Weight management and Atrial Fibrillation: The impact of weight and risk factor management on AF burden in overweight and obese patients.

The Weight Management and Atrial Fibrillation is a multi-component prospective study aimed at investigating multiple research questions pertinent to obesity and atrial fibrillation: 1. The impact of weight and risk factor management on AF burden in overweight and obese patients 2. The impact of weight reduction prior to AF catheter ablation on procedure outcomes, in overweight and obese patients 3. The impact of weight reduction on the AF substrate and autonomic system modulation in overweight and obese patients: A mechanistic study (separate registration) Weight Management and Atrial Fibrillation: The impact of weight and risk factor management on AF burden in overweight and obese patients. Patients in the intervention group undergo a 2 phase physician-led weight management program concurrently with tight metabolic risk factor control. Upon randomization to the intervention arm, patients undergo a 2 month modified very low calorie diet (VLCD) and a gradually titrated low intensity exercise program. During the high intensity modified VLCD phase, patients will be prescribed a standard nutritionally complete meal replacement product (Prima Health Solutions, Kickstart) for 2 of the 3 daily meals. This will be ongoing for 2 months and used in conjunction with a didactic eating plan framework. Generally, patients will be prescribed an eating plan focusing on: 1. Calorie maintenance 800-1200 calories/day 2. Low glycemic index foods 3. High mono and poly unsaturated fats based foods 4. Low saturated fats, cholesterol and sodium based foods 5. Alcohol reduction (less than or equal to 30g/week) Patients will be required to maintain a lifestyle journal outlining: 1. Exercise (duration and type) 2. Food intake (quantity and type) 3. Blood pressure measurements Physical activity prescription is tailored as follows: 1. Initially 3 x 20 minute sessions of low intensity exercise per week (usually walking) 2. This is titrated upwards over the initial 2 months to 1 – 2 low intensity session(s) plus 1 – 2 moderate intensity session(s) per week. Moderate intensity sessions include, jogging, brisk walking, swimming, cross-trainer, rowing machine, cycling 3. In the case of limiting musculoskeletal conditions, hydrotherapy or aqua aerobics are utilized instead 4. Patients are encouraged to utilize pedometers to quantify their personal best and to aim to supersede this over time At commencement, they are issued with pre-specified written material on healthy eating, dining out, food shopping and physical activity. During the initial phase of the program, patients will be reviewed monthly in a specialized weight and risk factor management clinic along with their lifestyle journal. Following the 2 month high intensity phase, patients will undergo a more gradual weight management program with greater focus on permanent lifestyle change. During the second phase of the study, meal replacement sachets will be discontinued. Patients will be reviewed 3 monthly in the clinic for the remaining duration of follow-up (15-months). At baseline, weight, body mass index (BMI), waist circumference (WC), height, blood pressure as well as baseline demographic data are recorded. Patients have blood drawn for baseline fasting biochemistry (BUN, LFTs, INR, hsCRP, TSH, T4, Insulin, Glucose, Cholesterol, HDL, LDL and triglycerides). All patients undergo stringent risk factor identification and management. In addition to weight, metabolic risk factors include: 1. Smoking 2. Hyperlipidemia 3. Hypertension 4. Glucose intolerance or diabetes mellitus 5. Alcohol intake 6. Obstructive sleep apnea All patients undergo sleep apnea screening through overnight polysommnography at a dedicated sleep unit. When clinically indicated (in conjunction with AHI interpretation), CPAP may be prescribed and titrated. Patients are educated about tobacco and alcohol harm and provided with written education. Follow-up and feedback is provided on clinic visits. Alcohol reduction to less than or equal to 30g/week is aimed for, in view of established metabolic disease and cardiac arrhythmia. In the event of intermediate fasting glycemia, a 2 hour glucose tolerance test is undertaken. If glucose intolerant or insulin resistant continued lifestyle measures are pursued. Patients with frank diabetes are prescribed oral hypoglycemic agents and referred to a diabetes clinic. Hypertension is diagnosed based on family physician records and documented readings in the lifestyle journal. Management with a combination of lifestyle measures, salt reduction and pharmacotherapy is undertaken. Medication may be combined and titrated based on clinician judgment and patient tolerance. During the follow-up visits, patients will undergo face-to-face counseling and feedback based on anthropometric measures and lifestyle journal. Patients will have access to 24 hour email and telephone support in addition to additional counseling sessions if required. At each appointment, data is entered into the OBEMAN software program. Periodic measurements include: 1. BMI, WC, blood pressure, 12-lead ECG (baseline and three monthly) 2. Anti-hypertensive and anti-arrhythmic medication usage (baseline and three monthly) 3. Atrial Fibrillation Severity Scale (AFSS) (baseline and 3, 9, 12 and 15 months) 4. 