The effect of cardiac rehabilitation exercise training on left ventricular remodelling in patients with recent myocardial infarction

 

The present thesis examined the effect of cardiac rehabilitation (CR) exercise training on

reverse left ventricular (LV) remodelling in a cohort of post-myocardial infarction (MI) patients

with mildly abnormal LV ejection fraction (LVEF). Specifically, the thesis aimed to evaluate

the effect of 10 weeks of exercise training on (1) the N-terminal fragment of the counter

regulatory neurohormone brain natriuretic peptide (NT-pro-BNP), (2) LV structural and

functional parameters through the use of conventional echocardiography, and (3) LV mechanics

via the application of speckle tracking echocardiography (STE). Accordingly, a large cohort of

patients completed a single longitudinal protocol to provide data for three separate experimental

studies.

A number of cardiovascular adaptations were observed following completion of 10 weeks of

CR exercise training. Firstly, an improvement in exercise capacity was evident. Secondly, study

one demonstrated that resting NT-pro-BNP was reduced and that the acute increase in NT-pro-

BNP observed following bouts of maximal and submaximal exercise may be attenuated.

Thirdly, in study two, LV volumetric adaptation was evidenced by reduced LV end diastolic

volume (EDV) and end systolic volume (ESV). Furthermore, a positive correlation between

reduced resting NT-pro-BNP and reduced EDV provided an indication of the relationship

between NT-pro-BNP and reverse LV volumetric remodelling. Finally, the main finding of

study three was related to LV functional adaptation, indicated by a reduction in LV twist and

twist velocity.

Collectively, findings from the three experimental studies presented in this thesis provide

evidence of volumetric and functional reverse LV remodelling, further to 10 weeks of CR

exercise training in post-MI patients. It is likely that these cardiac adaptations may contribute to

the improved cardiovascular exercise capacity and reduced mortality commonly witnessed

following CR exercise training in the post-MI population.