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Expert Review of Medical Devices 2023Advanced cardiac imaging is an important component in pre-procedural planning for ventricular tachycardia (VT) ablations. inHEART's proprietary software, inHEART Models,... (Review)
Review
INTRODUCTION
Advanced cardiac imaging is an important component in pre-procedural planning for ventricular tachycardia (VT) ablations. inHEART's proprietary software, inHEART Models, and its academic version, Multimodality Platform for Specific Imaging in Cardiology (MUSIC), provide detailed characterization of anatomical structures and scars.
AREAS COVERED
This review highlights the current overview of the market and offers insight into inHEART Models and MUSIC and its application during VT ablations with supporting case examples. An overview of the clinical profile and regulatory status of inHEART Models, and other competing technologies, such as Automatic Detection of Arrhythmia Substrate (ADAS) 3D software and Catheter Precision's View into Ventricular Onset (VIVO), are also discussed.
EXPERT OPINION
inHEART and MUSIC utilization has increased over the last few years and continues to establish its presence as an important aspect of VT ablations. Its unique proprietary software sets itself apart from others in the field. The introduction of dual source-photon counting detector computed tomography (PCD-CT) is expected to make significant advancements in the field and take imaging to a new level. inHEART's continued research in cardiac imaging and digital technology is expected to increase as is its global presence in the electrophysiology (EP) community.
Topics: Humans; Tachycardia, Ventricular; Heart; Heart Ventricles; Arrhythmias, Cardiac; Tomography, X-Ray Computed; Catheter Ablation
PubMed: 37584235
DOI: 10.1080/17434440.2023.2247983 -
Circulation. Arrhythmia and... Aug 2022Coronary venous ethanol ablation (VEA) can be used as a strategy to treat ventricular arrhythmias arising from the left ventricular summit, but collateral flow and...
BACKGROUND
Coronary venous ethanol ablation (VEA) can be used as a strategy to treat ventricular arrhythmias arising from the left ventricular summit, but collateral flow and technical challenges cannulating intramural veins in complex venous anatomies can limit its use. Advanced techniques for VEA can capitalize on collateral vessels between target and nontarget sites to improve success.
METHODS
Of 55 patients with left ventricular summit ventricular arrhythmia, advanced techniques were used in 15 after initial left ventricular summit intramural vein mapping failed to show suitable targets for single vein, single-balloon VEA. All patients had previous radiofrequency ablation attempts. Techniques included: double-balloon for distal protection to block distal flow and target the proximal portion of a large intramural vein where best signal was proximal (n=6); balloons in 2 different left ventricular summit veins for a cross-fire multivein VEA (n=4); intramural collateral vein-to-vein cannulation to reach of targeted vein via collateral with antegrade ethanol and proximal balloon block (n=2); prolonged ethanol dwell time for vein sclerosis of large intramural vein and subsequent VEA (n=3); and intramural collateral VEA (n=1).
RESULTS
Fifteen (8 females) patients (age 60.6±17.6 years) required advanced techniques. Procedure time was 210±49.9 minutes, fluoroscopy time was 25.3±14.1 minutes, and 113±17.9 cc of contrast was utilized. A median of 7 cc of ethanol was delivered (range, 4-15 cc). Intraprocedural radiofrequency ablation was delivered before ethanol in 9 out of 15 patients but failed. Ethanol achieved acute success in all 15 patients. Ethanol was used as the sole treatment in two patients. At a median follow-up of 194 days, one patient experienced recurrence.
CONCLUSIONS
Advanced techniques capitalizing on venous anatomy can enable successful VEA and selective targeting of arrhythmogenic sites, by blocking distal flow, utilization of collaterals between nontarget and target veins and multivein VEA. Understanding individual anatomy is critical for VEA success.
Topics: Adult; Aged; Catheter Ablation; Electrocardiography; Ethanol; Female; Heart Ventricles; Humans; Middle Aged; Tachycardia, Ventricular; Treatment Outcome; Ventricular Premature Complexes
PubMed: 35917467
DOI: 10.1161/CIRCEP.122.011017 -
Europace : European Pacing,... Jan 2021
Topics: Catheter Ablation; Heart Ventricles; Humans
PubMed: 33230529
DOI: 10.1093/europace/euaa360 -
Europace : European Pacing,... Apr 2023Data on ventricular pulsed-field ablation (PFA) are sparse in the setting of chronic myocardial infarction (MI). The objective of this study was to compare the...
AIMS
Data on ventricular pulsed-field ablation (PFA) are sparse in the setting of chronic myocardial infarction (MI). The objective of this study was to compare the biophysical and histopathologic characteristics of PFA in healthy and MI swine ventricular myocardium.
