Progress in zero-fluoroscopy implantation of cardiac electronic device

Radiation Exposure, Training, and Safety in Cardiology

Exposure to ionizing radiation is an inherent occupational health hazard in clinical cardiology. Health risks have been reported previously, including predilection to cancer. In addition, orthopedic injury due to prolonged wearing of heavy protective lead aprons, which are mandatory to reduce radiation risk, have been extensively documented. Cardiology as a specialty has grown with rising volumes of increasingly complex procedures. This includes electrophysiological, coronary, and structural intervention, advanced heart failure/transplant management, and diagnostic imaging. Both the operator as well imaging specialists are exposed to radiation, particularly in structural interventions where interventional cardiologists and structural imagers work closely. Increasingly, women interested in cardiology may deselect the field due to radiation concerns. This expert document highlights the risks of radiation exposure in cardiology, including practical tips within various subspecialty fields such as interventional/structural cardiology, electrophysiology, imaging, advanced heart failure, and pediatric cardiology.

New Guidelines of Pediatric Cardiac Implantable Electronic Devices: What Is Changing in Clinical Practice?

Guidelines are important tools to guide the diagnosis and treatment of patients to improve the decision-making process of health professionals. They are periodically updated according to new evidence. Four new Guidelines in 2021, 2022 and 2023 referred to pediatric pacing and defibrillation. There are some relevant changes in permanent pacing. In patients with atrioventricular block, the heart rate limit in which pacemaker implantation is recommended was decreased to reduce too-early device implantation. However, it was underlined that the heart rate criterion is not absolute, as signs or symptoms of hemodynamically not tolerated bradycardia may even occur at higher rates. In sinus node dysfunction, symptomatic bradycardia is the most relevant recommendation for pacing. Physiological pacing is increasingly used and recommended when the amount of ventricular pacing is presumed to be high. New recommendations suggest that loop recorders may guide the management of inherited arrhythmia syndromes and may be useful for severe but not frequent palpitations. Regarding defibrillator implantation, the main changes are in primary prevention recommendations. In hypertrophic cardiomyopathy, pediatric risk calculators have been included in the Guidelines. In dilated cardiomyopathy, due to the rarity of sudden cardiac death in pediatric age, low ejection fraction criteria were demoted to class II. In long QT syndrome, new criteria included severely prolonged QTc with different limits according to genotype, and some specific mutations. In arrhythmogenic cardiomyopathy, hemodynamically tolerated ventricular tachycardia and arrhythmic syncope were downgraded to class II recommendation. In conclusion, these new Guidelines aim to assess all aspects of cardiac implantable electronic devices and improve treatment strategies.

Zero to minimal fluoroscopy for cardiac electronic device implantation: A systematic review and meta-analysis

Background

Fluoroscopy is conventionally performed for cardiac implantable electronic device (CIED) therapy and carries radiation drawback for both patients and medical workers. Recently, zero to minimal fluoroscopy (ZMF) approach is introduced to reduce radiation exposure of fluoroscopy. This study compares the feasibility and safety of ZMF approach to fluoroscopy for CIEDs therapy in adults.

Method

A systematic literature search was conducted on PubMed, ScienceDirect, and Web of Science in March 2023. All observational or experimental studies comparing ZMF approach to fluoroscopy for adult CIEDs therapy were included. Reviews, case report/series, animal studies, and non-English articles were excluded. The success rate, procedural time, fluoroscopy time, radiation dose, and complications rate were compared for each approach.

Results

Seven articles for permanent and three articles for temporary CIEDs were included for analysis. The success rate of ZMF for permanent CIEDs was similar to fluoroscopy method (OR: 0.77, 95% CI: 0.33-4.15). The procedural time of ZMF was similar to fluoroscopy for both permanent and temporary CIEDs (standardized mean difference [SMD]: 0.10, 95% CI: -0.35 to 0.55 and SMD: -0.71, 95% CI: -1.87-0.44, respectively). However, ZMF approach markedly reduced the fluoroscopy time and radiation exposure for permanent CIEDs (SMD: -1.80, 95% CI: -2.49 to -1.12 and SMD: -1.26, 95% CI: -2.24 to -0.29). The complication rate was similar for permanent CIEDs (OR: 1.08, 95% CI: 0.41-2.84), yet lowered for temporary CIEDs (OR: 0.34, 95% CI: 0.20-0.59).

