Atrial Fibrillation With Sinus Node Dysfunction: Intensive Device Follow-up

Study Overview
=================
Brief Summary
-----------------
The study will try to access the efficacy of atrial pacing, medication and radiofrequency ablation in treating patients with paroxysmal atrial fibrillation and sinus node dysfunction; to identify the response to these treatments in patients with functional and organic sinus node dysfunction respectively; to explore the necessity of pacemaker implantation in patients with functional sinus node dysfunction. Patients who meet the inclusion criteria will receive pacemaker implantation followed by trial pacing, medication and radiofrequency ablation of AF. Device data will be analyzed to answer the question. And after follow-up of 1 year, lower rate of pacemaker will be set as 40 bpm for patients without AF. The proportion of pacing and patients' tolerance will be analyzed.

Official Title
-----------------
Stepwise Atrial Fibrillation supprEssion Treatment in Patients With Paroxysmal Atrial Fibrillation and Sinus Node Dysfunction: Intensive Device Follow-up

Conditions
-----------------
Sinus Node Dysfunction, Atrial Fibrillation

Intervention / Treatment
-----------------
* Other: programing of pacemaker
* Procedure: AF ablation
* Drug: Anti arryhthmic drugs


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age from 18 - 80 years Longest RR interval ≥ 3 seconds in sinus rhythm or when atrial arrhythmia (atrial fibrillation/atrial arrhythmia/atrial flutter) is converted to sinus rhythm (documented by either holter monitor or electrogram). Meet the indications of permanent pacemaker implantation in patients with SND according to the 2012 ACCF/AHA/HRS Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities. Evidence of paroxysmal atrial fibrillation ( two or more symptomatic episodes within 6 months) Willing to sigh informed consent Exclusion Criteria: Type II second-degree or three-degree atrioventricular block (in sinus rhythm) Intrinsic PR interval ≥ 300 ms in sinus rhythm Persistent AF（including long-standing persistent AF） Severe structural heart disease(e.g. ischemic heart disease that requires revascularization, rheumatic heart disease that requires valve replacement, cardiomyopathy except hypertensive myocardial hypertrophy) Work high above the ground or heavy physical labour Malignant ventricular arrhythmias New York Heart Association (NYHA) class III or IV AF secondary to electrolyte imbalance, thyroid dysfunction, vasovagal reaction or other reversible or non-cardiac causes Previous procedures dealing with AF (including radiofrequency ablation and surgical operation) Cardiac implantable electronic device implantation history Severe hepatic and renal dysfunction(serum creatinine above the upper normal limit of the center, or chronic renal dysfunction ; ALT or AST more than 2 times the upper normal limit of the center, or bilirubin more than 2 times the upper normal limit of the center, or hepatic cirrhosis) Contraindication to propafenone/amiodarone/dronedarone(except bradycardia) Contraindication to oral anticoagulants Women who are pregnant Presence of malignant tumor Severe coagulation disorder (without any anticoagulation treatment) The investigators do not think the patient is eligible for this study Patient is unwilling to cooperate with the study procedures

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Baseline<br>After implantation of pacemaker, the pacing mode and the lower rate of pacemaker will be set as VDD and 50/45 bpm respectively, to get the baseline burden of atrial fibrillation without atrial pacing. Except for beta-blockers digoxin, and CCB to control heart rate, anti-arrhythmic drugs (AAD) will not be prescribed. Patients who can not tolerate will drop out. After follow-up of at least 3 month, patients with AF lasting longer than one minute detected by pacemaker will go to next group / stage (Atrial Pacing, Step1). | Other: programing of pacemaker<br>* Different programing parameters will be set in different group/stage<br>|
| Atrial Pacing (Step 1)<br>After Baseline and after follow-up of at least 3 month, patients with AF lasting longer than one minute detected by pacemaker will come to this group /stage (Atrial Pacing). At this stage, the pacing mode and the lower rate of pacemaker will be set as DDD and 70/60 bpm respectively, to perform relatively high-rate atrial pacing. Except for beta-blockers digoxin, and CCB to control heart rate, anti-arrhythmic drugs (AAD) will not be prescribed. After follow-up of at least 3 month, patients with AF lasting longer than one minute detected by pacemaker will go to next group/stage (AAD, Step1). | Other: programing of pacemaker<br>* Different programing parameters will be set in different group/stage<br>|
| AAD (Step 2)<br>After Step 1, and after follow-up of at least 3 month, patients with AF lasting longer than one minute detected by pacemaker will come to this group/stage. Anti-arrhythmic drugs including propafenone, amiodarone and dronedarone will be prescribed. After follow-up of at least 6 month, patients with AF lasting longer than one minute detected by pacemaker will go to next group/stage (RFCA, Step3). | Procedure: AF ablation<br>* AF ablation can only be performed in Step 3<br>|
| RFCA (Step 3)<br>After Step 2, and after follow-up of at least 6 month, patients with AF lasting longer than one minute detected by pacemaker will come to this group/stage (RFCA, Step3). Patients will receive catheter ablation of AF, up to patients' willingness. After follow-up of at least 12 month, patients without AF lasting longer than one minute detected by pacemaker will go to next group/stage (SAFE PAF-SND II). | Procedure: AF ablation<br>* AF ablation can only be performed in Step 3<br>Drug: Anti arryhthmic drugs<br>* Anti arryhthmic drugs can be prescribed in Step 2, Step3 and SAFE PAF-SND<br>|
| SAFE PAF-SND II<br>After RFCA, and after follow-up of at least 12 month, patients without AF lasting longer than one minute detected by pacemaker will come to this group/stage (SAFE PAF-SND II). At this stage, the pacing mode and the lower rate of pacemaker will be set as VDD and 40 bpm respectively. If the patient can not tolerate, the the pacing mode and the lower rate of pacemaker will be set as DDD/DDDR and 60 bpm. If the patient has no symptom related to bradycardia, he/she will be followed up until the end of this study. | Other: programing of pacemaker<br>* Different programing parameters will be set in different group/stage<br>Procedure: AF ablation<br>* AF ablation can only be performed in Step 3<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| proportion of ventricular pacing |  | through study completion, an average of 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| symptom related to bradycardia |  | through study completion, an average of 2 years | 
| AF burden |  | through study completion, an average of 2 years |