Non-invasive focus localization, right ventricular epicardial potential mapping in patients with an MRI-conditional pacemaker system ‐ a pilot study

Abstract

BackgroundWith the advent of magnetic resonance imaging (MRI) conditional pacemaker systems, the possibility of performing MRI in pacemaker patients has been introduced. Besides for the detailed evaluation of atrial and ventricular volumes and function, MRI can be used in combination with body surface potential mapping (BSPM) in a non-invasive inverse potential mapping (IPM) strategy. In non-invasive IPM, epicardial potentials are reconstructed from recorded body surface potentials (BSP). In order to investigate whether an IPM method with a limited number of electrodes could be used for the purpose of non-invasive focus localization, it was applied in patients with implanted pacing devices. Ventricular paced beats were used to simulate ventricular ectopic foci.MethodsTen patients with an MRI-conditional pacemaker system and a structurally normal heart were studied. Patient-specific 3D thorax volume models were reconstructed from the MRI images. BSP were recorded during ventricular pacing. Epicardial potentials were inversely calculated from the BSP. The site of epicardial breakthrough was compared to the position of the ventricular lead tip on MRI and the distance between these points was determined.ResultsFor all patients, the site of earliest epicardial depolarization could be identified. When the tip of the pacing lead was implanted in vicinity to the epicardium, i.e. right ventricular (RV) apex or RV outflow tract, the distance between lead tip position and epicardial breakthrough was 6.0 ± 1.9 mm.ConclusionsIn conclusion, the combined MRI and IPM method is clinically applicable and can identify sites of earliest depolarization with a clinically useful accuracy.Electronic supplementary materialThe online version of this article (doi:10.1007/s10840-015-0054-9) contains supplementary material, which is available to authorized users.

The evolution of stem-cell transplantation in multiple myeloma

“…56 Despite these results, there has been some evidence that patients with high-risk cytogenetics like 17p deletion do benefit with a tandem transplant. 54,57 Transplant as salvage therapy Second ASCT is a safe and effective therapy in eligible patients with relapsed MM. Alvares and colleagues found that patients with a PFS of <18 m after first ASCT had a median OS of <6 m whereas those with a PFS of ⩾18 m showed a median OS approaching 3 years.…”

“…56 Despite these results, there has been some evidence that patients with high-risk cytogenetics like 17p deletion do benefit with a tandem transplant. 54,57…”