Twelve-Lead ECG Optimization of Cardiac Resynchronization Therapy in Patients With and Without Delayed Enhancement on Cardiac Magnetic Resonance Imaging.

Background Delayed enhancement ( DE ) on magnetic resonance imaging is associated with ventricular arrhythmias, adverse events, and worse left ventricular mechanics. We investigated the impact of DE on cardiac resynchronization therapy ( CRT ) outcomes and the effect of CRT optimization. Methods and Results We studied 130 patients with ejection fraction ( EF ) ≤40% and QRS ≥120 ms, contrast cardiac magnetic resonance imaging, and both pre- and 1-year post- CRT echocardiograms.

QRS Complex Detection and Measurement Algorithms for Multichannel ECGs in Cardiac Resynchronization Therapy Patients.

We developed an automated approach for QRS complex detection and QRS duration (QRSd) measurement that can effectively analyze multichannel electrocardiograms (MECGs) acquired during abnormal conduction and pacing in heart failure and cardiac resynchronization therapy (CRT) patients to enable the use of MECGs to characterize cardiac activation in such patients. The algorithms use MECGs acquired with a custom 53-electrode investigational body surface mapping system and were validated using previously collected data from 58 CRT patients. An expert cohort analyzed the same data to determine algorithm accuracy and error.

Body surface activation mapping of electrical dyssynchrony in cardiac resynchronization therapy patients: Potential for optimization.

Background: Electrical synchronization is likely improved by cardiac resynchronization therapy (CRT), but is difficult to quantify with 12-lead ECG. We aimed to quantify changes in electrical synchrony and potential for optimization with CRT using a body-surface activation mapping (BSAM) system.

Methods: Standard deviation of activation times (SDAT) was calculated in 94 patients using BSAM at baseline CRT (CRT), native, and different CRT configurations.

Left ventricular-only pacing in heart failure patients with normal atrioventricular conduction improves global function and left ventricular regional mechanics compared with biventricular pacing: an adaptive cardiac resynchronization therapy sub-study.

Aims: Right ventricular (RV) pacing can impair left ventricular (LV) function. When timed with native RV activation, LV-only pacing may cause greater improvements in LV function than biventricular pacing. This study compared the chronic effects of cardiac resynchronization therapy (CRT) on LV mechanics between biventricular pacing and LV-only pacing in patients with normal atrioventricular (AV) conduction.

Changes in electrical dyssynchrony by body surface mapping predict left ventricular remodeling in patients with cardiac resynchronization therapy.

Background: Electrical activation is important in cardiac resynchronization therapy (CRT) response. Standard electrocardiographic analysis may not accurately reflect the heterogeneity of electrical activation.

Objective: We compared changes in left ventricular size and function after CRT to native electrical dyssynchrony and its change during pacing.

Long-Term Echocardiographic Response to Cardiac Resynchronization Therapy in Initial Nonresponders.

Objectives: The aim of this study was to investigate the frequency and clinical implications of a delayed echocardiographic response to cardiac resynchronization therapy (CRT).

Background: Long-term prognosis for CRT patients is routinely based on the assessment of echocardiograms after 6 to 12 months of therapy. Some patients, however, may require a longer period of therapy before echocardiographic improvements are detectable.

An agent-based model of the response to angioplasty and bare-metal stent deployment in an atherosclerotic blood vessel.

Purpose: While animal models are widely used to investigate the development of restenosis in blood vessels following an intervention, computational models offer another means for investigating this phenomenon. A computational model of the response of a treated vessel would allow investigators to assess the effects of altering certain vessel- and stent-related variables. The authors aimed to develop a novel computational model of restenosis development following an angioplasty and bare-metal stent implantation in an atherosclerotic vessel using agent-based modeling techniques.