Effects of Exercise Training on Heart Failure Measured Using Seismocardiography
Date
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Heart failure has become a growing health concern across most of the Western
world and will soon become a global health focus. The nature of the disease presents
with a very high mortality rate. In Canada alone, the average mortality rate is
approximately 50% within the first five years of diagnosis [1]. Exercise has now become
a common treatment modality for many chronic disease conditions including heart
failure. As heart failure advances, the myocardium goes through a remodeling phase that
alters the contractility of the heart and its pumping efficiency. Exercise is known to lead
to a positive remodeling of the myocardium in healthy populations, but the degree to
which exercise reverses pathological remodeling in individuals with heart failure remains
to be determined.
The purpose of this study was to analyze the Systolic Timing Intervals (STI) of
the myocardium, specifically left ventricular ejection time (LVET) and the pre-ejection
period (PEP) using seismocardiography (SCG), as well as to investigate the functional
health changes measured using the six-minute walk test (6MWT). Participants exercised
three times per week for a period of 12 weeks involving a combination of aerobic and
resistance type activities. The SCG screening and 6MWT were performed at the
commencement, and at the 12 week point of their exercise program. Eleven individuals
participated in this study with varying etiologies for heart failure (ischemic n=6 and nonischemic
n=5). Among the individuals with ischemic heart failure, significant
improvement were observed in 6MWT distance, (477.0±127.0m to 539.3±113.9m t(5)=-
3.01, p=0.030), but no significant improvements were noted in indices of myocardial
function. However, in the non-ischemic group, significant changes were noted in indices
iii
of myocardial function including LVET (449.6±36.0ms to 438.4±30.5ms t(149)=4.28,
p=<0.001), and PEP (128.0±23.5ms to 119.9±18.5ms t(149)=6.87, p=<0.001), but no
statistically significant changes were observed in 6MWT distance (p=0.056). This study
showed that SCG can be used to record the mechanical function of the heart in
individuals with heart failure, that exercise training can produce positive mechanical
changes to the heart for individuals with non-ischemic heart failure, and exercise capacity
can increase in for individuals with ischemic based heart failure.