Symptom burden, Metabolic profile, Ultrasound findings, Rhythm, neurohormonal activation, haemodynamics and health-related quality of life in patients with atrial Fibrillation (SMURF): a protocol for an observational study with a randomised interventional component

INTRODUCTION: Atrial fibrillation (AF) is the most common cardiac arrhythmia, with an estimated prevalence of 1.5–2%. It is an independent risk factor for ischaemic stroke and is estimated to cause about 20–25% of all stroke cases. AF has a great impact on health-related quality of life (HRQoL); however, one unresolved issue related to AF is the wide variation in its symptoms. METHODS AND ANALYSIS: The symptom burden, metabolic profile, ultrasound findings, rhythm, neurohormonal activation, haemodynamics and HRQoL in patients with AF (Symptom burden, Metabolic profile, Ultrasound findings, Rhythm, neurohormonal activation, haemodynamics and health-related quality of life in patients with atrial Fibrillation, SMURF) study is a prospective observational, cohort study, with a randomised interventional part. The aim of the study is to investigate, in patients with AF, the relationship between symptom burden and metabolic aspects, atrial function and different neurohormones, and the effect of radiofrequency ablation (RFA). The interventional part of the study will give an insight into the neurohormonal and intracardiac pressure changes directly after initiation of AF. Consecutive patients with symptomatic AF accepted for treatment with RFA for the first time at Linköping University Hospital are eligible for participation. The enrolment started in January 2012, and a total of 200 patients are to be included into the study, with 45 of them being enrolled into the interventional study with initiation of AF. The sample size of the interventional study is based on a small pilot study with 5 patients induced to AF while 2 served as controls. The results indicated that, in order to find a statistically significant difference, there was a need to include 28 patients; for safety reasons, 45 patients will be included. ETHICS AND DISSEMINATION: The SMURF study is approved by the Regional Ethical Review Board at the Faculty of Health Sciences, Linköping, Sweden. The results will be presented through peer-review journals and conference presentation. TRIAL REGISTRATION NUMBER: NCT01553045; Pre-results.