Is Plasma High Sensitive Cardiac Troponin I an Indicator of Cardiac Ischemic Injury after exercise test in healthy volunteers?

Recent studies suggest that intensive exercise in healthy volunteers induces a
rise in plasma troponin I as measured with a highly sensitive Elisa technique
(hs-troponin I). This observation suggests that intensive exercise challenges
the heart sufficiently to induce a mismatch in oxygen demand and supply
resulting in mild cardiac injury. This opens a new window of opportunities to
study interventions for their efficacy to modulate ischemia-reperfusion injury.
To further characterize the rise in plasma hs-troponin I after intensive
exercise, we will study the time course of troponin appearance in plasma.
Furthermore, we will explore the effect of remote ischemic preconditioning
(RIPC) on this plasma troponin appearance. RIPC is a proven tool to protect
the heart against ischemia-reperfusion injury. Based on literature, we
hypothesize that RIPC releases Toll Like Receptor (TLR) ligands from the
remote organ that induces tolerance against subsequent exposure to TLR
ligands.

The primary objective of the study is to explore the efficacy of intensive
bicycle exercise test to induce cardiac micro-injuries by measurement of serum
concentrations of hs-troponin I in healthy volunteers. The secondary objectives
of this study are:
a)To investigate the cardioprotective effect of forearm RIPC during
subsequent submaximal intensive bicycle exercise test;
b) To study if RIPC releases TLR agonists into the circulation which induce
tolerance to subsequent TLR stimulation by using ex-vivo assays with
circulating leucocytes and plasma that are collected before and after the RIPC
protocol

Single center, Pilot study

Remote ischemic preconditioning
(Sub)maximal bicycle exercise tests

Since many years ago several types of exercise test (treadmill, bicycle) have
been used for detecting ischemia in the patients suspected to ischemic
cardiovascular diseases. Bicycle test is an alternative to treadmill testing .
It can also serve as a less expensive, portable substitute for testing. Bicycle
exercise test can induce cardiac ischemia in healthy subjects and the patients
with cardiovascular disease . However, the cardiac ischemia which developed
following bicycle test is not harmful in healthy volunteers. Several previous
studies have been shown the safety of RIPC protocol and no adverse effects have
been reported in this regard. Therefore, it seems that bicycle exercise text
and RIPC are two safe procedures with less probable adverse effect in healthy
volunteers.
This pilot study will provide a feasible model to elucidate valuable unknown
points regarding the mechanism of RIPC in prevention of reperfusion-ischemia
which will be extremely helpful for the further studies.
Potential risks of bicycle exercise test could be considered in very rare
cases as:
Acute coronary syndromes, acute respiratory events and sudden cardiac death.
Sudden cardiac death is rare in apparently healthy individuals60. In
individuals under the age of 40 years, sudden cardiac death is usually
attributed to congenital heart disease, whereas CAD is a more likely cause for
those over age 40. In our individuals these attributed risk factors will be
assessed by pre-assessments.
The incidence of major cardiovascular complications during outpatient cardiac
exercise programs has been estimated to be 1 in 60 000 participant hours.
Musculoskeletal Injuries: include direct injuries such as bruises, sprains, and
strains, and indirect problems such as arthritis and back pain. Musculoskeletal
Injuries could be prevented by sufficient education of the individuals before
the bicycle tests.