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Aims Successful ventricular arrhythmia (VA) ablation requires identification of functionally critical sites during contact mapping. Estimation of the peak frequency (PF) component of the electrogram (EGM) may improve correct near-field (NF) annotation to identify circuit segments on the mapped surface. In turn, assessment of NF and far-field (FF) EGMs may delineate the three-dimensional path of a ventricular tachycardia (VT) circuit. Methods and results A proprietary NF detection algorithm was applied retrospectively to scar-related re-entry VT maps and compared with manually reviewed maps employing first deflection (FDcorr) for VT activation maps and last deflection (LD) for substrate maps. Ventricular tachycardia isthmus location and characteristics mapped with FDcorr vs. NF were compared. Omnipolar low-voltage areas, late activating areas, and deceleration zones (DZ) in LD vs. NF substrate maps were compared. On substrate maps, PF estimation was compared between isthmus and bystander sites. Activation mapping with entrainment and/or VT termination with radiofrequency (RF) ablation confirmed critical sites. Eighteen patients with high-density VT activation and substrate maps (55.6% ischaemic) were included. Near-field detection correctly located critical parts of the circuit in 77.7% of the cases compared with manually reviewed VT maps as reference. In substrate maps, NF detection identified deceleration zones in 88.8% of cases, which overlapped with FDcorr VT isthmus in 72.2% compared with 83.3% overlap of DZ assessed by LD. Applied to substrate maps, PF as a stand-alone feature did not differentiate VT isthmus sites from low-voltage bystander sites. Omnipolar voltage was significantly higher at isthmus sites with longer EGM durations compared with low-voltage bystander sites. Conclusion The NF algorithm may enable rapid high-density activation mapping of VT circuits in the NF of the mapped surface. Integrated assessment and combined analysis of NF and FF EGM-components could support characterization of three-dimensional VT circuits with intramural segments. For scar-related substrate mapping, PF as a stand-alone EGM feature did not enable the differentiation of functionally critical sites of the dominant VT from low-voltage bystander sites in this cohort. [ABSTRACT FROM AUTHOR]

Accessing the pericardial space safely and efficiently is an important skill for interventional cardiac electrophysiologist. With the increased recognition of the complexity of the 3‐dimensional arrhythmogenic substrate due to advances in imaging and mapping technologies there has been an expansion of epicardial procedures in recent years. Equally, minimally invasive implantation of epicardial pacing, cardiac resynchronization, or defibrillation leads is expanding in specific patients where transvenous systems are contraindicated or their long term sequelae should be ideally avoided. Selective delivery of intrapericardial pharmacological antiarrhythmic therapy is yet another potential indication, albeit still investigational. The expanding indications for percutaneous epicardial procedures is contrasted by the still substantial risk and challenges associated with accessing the pericardial space. Myocardial perforation, coronary artery laceration, and damage to the surrounding organs are all recognized and feared complications. A number of innovative epicardial access techniques have been proposed to overcome the difficulties and risks of traditional dry subxiphoid punctures and may allow for more widespread use of epicardial access in the future. We review 10 different established and novel subxiphoidal epicardial access techniques describing procedural success rates, safety profile and overall experience. The technical aspects as well as access times and costs for extra equipment will be reviewed. Finally, an outlook of reported preclinical techniques awaiting in‐human feasibility studies is provided. [ABSTRACT FROM AUTHOR]

