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Heart Rhythm O2 Apr 2024Cardiac radioablation is a new treatment for patients with refractory ventricular tachycardia (VT). The target for cardiac radioablation is subject to cardiorespiratory...
BACKGROUND
Cardiac radioablation is a new treatment for patients with refractory ventricular tachycardia (VT). The target for cardiac radioablation is subject to cardiorespiratory motion (CRM), the heart's movement with breathing and cardiac contraction. Data regarding the magnitude of target CRM are limited but are highly important for treatment planning.
OBJECTIVES
The study sought to assess CRM amplitude by using ablation catheter geometrical data.
METHODS
Electroanatomic mapping data of patients undergoing catheter ablation for VT at 3 academic centers were exported. The spatial position of the ablation catheter as a function of time while in contact with endocardium was analyzed and used to quantify CRM.
RESULTS
Forty-four patients with ischemic and nonischemic cardiomyopathy and VT contributed 1364 ablation lesions to the analysis. Average cardiac and respiratory excursion were 1.62 ± 1.21 mm and 12.12 ± 4.10 mm, respectively. The average ratio of respiratory to cardiac motion was approximately 11:1. CRM was greatest along the craniocaudal axis (9.66 ± 4.00 mm). Regional variations with respect to respiratory and cardiac motion were observed: basal segments had smaller displacements vs midventricular and apical segments. Patient characteristics (previous cardiac surgery, height, weight, body mass index, and left ventricular ejection fraction) had a statistically significant, albeit clinically moderate, impact on CRM.
CONCLUSION
CRM is primarily determined by respiratory displacement and is modulated by the location of the target and the patient's biometric characteristics. The patient-specific quantification of CRM may allow to decrease treatment volume and reduce radiation exposure of surrounding organs at risk while delivering the therapeutic dose to the target.
PubMed: 38690147
DOI: 10.1016/j.hroo.2024.03.006 -
Heart Rhythm O2 Apr 2024Defining postinfarct ventricular arrhythmic substrate is challenging with voltage mapping alone, though it may be improved in combination with an activation map....
BACKGROUND
Defining postinfarct ventricular arrhythmic substrate is challenging with voltage mapping alone, though it may be improved in combination with an activation map. Omnipolar technology on the EnSite X system displays activation as vectors that can be superimposed onto a voltage map.
OBJECTIVE
The study sought to optimize voltage map settings during ventricular tachycardia (VT) ablation, adjusting them dynamically using omnipolar vectors.
METHODS
Consecutive patients undergoing substrate mapping were retrospectively studied. We categorized omnipolar vectors as uniform when pointing in one direction, or in disarray when pointing in multiple directions. We superimposed vectors onto voltage maps colored purple in tissue >1.5 mV, and the voltage settings were adjusted so that uniform vectors appeared within purple voltages, a process termed dynamic voltage mapping (DVM). Vectors in disarray appeared within red-blue lower voltages.
RESULTS
A total of 17 substrate maps were studied in 14 patients (mean age 63 ± 13 years; mean left ventricular ejection fraction 35 ± 6%, median 4 [interquartile range 2-8.5] recent VT episodes). The DVM mean voltage threshold that differentiated tissue supporting uniform vectors from disarray was 0.27 mV, ranging between patients from 0.18 to 0.50 mV, with good interobserver agreement (median difference: 0.00 mV). We found that VT isthmus components, as well as sites of latest activation, isochronal crowding, and excellent pace maps colocated with tissue along the DVM border zone surrounding areas of disarray.
CONCLUSION
DVM, guided by areas of omnipolar vector disarray, allows for individualized postinfarct ventricular substrate characterization. Tissue bordering areas of disarray may harbor greater arrhythmogenic potential.
PubMed: 38690145
DOI: 10.1016/j.hroo.2024.02.006 -
Frontiers in Cardiovascular Medicine 2024Signal-averaged electrocardiography (SAECG) provides diagnostic and prognostic information regarding cardiac diseases. However, its value in other nonischemic...
Signal-averaged electrocardiography as a noninvasive tool for evaluating the ventricular substrate in patients with nonischemic cardiomyopathy: reassessment of an old tool.
INTRODUCTION
Signal-averaged electrocardiography (SAECG) provides diagnostic and prognostic information regarding cardiac diseases. However, its value in other nonischemic cardiomyopathies (NICMs) remains unclear. This study aimed to investigate the role of SAECG in patients with NICM.
METHODS AND RESULTS
This retrospective study included consecutive patients with NICM who underwent SAECG, biventricular substrate mapping, and ablation for ventricular arrhythmia (VA). Patients with baseline ventricular conduction disturbances were excluded. Patients who fulfilled at least one SAECG criterion were categorized into Group 1, and the other patients were categorized into Group 2. Baseline and ventricular substrate characteristics were compared between the two groups. The study included 58 patients (39 men, mean age 50.4 ± 15.5 years), with 34 and 24 patients in Groups 1 and 2, respectively. Epicardial mapping was performed in eight (23.5%) and six patients (25.0%) in Groups 1 and 2 ( = 0.897), respectively. Patients in Group 1 had a more extensive right ventricular (RV) low-voltage zone (LVZ) and scar area than those in Group 2. Group 1 had a larger epicardial LVZ than Group 2. Epicardial late potentials were more frequent in Group 1 than in Group 2. There were more arrhythmogenic foci within the RV outflow tract in Group 1 than in Group 2. There was no significant difference in long-term VA recurrence.
