Proposed research:
This pilot study will evaluate the potential efficacy and feasibility of risk factor
modification in patients with a known history of symptomatic paroxysmal and persistent AFIB
(in sinus rhythm) by implementing current evidence-based lifestyle recommendations as well as
gain an understanding of the impact of these changes in the gut microbiome.
Objectives:
This study aims to determine if a multicomponent risk factor modification intervention
(dietary intervention, exercise regimen and behavioural therapy) implemented using a basic
healthcare team reduces the burden of AFIB at 12 months by decreasing the length and number
of AFIB episodes. This study aims to assess the impact of these interventions on AFIB-related
symptoms, quality of life and rhythm status (documented on an implantable loop recorder
[ILR]).This study aims to examine the gut microbiota and identify potential organisms which
may be present in higher concentrations in patients with an elevated BMI and AFIB and how
these organism levels may alter with dietary changes.
Study Design:
Baseline Screening & Follow-Up Assessments and Procedures:
As part of our current clinical practice, all participants will undergo a clinical assessment
which includes a 12-lead ECG and BP (this will be repeated at all follow-up visits: 1, 3, 6,
and 12 months). Demographic data and body composition measurements (i.e. waist circumference)
will also be obtained from participants' medical charts or from each participant directly.
Screening for Diabetes mellitus, hyperlipidemia, obstructive sleep apnea and hypertension
will also be completed at the first baseline visit.
If not checked within the prior 6 months, all participants will have a baseline blood sample
drawn at the first baseline visit to test for baseline sodium (Na), potassium (K), urea,
creatinine, free thyroxine (T4) and thyroid stimulating hormone (TSH) (this will be repeated
at 12 months). HbA1C (prediabetes/Diabetes mellitus testing) and a fasting lipid profile
(hyperlipidemia testing) will also be measured at baseline and repeated at 12 months if
applicable (i.e. HbA1C in those with prediabetes or Diabetes mellitus and a fasting lipid
profile in those with hyperlipidemia).
If not performed within the past 12 months, all participants will undergo a baseline
transthoracic echocardiogram (TTE). A follow-up TTE will be repeated at the 12-month visit.
AFIB: At the first baseline visit and all follow-up visits, AFIB-related symptom burden
(using the AFSS - Appendix I) and quality of life (using the AFEQT - Appendix II) will be
assessed. All participants will undergo implantation of an implantable loop recorder (ILR) at
their first baseline visit (Appendix VIII). This device will continually record the
participants' heart rate and rhythm for a period of 12 months and will record any episodes of
AFIB. These data will be downloaded by a technician during each follow-up visit (1, 3, 6, and
12 months) and stored in a secure manner. Principal and Co-Investigators will be blinded to
these data. The ILR will be removed from participants during their final follow-up visit (at
12 months).
Apple Watch: All participants will be supplied with an Apple Watch in order to monitor their
levels of physical activity (i.e. step counts and physical activity duration). For this
reason, participants are required to own/have daily access to (i.e. provided by the research
team) an iPhone to sync with the Apple Watch. The watch will be integrated with 2 apps
(Cardiogram and Lose It) to record and keep track of physical activity, caloric intake and
will also monitor heart rate. Participants will be trained on the use of the watch and apps.
Participants will also be instructed to put this watch on first thing in the morning and not
remove it until the evening when heading to bed throughout the duration of the trial.
Participants will be asked to send data from the apps to the research team by email on a
weekly basis. Participants will be asked to return the Apple Watch at their final follow-up
visit (at 12 months).
Physical activity: Physical activity levels will be assessed using the IPAQ and MESA TWPAS
Questionnaire at the first baseline visit. These questionnaires will also be administered at
all follow-up visits (1, 3, 6, and 12 months). Participants will be asked to share data from
the Cardiogram app with the research team on a weekly basis.
Diet: The diets of all participants will be evaluated at the first baseline visit and
follow-ups (1, 3, 6, and 12 months) using the Mediterranean Diet Score Tool. Participants
will be asked to enter all food consumed into the Lose It app each day and send this
information to the research team on a weekly basis. Only participants in the intervention
group will be provided with the Mediterranean Diet Handout at baseline.