Contemporary cardiac imaging allows for detailed non-invasive assessment of structural alterations of the atria implicated in the initiation and maintenance of atrial arrhythmias. Left atrial wall thickness (LAWT) may be an important parameter reflecting atrial remodelling as it is thought that LAWT increases in the presence of AF and may further promote its perpetuation. Tissue thickness may also be important to success and safety of AF ablation given the importance of creating durable, transmural lesions without causing collateral damage. Different calculation methods for quantifying local LAWT exist. An understanding of quantitative differences between estimation methods is relevant if LAWT-guided ablation strategies are pursued. We aimed to compare the results of LAWT measurement within the same cohort using a semi-automated eikonal-equation based workflow against a proprietary automated nearest-point LAWT estimation approach. In a prospective case-control study, patients with AF and controls without AF but with clinical indication for cardiac computed tomographic angiography (CCTA) were recruited. Prospective, ECG-gated CCTAs were acquired and the best diastolic sequence identified. 42 AF patients (35.7% female, mean age 64.6 +/- 10.2, CHA2DS2-VASc 2.48 +/- 1.5, 69.0% paroxysmal AF, 31% persistent AF, mean LVEF 57.9 +/- 10.5%) and 37 controls (35.1% female, mean age 56.6 +/- 7.2, CHA2DS2-VASc 1.54 +/- 1, mean LVEF 60.4 +/- 4.9%) were recruited. A total of 76 contrast enhanced CTs (37 Control, 39 AF) were acquired. Mean wall thickness between the two methods showed moderate, statistically significant correlation (r 0.499 p < 0.001). Mean LAWT was higher using ADAS LAWT estimation in all groups (total, AF and control) with a mean difference of 0.39mm (p 0.001). Both methods identified a statistically significant increase in LAWT in AF patients when compared to controls. There was no significant difference in standard derivation between estimation methods. In conclusion, fully automated nearest point LAWT estimation and semi-automated eikonal based LAWT estimation method yield a moderate, statistically significant correlation with mean difference in the sub-millimetre range. Even though the latter is statistically significant, for clinical ablation procedures these differences are likely to be of negligible clinical relevance. Available local expertise and software for LAWT estimation may determine the preferred employed approach. [ABSTRACT FROM AUTHOR]

Implantable cardioverter-defibrillators (ICDs) have revolutionized the treatment of acquired or inherited cardiac diseases associated with a high risk of sudden cardiac death due to ventricular tachyarrhythmias. Contemporary ICD devices offer reliable arrhythmia detection and discrimination algorithms and deliver highly efficient tachytherapies. Percutaneously inserted transvenous defibrillator coils with pectoral generator placement are the first-line approach in the majority of adults due to their extensively documented clinical benefit and efficiency with comparably low periprocedural implantation risks as well as the option of providing pain-free tachycardia treatment via anti-tachycardia pacing (ATP), concomitant bradycardiaprotection, and incorporation in a cardiac resynchronization therapy if indicated. Yet, expanding ICD indications particularly among younger and more complex patient groups as well as the increasingly evident long-term consequences and complications associated with intravascular lead placements promoted the development of alternative ICD configurations. Most established in daily clinical practice is the subcutaneous ICD but other innovative extravascular approaches like epicardial, pericardial, extra-pleural, and most recently substernal defibrillator coil placements have been introduced as well to overcome shortcomings associated with traditional devices and allow for individualized treatment strategies tailored to the patients characteristics and needs. The review aims to provide practical solutions for common complications encountered with transvenous ICD systems including restricted venous access, high defibrillation/fibrillation thresholds (DFTs), and recurrent device infections. We summarize the contemporary options for non-traditional extravascular ICD configurations outlining indications, advantages, and disadvantages. [ABSTRACT FROM AUTHOR]

Cardiac involvement in the rare monogenic autosomal recessive Alström syndrome (ALMS) may manifest as infantile, juvenile or adult dilated or restrictive cardiomyopathy. Case reports have described ventricular arrhythmias and conduction system disease, though little is known about atrial arrhythmia burden and management in these patients. This case presents a possible underreported atrial phenotype of the ALMS with exceptionally advanced structural remodelling with atrial scar encompassing nearly the entire left atrium in a young patient. It highlights the difficulties in managing these patient with medical rate and rhythm control due to frequent multi-organ involvement and concomitant conduction system disease, as well as the challenges faced during invasive activation mapping in an exceptionally disease atrial myocardium with ubiquitous complex low amplitude EGMs undermining the value of high density mapping with automated annotation algorithms. [ABSTRACT FROM AUTHOR]

