Effect of Peri-Infarct Pacing Early After Myocardial Infarction

Abstract

Background-Left ventricular (LV) remodeling has been attributed to the segmental loss of viable myocardium due to myocardial infarction (MI), which results in redistribution of cardiac workload, with increased regional wall stress in and around the infarct zone. Because ventricular pacing has been shown to reduce regional wall stress and workload in regions near the pacing site, this trial was designed to test whether chronic pacing near the infarct attenuates LV remodeling. Methods and Results-Eighty patients with an anterior MI, peak creatine kinase Ͼ2000 mU/mL, ejection fraction Յ35%, wall motion abnormality (WMA)

Efficacy of cardiac resynchronization in acutely infarcted canine hearts with electromechanical dyssynchrony

“…Others have applied CRT to the post-MI rabbit heart without any conduction delay, and found benefits on chronic remodeling 20 . The use of PIZ-CRT was tested in post-MI patients with a narrow QRS 21 , though no effects on 1-year cardiac remodeling or clinical outcomes were found. However, these conditions differ from the present investigation in that we made pseudo-LBBB the baseline state.…”

Prognostic implications of left ventricular global longitudinal strain in heart failure patients with narrow QRS complex treated with cardiac resynchronization therapy: a subanalysis of the randomized EchoCRT trial

“…21,22 The Prevention of Myocardial Enlargement and Dilation Post Myocardial Infarction (MENDMI) study 21 and the Post-Myocardial Infarction Remodelling Prevention Therapy (PRomPT) trial 22 showed that pacing close to the infarcted area did not prevent LV dilatation or reduced heart failure hospitalization and/or all-cause mortality. The patients included in MENDMI and PROMPT differ significantly from the patients in the EchoCRT trial, who presented with more advanced LV remodelling and higher burden of LV myocardial scar/fibrosis.…”

Mechanical Regulation of Fibroblast Migration and Collagen Remodeling in Healing Myocardial Infarcts

“…It is important to understand the effects of these cues if interventions are to be designed that seek to preserve cardiac function after infarction by controlling the anisotropy of infarct scar. Furthermore, many proposed therapies for myocardial infarction, such as injection of cells or polymers (Christman et al, 2004), implantation of materials for structural support (Kelley et al, 1999), and peri-infarct pacing (Chung et al, 2010) …”

“…We identified environmental factors and fibroblast behaviors that regulate anisotropy of infarct scar tissue and embedded this understanding in a computational framework that can be used to identify interventions that modify the properties of infarct scar for therapeutic benefit. Because a myriad of potential therapies for myocardial infarction are currently in development (Johnston et al, 2009;Chung et al, 2010;Morita et al, 2011;, we can use the model to anticipate unintended impacts of such interventions on the collagen fiber structure of infarct scar, and ultimately on heart function. This research has the potential to reduce the occurrence of heart failure and improve the quality of life of patients after myocardial infarction.…”

“…By understanding the factors that determine whether collagen fibers are organized into isotropic or anisotropic structures, we may be able to control infarct scar anisotropy for experimental investigation of its impact on heart function and possibly for therapeutic benefit. Because a myriad of potential therapies for myocardial infarction are currently in development (Johnston et al, 2009;Chung et al, 2010;Morita et al, 2011;, we may also be able to anticipate unintended impacts of such interventions on the collagen fiber structure, and in turn, mechanical properties, of infarct scar.…”