Radiation-free Anatomical Direct Imaging Approach for No-fluoroscopy Cardiac Electrode Implantation

Feasibility and Safety of Transthoracic Echocardiography-Guided Permanent Pacemaker Implantation Without Fluoroscopy

Permanent pacemaker implantation is traditionally performed under fluoroscopic (X-ray) guidance. Although effective, fluoroscopy exposes patients and medical staff to ionizing radiation. Transthoracic echocardiography (TTE) is a non-invasive ultrasound imaging technique that allows real-time visualization of cardiac structures without radiation exposure. However, its role in guiding permanent pacemaker implantation has not been systematically evaluated.

This study aims to assess the feasibility and safety of performing permanent pacemaker implantation under sole TTE guidance. In the first phase, eligible patients will undergo pacemaker implantation guided only by transthoracic echocardiography. In the second phase, outcomes of patients treated with TTE guidance will be compared with matched patients undergoing conventional fluoroscopy-guided implantation. The study will evaluate procedural success, lead positioning accuracy, electrical performance, complication rates, and elimination of radiation exposure. The overall goal is to determine whether a radiation-free imaging strategy can safely replace conventional fluoroscopic guidance in selected patients requiring pacemaker implantation.

Fluoroscopy-guided permanent pacemaker implantation has been the standard imaging strategy for decades. While fluoroscopy provides reliable projection-based visualization of lead advancement, it exposes patients and medical personnel to ionizing radiation and does not allow direct visualization of myocardial tissue contact or early structural complications. Increasing awareness of cumulative radiation exposure has led to the exploration of alternative imaging strategies in structural and electrophysiological interventions.

Transthoracic echocardiography (TTE) provides real-time, radiation-free visualization of cardiac chambers, septal structures, valvular anatomy, and the pericardial space. TTE has been successfully applied in selected structural heart procedures; however, its use in guiding permanent pacemaker implantation has not been systematically studied. The principal challenges of TTE-guided pacing include limited visualization of the entire lead shaft, difficulty in assessing three-dimensional orientation, and uncertainty regarding fixation mechanics. With procedural refinements and structured imaging protocols, these limitations may be overcome.

This study is designed to evaluate a radiation-free implantation strategy using sole transthoracic echocardiographic guidance. The first component prospectively assesses procedural feasibility and safety in consecutively enrolled patients. The second component compares outcomes of the TTE-guided cohort with a matched cohort undergoing conventional fluoroscopy-guided implantation. The same prospectively enrolled TTE cohort will serve both feasibility assessment and comparative analysis.

The central hypothesis is that TTE-guided pacemaker implantation can achieve high procedural success and acceptable electrical performance while eliminating radiation exposure and maintaining safety comparable to conventional fluoroscopic guidance. By leveraging direct septal visualization and continuous structural monitoring, this approach may provide mechanistic advantages in lead positioning accuracy and complication detection.

If validated, this strategy could represent an important step toward fully radiation-free electrophysiological and structural cardiac interventions.

Inclusion Criteria:

1. Age ≥ 18 years
2. Indication for permanent pacemaker implantation according to current ESC or ACC/AHA guidelines
3. Adequate transthoracic echocardiographic acoustic window allowing visualization of right atrium, right ventricle, and interventricular septum
4. Ability to provide written informed consent

Exclusion Criteria:

1. Inadequate transthoracic acoustic window precluding reliable visualization of right-sided cardiac structures
2. Severe tricuspid regurgitation (moderate-to-severe or greater)
3. Left ventricular ejection fraction <35% without indication for cardiac resynchronization therapy
4. Documented malignant ventricular arrhythmia requiring implantable cardioverter-defibrillator as primary indication
5. Intrinsic heart rate <40 beats per minute with hemodynamic instability requiring emergent pacing
6. Active systemic infection
7. Pregnancy
8. Life expectancy less than 12 months due to non-cardiac comorbidities