Ablation of Atrial Fibrillation Clinical Trial
Official title:
Atrial Fibrillation Ablation The Hybrid Approach Versus Traditional Management
Rationale: To determine the most beneficial ablation methodology for individual patients
with paroxysmal or persistent atrial fibrillation (defined by the Heart Rhythm Society) as
surgeons and electrophysiologists work together on a convergent procedure (hybrid) to place
the epicardial and endocardial ablation lines.
Objectives: Catheter and surgical ablation are being offered today to patients with drug
refractory and symptomatic atrial fibrillation. This study is designed to assess the most
efficient ablation approach in patients with paroxysmal and persistent atrial fibrillation.
In patients with left atrium size of less than 5.0 cm, a Hybrid approach (pulmonary vein
isolation performed surgically will be combined with right and left atrial flutter lines
performed using a transcatheter approach) will be compared to percutaneous catheter ablation
to isolate the pulmonary veins and apply the left and right atrial flutter lines with
removal of LA appendage. In the group of patients with left atrial size 5.0-6.0 cm the
Hybrid approach is going to be compared to the minimally invasive Cox-Maze III procedure.
Our hypotheses with regard to the rate of return to sinus rhythm off antiarrhythmic drugs at
6 months will demonstrate that the Hybrid approach is going to be a: superior to
percutaneous catheter ablation in the less than 5 cm left atrial group and b: non-inferior
when compared to the Cox-Maze III procedure in the 5-6 cm left atrial cm group.
We hypothesize that the safety of all procedures will show no differences and that there
will be no differences in clinical complications between groups.
Study Type: This is an experimental study in which patients who present with either
paroxysmal or persistent atrial fibrillation will be randomized based on their left atrial
size (≤ 5.0 or > 5.0 but < 6.1 cm) to receive a hybrid ablation approach vs percutaneous
catheter where in both procedures ablation will include pulmonary vein isolation with a left
and right atrial flutter line for patients with a left atrium ≤ 5.0 cm. and hybrid approach
will be compared to the Cox Maze III procedure for patients with a left atrium > 5.0 < 6.1
cm .
Study Design: One hundred and fifty two patients (n=152) with persistent or paroxysmal
atrial fibrillation who present for surgical or catheter ablation intervention are to be
enrolled. The study will take place at the Inova Heart and Vascular Institute in Falls
Church, VA in the specially designed hybrid surgical suite in the cardiovascular operating
area. We expect enrollment to take (two years study duration). Patients will be included if
they present for ablation with paroxysmal or persistent atrial fibrillation as defined by
the Heart Rhythm Society and their left atrium is < 6.1 cm (volume). Patients will be
excluded if they present with long standing persistent atrial fibrillation as defined by the
Heart Rhythm Society, require other cardiac surgery, are unable to take anticoagulation or
require prescribed anti arrhythmic medication for reason other than atrial fibrillation,
have a left atrium measuring greater than 6.0 cm (volume),have had previous catheter
ablation for atrial fibrillation (Do not exclude for prior AVNRT) or a pacemaker, are less
than 18 years of age, are unable or unwilling to be followed according to set protocol to
include implantation of a heart monitor 6 weeks prior to their ablation procedure.
Study Methodology: This is an experimental study in which patients who present with either
paroxysmal or persistent atrial fibrillation will be randomized based on their left atrial
size.
For patients with a left atrium size of less than 5.0 cm, a Hybrid approach (pulmonary vein
isolation performed surgically will be combined with right and left atrial flutter lines
performed using a transcatheter approach) will be compared to percutaneous catheter ablation
to isolate the pulmonary veins and apply the left and right atrial flutter lines. In the
group of patients with left atrial size of 5.0-6.0 cm the Hybrid approach is going to be
compared to the minimally invasive Cox-Maze III procedure (Figure 1). Each patient
regardless of procedure will have their left atrial appendage closed. All patients will
receive an internal event monitor (Reveal XT) which will be placed 6 weeks before their
procedure to establish atrial fibrillation burden. All patients will also be given a health
related quality of life and a symptom frequency and severity tool to fill out prior to their
ablation and at 3 and 6 months post ablation.
The primary outcome will be the rate of return to sinus rhythm as defined by the Heart
Rhythm Society Guidelines (sinus rhythm maintained off anti arrhythmic medications and any
monitored atrial arrhythmia greater than 30 seconds will be considered a recurrence) at 6
months and atrial fibrillation burden
The secondary outcomes will include:
Number and type of procedural complications Number of embolic strokes The number of major
bleeding events as defined by the need to receive a transfusion for the amount of blood lost
and or hemorrhagic stroke while receiving anticoagulation therapy.
Reported improvement in patients' self reported health related quality of life and their
symptom frequency and severity at 3 and 6 months
Statistical Methodology: Since this is a proof of concept study without any prior literature
to obtain margins, we used the current rate of return to sinus rhythm as our margins to
determine sample size. This is fully explained in section 4.2. Based on these calculations,
152 patients will be randomized as described above. Descriptive statistics will be used to
characterize the patient population. T-tests and ANOVAs will be used to look for differences
between groups within the continuous data. Chi square, Fisher's Exact test and/or McNemar's
Test will be used to look for differences among categorical variables. For all analyses, a
two-sided p value <0.05 will be used to determine significance.
To analyze the primary objective, the percentage of patients in each group who return to
normal sinus rhythm will be calculated. Chi square analysis, or logistic regression if
covariates are required, will be used to test for differences in the odds of returning to
normal sinus rhythm between the treatment groups in both arms of the study. Chi square
and/or logistic regression will also be used to assess the secondary aim regarding
complications between the treatment groups. For the left atrial size > 5.0 but < 6.1 cm arm
of the study, testing for non-inferiority of complication rates will be conducted using the
treatment effect and 95% confidence intervals. These will be compared against the 10%
non-inferiority margins, to assess whether the treatment effect and 95% confidence interval
fall entirely within the margins. Lastly, repeated measures analysis of variance (ANOVA)
will be conducted to examine the secondary aim regarding change in health-related quality of
life by treatment groups.
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Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Treatment