Is left ventricular function reduced after ultra-endurance exercise?

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Norwegian Health Association

Introduction

Ultra-endurance exercise can be harmful according to previous studies, indicated by reduction in functional parameters and increase in cardiac biomarkers. Changes in load and heart rate with exercise influence left ventricle systolic function, making assessment of standard echocardiographic examination difficult.

Purpose

We investigated the effect of ultra-endurance exercise on myocardial function acutely and at restitution.

Methods

We investigated 10 participants aged 46 ±7 years, before (baseline), within 142 ± 78 minutes after finish (post run) and 5-10 days after (restitution) an ultra-endurance race (3.8 km swimming, 180 km bicycling and 42 km running with a total elevation of 5200 m). Echocardiography was performed at the three time points, including cardiac morphology and -function. Ejection fraction (EF) and stroke volume (SV) were measured by Simpson biplane. Cardiac output was calculated from SV and heart rate (HR). Cardiac power was calculated as the product of CO, mean arterial blood pressure and the conversion factor to Watt (W) 0.00222. Global longitudinal strain (GLS) was calculated using speckle-tracking echocardiography, and myocardial work was calculated by non-invasive pressure-strain analysis.

Results

Acutely after exercise, myocardial function by GLS (p = 0.002), myocardial work (p < 0.001), mitral annular plane systolic excursion (MAPSE, p = 0.003) and EF (p = 0.004) were substantially reduced compared to baseline, whereas cardiac power and cardiac output (CO) were maintained (see table and figure). Heart rate was moderately increased (p < 0.001). End-diastolic volume (EDV) as an index of preload was numerically, but not significantly reduced. End systolic volume (ESV) was numerically increased (p = NS) even though systolic blood pressure (sBP) was reduced (p = 0.01) post race. After restitution all parameters returned to baseline levels.

Conclusions

The temporary reduced strain and EF may be a physiologic response due to the higher heart rate. However, despite reduced systolic pressure the heart did not contract to a lower end systolic volume. This suggests loss of contractile function compensated by increase in heart rate. The findings should be explored in further studies. Abstract Figure  Abstract Table

Performance of Norwegian civilian EMTs and army medics in penetrating trauma: a controlled simulation-based assessment

Background

Penetrating trauma kills rapidly. Thorough and efficient examination and aggressive hemorrhage control is important to save lives. The aim of this study was to assess the skills of civilian Emergency Medical Technicians (EMTs) in bleeding examination and control compared to Army Medics. Our hypothesis was that civilian pre‐hospital systems perform at a lower level compared to an expert group, and did not have sufficient focus on education and training in examination and treatment of penetrating injuries.

Material and methods

We included 60 volunteer Certified EMTs and Army Medics. First, the participants examined a wounded patient. Second, the participants were presented a patient with a penetrating injury on a pork side fixated to the thigh with an artificial arterial bleeding.

Results

The EMTs took significantly shorter time examining, median 1 min 5 s vs. 3 min 58 s (P < 0.001). 5/30 (17%) of EMTs and 28/30 (93%) of army medics did an approved gauze wound packing of the penetrating injury (P < 0.001). EMTs took (median) 18 s and army medics 8 s to hemostasis regardless of approved packing or not (P < 0.001). Time spent on the packing was (median) 1 min 50 s vs. 5 min 47 s respectively (P < 0.001). Increasing time spent on the procedure showed significantly better chance of a successful procedure.

Conclusion

The EMTs had lower accuracy in examination but used significantly shorter time than the Army Medics. The treatment part of the study showed poor EMT performance compared to the Army Medics. This study indicates that more wound packing training needs to be incorporated into initial and ongoing civilian EMT training.