Optimization of Lead Placement in the Right Ventricle During Cardiac Resynchronization Therapy. A Simulation Study

Abstract

Patients suffering from heart failure and left bundle branch block show electrical ventricular dyssynchrony causing an abnormal blood pumping. Cardiac resynchronization therapy (CRT) is recommended for these patients. Patients with positive therapy response normally present QRS shortening and an increased left ventricle (LV) ejection fraction. However, around one third do not respond favorably. Therefore, optimal location of pacing leads, timing delays between leads and/or choosing related biomarkers is crucial to achieve the best possible degree of ventricular synchrony during CRT application. In this study, computational modeling is used to predict the optimal location and delay of pacing leads to improve CRT response. We use a 3D electrophysiological computational model of the heart and torso to get insight into the changes in the activation patterns obtained when the heart is paced from different regions and for different atrioventricular and interventricular delays. The model represents a heart with left bundle branch block and heart failure, and allows a detailed and accurate analysis of the electrical changes observed simultaneously in the myocardium and in the QRS complex computed in the precordial leads. Computational simulations were performed using a modified version of the O'Hara et al. action potential model, the most recent mathematical model developed for human ventricular electrophysiology. The optimal location for the pacing leads was determined by QRS maximal reduction. Additionally, the influence of Purkinje system on CRT response was assessed and correlation analysis between several parameters of the QRS was made. Simulation results showed that the right ventricle (RV) upper septum near the outflow tract is an alternative location to the RV apical lead. Furthermore, LV endocardial pacing provided better results as compared to epicardial stimulation. Finally, the time to reach the 90% of the QRS area was a good predictor of the instant at which 90% of the ventricular tissue was activated. Thus, the time to reach the 90% of the QRS area is suggested as an additional index to assess CRT effectiveness to improve biventricular synchrony.

Computational analysis of vulnerability to reentry in acute myocardial ischemia

“…The geometry of the ischemic central zone (ICZ) and border zone (BZ) was obtained based on the gray intensity of each pixel [4] ( Figure 1). The His-Purkinje system (HPS) network used in this work was the same network developed in our previous study [5]. It comprises two and three main branches in its right and left section, respectively.…”

“…Our simulations were performed using a modified version of the O'Hara ventricular action potential model [6], that includes the changes described in our previous work [5]. Alteration caused by acute ischemia was introduced in the model by modifying and incorporating several currents.…”

Prevention of non-response to cardiac resynchronization therapy: points to remember

“…However, post hoc analysis in large studies demonstrated no differences in cardiac remodeling and clinical endpoints in patients who underwent CRT irrespective of placement of the right ventricular electrode at the apex or septum [18]. A computer simulation of Biventricular pacing found that the right ventricular upper septum near the outflow tract was an alternative location for the right ventricular apex leads [19]. More clinical trials are needed to accumulate strong evidence regarding the positioning of the right ventricular electrode.…”

The desire for physiological pacing: Are we there yet?

“…Although CRT has been very extensively studied little attention has been made of the right ventricular lead position. A theoretical mathematical model suggested the optimal LV lead position was dependent upon the position of the RV lead . For example, a RV high septal/outflow tract lead position worked best with the LV lead in the lateral wall whereas with the lead at RVA the optimal LV lead location was at the epicardial LV antero‐basal wall.…”