Kari Nytrøen

  • Postdoctoral research fellow, PhD, M.Sc

Kari Nytrøen successfully defended her thesis "Chronotropic responses and effect of high intensity interval based aerobic exercise in heart transplant recipients." in February 2014.

Physiotherapist and doctoral candidate Kari Nytrøen found that high-intensity interval training is a safe and effective form of exercise that improves stamina, enduring muscle strength and overall health in stable heart transplant patients.

Interval training is known for its positive effects. Nytrøen and co-workers wanted to investigate whether interval training has the same good effect among heart transplant patients as it has in the rest of the population. This type of exercise has been considered "unphysiologic" for heart transplant patients as they lack nerve supply to the new heart, leading to reduced heart rate response.

In this thesis it was shown that the heart rate response is partially normalized in most patients one year after transplantation and that the interval training performed by patients on average 4 years after transplantation led to:
- Increased oxygen uptake / better fitness (13% increase)
- Increased endurance of muscle strength (17% increase)  
- Better quality of life  
- Decreased progression (> 50%) of vasculopathy (a special form of arteriosclerosis affecting cardiac transplant patients = cardiac allograft vasculopathy)  

In conclusion, interval training is a safe and effective form of exercise that is recommended to improve the fitness and health of all heart transplant recipients well in way in the recovery process, given that their condition has remained stable and that they are othervise healthy. In addition to improved fitness and enduring muscle strength, interval training slows the development of vasculopathy, which may lead to reduced morbidity and mortality in this patient population.

 

Publications 2022

Rafique M, Solberg OG, Gullestad L, Bendz B, Holm NR, Neghabat O, Dijkstra J, Nytroen K, Rolid K, Lunde K (2022)
A randomized clinical study using optical coherence tomography to evaluate the short-term effects of high-intensity interval training on cardiac allograft vasculopathy: a HITTS substudy
Clin. Transplant., 36 (1), e14488
DOI 10.1111/ctr.14488

Publications 2021

Christensen AH, Nygaard S, Rolid K, Nytroen K, Gullestad L, Fiane A, Thaulow E, Dohlen G, Saul JP, Wyller VBB (2021)
Early Signs of Sinoatrial Reinnervation in the Transplanted Heart
Transplantation, 105 (9), 2086-2096
DOI 10.1097/TP.0000000000003580

Kienlin S, Poitras ME, Stacey D, Nytroen K, Kasper J (2021)
Ready for SDM: evaluating a train-the-trainer program to facilitate implementation of SDM training in Norway
BMC Med. Inform. Decis. Mak., 21 (1), 140
DOI 10.1186/s12911-021-01494-x

Wyller VBB, Nygaard S, Christensen AH, Rolid K, Nytroen K, Gullestad L, Fiane A, Thaulow E, Dohlen G, Saul JP (2021)
Functional evidence of low-pressure cardiopulmonary baroreceptor reinnervation 1 year after heart transplantation
Eur. J. Appl. Physiol., 121 (3), 915-927
DOI 10.1007/s00421-020-04586-0

Publications 2020

Kienlin S, Nytroen K, Stacey D, Kasper J (2020)
Ready for shared decision making: Pretesting a training module for health professionals on sharing decisions with their patients
J. Eval. Clin. Pract., 26 (2), 610-621
DOI 10.1111/jep.13380

Nytroen K, Rolid K, Yardley M, Gullestad L (2020)
Effect of high-intensity interval training in young heart transplant recipients: results from two randomized controlled trials
BMC Sports Sci. Med. Rehabil., 12 (1), 35
DOI 10.1186/s13102-020-00180-1

Rolid K, Andreassen AK, Yardley M, Gude E, Bjorkelund E, Authen AR, Grov I, Broch K, Gullestad L, Nytroen K (2020)
Long-term effects of high-intensity training vs moderate intensity training in heart transplant recipients: A 3-year follow-up study of the randomized-controlled HITTS study
Am. J. Transplant., 20 (12), 3538-3549
DOI 10.1111/ajt.16087

Rolid K, Andreassen AK, Yardley M, Gude E, Bjorkelund E, Authen AR, Grov I, Pettersen KI, Dall CH, Karason K, Broch K, Gullestad L, Nytroen K (2020)
High-intensity interval training and health-related quality of life in de novo heart transplant recipients - results from a randomized controlled trial
Health Qual. Life Outcomes, 18 (1), 283
DOI 10.1186/s12955-020-01536-4

Publications 2019

Nygaard S, Christensen AH, Rolid K, Nytroen K, Gullestad L, Fiane A, Thaulow E, Dohlen G, Godang K, Saul JP, Wyller VBB (2019)
Autonomic cardiovascular control changes in recent heart transplant recipients lead to physiological limitations in response to orthostatic challenge and isometric exercise
Eur. J. Appl. Physiol., 119 (10), 2225-2236
DOI 10.1007/s00421-019-04207-5

Nytroen K, Rolid K, Andreassen AK, Yardley M, Gude E, Dahle DO, Bjorkelund E, Authen AR, Grov I, Wigh JP, Dall CH, Gustafsson F, Karason K, Gullestad L (2019)
Effect of High-Intensity Interval Training in De Novo Heart Transplant Recipients in Scandinavia One-Year Follow-Up of the HITTS Randomized, Controlled Study
Circulation, 139 (19), 2198-2211
DOI 10.1161/CIRCULATIONAHA.118.036747

