The DUAL-ICE study is a single-center, prospective, randomized controlled study. The main purpose is to verify that renal artery cryoablation combined with pulmonary vein cryoablation can reduce the recurrence of atrial fibrillation in hypertensive patients with paroxysmal atrial fibrillation and substandard hypertension, and to further verify the clinical significance of one-stop cardio-renal combined cryoablation therapy for hypertension control.

Hypertension is a major risk factor for the high morbidity and mortality of cardiovascular diseases in the world. As a common arrhythmia, the autonomic nervous system plays an important role in the occurrence and maintenance of atrial fibrillation [1,2]. Enhancement of central sympathetic nervous system activity and stimulation of the efferent sympathetic nerve of the heart can promote the occurrence and development of atrial fibrillation [3]. Hypertension is an important risk factor for the occurrence of atrial fibrillation, and the incidence of complications such as heart failure, coronary heart disease and left ventricular hypertrophy is increased in patients with atrial fibrillation with poor blood pressure control [4-6]. Therefore, hypertension management in patients with atrial fibrillation is particularly important.

However, a 2014 study of SYMPLICITY HTN-3 with a sample size of 535 people showed that RDN could not significantly reduce blood pressure [10], which put the study of RDN into a dilemma. Since then, researchers have optimized the study design, and some more detailed results have suggested a significant antihypertensive effect of RDN [11-13].

At present, there are few reports on the cryo-ablation of renal sympathetic nerve in the RDN studies, only the case of cryo-ablation of renal artery by Dr.Prochnau et al in Germany in 2014, which is still a technical blank in China [14]. At present, catheter ablation has been widely recognized in the treatment of paroxysmal atrial fibrillation. In terms of patient comfort and efficacy, cryo-ablation promoted in recent years shows greater advantages than radiofrequency ablation, which has the characteristics of less damage to surrounding tissues and faster recovery of vascular endothelial function. Therefore, the application of cryoablation in the field of RDN may be similar to the effect of pulmonary vein ablation. The purpose of our study was to investigate whether renal artery cryoablation combined with pulmonary vein cryoablation reduces the recurrence rate of atrial fibrillation compared with pulmonary vein cryoablation alone.

Inclusion Criteria:

1. Age ≥18 years old, and <75 years old, gender is not limited;
2. Hypertensive patients with symptomatic paroxysmal atrial fibrillation to be treated by catheter ablation with substandard blood pressure. SBP ≥ 150 mmHg or DBP ≥ 90 mmHg in patients taking at least one antihypertensive drug;
3. Agree to participate and sign the informed consent.

Exclusion Criteria:

1. Cannot accept catheter ablation (such as thrombus in left atrium/left atrial appendage, recent myocardial infarction, stroke, etc.);

2. Patients with obvious bleeding tendency or unable to accept postoperative anticoagulation;

3. The anteroposterior diameter of left atrium indicated by echocardiography was ≥50mm;

4. A history of left atrial surgery or left atrial interventional therapy (including cryo-ablation, radiofrequency ablation, left atrial appendage occlusion, etc.);

5. NYHA grade IV congestive heart failure or LVEF <30%;

6. patients with valvular atrial fibrillation and secondary atrial fibrillation (such as uncontrolled hyperthyroidism, acute alcoholism, atrial fibrillation after cardiac surgery, etc.);

7. Patients with typical atrial fluttering or other supraventricular tachycardia (duration greater than 30s) confirmed by preoperative electrocardiogram or dynamic electrocardiogram;

8. Severe organic heart disease, including moderate to severe mitral insufficiency or stenosis, previous myocardial infarction, hypertrophic cardiomyopathy, etc.;

9. Patients with secondary hypertension;

10. Uncontrollable pulmonary hypertension;

11. Patients with glomerular filtration rate (EGFR) < 45ml/min/1.73m2 or patients with chronic kidney disease, nephrotic syndrome, polycystic kidney disease and other renal diseases were estimated according to MDRD calculation method;

12. Renal artery imaging (renal artery CTA) exclusion criteria:

    1. inability to access the renal vascular system;
    2. Diameter of renal aorta less than 4 mm or length less than 20 mm;
    3. Hemodynamic or anatomical renal artery abnormalities or stenosis;
    4. A history of previous renal artery interventions, including balloon angioplasty or stenting;
    5. There are multiple unilateral renal aortas leading to the kidney;

13. Participated in other clinical studies and not yet enrolled in the group;

14. Women who are pregnant, lactating or preparing to become pregnant;

15. Life expectancy less than 1 year;

16. Other conditions that are not suitable for inclusion in this study as assessed by the researcher, such as mental disorders or psychological disorders;

17. A history of acute coronary events or percutaneous coronary stent intervention, a history of stroke or transient ischemic attack, and extensive atherosclerosis with intravascular thrombosis within the last 6 months;

18. Patients with ICD implantation history or CRT treatment history.

We used participant single blindness. To ensure single blindness, femoral artery puncture and renal arteriography were performed in the control group after cryoablation.