular conduction in BBB was simulated. The mechanics of myocardial tissues were computed with time-, sarcomere length-dependent uniaxial active stress initiated at the time of depolarization. The quantification of mechanical intra- and interventricular asynchrony of BBB was then investigated using the finite-element method with an eight-node isoparametric element. The simulation results show that (1) there exists inter- and intraventricular systolic dyssynchrony during BBB; (2) RBBB may have more mechanical synchrony and better systolic function of the left ventricle (LV) than LBBB; (3) the ventricles always move toward the early-activated ventricle; and (4) the septum experiences higher stress than left and right ventricular free walls in BBB. The simulation results validate clinical and experimental recordings of heart deformation and provide regional quantitative estimates of ventricular wall strain and stress. The present work suggests that an electromechanical heart model, incorporating real geometry and fiber orientations, may be helpful for better understanding of the mechanical implications of congestive heart failure (CHF) caused by BBB.

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Section: Discussionsupporting

confidence: 78%