Atrial Substrate Modification With Aggressive Blood Pressure Lowering to Prevent AF (SMAC AF)

Atrial fibrillation (AF) is a very common arrhythmia causing many symptoms resulting in numerous hospitalizations. Catheter ablation is a technique that has evolved significantly to improve symptomatic recurrences, but does not offer a 100% cure rate. We hypothesize that the use of aggressive BP lowering will reduce the rate of recurrent AF after catheter ablation for AF. We plan a randomized clinical trial of aggressive BP lowering versus standard BP control to investigate this. The primary outcome will be time to recurrent AF.

Background: Atrial fibrillation (AF) is the most common sustained arrhythmia and is associated with significant morbidity, necessitating treatment. Radiofrequency ablation for atrial fibrillation/flutter has evolved significantly and is the closest we have come to a 'cure' for these dysrhythmias. Recurrence of atrial fibrillation in those who have undergone radiofrequency ablation as treatment AF is up to 40% at one year and higher in those with persistent AF. Hypertension is a potent risk factor for AF, but recent studies have demonstrated that even modest increases in BP may lead to a higher incidence of AF. There is no clinical trial evidence to date that has investigated aggressive BP control in patients post radiofrequency ablation for AF to prevent recurrent AF.

Objective: We propose to determine if aggressive BP control reduces recurrent AF post ablation.

Hypothesis: Aggressive BP lowering will reduce the incidence of recurrent AF post ablation.

Research Plan:

Study Design. This will be a randomized open label trial in patients who are post catheter ablation for atrial fibrillation. Randomization to either aggressive BP lowering or standard BP control will occur six months prior to the procedure.

Study Population. Patients will be included if they have persistent AF and intend to have a catheter ablation procedure for AF.

Followup. Patients will be followed at 3 monthly intervals for a minimum duration of one year.

Outcome Measures. The primary outcome will be time to symptomatic recurrence of atrial fibrillation. The secondary outcome will be overall burden of atrial fibrillation at one year. The third outcome measure will be quality of life pre and post ablation. Other outcome measures include: recurrent ablation therapy, recurrent atrial tachycardia or atrial flutter, thromboembolic events, changes in biomarkers (CRP and BNP) from baseline, to 3 months and 6 months.

Statistical Analysis. Kaplan-Meier analysis of the primary outcome will be performed. A Cox proportional hazards model will be constructed to assess the effect of variables chosen a priori on the primary outcome.

• Active Comparator: 1
  Aggressive Blood Pressure control
  Intervention: Other: Aggressive Blood Pressure control
• Active Comparator: 2
  Standard Blood Pressure control
  Intervention: Other: Aggressive Blood Pressure control

Inclusion Criteria:

Persistent AF to undergo catheter ablation

Exclusion Criteria:

• Unable to give informed consent
• Women of child-bearing potential
• Other noncardiovascular medical condition making 1 year survival unlikely
• Less than 18 years of age