METHODS AND RESULTS
Myocardial infarction swine (n = 8) underwent coronary balloon occlusion and survived for 30 days. We then performed endocardial unipolar, biphasic PFA of the MI border zone and a dense scar with electroanatomic mapping and using an irrigated contact force (CF)-sensing catheter with the CENTAURI System (Galaxy Medical). Lesion and biophysical characteristics were compared with three controls: MI swine undergoing thermal ablation, MI swine undergoing no ablation, and healthy swine undergoing similar PFA applications that included linear lesion sets. Tissues were systematically assessed by gross pathology utilizing 2,3,5-triphenyl-2H-tetrazolium chloride staining and histologically with haematoxylin and eosin and trichrome. Pulsed-field ablation in healthy myocardium generated well-demarcated ellipsoid lesions (7.2 ± 2.1 mm depth) with contraction band necrosis and myocytolysis. Pulsed-field ablation in MI demonstrated slightly smaller lesions (depth 5.3 ± 1.9 mm, P = 0.0002), and lesions infiltrated into the irregular scar border, resulting in contraction band necrosis and myocytolysis of surviving myocytes and extending to the epicardial border of the scar. Coagulative necrosis was present in 75% of thermal ablation controls but only in 16% of PFA lesions. Linear PFA resulted in contiguous linear lesions with no gaps in gross pathology. Neither CF nor local R-wave amplitude reduction correlated with lesion size.
CONCLUSION
Pulsed-field ablation of a heterogeneous chronic MI scar effectively ablates surviving myocytes within and beyond the scar, demonstrating promise for the clinical ablation of scar-mediated ventricular arrhythmias.
Topics: Swine; Animals; Cicatrix; Myocardium; Heart Ventricles; Heart; Myocardial Infarction; Arrhythmias, Cardiac; Catheter Ablation; Tachycardia, Ventricular
PubMed: 36793229
DOI: 10.1093/europace/euac252 -
JACC. Clinical Electrophysiology Sep 2023Intraprocedural identification of intramural septal substrate for ventricular tachycardia (ISS-VT) in nonischemic cardiomyopathy (NICM) is challenging. Delayed (>40 ms)...
BACKGROUND
Intraprocedural identification of intramural septal substrate for ventricular tachycardia (ISS-VT) in nonischemic cardiomyopathy (NICM) is challenging. Delayed (>40 ms) transmural conduction time (DCT) with right ventricular basal septal pacing has been previously shown to identify ISS-VT.
OBJECTIVES
This study sought to determine whether substrate catheter ablation incorporating areas of DCT may improve acute and long-term outcomes.
METHODS
We included patients with NICM and ISS-VT referred for catheter ablation between 2016 and 2020. ISS-VT was defined by the following: 1) confluent septal areas of low unipolar voltage (<8.3 mV) in the presence of normal or minimal bipolar abnormalities; and 2) presence of abnormal electrograms in the septum. Substrate ablation was guided by the following: 1) activation and/or entrainment mapping for tolerated VT and pace mapping with ablation of abnormal septal electrograms for unmappable VTs (n = 57, Group 1); and 2) empirically extended to target areas of DCT during right ventricular basal septal pacing regardless of their participation in inducible VT(s) but sparing the conduction system when possible (n = 24, Group 2).
RESULTS
There were no significant baseline differences between Groups 1 and 2. Noninducibility of any VT programmed stimulation at the end of ablation was higher in Group 2 compared with Group 1 (80% vs 53%; P = 0.03). At 12-month follow-up, single-procedure VT-free survival was significantly higher (79% vs 46%; P = 0.006) and the time to VT recurrence was longer (mean 10 ± 3 months vs 7 ± 4 months; P = 0.02) in Group 2 compared with Group 1.
CONCLUSIONS
In patients with NICM and ISS-VT, a substrate ablation strategy that incorporates areas of DCT appears to improve freedom from recurrent VT.
Topics: Humans; Tachycardia, Ventricular; Cardiac Conduction System Disease; Catheter Ablation; Heart Conduction System; Heart Ventricles
PubMed: 37480866
DOI: 10.1016/j.jacep.2023.05.028 -
Journal of Cardiovascular... Mar 2023The anatomical substrate for idiopathic left ventricular tachycardia (ILVT) remains speculative. Purkinje networks surrounding false tendons (FTs) might be involved in...
INTRODUCTION
The anatomical substrate for idiopathic left ventricular tachycardia (ILVT) remains speculative. Purkinje networks surrounding false tendons (FTs) might be involved in the reentrant circuit of ILVT. The objective was to evaluate the anatomical and electrophysiological features of false tendons FTs in relation to ILVT.
