Exercise-based Cardiac Rehabilitation for Atrial Fibrillation

Changes in atrial fibrillation burden as measured by the University of Toronto Atrial Fibrillation Severity Scale (AFSS). The AFSS is a disease-specific measure used to capture subjective and objective ratings of disease burden in patients with atrial fibrillation. It assesses atrial fibrillation burden (score 1-30; higher scores indicate higher burden); Global Well Being (a visual analogue scale ranging from 1-10, indicating a patient reports as having a worst possible life [0] to the best possible life[10]); AF symptom score (score of 0-35; higher scores indicate more bothered by AF symptoms); and health care utilization (score of 0-21; higher scores indicate greater health care utilization).

AF recurrence will be measured using the AliveCor KardiaMobile which is a hand-held one lead electrocardiogram (ECG) device.

Kardia Mobile is an FDA approved device that allows six lead ECG recording for 30 seconds using the patient's smart phone. The device has a automated algorithm that interprets the ECG as either 'sinus rhythm', 'AF', or 'unclassified'. We will be collecting the counts of these classifications to assess the number of AF episodes.

Health related quality of life as measured by the Atrial Fibrillation Effect on Quality of Life Questionnaire (AFEQT). The AFEQT assesses 4 domains: symptoms, activities, treatment concern, treatment satisfaction, and a summary score that includes the first 3 domains. Patients will assess the impact of AF on their health status during the previous 4 weeks. Responses are presented on a 7-point Likert scale. Raw scores within each domain are transformed from a 0 (most severe symptoms) to a 100 scale (no limitations or disability).

The 5-level EuroQol-5 Dimensions (EQ-5D-5L) is a parsimonious measure of health-related quality of life consisting of five dimensions: mobility, self-care, usual activities, pain/discomfort, anxiety/depression. It also includes a Visual Analogue Scale (EQ-VAS) aimed at capturing participants' rating of their 'health today' on a scale from 0-100 with 100 being the best state and 0 being the worst state.

The EQ-5D will also be used to inform economic evaluation.

Maximal oxygen consumption (VO2peak) will be measured using cardiopulmonary exercise testing (CPET). Peak exhaustion will be evaluated by several variables (e.g. respiratory exchange ratio ≥T 1.10, heart rate and subjective exhaustion of the patient). VO2peak will be defined as the peak VO2 reached during the test. The test will be performed by two members of the research team. For safety reasons, pre-set criteria for initiation and/or termination of the test have been defined.

Additional variables will include ventilatory thresholds (VT1 and VT2), VO2 slopes, and O2 pulse.

The maximum walking distance (in metres) within 6 minutes will be used to assess exercise capacity, measured via the six-minute walk test (6MWT).

Transthoracic Echocardiography (echo) will be performed by a clinically accredited echocardiographic. Cardiac structure and function will be assessed non-invasively with the participant lying on their left side. Standard 2-dimensional (2D), 3-dimensional (3D) Doppler, tissue-Doppler (TDI) and M Mode scans will be performed using a commercially available ultrasound system (Vivid iQ, GE Medical, Horton, Norway) with a 1.5-4 megahertz (MHz) phased array transducer applied to the participant's chest.

A full level 2 transthoracic assessment in keeping with the British Society of Echocardiography) BSE minimum dataset, including left ventricular ejection fraction, left atrial volume, left atrial strain (and rate), left atrial volumetric function, left ventricle filling pressures, right atrial strain and exploratory 3D volumes.