[High-resolution 3D mapping : Opportunities and limitations of the Rhythmia™ mapping system]

Progress of Conductivity and Conduction Velocity Measured in Human and Animal Hearts

Cardiac conduction velocity (CV) is a critical electrophysiological characteristic of the myocardium, representing the speed at which electrical pulses propagate through cardiac tissue. It can be delineated into longitudinal, transverse, and normal components in the myocardium. The CV and its anisotropy ratio are crucial to both normal electrical conduction and myocardial contraction, as well as pathological conditions where it increases the risk of conduction block and reentry. This comprehensive review synthesizes longitudinal and transverse CV values from clinical and experimental studies of human infarct hearts, including findings from the isthmus and outer loop, alongside data derived from animal models. Additionally, we explore the anisotropic ratio of conductivities assessed through both animal and computational models. The review culminates with a synthesis of scientific evidence that guides the selection of CV and its corresponding conductivity in cardiac modeling, particularly emphasizing its application in patient-specific cardiac arrhythmia modeling.

Compatibility assessment of a temperature-controlled radiofrequency catheter with a novel electroanatomical mapping system

Background

The novel DiamondTemp ablation system (DTA) and EnSiteX mapping System (EAM) are both CE-Marked and FDA approved medical devices. The DTA has been validated by its manufacturer only in combination with previous version of EnSite System-EnSite Precision. The aim of this study was to evaluate compatibility of DTA with EnSite X with a previously developed protocol.

Methods

Three configurations were tested: 3.1. Medtronic Generator connection Box (GCB) and AmpereConnect cable; 3.2. the Medtronic GCB-E and electrogram out cable from GCB to EAM; 3.3. Direct connection of DTA to EAM using intracardiac out cable with no GCB.

Results

The previously developed universal method for compatibility assessment of ablation catheters and navigation systems was used with success for assessing DTA and EnSite X EAM compatibility, with reproducible results. Accuracy of DTA visualization with different setups was evaluated with a phantom model measuring distances between DTA and reference points. DTA is compatible with EnSiteX EAM with a safety and reliability profile guaranteed, if within the described specifications. In particular, careful setup is mandatory to achieve good clinical outcomes as only setup 3.2 is viable for both NavX and Voxel Mode and demonstrated satisfactory results and accuracy. Setup 3.3 showed a significant shift immediately after catheter insertion. Catheter position was away from baseline points and the dislocation increased during the radiofrequency delivery.

Conclusions

Previously developed method for compatibility assessment of ablation catheters and navigation systems has been used for a new EAM. DTA is compatible with EnSiteX EAM with proper configuration.

[Electromagnetic interference in 3D-mapping procedures]

Catheter-based ablation is nowadays a safe and widespread procedure for the treatment of cardiac arrhythmia. This requires exact anatomical knowledge both before and during the examination and is an important prerequisite for targeted treatment. At the beginning of the era of interventional catheter-based treatment, fluoroscopy was the only and usual means of visualization, whereas in the middle of the 1990s continuous 3D-mapping systems were developed for the non-fluoroscopic examination of patients. The correct use of these 3‑D systems, which non-fluoroscopically visualize the catheter and mostly identify mechanisms of arrhythmia in great detail, nowadays makes an important contribution to successful interventional catheter treatment of arrhythmia; however, it is not uncommon for patients with ventricular arrhythmia to also carry implanted electronic devices, such as pacemakers, defibrillators or less frequently left ventricular hemodynamic support systems. All implantable devices lead to electromagnetic interferences, which can complicate the diagnostics and treatment during electrophysiological examinations and ablation. This article addresses the adversities and experiences associated with magnet-based 3D systems and implantable electromagnetically active cardiac devices.

Universal Method of Compatibility Assessment for Novel Ablation Technologies With Different 3D Navigation Systems

Background

New technologies for ablation procedures are often produced by different companies with no cross-compatibility out of the box. This is not a negligible clinical problem since those separately developed devices are often used together. The aim of this study was to develop a bench-testing method to assess compatibility between the DiamondTemp ablation system (DTA) and the Rhythmia electroanatomic mapping system (EAM).

Methods

Different setups were tested. DTA was connected to the Rhythmia EAM using the following configurations: 3.1. An Ensite EPT GenConnect box (GCB) and Rhythmia Maestro GCB (Maestro GCB, native Rhythmia setup); 3.2. The Medtronic GCB-E and Maestro GCB; 3.3. The Medtronic GCB-E out via the Medtronic GCB-E directly to the Rhythmia at box 1 (pin A61 to A64).

Results

The DTA location was represented in real-time on the Rhythmia EAM. A proper tracking of the DTA was observed in all setups tested by visual comparison of physical catheter movements and its representation on EAM. In configuration 3.1, a significant shift was observed after the first radio frequency (RF) application; however, further applications caused no further shift. In setup 3.2, no significant shift was observed. The setup 3.3 showed a massive shift in the catheter position before ablation compared to baseline points acquired using the Orion catheter as a reference.

Conclusions

A universal and reproducible solution for compatibility testing between the various mapping systems and the ablation catheters has been described. DTA has been demonstrated as compatible with Rhythmia EAM with satisfactory results if a specific setup is used.

[Innovations in invasive electrophysiology : What awaits us?]

Technological developments in percutaneous catheter ablation for the treatment of cardiac arrhythmias have progressed from direct current shock ablation over the introduction of radiofrequency ablation to routine clinical procedures. Invasive electrophysiology is characterized by continuous technical innovation and an accompanying increasing understanding of underlying electrophysiologic mechanisms. A number of technical developments were promising, e.g., laser ablation, multipolar biphasic ablation, cryoballoon ablation, contact force, high density three-dimensional (3D) mapping, and the concept of rotors for atrial fibrillation ablation. Despite intense progress, one of the main challenges of catheter ablation is still the creation of tissue-specific chronic transmural lesions and avoidance of collateral damage. The purpose of this review is to present a status quo of catheter ablation of supraventricular tachycardia, atrial fibrillation, and ventricular tachycardia and to discuss future technical innovations and strategies. In the presence of the intense dynamic developments, this review can not consider all new approaches but will rather highlight some of the most promising innovations. Topics of discussion include the use of nonfluoroscopic catheter navigation, the introduction of new ablation tools, the development of alternative energy sources, the integration of new imaging modalities, and the establishment of novel ablation strategies.

Cardiac Mapping Systems: Rhythmia, Topera, EnSite Precision, and CARTO

Novel cardiac mapping systems allow a safe and highly accurate 3-D reconstruction of cardiac structures as well as fast and accurate visualization of cardiac arrhythmias. In addition, they are increasingly reducing the need for fluoroscopy in these procedures. The current state of the art, as well as the presentation of possible uses of individual systems and their limitations, is presented in this article. Cardiac mapping systems can significantly contribute to an optimal therapeutic decision making in invasive electrophysiology. This article introduces new developments of Rhythmia, Topera, EnSite Precision, and CARTO systems and provides a look ahead to the future.