METHODS
Intracardiac echocardiography (ICE) was conducted on patients with ILVT. The relationship of the FTs with ILVT was determined using electro-anatomical mapping.
RESULTS
Electrophysiological evaluation and radiofrequency ablation were conducted in 23 consecutive patients with ILVT. FTs were identified in 19/23 cases (82.6%) with P1 potentials during VT recorded at the FT in 14 of these patients (73.7%). Three FT types were identified. In type 1, the FT attached the septum to the base of the posteromedial papillary muscle (PPM) (4/19); type 2 FTs ran between the septum and the PPM apex (3/19), while in type 3, the connection occurred between the septum and apex (11/19) or between the septum and the LV free wall (1/19). The effective ILVT ablation sites were situated at the FT-PPM (3/19) and the FT-septum (16/19) attachment sites.
CONCLUSIONS
This series demonstrates the association between Purkinje fibers and FTs during catheter ablation of ILVT and verifies that left ventricular FTs are an important substrate in this type of tachycardia.
Topics: Humans; Electrocardiography; Tachycardia, Ventricular; Purkinje Fibers; Heart Ventricles; Catheter Ablation; Heart Defects, Congenital
PubMed: 36651353
DOI: 10.1111/jce.15822 -
European Heart Journal Mar 2022Mapping data of human ventricular fibrillation (VF) are limited. We performed detailed mapping of the activities underlying the onset of VF and targeted ablation in...
AIMS
Mapping data of human ventricular fibrillation (VF) are limited. We performed detailed mapping of the activities underlying the onset of VF and targeted ablation in patients with structural cardiac abnormalities.
METHODS AND RESULTS
We evaluated 54 patients (50 ± 16 years) with VF in the setting of ischaemic (n = 15), hypertrophic (n = 8) or dilated cardiomyopathy (n = 12), or Brugada syndrome (n = 19). Ventricular fibrillation was mapped using body-surface mapping to identify driver (reentrant and focal) areas and invasive Purkinje mapping. Purkinje drivers were defined as Purkinje activities faster than the local ventricular rate. Structural substrate was delineated by electrogram criteria and by imaging. Catheter ablation was performed in 41 patients with recurrent VF. Sixty-one episodes of spontaneous (n = 10) or induced (n = 51) VF were mapped. Ventricular fibrillation was organized for the initial 5.0 ± 3.4 s, exhibiting large wavefronts with similar cycle lengths (CLs) across both ventricles (197 ± 23 vs. 196 ± 22 ms, P = 0.9). Most drivers (81%) originated from areas associated with the structural substrate. The Purkinje system was implicated as a trigger or driver in 43% of patients with cardiomyopathy. The transition to disorganized VF was associated with the acceleration of initial reentrant activities (CL shortening from 187 ± 17 to 175 ± 20 ms, P < 0.001), then spatial dissemination of drivers. Purkinje and substrate ablation resulted in the reduction of VF recurrences from a pre-procedural median of seven episodes [interquartile range (IQR) 4-16] to 0 episode (IQR 0-2) (P < 0.001) at 56 ± 30 months.
CONCLUSIONS
The onset of human VF is sustained by activities originating from Purkinje and structural substrate, before spreading throughout the ventricles to establish disorganized VF. Targeted ablation results in effective reduction of VF burden.
KEY QUESTION
The initial phase of human ventricular fibrillation (VF) is critical as it involves the primary activities leading to sustained VF and arrhythmic sudden death. The origin of such activities is unknown.
KEY FINDING
Body-surface mapping shows that most drivers (≈80%) during the initial VF phase originate from electrophysiologically defined structural substrates. Repetitive Purkinje activities can be elicited by programmed stimulation and are implicated as drivers in 37% of cardiomyopathy patients.
TAKE-HOME MESSAGE
The onset of human VF is mostly associated with activities from the Purkinje network and structural substrate, before spreading throughout the ventricles to establish sustained VF. Targeted ablation reduces or eliminates VF recurrence.
Topics: Body Surface Potential Mapping; Brugada Syndrome; Catheter Ablation; Electrocardiography; Heart Ventricles; Humans; Ventricular Fibrillation
PubMed: 35134898
DOI: 10.1093/eurheartj/ehab893 -
Cardiac Electrophysiology Clinics Jun 2021This article reviews the basis for image integration of intracardiac echocardiography (ICE) with three-dimensional electroanatomic mapping systems and preprocedural... (Review)
Review
This article reviews the basis for image integration of intracardiac echocardiography (ICE) with three-dimensional electroanatomic mapping systems and preprocedural cardiac imaging modalities to enhance anatomic understanding and improve guidance for atrial and ventricular ablation procedures. It discusses the technical aspects of ICE-based integration and the clinical evidence for its use. In addition, it presents the current technical limitations and future directions for this technology. This article also includes figures and videos of clinical representative arrhythmia cases where the use of ICE is key to a safe and successful outcome.
