Exercise reduced burden of atrial fibrillation

Vegard Malmo. Foto: Andrea Hegdahl Tiltnes / NTNU“Time in atrial fibrillation and symptoms of the disease were reduced, and exercise capacity, cardiac function, lipid levels and quality of life were improved in the patients preforming high intensity interval training”, PhD candidate at CERG and medical doctor at St. Olavs Hospital,  Vegard Malmo.

He is first author in the paper “Aerobic Interval training reduces the burden of atrial fibrillation in the short term: A randomized trial” recently published in Circulation. In this study, 51 persons with non-permanent atrial fibrillation (AF) were randomized either to high intensity interval training (four 4-minute intervals at 85-95% of peak heart) rate three times a week for 12 weeks or a control group (continuing their earlier exercise habits). Minutes of AF each day was monitored continuously with an implanted recorder. In addition cardiac function, exercise capacity, lipid status, quality of life and AF symptoms were assessed.

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High fitness reduces risk of atrial fibrillation

Two women running outdoorOverweight, hypertension, diabetes and sleep apnea increases the risk of developing atrial fibrillation (AF). Interventions aimed at these risk factors are known to reduce the risk and improve the outcome for most cardiovascular diseases. However, there has been lacking knowledge on the effect of such interventions on AF, and there has been considerable attention on the finding that large amounts of endurance exercise increases the risk of developing AF. Recent years, there have been published some studies examining this topic.

Read also: CERG at ESC 2014

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CERG at ESC 2014

bilde 3Vegard Malmo presented the poster “Aerobic interval training reduces the burden of atrial fibrillation”. The study shows that aerobic interval training for 12 weeks clearly reduces the burden of AF in symptomatic patients. It is followed by a significant improvement in VO2max, left atrial and ventricular function, cholesterol levels, and quality of life. Further studies are needed to evaluate the underlying mechanisms and the effect of exercise training for a longer period of time. The study was presented at the ESC Congress in Barcelona who was arranged August 30th to September 3d.

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Summary – day 2 of the seminar

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Erich Gnaiger visiting the mitochondrial lab

Thursday evening involved a refreshing expedition in extreme weather followed by a delicious dinner in traditional surroundings. Luckily, everybody survived the storm and were ready for a new day full of scientific input. Day 2 started with a session focusing on mitochondrial function. First speaker was professor Erich Gnaiger from Medical University of Innsbruck, Austria – with the most suitable tie of the day:) His scientific contribution to the field of mitochondrial physiology and pathology is quite impressive, including significant contribution to more than 200 publications. Gnaiger is also the initiator and chairman of the International Mitochondrial Physiology Society. His lesson gave insight into mitochondrial respiratory control and early defects of oxidative phosphorylation in hearts affected by heart failure. Several studies have also shown the negative effects of an inactive lifestyle on the mitochondrial function in the heart. We even learned that human beings have very much in common with pigs – although there are some differences.

Dr. Boyett and CERG's Morten A. Høydal

Dr. Boyett and CERG’s Morten A. Høydal

The next session addressed basic mechanisms of cardiac function. Professor of Cardiac Electrophysiology Mark Boyett from the University of Manchester has been investigating the “ion channels” of the heart for several years, and held the presentation “Exercise training reduces the resting heart rate via downregulation of the funny channel, HCN4, and the funny current, If”. Further, Dr. Daniele Catalucci from Humanitas Clinical and Research Center and National Research Counsil (CNR) in Italy presented “Novel insights and new corrective strategies for the recovery of cardiac perfomance”.The calcium handling in the myocytes represents a very central part of the research activity in CERG, for instance as shown in this blog post. Several of our researchers therefore listened extra carefully when dr. Luigi Venetucci from the University of Manchester spoke about inherited calcium channelopathies in the pathophysiology of arrhytmias. This research plays an important role in the development of new drugs. However, as shown in our group, exercise training also affects the calcium handling in the myocytes, for instance with reduced phosphorylation of cytosolic CaMKII, which again is associated with improved contractile function.

IMGP4791Almost 40 % of heart failure patients have atrial fibrillation. Dr. Anthony J. Workman, University of Glasgow, gave us a very useful introduction to basic mechanisms of this disease, with insights from human atrial cells and cells from rabbits with heart failure. Workman and his colleagues have demonstrated that electric currents and voltage signals generated by single heart cells obtained from patients with AF are disturbed in a way that may exacerbate the disease, by so-called “electrical remodelling”. For example, the atrial cell’s refractory period is reduced, which may promote a rapid and chaotic rhythm. He also investigates the effects of beta-blockers, as well as the effect of heart failure, on electric currents, calcium movements and the proteins which regulate these, in human atrial cells and tissues.

IMGP4796Is cardiopulmonary exercise testing (CPET) more than VO2max? Definitely yes, according to dr. Sandy Jack, from the University of Southampton. She is a routined teacher of several CPET courses, with many of the CERG researchers as satisfied students. Her lesson highlighted the use of exercise testing in preoperative assessment and perioperative management, including prehabilitation in cancer patients undergoing major surgery. Further, research suggests that exercise enhances the effect of chemotherapy in cancer patients.

The scientific program was followed by the arrangement “Man in Extreme Environments” at Samfundet. More about that in the next blog post!

Maria Henningsen, CERG