An Infant Phantom for Pediatric Pericardial Access and Electrophysiology Training

A phantom for targeted endomyocardial biopsy training

Endomyocardial biopsy (EMB) of the right ventricular (RV) septal surface during cardiac catheterization is the standard method to assess cardiac allograft rejection, heart failure, or inflammatory cardiomyopathies. We developed methodology using a three-dimensional (3D) printed phantom to provide proof of concept for using biplane overlay technology for targeted EMB. A standard bioptome and steerable sheath were used to discern feasibility of biopsy for seven regions of the RV septum guided by 3D overlay. This novel biopsy phantom can help train operators in biopsy techniques, and biplane overlay technology has the potential to advance targeted EMB in transplant and cardiomyopathy populations.

A novel videoscope and tool kit for percutaneous pericardial access under direct visualization

BACKGROUND

Pericardial access is necessary for the application of epicardial cardiac therapies including ablation catheters, pacing and defibrillation leads, and left atrial appendage closure systems. Pericardial access under fluoroscopic guidance is difficult in patients without pericardial effusions and may result in coronary artery damage, ventricular injury, or perforation with potentially life-threatening pericardial bleeding in up to 10% of cases. There is a clinical need for a pericardial access technique to safely deliver epicardial cardiac therapies.

METHODS

In this paper, we describe the design and evaluation of a novel videoscope and tool kit to percutaneously access the pericardial space under direct visualization. Imaging is performed by a micro-CMOS camera with an automatic gain adjustment software to prevent image saturation. Imaging quality is quantified using known optical targets, while tool performance is evaluated in pediatric insufflation and pericardial access simulators. Device safety and efficacy is demonstrated by infant porcine preclinical studies (N = 6).

RESULTS

The videoscope has a resolution of 400 × 400 pixels, imaging rate of 30 frames per second, and fits within the lumen of a 14G needle. The tool can resolve features smaller than 39.4 µm, achieves a magnification of 24x, and has a maximum of 3.5% distortion within the field of view. Successful pericardial access was achieved in pediatric simulators and acute in vivo animal studies. During in vivo testing, it took the electrophysiologist an average of 66.83 ± 32.86 s to insert the pericardial access tool into the thoracic space and visualize the heart. After visualizing the heart, it took an average of 136.67 ± 80.63 s to access the pericardial space under direct visualization. The total time to pericardial access measured from needle insertion was 6.7 × quicker than pericardial access using alternative direct visualization techniques. There was no incidence of ventricular perforation.

CONCLUSIONS

Percutaneous pericardial access under direct visualization is a promising technique to access the pericardial space without complications in simulated and in vivo animal models.

Design and Functionality of a Multilumen Thoracic Access Port for Pericardial Access Under Direct Visualization

Small vasculature, venous obstruction, or congenital anomalies can preclude transvenous access to the heart, often resulting in open chest surgery to implant cardiac therapy leads for pacing, defibrillation, or cardiac resynchronization. A minimally invasive approach under direct visualization could reduce tissue damage, minimize pain, shorten recovery time, and obviate the need for fluoroscopy. Therefore, PeriPath was designed as a single-use, low-cost pericardial access tool based on clinical requirements. Its mechanical design aids in safe placement of conductive leads to the pericardium using a modified Seldinger technique. The crossed working channels provide an optimal view of the surgical field under direct visualization. Finite element analysis (FEA) confirms that the device is likely not to fail under clinical working conditions. Mechanical testing demonstrates that the tensile strength of its components is sufficient for use, with minimal risk of fracture. The PeriPath procedure is also compatible with common lead implantation tools and can be readily adopted by interventional cardiologists and electrophysiologists, allowing for widespread implementation. Prior animal work and a physician preliminary validation study suggest that PeriPath functions effectively for minimally invasive lead implantation procedures.

Muscle usage and workload assessment of cardiac ablation procedure with the use of a novel catheter torque tool in a pediatric simulator

BACKGROUND

Cardiac ablation catheters are small in diameter and pose ergonomic challenges that can affect catheter stability. Significant finger dexterity and strength are necessary to maneuver them safely. We evaluated a novel torque tool to reduce muscle activation when manipulating catheters and improve perceived workload of ablation tasks. The objective was to evaluate measurable success, user perception of workload, and muscle usage when completing a simulated ablation task with and without the use of a catheter torque tool.

METHODS

Cardiology attendings and fellows were fitted with surface electromyographic (EMG) sensors on 6 key muscle groups in the left hand and forearm. A standard ablation catheter was inserted into a pediatric cardiac ablation simulator and subjects navigated the catheter tip to 6 specific electrophysiologic targets, including a 1-min simulated radiofrequency ablation lesion. Time to complete the task, number of attempts required to complete the lesion, and EMG activity normalized to percentage of maximum voluntary contraction were collected throughout the task. The task was completed 4 times, twice with and twice without the torque tool, in semi-randomized order. A NASA Task Load Index survey was completed by the participant at the conclusion of each task.

RESULTS

Time to complete the task and number of attempts to create a lesion were not altered by the tool. Subjectively, participants reported a significant decrease in physical demand, effort, and frustration, and a significant increase in performance. Muscle activation was decreased in 4 of 6 muscle groups.

CONCLUSION

The catheter torque tool may improve the perceived workload of cardiac ablation procedures and reduce muscle fatigue caused by manipulating catheters. This may result in improved catheter stability and increased procedural safety.