The purpose of this study is to examine if sending mild electrical signals just under your skin will improve atrial fibrillation symptoms by controlling your heart rate.

Patients will have a 1:1 randomization to receive subcutaneous electrical nerve stimulation (ScNS) to observe if the stimulation can reduce atrial fibrillation burden in patients with symptomatic atrial fibrillation (AF). All subjects will undergo the implant of a neurostimulator lead. The experimental group will receive stimulation and the control group will not receive stimulation. All subjects will complete the same follow up visits to compare the 2 groups.

Primary Objective: To test the hypothesis that chronic subcutaneous nerve stimulation can reduce AF burden in patients with severe symptomatic AF unresponsive to conventional therapies

The secondary objective:

To test the hypotheses that the effect of ScNS on the following endpoints is different between the two randomization groups:

1. Time-dependent reduction of AF burden
2. Effects of ScNS on ventricular rate control during AF
3. Reduction of SKNA
4. Improvement of quality of life

The study will enroll patients with symptomatic atrial fibrillation unresponsive to conventional therapy defined by not responding to at least 1 antiarrhythmic drug. The study will enroll 30 patients, including 15 men and 15 women between the 18 and 75 years old. There will be no sex/gender/racial/ethnic based exclusion. Patients will be enrolled from the Cedars Sinai Medical Center.

The patients will undergo surgical implantation of an externalized lead under the skin on the chest wall. The wire is then connected to a neurostimulator. The experimental group (Group A) will receive ScNS (3.5mA) for two weeks. The sham group (Group B) will receive sham (0 mA) stimulation for two weeks. The AF burden will be assessed by a 7-day mobile cardiac telemetry device provided by Preventice. An additional mobile cardiac telemetry device, Bittium Faros, will also be worn at similar time points to monitor skin sympathetic nerve activity. An Apple watch will be used to collect additional information on the frequencies of AF between the Baseline Visit until the 3 Month Visit 7 Day Mobile Cardiac Telemetry is complete. After completion of the week 3 visit, the sham group (Group B) will be able to receive ScNS (3.5 mA) for two weeks. The AF burden will be assessed post-procedure by mobile cardiac telemetry by Preventice and Bittium Faros

Study duration: 36 Months

Subject duration: up to 5 months.

Inclusion Criteria:

• 18 to 75 years of age

• Symptomatic Paroxysmal AF.

  • Symptomatic paroxysmal AF is defined by AF with patient-reported perception of one or more of the following symptoms: palpitations, dizziness/presyncope, syncope, dyspnea, chest pain, malaise, and fatigue and activity intolerance.
  • There is at least one ECG-documented AF episode.

• Unresponsive to conventional therapy is defined by not responding to at least 1 antiarrhythmic drug (class I, class III, or atrioventricular nodal blocker).

• The left atrial size <50 mm by transthoracic echocardiography documented by eligibility visit echocardiogram

• Documented atrial fibrillation as defined as atrial fibrillation >30 seconds in duration with an atrial fibrillation burden determined by a minimum of 7 days of continuous ePatch monitoring within 6 months before surgery.

Exclusion Criteria:

• Patients without AF episodes during monitoring period will be excluded from the study and count as screen failure
• Left ventricular ejection fraction <40%
• Heart failure with functional classes III or IV
• Recurrent vasovagal syncope
• Valvular AF (severe mitral regurgitation, mitral stenosis)
• Congenital heart diseases
• Wolff Parkinson-White Syndrome
• Stroke within the past 6 months
• Any history of myocardial infarction
• Malignancies with a life expectancy of < 1 year
• A history of ablation procedures to treat left atrial tachyarrhythmias or other serious comorbidity
• Any history of sustained ventricular tachycardia (VT) defined by (1) > 30 s in duration or (2) < 30 s in duration, but is associated with hemodynamic consequences such as hypotension and syncope.
• Patients with a vagal nerve stimulator
• Active thyrotoxicosis
• Sick sinus syndrome with symptomatic bradycardia
• Heart rate < 50 beats per minute in sinus rhythm on 12-lead ECG
• Systolic blood pressure < 90 mm Hg
• Any experimental medication concomitantly or within 4 weeks of participation in the study
• Subjects with cardiac implantable electronic device (CIED) such as pacemakers and implantable cardioverter-defibrillators (ICDs)
• Pre-existing neuromodulation devices, such as vagal nerve stimulators, spinal cord stimulators and sacral nerve stimulators
• People with a history of allergy to ECG electrodes, adhesive tape, or nylon
• Pregnant women

Due to low baseline burden (<1%), 2 randomized subjects from each group were excluded from efficacy analysis. Therefore, although randomized, baseline measures were not and analyzed.

Adverse event data was collected for participants from Eligibility timepoint until Week 12/Month 3 MCT monitoring was completed.

A crossover option was only given to those randomized to sham group initially, after the completion of the primary endpoint (Week 3 FU).

Subjects will not be aware whether the ScNS is turned on or off. However, after three weeks from the initial surgery, control subjects that decide to the second procedure will be aware of what group they were randomized to.