7 day Holter recording (baseline and 15 months) 5. Transthoracic echocardiography (baseline and 15 months) 6. Cardiac MRI (baseline and 15 months) 7. Fasting plasma biochemistry (baseline and 15 months) Weight Management and Atrial Fibrillation: The impact of weight reduction and risk factor management prior to AF catheter ablation on procedure outcomes, in overweight and obese patients. The aim of this sub-study is to determine the impact of weight and risk factor management prior to catheter ablation on procedure outcomes, in overweight and obese subjects. Patients who have undergone weight and risk factor modification and are clinical candidates for catheter ablation are recruited into this arm of the study. Patients undergo the weight and risk factor management program as per the protocol in the sub-study, “Weight Management and Atrial Fibrillation: The impact of weight and risk factor management on AF burden in overweight and obese patients” (above). Patients who attain either end-point: 1. BMI < 27 and/or WC < 100cm (males) [<90cm (females)] 2. 15 month follow-up Patients who remain symptomatic of AF are eligible to undergo a catheter ablation. Following the catheter ablation procedure, patients continue to undergo weight and risk factor management with three monthly follow-up for 24 months post procedure. The recurrence of AF post ablation is determined on follow-up. Periodic measurements following catheter ablation include: 1. BMI, WC, blood pressure, 12-lead ECG (baseline and three monthly following procedure, for 24 months) 2. Anti-hypertensive and anti-arrhythmic medication usage (baseline and three monthly following procedure, for 24 months) 3. Atrial Fibrillation Severity Scale (AFSS) (three monthly following procedure, for 24 months) 4. 7 day Holter recording (baseline and 24 months) 5. Transthoracic echocardiography (baseline and 24 months) 6. Cardiac MRI (baseline and 24 months) 7. Fasting plasma biochemistry (baseline and 24 months) Weight Management and Atrial Fibrillation: The impact of weight reduction on the AF substrate and autonomic system modulation in overweight and obese patients: A mechanistic study. This study will be registered separately. It is mentioned briefly outlined here due to its overlapping nature and common steering committee. The aim of this sub-study is to investigate the changes in the autonomic system and arrhythmogenic substrate with weight reduction, and the effect this has on AF burden. Patients who have undergone weight and risk factor modification as per protocol for the sub-study, “Weight Management and Atrial Fibrillation: The impact of weight and risk factor management on AF burden in overweight and obese patients” (above), are eligible for entry into this sub-study. The aim of this sub-study is to determine the changes in autonomic tone and AF substrate with weight and risk factor management. The periodicity of follow-up data recording is as follows: 1. BMI, WC, blood pressure, 12-lead ECG (baseline and three monthly) 2. Anti-hypertensive and anti-arrhythmic medication usage (baseline and three monthly) 3. Atrial Fibrillation Severity Scale (AFSS) (baseline and 3, 9, 12 and 15 months) 4. 7 day Holter recording (baseline and 15 months) 5. Heart rate variability (baseline and 15 months) 6. Exercise stress testing (baseline and 15 months) 7. Head up tilt table testing (baseline and 15 months) 8. Transthoracic echocardiography (baseline and 15 months) 9. Delayed enhancement Cardiac MRI (baseline and 15 months) 10. Fasting plasma biochemistry (baseline and 15 months) Control/comparator group: Standard care is provided for the control group. This consists of: 1. Written material and verbal advice through direct contact counseling 2. 3g/day of marine omega triglycerides (docosahexaenoic acid and eicosapenteanoic acid) 3. Scheduled 3 monthly clinic visits As for the intervention arm, patients are required to maintain a lifestyle journal which is reviewed three monthly. Diet and exercise counseling is provided via written material as a once-off session at commencement of participation. Risk factors identification, management and data recording is carried out as per the intervention group.