Physical activity after cardiac arrest; protocol of a sub-study in the Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest trial (TTM2)

Aims: The primary aim of this study is to investigate whether out-of-hospital cardiac arrest (OHCA) survivors have lower levels of self-reported physical activity compared to a non-cardiac arrest (CA) control group who had acute myocardial infarction (MI). Additional aims are to explore potential predictors of physical inactivity (older age, female gender, problems with general physical function, global cognition, mental processing speed/attention, anxiety symptoms, depression symptoms, kinesiophobia, fatigue), and to investigate the relationship between self-reported and objectively measured physical activity among OHCA-survivors. Methods: The Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest trial (TTM2-trial) collects information regarding age, gender, self-reported physical activity, general physical function, global cognition and mental processing speed/attention at 6 months after OHCA. In this TTM2-trial cross-sectional prospective sub-study, participants at selected sites are invited to an additional follow-up meeting within 4 weeks from the main study follow-up. At this meeting, information regarding anxiety symptoms, depression symptoms, kinesiophobia and fatigue is collected. The OHCA-survivors are then provided with an objective measure of physical activity, a hip-placed accelerometer, to wear for one week, together with a training diary. At the end of the week, participants are asked to once again answer two self-reported questions regarding physical activity for that specific week. MI-controls attend a single follow-up meeting and perform the same assessments as the OHCA-survivors, except from wearing the accelerometer. We aim to include 110 OHCA-survivors and 110 MI-controls in Sweden, Denmark and the United Kingdom. Conclusion: The results from this sub-study will provide novel information about physical activity among OHCA-survivors.