Conclusion

ZMF had similar success rate, procedural time, and sum complication rate for permanent CIEDs implantation with a significant reduction of fluoroscopy time and radiation exposure.

Case Report: Fluoroless implantation of left branch bundle pacing in a pregnant patient

A pregnant patient had symptomatic atrial standstill and indications for pacing therapy with an expected high ventricular pacing ratio. With the consideration of potential pacing-induced cardiomyopathy in the future we conducted zero-fluoro left bundle branch pacing (zLBBP) implantation for heart failure prevention. An ex vivo 3D cardiac model (Medtronic, USA) was used preoperatively to simulate the zLBBP implantation to improve procedure safety and efficiency. Intraoperatively, the simulation steps were followed, and a combination of electroanatomic navigation systems (EANS) and intracardiac echocariography (ICE) were used to ensure that the procedure was performed efficiently and safely.

Feasibility and safety of zero-fluoroscopy left bundle branch pacing: An initial experience

INTRODUCTION

Left bundle branch pacing (LBBP) has emerged in recent years as a new pacing modality, providing patients with a narrower paced QRS than conventional pacing and stable pacing parameters. At the same time, there is a growing concern about the use of fluoroscopy in pacemaker implantations, given its harmful effects on both patients and operators. However, there are no prior experiences of zero-fluoroscopy in LBBP procedure.

METHODS

We conducted an observational prospective study recruiting consecutive patients that underwent zero-fluoroscopy LBBP pacemaker implantation. A 6-month follow-up visit was programmed for every patient. The main goal of our study was to assess the efficacy, feasibility, and safety of the procedure.

RESULTS

From January 2021 to February 2022, we included 10 patients, 8 males. The average age was 63 ± 4 years. The procedure was successful in all patients. We observed a significant reduction in paced QRS width compared with basal QRS width (149 ± 31.9 vs. 116 ± 15.6 ms, p = .02). All device parameters remained stable at 6-month follow-up: no significant differences in mean impedance (700.5 ± 136.4 vs. 494 ± 72.7 Ohm, p = .09), capture threshold (0.67 ± 0.2 vs. 0.83 ± 0.2 V @ 0.4 ms, p = .27) or endocardial V-wave amplitude (10.6 ± 5.2 vs. 13.9 ± 6.3 mV, p = .19). No complications were reported in any case.

CONCLUSION

Zero-fluoroscopy LBBP is feasible and safe, and it may be considered in cases where radiation exposure is contraindicated or especially undesirable. Future randomized clinical trials are needed for the widespread use of this new technique.

Contactless Electrocatheter Tracing within Human Body via Magnetic Sensing: A Feasibility Study

During surgical procedures, real-time estimation of the current position of a metal lead within the patient's body is obtained by radiographic imaging. The inherent opacity of metal objects allows their visualization using X-ray fluoroscopic devices. Although fluoroscopy uses reduced radiation intensities, the overall X-ray dose delivered during prolonged exposure times poses risks to the safety of patients and physicians. This study proposes a potential alternative to real-time visualization of a lead inside the human body. In principle, by making a weak current flow through the lead and measuring the related magnetic field generated outside the body, it is possible to trace the position of the lead. This hypothesis was verified experimentally via two tests: one carried out on a curved copper wire in air and one carried out on a real pacemaker lead in a saline solution. In the second test, a pacemaker lead and a large return electrode were placed in a tank filled with a saline solution that reproduced the mean resistivity of the human torso. In both tests, a current flowed through the lead, which consisted of square pulses with short duration, to avoid any neuro-muscular stimulation effects in a real scenario. A small coil with a ferrite core was moved along a grid of points over a plastic sheet and placed just above the lead to sample the spatial amplitude distribution of the magnetic induction field produced by the lead. For each measurement point, the main coil axis was oriented along the x and y axes of the plane to estimate the related components of the magnetic induction field. The two matrices of measurements along the x and y axes were further processed to obtain an estimate of lead positioning. The preliminary results of this study support the scientific hypothesis since the positions of the leads were accurately estimated. This encourages to deepen the investigation and overcome some limitations of this feasibility study.

Fluoroless 3D mapping-guided pacemaker implant in a pregnant patient

We describe a case of pacemaker implant guided by intracardiac echocardiography and three-dimensional anatomical mapping in a pregnant patient, with no peri-procedural use of radiation.