Automated catheter tip repositioning for intra-cardiac echocardiography

A practical guide and review of the literature on zero-fluoroscopy electrophysiology catheter navigation by intracardiac echocardiography

Navigation of electrophysiology (EP) catheters using intracardiac echocardiography (ICE) is an emerging technique to avoid fluoroscopy and simplify EP procedures. It enables zero-fluoroscopy catheter ablation of most common arrhythmias such as atrial fibrillation, atrioventricular-nodal-reentry-tachycardia, or cavotricuspid isthmus-dependent atrial flutter. In this practical guide, we share our experience and illustrate the principles as well as common manoeuvres for endovascular and intracardiac EP catheter navigation relying solely on ICE visualisation. We also review the available data and highlight the topics which require further investigation in this field.

Structural Heart Imaging Using 3-Dimensional Intracardiac Echocardiography: JACC: Cardiovascular Imaging Position Statement

3-dimensional (3D) intracardiac echocardiography (ICE) is emerging as a promising complement and potential alternative to transesophageal echocardiography for imaging guidance in structural heart interventions. To establish standardized practices, our multidisciplinary expert position statement serves as a comprehensive guide for the appropriate indications and utilization of 3D-ICE in various structural heart procedures. The paper covers essential aspects such as the fundamentals of 3D-ICE imaging, basic views, and workflow recommendations specifically tailored for ICE-guided structural heart procedures, such as transeptal puncture, device closure of intracardiac structures, and transcatheter mitral and tricuspid valve interventions. Current challenges, future directions, and training requirements to ensure operator proficiency are also discussed, thereby promoting the safety and efficacy of this innovative imaging modality to support expanding its future clinical applications.

Ventricular premature beats in a pregnant woman originating from trabeculae carneae in the right ventricle treated with radiofrequency ablation without X-ray guidance: a case report

BACKGROUND

Premature ventricular beats increase the cardiac load in pregnant women, leading to symptoms, such as palpitations. In severe instances, they may reduce placental perfusion, potentially causing intrauterine distress and developmental delays in the fetus, which could result in miscarriage or stillbirth. Fluoroscopy-less ablation offers significant advantages for pregnant women, including reduced radiation exposure, enhanced treatment precision, and a lower incidence of postprocedure complications.

CASE PRESENTATION

This case describes how radiofrequency catheter ablation was used on a pregnant Chinese woman who was identified with frequent ventricular premature beats originating from the high septal margin trabeculae carneae of the right ventricle. The rarity of this premature beat focus poses challenges for electrophysiology mapping and ablation; however, the ablation ultimately succeeded. In this case report, the clinical manifestations, electrocardiogram, ablation procedure, and patient prognosis are reported and discussed.

CONCLUSION

X-ray free ablation clearly reduces radiation exposure while maintaining a high success rate and safety of the ablation procedure.

An Ultrasound Matrix Transducer for High-Frame-Rate 3-D Intra-cardiac Echocardiography

OBJECTIVE

Described here is the development of an ultrasound matrix transducer prototype for high-frame-rate 3-D intra-cardiac echocardiography.

METHODS

The matrix array consists of 16 × 18 lead zirconate titanate elements with a pitch of 160 µm × 160 µm built on top of an application-specific integrated circuit that generates transmission signals and digitizes the received signals. To reduce the number of cables in the catheter to a feasible number, we implement subarray beamforming and digitization in receive and use a combination of time-division multiplexing and pulse amplitude modulation data transmission, achieving an 18-fold reduction. The proposed imaging scheme employs seven fan-shaped diverging transmit beams operating at a pulse repetition frequency of 7.7 kHz to obtain a high frame rate. The performance of the prototype is characterized, and its functionality is fully verified.

RESULTS

The transducer exhibits a transmit efficiency of 28 Pa/V at 5 cm per element and a bandwidth of 60% in transmission. In receive, a dynamic range of 80 dB is measured with a minimum detectable pressure of 10 Pa per element. The element yield of the prototype is 98%, indicating the efficacy of the manufacturing process. The transducer is capable of imaging at a frame rate of up to 1000 volumes/s and is intended to cover a volume of 70° × 70° × 10 cm.

CONCLUSION

These advanced imaging capabilities have the potential to support complex interventional procedures and enable full-volumetric flow, tissue, and electromechanical wave tracking in the heart.

Separable Tendon-Driven Robotic Manipulator with a Long, Flexible, Passive Proximal Section

This work tackles practical issues which arise when using a tendon-driven robotic manipulator (TDRM) with a long, flexible, passive proximal section in medical applications. Tendon-driven devices are preferred in medicine for their improved outcomes via minimally invasive procedures, but TDRMs come with unique challenges such as sterilization and reuse, simultaneous control of tendons, hysteresis in the tendon-sheath mechanism, and unmodeled effects of the proximal section shape. A separable TDRM which overcomes difficulties in actuation and sterilization is introduced, in which the body containing the electronics is reusable and the remainder is disposable. An open-loop redundant controller which resolves the redundancy in the kinematics is developed. Simple linear hysteresis compensation and re-tension compensation based on the physical properties of the device are proposed. The controller and compensation methods are evaluated on a testbed for a straight proximal section, a curved proximal section at various static angles, and a proximal section which dynamically changes angles; and overall, distal tip error was reduced.

Catheter navigation by intracardiac echocardiography enables zero-fluoroscopy linear lesion formation and bidirectional cavotricuspid isthmus block in patients with typical atrial flutter

INTRODUCTION

One of the most helpful aspects of intracardiac echocardiography (ICE) implementation in electrophysiological studies (EPS) is the real-time visualisation of catheters and cardiac structures. In this prospective study, we investigated ICE-guided zero-fluoroscopy catheter navigation during radiofrequency (RF) ablation of the cavotricuspid isthmus (CTI) in patients with typical atrial flutter (AFL).

METHODS AND RESULTS

Thirty consecutive patients (mean age 72.9 ± 11.4 years, 23 male) with ongoing (n = 23) or recent CTI-dependent AFL underwent an EPS, solely utilizing ICE for catheter navigation. Zero-fluoroscopy EPS could be successfully accomplished in all patients. Mean EPS duration was 41.4 ± 19.9 min, and mean ablation procedure duration was 20.8 ± 17.1 min. RF ablation was applied for 6.0 ± 3.1 min (50W, irrigated RF ablation). Echocardiographic parameters, such as CTI length, prominence of the Eustachian ridge (ER), and depth of the CTI pouch on the ablation plane, were assessed to analyse their correlation with EPS- or ablation procedure duration. The CTI pouch was shallower in patients with an ablation procedure duration above the median (4.8 ± 1.1 mm vs. 6.4 ± 0.9 mm, p = 0.04), suggesting a more lateral ablation plane in these patients, where the CTI musculature is stronger. CTI length or ER prominence above the respective median did not correlate with longer EPS duration.

CONCLUSIONS

Zero-fluoroscopy CTI ablation guided solely by intracardiac echocardiography in patients with CTI-dependent AFL is feasible and safe. ICE visualisation may help to localise the optimal ablation plane, detect and correct poor tissue contact of the catheter tip, and recognise early potential complications during the ablation procedure.