Sensor-Based Electromagnetic Navigation to Facilitate Implantation of Left Ventricular Leads in Cardiac Resynchronization Therapy

Smart Pacemaker: A Review

Since the first pacemaker was implanted, nearly 60 years have passed. Since then, pacemaker technology has made major advancements that have increased both its safety and effectiveness in treating people with bradyarrhythmias. The repeated stimulation of cells in specialized "pacemaker" regions of the mammalian heart and the transmission of stimulus via the ventricles serve as evidence that the electrical function of the mammalian heart is necessary for a regular mechanical (pump) role. The development of action potentials in individual cardiac cells is linked to myocardial electrical activity and the heart's regular cooperative electrical functioning. A container or pulse initiator that houses the battery and electronics, as well as lines that connect to the myocardium to deliver a depolarizing pulse and detect intrinsic cardiac stimulation, are all parts of a pacemaker. Defibrillators could be used with artificial hearts that have electrical pacemakers integrated into them in order to treat arrhythmia, heart failure, and cardiac arrest. Modern pacemakers have units for supporting patients with other disorders like "heart failure," which happens when the heart does not pump as forcefully as it should. While many pacemakers are effective in treating different types of arrhythmias (irregular heartbeats), they also have units for treating them.

Peripheral Interventions Radiation Exposure Reduction Using a Sensor-Based Navigation System: A Proof-of-Concept Study

Background

Intravascular catheter positioning is done with radiography imaging. Increasing evidence indicates excessive ionizing radiation exposure for patients and physicians during catheterization procedures, making solutions to reduce radiation exposure a priority. This study evaluated the feasibility and impact of using sensor-based magnetic navigation on (i) fluoroscopy time and (ii) positioning accuracy and safety of a peripheral angioplasty balloon catheter.

Methods

All patients (n = 10) underwent a balloon-positioning protocol using 2 navigation methods sequentially: (i) magnetic navigation with minimal fluoroscopy; (ii) fluoroscopic navigation. The navigation method order was randomized, and 4 consecutive placements per method were performed. A target vascular bifurcation was used as a fiduciary landmark for both methods to determine accuracy.

Results

Balloon placements were successful with both navigation methods in all subjects, and no adverse events occurred. Magnetic guidance led to significant reductions in fluoroscopy time (0.37 ± 1.5 vs 15.0 ± 8.1 seconds, P < 0.001) and dose (0.3 ± 1.2 vs 24.1 ± 23.8 μGy.m², P < 0.01). The time duration for balloon alignment was similar for the 2 navigation methods (4.8 ± 1.4 vs 4.8 ± 2.3 seconds, P = 0.89), and the accuracy was almost identical (0.51 ± 0.41 vs 0.51 ± 0.32 mm, P = 0.97).

Conclusions

These results demonstrate the feasibility of using sensor-based magnetic guidance during simple peripheral interventional procedures; a significant reduction in ionizing radiation was achieved, with excellent positioning accuracy and safety. The clinical applications of magnetic guidance for device navigation during more complex percutaneous procedures should be evaluated.

Impact of electroanatomical mapping-guided lead implantation on procedural outcome of His bundle pacing

Aims

Conventional His bundle pacing (HBP) can be technically challenging and fluoroscopy-intense, particularly in patients with His-Purkinje conduction disease (HPCD). Three-dimensional electroanatomical mapping (EAM) facilitates non-fluoroscopic lead navigation and HB electrogram mapping. We sought to assess the procedural outcome of routine EAM-guided HBP compared with conventional HBP in a real-world population and evaluate the feasibility and safety of EAM-guided HBP in patients with HPCD.

Methods and results 

We included 58 consecutive patients (72 ± 13 years; 71% male) who underwent an attempt to conventional (EAM− group; n = 29) or EAM-guided (EAM+ group; n = 29) HBP between June 2019 and April 2020. The centre’s learning curve was initially determined (n = 40 cases) to define the conventional control group and minimize outcome bias favouring EAM-guided HBP. His bundle pacing was successful in 26 patients (90%) in the EAM+ and 27 patients (93%) in the EAM− group (P = 0.64). The procedure time was 90 (73–135) and 110 (70–130) min, respectively (P = 0.89). The total fluoroscopy time [0.7 (0.5–1.4) vs. 3.3 (1.4–6.5) min; P &lt; 0.001] and fluoroscopy dose [21.9 (9.1–47.7) vs. 78.6 (27.2–144.9) cGycm2; P = 0.001] were significantly lower in the EAM+ than EAM− group. There were no significant differences between groups in His capture threshold (1.2 ± 0.6 vs. 1.4 ± 1.0 V/1.0 ms; P = 0.33) and paced QRS duration (113 ± 15 vs. 113 ± 17 ms; P = 0.89). In patients with HPCD, paced QRS duration was similar in both groups (121 ± 15 vs. 123 ± 12 ms; P = 0.77). The bundle branch-block recruitment threshold tended to be lower in the EAM+ than EAM− group (1.3 ± 0.7 vs. 1.8 ± 1.2 V/1.0 ms; P = 0.31). No immediate procedure-related complications occurred. One patient (2%) experienced lead dislodgement during 4-week follow-up.

Conclusion 

Implementation of routine EAM-guided HBP lead implantation is feasible and safe in a real-world cohort of patients with and without HPCD and results in a tremendous reduction in radiation exposure without prolonging procedure time or increasing procedure-related complications.

Radiation exposure during cardiac device implantation: Lessons learned from a multicenter registry

BACKGROUND

Little data are available about radiation exposure during cardiac electrical device implantation, and no dose reference levels have been published. This multicenter, prospective, observational study assesses patient and staff radiation exposure during cardiac device implantations, and aims at defining dose reference levels.