Topics: Arrhythmias, Cardiac; Catheter Ablation; Echocardiography, Three-Dimensional; Electrophysiologic Techniques, Cardiac; Heart Atria; Heart Ventricles; Humans; Image Interpretation, Computer-Assisted
PubMed: 33990275
DOI: 10.1016/j.ccep.2021.03.007 -
Journal of Interventional Cardiac... Jan 2023Currently, RF ablation is limited in its ability to deliver deep lesions, as most of the energy delivered to the tissue is dissipated in the first few millimeters from...
BACKGROUND
Currently, RF ablation is limited in its ability to deliver deep lesions, as most of the energy delivered to the tissue is dissipated in the first few millimeters from the catheter tip. Focused electric field (FEF) is a novel technology with the potential to ablate deeper than currently available RF catheters. This work is the first proof of concept of FEF technology.
OBJECTIVE
To introduce FEF technology and demonstrate its feasibility as an ablation tool.
METHODS
We constructed a FEF catheter with a truncated dome-shaped tip, creating a toroidal ablating surface. We performed ablation ex vivo in porcine hearts and examined ablation characteristics using both tissue sectioning and real-time thermal imaging.
RESULTS
RF lesions were 9.1 ± 1.0 mm wide by 6.1 ± 1.1 mm deep with ablation using a conventional irrigated tip catheter (Thermocool SF). In contrast, lesions created using FEF ablation were 12.8 ± 1.6 mm wide and 14.0 ± 1.6 mm deep. Steam pops were less frequent in the FEF group. Thermal imaging demonstrated that in contrast to an irrigated tip RF catheter, the FEF catheter generated a uniform temperature profile down to a maximum depth exceeding 15 mm.
CONCLUSION
This study is the first proof of concept of FEF technology. Using a novel toroidal catheter tip design, the electric field remains confined to a narrow tissue region, thus avoiding the rapid fall off in energy delivery from the tissue surface inherent to current RF catheter designs. FEF ablation may allow delivery of deeper ablations lesions with potentially lower risk of tissue hyperthermia than conventional catheters. Future studies are needed.
Topics: Animals; Swine; Catheter Ablation; Therapeutic Irrigation; Equipment Design; Cardiac Catheters; Heart Ventricles
PubMed: 35779156
DOI: 10.1007/s10840-022-01276-z -
Heart Rhythm Oct 2023Ventricular arrhythmias (VAs) originating from papillary muscles (PAPs) can be challenging when targeted with catheter ablation. Reasons may include premature...
BACKGROUND
Ventricular arrhythmias (VAs) originating from papillary muscles (PAPs) can be challenging when targeted with catheter ablation. Reasons may include premature ventricular complex pleomorphism, structurally abnormal PAPs, or unusual origins of VAs from PAP-myocardial connections (PAP-MYCs).
OBJECTIVE
The purpose of this study was to correlate PAP anatomy with mapping and ablation of PAP VAs.
METHODS
In a series of 43 consecutive patients with frequent PAP arrhythmias referred for ablation, the anatomy and structure of PAPs and VA origins were analyzed using multimodality imaging. Successful ablation sites were analyzed for location on the PAP body or a PAP-MYC.
RESULTS
In a total of 17 of 43 patients (40%), VAs originated from a PAP-MYC (in 5 of 17 patients, the PAP inserted into the mitral valve anulus); and in 41 patients, VAs originated from a PAP body. VAs from a PAP-MYC more often had delayed R-wave transition than did other PAP VAs (69% vs 28%; P < .001). Patients with failed procedures had more PAP-MYCs (24.8 ± 8 PAP-MYCs per patient vs 16 ± 7 PAP-MYCs per patient; P < .001).
CONCLUSION
Multimodality imaging identifies anatomic details of PAPs that facilitate mapping and ablation of VAs. In more than a third of patients with PAP VAs, VAs originate from connections between PAPs and the surrounding myocardium or between other PAPs. VA electrocardiographic morphologies are different when VAs originate from PAP-connection sites as compared with VAs originating from the PAP body.
Topics: Humans; Papillary Muscles; Tachycardia, Ventricular; Ventricular Premature Complexes; Electrocardiography; Mitral Valve; Catheter Ablation; Heart Ventricles
PubMed: 37329938
DOI: 10.1016/j.hrthm.2023.06.009