Normality Index of Ventricular Contraction Based on a Statistical Model from FADS

Luis Jiménez-Ángeles,Verónica Medina-Bañuelos,David Bialostozky,Enrique Vallejo,Raquel Valdés-Cristerna

doi:10.1155/2013/617604

Abstract

Radionuclide-based imaging is an alternative to evaluate ventricular function and synchrony and may be used as a tool for the identification of patients that could benefit from cardiac resynchronization therapy (CRT). In a previous work, we used Factor Analysis of Dynamic Structures (FADS) to analyze the contribution and spatial distribution of the 3 most significant factors (3-MSF) present in a dynamic series of equilibrium radionuclide angiography images. In this work, a probability density function model of the 3-MSF extracted from FADS for a control group is presented; also an index, based on the likelihood between the control group's contraction model and a sample of normal subjects is proposed. This normality index was compared with those computed for two cardiopathic populations, satisfying the clinical criteria to be considered as candidates for a CRT. The proposed normality index provides a measure, consistent with the phase analysis currently used in clinical environment, sensitive enough to show contraction differences between normal and abnormal groups, which suggests that it can be related to the degree of severity in the ventricular contraction dyssynchrony, and therefore shows promise as a follow-up procedure for patients under CRT.

Highlights

Heart failure (HF) is defined as a complex clinical syndrome that can result from any structural or functional cardiac disorder and that impairs the ability of the ventricle to fill or eject blood [1]
Several clinical studies have shown that cardiac resynchronization therapy (CRT) contributes to an increase in the life expectancy of subjects diagnosed with cardiac failure, of the type where the left ventricle ejection fraction is under 35% or classified in levels III or IV, according to the New York Heart Association [5,6,7] criteria
The information obtained for the 3-MSF (F1, F2, and F3) of the left and right ventricular regions was projected into scatter plots to observe differences between populations and between ventricular regions

Summary

Introduction

Heart failure (HF) is defined as a complex clinical syndrome that can result from any structural or functional cardiac disorder and that impairs the ability of the ventricle to fill or eject blood [1]. Dyssynchronous contraction can be palliated by electrically activating in a synchronized form the right and left ventricles with a multisite pacemaker device. This kind of treatment is called cardiac resynchronization therapy (CRT). Several clinical studies have shown that CRT contributes to an increase in the life expectancy of subjects diagnosed with cardiac failure, of the type where the left ventricle ejection fraction is under 35% or classified in levels III or IV, according to the New York Heart Association [5,6,7] criteria. In a metaanalysis of several CRT trials, evidence showed that HF hospitalizations were reduced by 32% and that all-cause mortality decreased by 25% after approximately 3 months of therapy [8]. In a randomized controlled trial comparing optimal medical therapy alone with optimal medical therapy plus CRT (without a defibrillator), CRT significantly reduced the combined risk of death by any cause and decreased the unplanned hospital admission for a major cardiovascular event by 37% [9]

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Discussion

Conclusion