Nytroen K, Rolid K, Gullestad L (2019)
Response by Nytroen et al to Letter Regarding Article, "Effect of High-Intensity Interval Training in De Novo Heart Transplant Recipients in Scandinavia"
Circulation, 140 (17), E735-E736
DOI 10.1161/CIRCULATIONAHA.119.042458

Publications 2018

Eiring O, Brurberg KG, Nytroen K, Nylenna M (2018)
Rapid methods including network meta-analysis to produce evidence in clinical decision support: a decision analysis
Syst. Rev., 7, 168
DOI 10.1186/s13643-018-0829-z

Publications 2017

Eiring O, Nytroen K, Kienlin S, Khodambashi S, Nylenna M (2017)
The development and feasibility of a personal health-optimization system for people with bipolar disorder
BMC Med. Inform. Decis. Mak., 17, 102
DOI 10.1186/s12911-017-0481-x

Yardley M, Gullestad L, Bendz B, Bjorkelund E, Rolid K, Arora S, Nytroen K (2017)
Long-term effects of high-intensity interval training in heart transplant recipients: A 5-year follow-up study of a randomized controlled trial
Clin. Transplant., 31 (1), e12868
DOI 10.1111/ctr.12868

Yardley M, Ueland T, Aukrust P, Michelsen A, Bjorkelund E, Gullestad L, Nytroen K (2017)
Immediate response in markers of inflammation and angiogenesis during exercise: a randomised cross-over study in heart transplant recipients
Open Heart, 4 (2), UNSP e000635
DOI 10.1136/openhrt-2017-000635

Publications 2016

Eiring O, Nylenna M, Nytroen K (2016)
Patient-Important Outcomes in the Long-Term Treatment of Bipolar Disorder: A Mixed-Methods Approach Investigating Relative Preferences and a Proposed Taxonomy
Patient, 9 (2), 91-102
DOI 10.1007/s40271-015-0128-x

Nytroen K, Yardley M, Rolid K, Bjorkelund E, Karason K, Wigh JP, Dall CH, Arora S, Aakhus S, Lunde K, Solberg OG, Gustafsson F, Prescott EIB, Gullestad L (2016)
Design and rationale of the HITTS randomized controlled trial: Effect of High-intensity Interval Training in de novo Heart Transplant Recipients in Scandinavia
Am. Heart J., 172, 96-105
DOI 10.1016/j.ahj.2015.10.011

Yardley M, Havik OE, Grov I, Relbo A, Gullestad L, Nytroen K (2016)
Peak oxygen uptake and self-reported physical health are strong predictors of long-term survival after heart transplantation
Clin. Transplant., 30 (2), 161-169
DOI 10.1111/ctr.12672

Publications 2015

Eiring O, Landmark BF, Aas E, Salkeld G, Nylenna M, Nytroen K (2015)
What matters to patients? A systematic review of preferences for medication-associated outcomes in mental disorders
BMJ Open, 5 (4), e007848
DOI 10.1136/bmjopen-2015-007848

Publications 2014

Nytroen K, Rustad LA, Gude E, Hallen J, Fiane AE, Rolid K, Holm I, Aakhus S, Gullestad L (2014)
Muscular exercise capacity and body fat predict VO2peak in heart transplant recipients
Eur. J. Prev. Cardiol., 21 (1), 21-29
DOI 10.1177/2047487312450540

Rustad LA, Nytroen K, Amundsen BH, Gullestad L, Aakhus S (2014)
One year of high-intensity interval training improves exercise capacity, but not left ventricular function in stable heart transplant recipients: A randomised controlled trial
Eur. J. Prev. Cardiol., 21 (2), 181-191
DOI 10.1177/2047487312469477

Publications 2013

Nytroen K, Gullestad L (2013)
Effect of Exercise in Heart Transplant Recipients
Am. J. Transplant., 13 (2), 527
DOI 10.1111/ajt.12046

Nytroen K, Rustad LA, Erikstad I, Aukrust P, Ueland T, Lekva T, Gude E, Wilhelmsen N, Hervold A, Aakhus S, Gullestad L, Arora S (2013)
Effect of high-intensity interval training on progression of cardiac allograft vasculopathy
J. Heart Lung Transplant., 32 (11), 1073-1080
DOI 10.1016/j.healun.2013.06.023

Rustad LA, Nytroen K, Andreassen A, Geiran O, Endresen K, Gullestad L, Aakhus S, Amundsen BH (2013)
Heart transplant systolic and diastolic function is impaired by prolonged pretransplant graft ischaemic time and high donor age: an echocardiographic study
Eur. J. Cardio-Thorac. Surg., 44 (2), E97-E104
DOI 10.1093/ejcts/ezt233

Publications 2012

Nytroen K, Rustad LA, Aukrust P, Ueland T, Hallen J, Holm I, Rolid K, Lekva T, Fiane AE, Amlie JP, Aakhus S, Gullestad L (2012)
High-Intensity Interval Training Improves Peak Oxygen Uptake and Muscular Exercise Capacity in Heart Transplant Recipients
Am. J. Transplant., 12 (11), 3134-3142
DOI 10.1111/j.1600-6143.2012.04221.x

Publications 2011

Nytroen K, Myers J, Chan KN, Geiran OR, Gullestad L (2011)
Chronotropic Responses to Exercise in Heart Transplant Recipients 1-Yr Follow-Up
Am. J. Phys. Med. Rehabil., 90 (7), 579-588
DOI 10.1097/PHM.0b013e31821f711d

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