NEWS To diagnose heart and lung function in healthcare, confirmed reference values are needed. With her thesis, Sofia Erelund wants to show that sex- and population-adapted reference values are of great importance for correct diagnosis and treatment.
In ECG examinations in females and males of varying ages (20–90 years), sex and age, differences were seen in most parameters. Today, these differences are not always taken into account. In the worst case, this can lead to delayed diagnosis or treatment. Furthermore, a sub-study showed that an international reference material underestimates lung function in both women and men in the northern population. The study also showed that with updated values, the international model can be better adapted to our population.
"Females have both smaller hearts and lungs than males, which should be more clearly reflected in the reference values used in diagnostics of heart and lung function," says Sofia Erelund.
Sofia has also studied the variation in the pulse that normally occurs between each heartbeat, partly in patients with rheumatism and partly in women with coronary artery disease. The method is called heart rate variability and it is used to study the activity of the autonomic nervous system. Heart rate variability is often investigated at rest, but in both studies, Sofia Erelund was able to show that various provocations, such as deep breathing, were needed to see differences compared to the healthy controls.
"My studies indicate that heart rate variability, an indicator of the health of the autonomic nervous system, is lower in patients with rheumatism compared to healthy patients. This impaired autonomic function may pose a risk of suffering from high blood pressure.”
In females with coronary artery disease, lower heart rate variability was seen compared to healthy females. At follow-up after 20 years, there was no difference in survival between the females who were over 60 years of age at baseline and the age-matched control group. On the other hand, females who were under 60 years of age at the start of the study had a higher risk of death than the control group.
"In contrast to other studies, we were able to show that the females in the patient group who had the lowest heart rate variability did not have the greatest risk of dying," says Sofia Erelund.
"The patients who died had higher heart rate variability after a provocation of the sympathetic nervous system by changing the position of the body from lying down to standing. This indicates a higher level of sympathetic activity than in the patients who were still alive.”
Sofia Erelund's research highlights the importance of updating and adapting reference materials to reflect the population being studied.
"The thesis also emphasizes the importance of using tests that include various provocations, which can reveal hidden abnormalities in the heart's autonomic function that are not visible during rest," says Sofia Erelund.
Sofia Erelund is 39 years old, born and raised in Umeå. She has studied the Biomedical Laboratory Science program with a specialization in clinical physiology at Umeå University and then a master's degree at Karolinska Institutet, Stockholm. PhD student at the Department of Surgery and Perioperative Sciences, Umeå University. Active as a biomedical analyst at the Arrhythmia Unit NUS at 20% and 80% employed as a lecturer at the Biomedical Laboratory Science program.
On Friday 1 December, Sofia Erelund, Department of Surgery and Perioperative Sciences at Umeå University, defends her thesis entitled Heart and Lung Function in Health and Disease. The dissertation takes place at 13:00 in Bergasalen, University Hospital of Umeå. Faculty opponent is Professor Carl-Johan Carlhäll, Linköping University.
