The implantation of cardiac electronic devices is a common procedure in the Electrophysiology Laboratory. The most commonly used venous access sites are the cephalic, the axillary and the subclavian vein.

Studies comparing these options have been conducted in the past. Axillary venous access can be achieved either through axillary vein angiography or by ultrasound guidance. Nevertheless, appropriate training is required for the ultrasound-guided axillary puncture technique-as well as for the cephalic vein cutdown technique.

Data from randomized trials regarding direct comparison of the two methods in terms of efficacy and safety are very limited.

The purpose of the study is the comparison of the efficacy and safety of the ultrasound-guided axillary venous access technique versus the cephalic venous access using the cut-down technique in patients requiring intravenous cardiac device (single-chamber/dual-chamber pacemaker/defibrillator) implantation.

This study is a single-center, randomized, clinical trial. Its purpose is the comparison of the ultrasound-guided axillary venous access technique versus the cephalic venous access using the cut-down technique in cardiac device implantation procedures. Prerequisite for starting patients' recruitment is that the operators have undergone a training phase in ultrasound-guided axillary vein puncture in the Interventional Radiology Laboratory and have completed at least 30 procedures. A GE V-scan device with a special linear transducer for vessel examination will be utilized for the ultrasound guidance. Micropuncture technique will be performed for venous access.

Eligibility criteria:

Inclusion criteria

• Age ≥ 18 years
• Indication for single- or dual-chamber pacemaker of defibrillator implantation
• Written informed consent Exclusion criteria
• Indication for biventricular pacemaker or defibrillator
• Upgrade in pacing or defibrillation system

After the operators' training phase, candidates for pacemaker or defibrillator (single- or dual-chamber) implantation who fulfill the inclusion criteria will be randomly assigned with 1:1 allocation to one of the Groups:

A. ultrasound-guided axillary venous access B. cephalic venous access through the cut-down technique In case of access failure in Group A, the alternative puncture options are through the cephalic vein, the axillary vein with angiography guidance, the axillary vein without angiography guidance or the subclavian vein. In case of access failure in Group B which includes the insertion of only one lead wire or none, the alternative puncture options are through the axillary vein with angiography, the axillary vein without angiopraghy or the subclavian vein.

Data of the study participants that will be recorded include: demographics, Body Mass Index (BMI), cardiovascular risk factors, comorbidities, indication for cardiac device implantation, type of device (pacemaker/defibrillator, single-chamber/dual-chamber), side of implantation (right, left), type of pocket (subcutaneous, submuscular).

Regarding NOAC administration, patients will undergo the implantation procedure after cessation of rivaroxaban for at least 20 hours before the procedure and apixaban or dabigatran for at least 16 hours before the procedure. Longer periods of cessation will be applied in patients with renal dysfunction. In patients on treatment with acenocoumarol or warfarin, procedures will be performed without discontinuation of the drugs with target INR=2.

Regarding anticoagulation management in patients with mechanical valves the following anticoagulation management plan will be applied: i) in patients with metallic aortic valve, no discontinuation of anticoagulation with target INR=2 and ii) in patients with metallic mitral valve, no discontinuation of anticoagulation, with target INR<3-4.

The study hypothesis is that ultrasound-guided axillary venous access will lead to a higher rate of successful implantation procedures compared to cephalic vein access through the cut-down technique.

Based on available research data and pilot data, the hypothesis is that the success rate in ultrasound-guided axillary venous access group will be 90% compared to 65% in the cephalic venous access group. A sample size of 57 patients in each group is expected to offer statistic power of 90% (a=0.05, two-tailed) to the aforementioned result.

The study has been approved by the Ethics Committee of the University Hospital of Patras. All candidates will participate after written informed consent.

Inclusion Criteria:

• Age ≥ 18 years
• Indication for single- or dual-chamber pacemaker of defibrillator implantation
• Written informed consent

Exclusion Criteria:

• Indication for biventricular pacemaker/defibrillator
• Upgrade in pacing or defibrillation system