METHODS

Patient demographic, procedural, and radiation data were obtained for 657 procedures from nine institutions. Physician and staff exposure were measured using real-time dosimeters worn beneath and above lead apron. Statistical analysis included fluoroscopy time (FT), dose-area product (DAP), and DAP adjusted for FT and body mass index.

RESULTS

Pacemakers and cardioverter defibrillators were implanted in 481 and 176 patients, respectively. Of these, 152 were treated with cardiac resynchronization therapy (CRT). Median FTs were 837s (interquartile range [IQR]: 480-1323), 117s (IQR: 69-209), and 101s (IQR: 58-162), and median DAPs were 1410 (IQR: 807-2601), 150 (IQR: 72-338), and 129 (IQR: 72-332) cGy.cm² for biventricular, dual chamber, and ventricular device implantation, respectively. Dose reference levels correspond to the third quartile values. During CRT, higher exposure was observed with four X-ray systems than with the two newer and customizable ones (adjusted DAP of 0.90 [IQR: 0.26-1.01] and 0.29 [IQR: 0.23-0.39], respectively; P < .001).

CONCLUSION

Based on real-life measurements, this multicenter registry provides dose reference levels and may help centers assess radiation exposure. Although biventricular device implantation was responsible for the highest radiation exposure, FT was meaningfully shortened compared to previously reported values. For a same FT, the use of new generators and custom settings has significantly reduced DAP.

Reducing radiation exposure during procedures performed in the electrophysiology laboratory

INTRODUCTION

Expert societies recently published strong recommendations to reduce the exposure of patients and staff to ionizing radiation (IR) during interventional and electrophysiology (EP) procedures. However, adherence to these guidelines remains difficult and the impact of implementing such recommendations is poorly characterized.

METHODS AND RESULTS

We conducted a single-center cohort study to quantify radiation exposure over time in three EP laboratories at the Montreal Heart Institute during 5,546 consecutive procedures from 2012 to 2015 by 11 primary operators. Overall, 2,618 (47.2%) procedures were catheter-based and 2,928 (52.8%) were device interventions. Interventions to reduce radiation exposure included educational initiatives to raise awareness (i.e., limiting cine acquisition, patient position, table height), slower frame rate, lower radiation dose per pulse, collimation, and integration with 3-D mapping systems and/or MediGuide technology. An 85% reduction in IR exposure was observed from 2012 to 2015, with the mean dose-area-product (DAP) decreasing from 7.65 ± 0.05 Gy·cm² to 1.15 ± 0.04 Gy·cm² (P < 0.001). This was true for catheter-based procedures (mean DAP 16.99 ± 0.08 to 2.00 ± 0.06 Gy·cm² , P < 0.001) and device interventions (mean DAP 4.18 ± 0.06 to 0.64 ± 0.05 Gy·cm² , P < 0.001). The median effective dose of IR recorded per quarter by 282 cervical dosimeters on EP staff decreased from 0.57 (IQR 0.18, 1.03) mSv in 2012 to 0.00 (IQR 0.00, 0.19) mSv in 2015, P < 0.001.

CONCLUSION

Enforcing good clinical practices with simple measures and low-dose fluoroscopy settings are highly effective in reducing IR exposure in the EP lab. These promising results should encourage other EP labs to adopt similar protective measures.

Combining electromagnetic navigation and 3-D mapping to reduce fluoroscopy time and achieve optimal CRT response

Implantation of cardiac resynchronization therapy (CRT) devices can be challenging, time consuming, and associated with high-dose x-ray exposure. We present the technique in which an electromagnetic navigation system (MediGuideTM, St. Jude Medical) and an electroanatomical three-dimensional mapping system (EnSite NavX, St Jude Medical) are usefully combined for implanting implantable cardioverter defibrillator CRT devices with strong reduction of x-ray exposure, and for targeting the most delayed regions in the activation maps avoiding scars for optimal CRT response.

Zero x-ray cardiac resynchronization therapy device implantation guided by a nonfluoroscopic mapping system: A pilot study

BACKGROUND

Fluoroscopic guidance is the standard tool used in device implantation. This means that both the patient and the operator are exposed to radiation, which may sometimes be high. The possibility of single-lead permanent pacemaker implantation without fluoroscopy has already been demonstrated.

OBJECTIVE

The aim of our study was to investigate the feasibility and reliability of biventricular device implantation guided only by an electroanatomic navigation system.

METHODS

Sixty-one patients with heart failure underwent implantation of a cardiac resynchronization therapy (CRT) device with or without defibrillator (CRT-D; CRT-P). The procedure was performed with or without fluoroscopy guidance (Rx+; Rx0). In the latter case, the EnSite Velocity system was used; this system is able to reconstruct the anatomy and activation of the cardiac chambers by simultaneously collecting a "cloud" of anatomical points from multiple electrodes.

RESULTS

Lead positioning was achieved in 24 of 26 patients undergoing CRT implantation without fluoroscopy (92% success). No complications were observed during the procedure and no catheter dislodgment occurred the day after the implantation or during 1-month follow-up. Procedure time progressively decreased from 136 minutes in the first case to 59 minutes in the last one, suggesting that operators gradually gained confidence while using the new technique.

CONCLUSION

Our study demonstrates the feasibility, efficacy, and safety of lead positioning guided only by the nonfluoroscopic EnSite Velocity mapping system without the use of fluoroscopy in CRT-P or CRT-D implantation. The benefits in terms of significantly reduced fluoroscopy exposure are associated with technical and clinical advantages.