Selecting the Appropriate Ablation Strategy: the Role of Endocardial and/or Epicardial Access

Ablation Modalities for Therapeutic Intervention in Arrhythmia-Related Cardiovascular Disease: Focus on Electroporation

Targeted cellular ablation is being increasingly used in the treatment of arrhythmias and structural heart disease. Catheter-based ablation for atrial fibrillation (AF) is considered a safe and effective approach for patients who are medication refractory. Electroporation (EPo) employs electrical energy to disrupt cell membranes which has a minimally thermal effect. The nanopores that arise from EPo can be temporary or permanent. Reversible electroporation is transitory in nature and cell viability is maintained, whereas irreversible electroporation causes permanent pore formation, leading to loss of cellular homeostasis and cell death. Several studies report that EPo displays a degree of specificity in terms of the lethal threshold required to induce cell death in different tissues. However, significantly more research is required to scope the profile of EPo thresholds for specific cell types within complex tissues. Irreversible electroporation (IRE) as an ablative approach appears to overcome the significant negative effects associated with thermal based techniques, particularly collateral damage to surrounding structures. With further fine-tuning of parameters and longer and larger clinical trials, EPo may lead the way of adapting a safer and efficient ablation modality for the treatment of persistent AF.

Medical three-dimensional printing opens up new opportunities in cardiology and cardiac surgery

Advanced percutaneous and surgical procedures in structural and congenital heart disease require precise pre-procedural planning and continuous quality control. Although current imaging modalities and post-processing software assists with peri-procedural guidance, their capabilities for spatial conceptualization remain limited in two- and three-dimensional representations. In contrast, 3D printing offers not only improved visualization for procedural planning, but provides substantial information on the accuracy of surgical reconstruction and device implantations. Peri-procedural 3D printing has the potential to set standards of quality assurance and individualized healthcare in cardiovascular medicine and surgery. Nowadays, a variety of clinical applications are available showing how accurate 3D computer reformatting and physical 3D printouts of native anatomy, embedded pathology, and implants are and how they may assist in the development of innovative therapies. Accurate imaging of pathology including target region for intervention, its anatomic features and spatial relation to the surrounding structures is critical for selecting optimal approach and evaluation of procedural results. This review describes clinical applications of 3D printing, outlines current limitations, and highlights future implications for quality control, advanced medical education and training.

Non-invasive Characterization of Focal Arrhythmia with Electromechanical Wave Imaging in Vivo

There is currently no established method for the non-invasive characterization of arrhythmia and differentiation between endocardial and epicardial triggers at the point of care. Electromechanical wave imaging (EWI) is a novel ultrasound-based imaging technique based on time-domain transient strain estimation that can map and characterize electromechanical activation in the heart in vivo. The objectives of this initial feasibility study were to determine that EWI is capable of differentiating between endocardial and epicardial sources of focal rhythm and, as a proof-of-concept, that EWI could characterize focal arrhythmia in one patient with premature ventricular contractions (PVCs) before radiofrequency (RF) ablation treatment. First, validation of EWI for differentiation of surface of origin was performed in seven (n = 7) adult dogs using four epicardial and four endocardial pacing protocols. Second, one (n = 1) adult patient diagnosed with PVC was imaged with EWI before the scheduled RF ablation procedure, and EWI results were compared with mapping procedure results. In dogs, EWI was capable of detecting whether pacing was of endocardial or epicardial origin in six of seven cases (86% success rate). In the PVC patient, EWI correctly identified both regions and surface of origin, as confirmed by results from the electrical mapping obtained from the RF ablation procedure. These results reveal that EWI can map the electromechanical activation across the myocardium and indicate that EWI could serve as a valuable pre-treatment planning tool in the clinic.

Identifying Risk and Management of Acute Haemodynamic Decompensation During Catheter Ablation of Ventricular Tachycardia

Radiofrequency catheter ablation (CA) has an established role in the management of patients with structural heart disease presenting with recurrent ventricular tachycardia (VT). Due to the complex underlying substrate, high burden of comorbidities and concomitant heart failure (HF) status, these patients may be at higher risk of periprocedural complications. The prolonged low-output state related to VT induction and mapping, as well as the fluid overload due to irrigated CA and the use of general anaesthesia, may decompensate the HF status, leading to multiple-organ failure and increase in early post-procedural mortality. Proper identification of patients at high risk of periprocedural acute haemodynamic decompensation (AHD) has important implications in terms of procedural planning (i.e. prophylactic use of mechanical assistance devices) and pre-procedural management in order to optimise the HF status. In the present manuscript we focus on the clinical predictors of AHD and the strategies to improve pre-procedural risk stratification, as well as the evidence supporting the use of haemodynamic support during CA procedures.

Anterior pericardial access to facilitate electrophysiology study and catheter ablation of ventricular arrhythmias: A single tertiary center experience

INTRODUCTION

Epicardial ablation is becoming an important part of management in patients with ventricular tachycardia (VT). Posterior epicardial access via the Sosa or needle-in-needle (NIN) approach for epicardial VT ablation is considered to be the method of choice for most electrophysiologists. Anterior epicardial access as an alternative technique has recently been proposed, but there are limited data about its safety, efficacy, and the rate of immediate complications. In this study, we report our experience with anterior epicardial access between 2009 and 2016.

METHODS

Between 2009 and June 2016, 100 consecutive patients underwent epicardial VT ablation using an anterior approach. The success rate, epicardial bleeding, and other complications related to the epicardial access in these patients were compared to the previously reported rate of complications in patients whom epicardial access was performed using the NIN or Sosa techniques.

RESULTS

Anterior epicardial access was obtained successfully in 100% of patients in the first attempt. The success rate of the anterior approach was comparable with the reported success rate of the NIN technique (100% vs. 100%, P value not significant) but better than the Sosa technique (100% vs. 94%, P = 0.012). None of the patients in the anterior approach series suffered from significant pericardial bleeding (defined as greater than 80 mL of blood loss), RV puncture/damage, or need for an emergent cardiac surgery.

CONCLUSION

An anterior epicardial approach is feasible and appears to have an acceptable safety profile in comparison with other epicardial approaches.