Gut microbiota: Participants will be provided with and trained on the use of "Poop" Kits.
Stool samples will be collected (2nd baseline visit and at 1, 3, 6, and 12 months) and
immediately stored at -80°C in Zymo collection devices. This deactivates active pathogens and
preserves DNA for future extraction. Analyses will occur in the Centre for the Analysis of
Genome Evolution and Function (CAGEF) at the University of Toronto, directed by Professor
David Guttman. Microbial DNA will then be extracted from the frozen fecal samples and the 16S
rRNA gene will be amplified. Analyses will be performed to determine levels of specific
metabolites that have been strongly correlated to obesity and metabolic syndrome, namely
monosaccharides and short-chain fatty acids (SCFAs).
Randomization: A randomization schedule will be prepared by the data coordinating centre at
Queens University, Kingston, Ontario using a computerized random number-generator. Random
allocation will be determined by a participant randomization software application (Dacima
Software Inc., IWRS: Interactive Web Response System). Participants will be randomized on a
1:1 fashion between active intervention and control.
Experimental arm: Multicomponent Risk Factor Modification Baseline - 12 months: Active
Lifestyle Intervention Participants in this intervention group will undergo the baseline and
follow-up assessments described earlier. The specific components of the experimental arm will
be tailored to the needs of the participants at their baseline visit for the study.
Throughout the trial, participants in this group will be called weekly by a member of the
research team to review and discuss each component of the lifestyle intervention (diet,
exercise, and behavioural therapy). Details of each component are explained below.
Diet will be assessed (at baseline and all follow-up visits) using the Mediterranean Diet
Score Tool (a 14-item questionnaire of adherence to the specified diet).Nutrition
prescription will be based on a Mediterranean-style diet and individualized based on the
participant's current weight and diet practices to optimize adherence. The diet will be
comprised of recommended daily intakes of 50% carbohydrates, 35% unsaturated fats, and 15%
protein. At baseline, basic information will be provided in written format using the
Mediterranean Diet Handout. Data from the individuals' Apple Watches will be monitored and
analyzed throughout the trial in order to assess compliance with these recommendations. Each
participant will receive feedback and advice from the research assistant during weekly
telephone sessions to motivate participants to make healthy changes to their diet in line
with the Mediterranean Diet recommendations. Personal individual recommendations for changes
to be introduced in the participant's diet in order to achieve a personalized goal. Research
personnel will highlight the advantages of following this diet as opposed to the risks of not
adhering to it. This approach has been successful in previous studies where behavioural
intervention was used to help participants quit smoking.
Physical activity levels will be assessed (at baseline and all follow-up visits) using the
IPAQ and MESA TWPAS. Exercise prescription was selected by investigators based on a recently
published Harvard Medical School Health Report 'Starting to Exercise'. This report recommends
individuals to perform 150 minutes of moderate aerobic exercise per week (equal to >30
minutes/day, most days of the week). Data from the individuals' Apple Watches will be
monitored and analyzed throughout the trial in order to assess compliance with these
recommendations. Each participant will receive feedback and advice from the research
assistant during weekly telephone sessions to motivate participants to gradually achieve
higher levels of physical activity. Participants will be invited to attend an optional
exercise class in which they walk along an indoor walking track for 60 minutes biweekly at
Providence Care Hospital, supervised by a research assistant and monitored by a medically
qualified Co-Investigator.
Comprehensive lifestyle intervention will include a structured behavioural change program
that includes regular self-monitoring of food intake, by entering all food consumed into the
Lose It app, which automatically calculates caloric intake, and physical activity. The
qualified research assistant will facilitate participant engagement sessions by telephone on
a weekly basis. During each session, the research assistant will assess the participant's
current level of adherence to the diet and exercise recommendations and will motivate them to
gradually achieve higher levels of exercise following the Harvard Medical School Health
Report and to make healthy adjustments to their diet following the Mediterranean Diet
Handout.
Control arm: Baseline - 12 months: Standard Clinical Practice In addition to receiving
standard of care AFIB treatment, participants in the control arm of this trial will undergo
all of the same baseline screening and follow-up assessments and procedures as the
intervention arm but will receive no lifestyle intervention (no diet, exercise regimen, or
behavioural therapy).