Impact of transvenous lead position on active-can ICD defibrillation: A computer simulation study

Optimizing lead placement in transvenous defibrillation remains central to the clinical aspects of the defibrillation procedure. Studies involving sup erior vena cava (SVC) return electrodes have found that left ventricular (L V) leads or septal positioning of the right ventricular (RV) lead minimizes the voltage defibrillation threshold (VDFT) in endocardial lead-->SVC defi brillation systems. However, similar studies have not been conducted for ac tive-can configurations. The goal of this study was to determine the optima l lead position to minimize the VDFT for systems incorporating an active ca n. This study used a high resolution finite element model of a human torso that includes the fiber architecture of the ventricular myocardium to find the role of lead positioning in a transvenous LEAD-->can defibrillation ele ctrode system. It was found that, among single lead systems, posterior posi tioning of leads in the right ventricle lowers VDFTs appreciably. Furthermo re, a septal location of leads resulted in lower VDFTs than free-wall posit ioning. Increasing the number of leads, and thus the effective lead surface area in the right ventricle also resulted in lower VDFTs. However, the lea d configuration that resulted in the lowest VDFTs is a combination of a mid -cavity right ventricle lead and a mid-cavity left ventricle lead. The addi tion of a left ventricular lead resulted in a reduction in the size of the low gradient regions and a change of its location from the left ventricular free wall to the septal wall.