C12529: Method to Predict Optimal ICD PlacementNovelty:
A method for computationally predicting electrically optimal placement sites for implantable cardioverter- defibrillators (ICDs), specifically in pediatric and congenital heart defect patients.
Value Proposition:
Standard procedures for implantation of ICDs typically cannot be used in pediatric and congenital heart defect (CHD) patients because of small heart size and congenitally altered anatomy. ICD implantation in this population is often individualized, and there are no standardized protocols for healthcare providers to follow. This variability in ICD placement in pediatric and CHD patients often results in suboptimal positioning of the device, leading to increased defibrillation threshold (DFT) and cardioversion threshold (CVT), meaning stronger electrical shocks are delivered to the patient. Increased shock energy is associated with damage to cardiac tissue, increased mortality, and pain and psychological trauma. This novel method identifies the optimal, patient-specific ICD configuration to minimize both DFT and CVT through advanced computational modeling and image processing techniques. Additional advantages of this computational method include:
• Develops smooth and locally refined active heart-torso models with realistic ventricular fiber architecture
• Functions using low-resolution clinical imaging scans as input images
•Determines electrically optimal ICD placement non-invasively prior to implantation
Technical Details:
Johns Hopkins researchers have developed a computational modeling method to predict electrically optimal placement sites for ICDs. In this model, axial torso MRI image slices are labeled by tissue type and are interpolated to reconstruct a 3D geometry of the torso. Electrical properties are assigned to the tissue types. Artifacts in the reconstruction associated with breathing motions are eliminated using horizontal and vertical long axis MRI scans of the heart. A finite element mesh is, then, constructed based on the heart-torso image with local refinement of the mesh in the ventricular region. Additional characteristics of the ventricular tissue, such as fiber and sheet orientations, and ionic processes in ventricular myocytes, are also assigned to the mesh. Once this finalized version of the heart-torso defibrillation model is developed, various locations and orientations of the ICD can and ICD leads can be assessed. To complete this assessment, ventricular tachycardia (VT) and ventricular fibrillation (VF) are induced in the heart and defibrillation shocks are delivered from varied ICD configurations in the constructed heart-torso model. Each model is repeated at several phases of VT and VF. Biphasic defibrillation or cardioversion shocks are delivered from ICD leads in each model configuration, and DFT and CVT are recorded as the lowest energy shocks needed to terminate the arrhythmia for all VF and VT phases, respectively. The ICD position with the lowest DFT and CVT is defined as the optimal ICD configuration.
Looking for Partners:
To develop and commercialize the technology as a device or procedure to predict the ideal placement of ICDs in patients who are not candidates for transvenous ICD placement, such as pediatric or CHD patients.
Stage of Development:
Method demonstrated with clinical images from a pediatric CHD patient
Data Availability:
Prototype
Publications/Associated Cases:
J Physiology, Sept 2013
