Isometric stress in cardiovascular magnetic resonance—a simple and easily replicable method of assessing cardiovascular differences not apparent at rest

Abstract

• Isometric exercise unmasks cardiovascular differences not evident at rest. • CMR is the reference standard for non-invasive cardiovascular assessment at rest. • A new easily replicable method combines isometric exercise with CMR. • Significant haemodynamic changes occur and differences are unmasked. • The physiological, isometric CMR stressor can be easily replicated.

The Cardiovascular Stress Response as Early Life Marker of Cardiovascular Health: Applications in Population-Based Pediatric Studies—A Narrative Review

“…Overweight subjects showed less increase in heart rate and cardiac output [52]. This is in accordance with a study done in 75 healthy volunteers (age 38.8 ± 10.9 years) that examined the effects of biceps isometric exercise and found that BMI is associated with reduced augmentation of the CO [35]. Isometric handgrip exercise during cMRI can also be used to examine coronary endothelial function (CEF) [59, 61, 62, 67, 86, BP blood pressure, BPM beats per minute, SBP systolic blood pressure, DBP diastolic blood pressure, HR heart rate, MAP mean arterial pressure, MVC maximum voluntary contraction, ΔHR difference in heart rate between rest and exercise, ΔMAP difference in mean arterial pressure between rest and exercise 87, 89-91, 93, 95, 104-106].…”

“…Adaptations to physical exercise may not only be impaired in clinical populations with known Figure of the cardiovascular stress response, focusing on the main effects in the exercising muscles, brain and the cardiovascular system cardiovascular or cardiac disease. Already, when subtle subclinical differences in cardiovascular health are present, this may lead to suboptimal adaptions of the cardiovascular system to the increased demands induced by exercise [34,35]. Thus, measurement of the cardiovascular stress response to physical exercise may reveal subtle pathology that would have been undetectable at rest in research settings with presumably healthy pediatric populations.…”

“…Studies are starting to emerge focused on the effects of well-known risk factors for an impaired childhood cardiovascular development on the cardiovascular stress response to exercise. Several studies suggest that a high childhood -Real-time scanning while exercising is possible without any motion artifacts [35] -Breath holds are feasible -Simple to implement and least expensive method -Good reproducibility [67] -Exercise cannot be performed to maximum exertion 3 min at 30% MVC At rest and during exercise, unfit obese/ overweight children had higher systolic, mean arterial pressure, and rate pressure product than fit obese/overweight children whose responses were similar to normal weight children, fit or unfit. Changes from rest, in cardiac output, cardiac index, and stroke volume were higher in unfit than in fit obese/overweight children [80] 217 children: age: 13 years 2,5 min at 30% MVC Significant increase in BP and HR which was larger in boys than in girls Mehta (1996) [74] 18 Schieken (1983) [76] 264 students: age: 9-18 years 3 min at 30% MVC Significant increase in BP and HR body mass index or a family history of hypertension may lead to alterations in the cardiovascular stress response to isometric handgrip exercise, although results are still inconsistent [51,81,82].…”

Exercise cardiovascular magnetic resonance: development, current utility and future applications

“…Isometric exercise involves the contraction of skeletal muscle without the elongation of the muscle, as such is also called static exercise [103]. This is feasible during CMR by IHG or isometric bicep exercise [104]. IHG exercise comprises the constant squeezing of a lever on a hand dynamometer, generally to a percentage of the subjects maximum force.…”

Factors mediating the pressor response to isometric muscle contraction: An experimental study in healthy volunteers during lower body negative pressure

“…Despite the powerful response of this mechanism being observed a decade ago, its hemodynamic mechanisms remain to be fully elucidated. It remains debatable whether the pressor response is due to increases in cardiac output (CO) [5][6][7][8][9], total peripheral resistance (TPR) [10][11][12][13][14] or both [15][16][17][18]. CO changes during IHG is primarily driven by an elevated heart rate (HR), whilst the stroke volume (SV) is slightly reduced due to the tachycardia and increased afterload, or even maintained following both augmented ventricular contractility [19,20] and constant or elevated preload via central blood volume mobilization [21].…”