Aims: Successful ventricular arrhythmia (VA) ablation requires identification of functionally critical sites during contact mapping. Estimation of the peak frequency (PF) component of the electrogram (EGM) may improve correct near-field (NF) annotation to identify circuit segments on the mapped surface. In turn, assessment of NF and far-field (FF) EGMs may delineate the three-dimensional path of a ventricular tachycardia (VT) circuit., Methods and Results: A proprietary NF detection algorithm was applied retrospectively to scar-related re-entry VT maps and compared with manually reviewed maps employing first deflection (FDcorr) for VT activation maps and last deflection (LD) for substrate maps. Ventricular tachycardia isthmus location and characteristics mapped with FDcorr vs. NF were compared. Omnipolar low-voltage areas, late activating areas, and deceleration zones (DZ) in LD vs. NF substrate maps were compared. On substrate maps, PF estimation was compared between isthmus and bystander sites. Activation mapping with entrainment and/or VT termination with radiofrequency (RF) ablation confirmed critical sites. Eighteen patients with high-density VT activation and substrate maps (55.6% ischaemic) were included. Near-field detection correctly located critical parts of the circuit in 77.7% of the cases compared with manually reviewed VT maps as reference. In substrate maps, NF detection identified deceleration zones in 88.8% of cases, which overlapped with FDcorr VT isthmus in 72.2% compared with 83.3% overlap of DZ assessed by LD. Applied to substrate maps, PF as a stand-alone feature did not differentiate VT isthmus sites from low-voltage bystander sites. Omnipolar voltage was significantly higher at isthmus sites with longer EGM durations compared with low-voltage bystander sites., Conclusion: The NF algorithm may enable rapid high-density activation mapping of VT circuits in the NF of the mapped surface. Integrated assessment and combined analysis of NF and FF EGM-components could support characterization of three-dimensional VT circuits with intramural segments. For scar-related substrate mapping, PF as a stand-alone EGM feature did not enable the differentiation of functionally critical sites of the dominant VT from low-voltage bystander sites in this cohort., Competing Interests: Conflict of interest: P.D.L. is supported by UCL/UCLH NIHR and Barts BRC. J.M. received speaker honoraria from Abbott Laboratories, Biosense Webster (J&J), and Boston Scientific. All remaining authors have declared no conflicts of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Implantable cardioverter-defibrillators (ICDs) have revolutionized the treatment of acquired or inherited cardiac diseases associated with a high risk of sudden cardiac death due to ventricular tachyarrhythmias. Contemporary ICD devices offer reliable arrhythmia detection and discrimination algorithms and deliver highly efficient tachytherapies. Percutaneously inserted transvenous defibrillator coils with pectoral generator placement are the first-line approach in the majority of adults due to their extensively documented clinical benefit and efficiency with comparably low periprocedural implantation risks as well as the option of providing pain-free tachycardia treatment via anti-tachycardia pacing (ATP), concomitant bradycardiaprotection, and incorporation in a cardiac resynchronization therapy if indicated. Yet, expanding ICD indications particularly among younger and more complex patient groups as well as the increasingly evident long-term consequences and complications associated with intravascular lead placements promoted the development of alternative ICD configurations. Most established in daily clinical practice is the subcutaneous ICD but other innovative extravascular approaches like epicardial, pericardial, extra-pleural, and most recently substernal defibrillator coil placements have been introduced as well to overcome shortcomings associated with traditional devices and allow for individualized treatment strategies tailored to the patients characteristics and needs. The review aims to provide practical solutions for common complications encountered with transvenous ICD systems including restricted venous access, high defibrillation/fibrillation thresholds (DFTs), and recurrent device infections. We summarize the contemporary options for non-traditional extravascular ICD configurations outlining indications, advantages, and disadvantages., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Society of Cardiology.)