Implications of aggressive cardiac risk factor management on the catheter ablation for atrial fibrillation

INTERVENTION: The study will be a multi‐center prospective randomized controlled study evaluating the effect of a structured weight and cardio‐metabolic risk factor management program on multiple outcomes pertinent to Atrial Fibrillation. The project will incorporate two distinct studies with respective primary and secondary outcomes. Phase 1 will primarily assess the impact of intervention on objectively measured AF burden and electroanatomical remodelling and or reverse remodelling of heart along with autonomic and thrombotic parameters.This will be first 6 months after enrolment. Phase 2 will evaluate the impact of intervention on success of catheter ablation along with autonomic and thrombotic parameters and will be from time of ablation until 60 months. The two phases of the program, weight loss and weight maintenance, will follow a previously described approach. This regime has been successfully used by another study from our group and was assessed and approved by the RAH REC. Weight loss will be achieved by using structured physician‐led motivational and goal‐directed face‐to‐face visits every 3 months. In addition, patients will be encouraged to utilize support counseling and schedule more frequent reviews, as they required. The intervention cohort will be subjected to periodic intensive one‐on‐one supportive counseling that will review goals achieved and further incremental goal setting. Nutritional behavior reflection, barriers to goal achievement and nutritional decision coaching will be the pillars of the 20‐40 minute counseling sessions. Subsequent to barrier identification, verbal and written tailored educational material will be provided. The participant could schedule additional intervening visits and/or physician at will in the event of an impending relapse. When additional support is required, 24‐hour email and telephone contact will be available. Initial weight reduction will be attempted by a meal plan and behavior modification program. Participants will be required to maintain a diet and activity diary. Meals will consist of high protein and low glycemic index, calorie controlled foods. If the patients did not loose 3% of weight after first 3 months they will then be prescribed very‐low‐calorie meal replacement sachets (Prima health solutions or Nestle Health Science) for 1‐2 meals a day. The initial goal will be to reduce body weight by 10% from baseline. Patients on meal replacement supplement will undergo weight loss in two distinct phases. Weight loss phase : Weight loss will be induced over 8 weeks using a modified very low calorie diet (VLCD) (800‐1200 Cal/day). Patients will be prescribed VLCD meal replacement diet for 1‐2 of their daily meals. Remaining meal will consist of high animal and plant protein, and low glycemic index (GI), calorie controlled foods. Weight maintenance phase : After patients achieved initial goal the meal replacement will be replaced with high protein and low glycemic index, calorie controlled foods. Further weight loss with diet will be attempted if indicated with a target BMI of 25 kg/m2. This phase will focus on slower weight loss and maintenance. This will occupy the remainder of the follow up period. During this phase, VLCD meal supplements will be gradually phased out and replaced with a low GI meal plan with emphasis on education for permanent lifestyle changes and behavior modification program. CONDITION: Atrial Fibrillation Metabolic Syndrome PRIMARY OUTCOME: *AF burden on loop recorder before AF ablation(%) ; *Electrophysiological changes in conduction velocity/ERP: EP study will be done at baseline and at the time of AF ablation. Electrophysiology study using diagnostic EP catheter. ; ; ; SECONDARY OUTCOME: *Autonomic remodeling assessed by heart rate variability and NA spillover. Will be assessed by Holter data, EST, Tilt table, Sleep study results. Lifestyle Journal ‐ Participants in the intervention group only are instructed to maintain a self‐monitoring lifestyle journal detailing food type, preparation method and amount consumed. Patients are advised to review the journal on a weekly basis on their own and to reflect on nutritional behavioral patterns. The journal functions to indicate, in addition to nutritional habits, blood pressure patterns (documented 2‐3 times daily, see below) and estimated energy expenditure. The maintenance of the journal is a dynamic process, whereby it may be relaxed when significant clinical (and anthropometric) progress is made and re‐initiated when healthy lifestyle divergence is evident or a weight re‐gain is impending. Exercise – In the intervention group, physical activity is prescribed initially at 20 minutes of low intensity (walking and/or aqua‐aerobics) thrice weekly and titrated over phase 1 to reach 45 minutes thrice weekly finally increasing to at least 200 min of moderate‐intensity physical activity in a week. Type of activity and duration is logged into the journal. Control group participants are not required to maintain a lifestyle journal and education regarding activity levels is issued in the form of specific written material. Low intensity exercise was prescribed initially for 20 minutes thrice weekly Control Group ‐ Standard care (control) group participants are issued with once off written and verbal advice regarding health nutrition and exercise guidelines at commencement of their participation and weight management i ; Atrial effective refractory period (ERP) will be evaluated at cycle lengths (CL) of 600 and 450 ms with an 8‐beat drive followed by an extra‐ stimulus, starting with an extra‐stimulus coupling interval of 150 ms increasing in 10‐ms increments. The ERP will be defined as the longest coupling interval failing to propagate to the atrium. At each site the ERP will be measured 3 times during each CL and averaged. If ERP varied by >10 ms, an additional 2 measurements were made, and the total number was averaged. The ERP was measured from the following sites: 1) distal‐CS; 2) proximal‐CS; 3) low lateral RA; 4) high lateral RA; 5) high septal RA. ; Isochronal activation maps (5‐ms intervals) of the atria will be created and regional conduction velocity determined in the direction of the wave‐front propagation (least isochronal crowding). An approximation of conduction velocity will be determined by expressing the distance between 2 points as a function of the difference in local activation time. Mean conduction velocity for each region will be determined by averaging the conduction velocity between 5 pairs of points, as previously described. For the purposes of evaluating regional conduction differences, each atrium will be segmented as noted in the preceding text. ; *Physical functioning, health‐related quality of life (HRQoL) in patients post AF ablation. Will be assessed by AFSS scoring and SF36 data. ; ; *Platelet function and endothelial function. ; *Endothelial Function tested by : Endo PAT, ADMA,ET‐1 ; *Platelet Function tested by MPV,TAT,P‐Selectin,ADP,Collagen,Thrombin,Serotonin ; ; ; All‐cause mortality – From History Re‐hospitalisation‐ from history INCLUSION CRITERIA: Paroxysmal and persistent AF BMI>27 Waist circumference >100 (male), >90 (female) Highly symptomatic AF Age >18 years and <65 years ; AF inducibility will be assessed using a standardized protocol of burst pacing in the proximal followed by distal coronary sinus and during programmed extra stimuli from the same sites. Pacing will be started at 200 ms and will be decreased in 5‐ms intervals until either AF initiates or there is loss of 1:1 capture. A fixed rate of decrement will be used at 5 ms per 3 seconds to ensure consistency. AF is defined as rapid irregular atrial rhythm lasting longer than 2 seconds. This protocol of induction will be repeated 10 times. Mean AF duration will be obtained from the average of all induced AF episodes. If AF persists beyond 5 minutes, no further induction will be tried. *Percentage of patients free from AF on loop recorder after AF ablation. The AF burden will be assessed by loop recorder data.