Pulmonary Vein Isolation Alone or in Combination With Substrate Modulation After Electric Cardioversion Failure

Atrial fibrillation (AF) is the most common heart rhythm disorder. It is the result of uncoordinated action of the atrial myocardial cells, causing rapid and irregular contraction of the heart's atria.

The AF prevalence in adults is currently estimated to be between 2% and 4% and is expected to increase by a factor of 2.3 in the next few years, due to the increased longevity of the general population and the increased search for undiagnosed AF. Increased age is an important risk factor for AF, but other increased comorbidities, including hypertension, diabetes, heart failure, coronary artery disease, chronic renal failure, obesity, and obstructive sleep apnoea syndrome, are also important; modifiable risk factors contribute strongly to the development and progression of AF (ESC Guideline, 2020).

The European Society of Cardiology (ESC) recommended pulmonary vein isolation (PVI) (Class IA) as first-line ablative strategy for persistent AF (Class IA) (ESC Guideline, 2020). However, PVI alone is only effective in treating about 40% to 60% of patients with persistent AF in the general population (unselected). If we apply this strategy to all patients (PVI alone), we accept to re-do ablative procedure in up to 60% of patients.

The second feasible strategy is to treat patients with persistent AF by PVI combined with substrate modulation (ESC Class IIb). This strategy, when done well, by creating irreversible lesions (Marshall-PLAN) can effectively treat 70% to 80% of AF patients. But this implies that the investigator will be doing unnecessary substrate modulation in up to 40% of patients, which can lead to increased risks associated with the ablative procedure, longer procedure times, multiple lesions, etc… In addition, incorrect or incomplete substrate modulation is pro-arrhythmic and leads to recurrences in the form of left atrial flutters, tolerance of which, is generally poor.

Both ablative strategies have been widely validated in large numbers of published studies.

The problem is to know when and for which patients to apply one or the other of the two strategies. Electric cardioversion could help in selecting the most appropriate strategy.

Inclusion criteria

Criteria to be validated for patients included before performing electric cardioversion:

• Persistent AF (continuous for at least 7 days without interruption according to information transmitted by the cardiologist and the patient), symptomatic and resistant to at leat one anti-arrhythmic drug treatment including amiodarone;

Criteria to be validated for patients included after performing electric cardioversion :

• Patient treated by electric cardioversion for persistent AF, symptomatic and resistant to anti-arrhythmic treatment including amiodarone and whom ablative procedure is planned in the following 4-6 weeks after electric cardioversion

Criteria to be validated for all patients included:

• Life expectancy > 5 years;
• Female or male between 18 and 80 years of age at the electric cardioversion time
• Affiliation to a health insurance system;
• Patient informed of the study and having signed informed consent

Criteria to be validated prior to randomization on the day of ablation (these patients may be randomized):

• Patient with failed electric cardioversion i.e. in AF, confirmed by ECG.

Exclusion criteria

Criteria to be validated before or after performing electric cardioversion (the study cannot be proposed to patients corresponding to these criteria):

• Current hyperthyroidism;
• Pregnant or breastfeeding woman;
• Patient with a Body Mass Index (BMI) greater than 35;
• Patient with severe Chronic Obstructive Pulmonary Disease (COPD);
• Patient with hypertrophic heart disease;
• Patient with a mechanical or biological mitral valve;
• Contraindications to anticoagulants;
• Transient Ischemic Attack (TIA) /stroke less than 6 months old;
• Psychiatric illness affecting follow-up;
• Left Ventricular Ejection Fraction (LVEF) < 40% ;
• Uncontrolled ischaemic heart disease (angina, myocardial ischaemia)
• Patients under legal protection
• Cardiac surgery on left atrium
• Inflammatory status in progress (cancer, rheumatoid arthritis, PPRZ, acute or chronic periodontitis, Crohn's disease, RCUH)
• Pulmonary embolism or phlebitis less than 6 months old
• Prior atrial fibrillation ablation
• Active cancer

Criteria to be validated before randomization, on the day of ablation (these patients cannot be randomized):

• Patient in sinus rhythm 4-6 weeks after electric cardioversion: these patients are included in the study registry.
• Patient with complete absence of sinus rhythm (less than 10 seconds) after 3 electric cardioversion attempts: these patients will discontinue from the study.