Silent Atrial Fibrillation - Screening of High-risk Groups for Atrial Fibrillation (The Silence Study)

Overview

The primary aim of the present study is to screen high-risk type 2 diabetes patients and heart failure patients without any history of atrial fibrillation (AF), ongoing oral anticoagulation (OAC) treatment, implanted device or recent stroke/Transient Ischemic Attack (TIA), for silent AF. Moreover, we aim to establish the prevalence of two or more risk factors for stroke in patients with heart failure and diabetes mellitus type 2 (DM2) with the aim of assessing the feasibility for this group to undergo AF screening. Overall, the aim of the study is to prevent stroke in high-risk patients groups through identification of silent (asymptomatic) atrial fibrillation.

The number of screened patients with respectively heart failure and type 2 diabetes with a risk score (Congestive Heart Failure, Hypertension, Aged 75 years or older, Diabetes, Stroke / transient cerebral ischemia, Vascular disease, Aged 65 years or older and Sex category (CHADSVASc)) of two or more, the number of these patients excluded due to AF or ongoing AF, the number of eligible patients not included for other reasons, and, finally, number of included patients will be listed. Patients eligible for screening will be supplied with a hand-held ECG-recorder developed by Zenicor Medical Systems (www.zenicor.com) and will transmit recordings 4 times daily (morning, midday, evening -at meals - and before bedtime) and in case of symptoms, for 14 days. The transmitted ECGs will be digitally stored, analyzed and screened for AF. All AF episodes will recorded and the day and time of the arrhythmia will be registered. Eligible patients will be given brief oral and the more thorough written patient information about the study, and offered an appointment for the first meeting, which will happen in the Cardiological out-patient clinic in Copenhagen University Hospital (Hvidovre) with a member of the project group. During the first meeting, the patient will get more information about the study and has the possibility to ask questions. If the patient wants to bring a relative or friend already at this meeting, this can be arranged. If the patient meets the criteria and is interested in participation he/she will be invited to participation in the study. The patient gets the rest of the information material, i.e. written informed consent declaration, and is given a period for questioning and consideration of participation for at least three days. If the patient wants another visit for further information and possibly with participation of a relative or friend, such a visit is scheduled, and the patient can be included at this visit, and written informed consent declaration can be given to the project group member. Heart failure patients will have a standardized echocardiography and diabetes patients will have supplementary registration of HbA1c, and latest blood glucose value. The latest level of creatinine and creatinine clearance will be registered for all patients (DM2 and congestive heart failure (CHF)). Every patient is given a Study identification (ID) number and there will be a key file linking this number and the patient ID; thus, the dataset is anonymized. All ECG's will be analyzed using a soft ware based algorithm which has been developed in order to exclude normal recordings (sinus rhythm without irregularities). Patients with newly detected AF will be referred to the local cardiology out-patient clinic or if present OAC clinic for treatment according to established guidelines including OAC treatment. Here the patients will be informed about the options of OAC treatment, the reasons why we want to offer it, including the risk of developing cerebral ischemic stroke, precautions with this treatment and the risks connected to OAC treatment. The treatment with OAC is not a part of the screening study.