CONCLUSION
In our NICM population, a positive SAECG was associated with a larger RV endocardial scar, epicardial scar/late potentials, and a higher incidence of arrhythmogenic foci in the RV outflow tract.
PubMed: 38689859
DOI: 10.3389/fcvm.2024.1306055 -
JACC. Basic To Translational Science Apr 2024The role of atrial metabolism alterations for initiation and atrial fibrillation (AF) persistence remains poorly understood. Therefore, we evaluated left atrial glucose...
The role of atrial metabolism alterations for initiation and atrial fibrillation (AF) persistence remains poorly understood. Therefore, we evaluated left atrial glucose metabolism by nicotinic acid derivative stimulated 18-fluorodeoxyglucose positron emission tomography in 36 patients with persistent AF undergoing catheter ablation before and 3 months after return to sinus rhythm and compared values against healthy controls. Under identical hemodynamics and metabolic conditions, and although left ventricular FDG uptake remained unchanged, patients in persistent AF presented significantly higher total left atrial and left atrial appendage uptake, which decreased significantly after return to sinus rhythm, despite improvement of passive and active atrial contractile function. These findings support a role of altered glucose metabolism and metabolic wasting underlying the pathophysiology of persistent AF.
PubMed: 38680960
DOI: 10.1016/j.jacbts.2023.11.001 -
Heart Rhythm Apr 2024Sinus rhythm activation time is useful to assess infarct border zone substrate.
BACKGROUND
Sinus rhythm activation time is useful to assess infarct border zone substrate.
OBJECTIVE
We sought to further investigate sinus activation in ventricular tachycardia (VT).
METHODS
Canine postinfarction data were analyzed retrospectively. In each experiment, an infarct was created in the left ventricular wall by left anterior descending coronary artery ligation. At 3 to 5 days after ligation, 196-312 bipolar electrograms were recorded from the anterior left ventricular epicardium overlapping the infarct border zone. Sustained monomorphic VT was induced by premature electrical stimulation in 50 experiments and was noninducible in 43 experiments. Acquired sinus rhythm and VT electrograms were marked for electrical activation time, and activation maps of representative sinus rhythm and VT cycles were constructed. The sinus rhythm activation signature was defined as the cumulative number of multielectrode recording sites that had activated per time epoch, and its derivative was used to predict VT inducibility and to define the sinus rhythm slow/late activation sequence.
RESULTS
Plotting mean activation signature derivative, a best cutoff value was useful to separate experiments with reentrant VT inducibility (sensitivity, 42/50) vs noninducibility (specificity, 39/43), with an accuracy of 81 of 93. For the 50 experiments with inducible VT, recording sites overlying a segment of isochrone encompassing the sinus rhythm slow/late activation sequence spanned the VT isthmus location in 32 cases (64%), partially spanned it in 15 cases (30%), but did not span it in 3 cases (6%).
CONCLUSION
The sinus rhythm activation signature derivative is assistive to differentiate substrate supporting reentrant VT inducibility vs noninducibility and to identify slow/late activation for targeting isthmus location.
PubMed: 38677360
DOI: 10.1016/j.hrthm.2024.04.082 -
Journal of Clinical Medicine Apr 2024Ventricular fibrillation (VF) is a common cause of sudden cardiac death in patients with channelopathies, particularly in the young population. Although pharmacological... (Review)
Review
Ventricular fibrillation (VF) is a common cause of sudden cardiac death in patients with channelopathies, particularly in the young population. Although pharmacological treatment, cardiac sympathectomy, and implantable cardioverter defibrillators (ICD) have been the mainstay in the management of VF in patients with channelopathies, they are associated with significant adverse effects and complications, leading to poor quality of life. Given these drawbacks, catheter ablation has been proposed as a therapeutic option for patients with channelopathies. Advances in imaging techniques and modern mapping technologies have enabled increased precision in identifying arrhythmia triggers and substrate modification. This has aided our understanding of the underlying pathophysiology of ventricular arrhythmias in channelopathies, highlighting the roles of the Purkinje network and the epicardial right ventricular outflow tract in arrhythmogenesis. This review explores the role of catheter ablation in managing the most common channelopathies (Brugada syndrome, congenital long QT syndrome, short QT syndrome, and catecholaminergic polymorphic ventricular tachycardia). While the initial results for ablation in Brugada syndrome are promising, the long-term efficacy and durability of ablation in different channelopathies require further investigation. Given the genetic and phenotypic heterogeneity of channelopathies, future studies are needed to show whether catheter ablation in patients with channelopathies is associated with a reduction in VF, and psychological distress stemming from recurrent ICD shocks, particularly relative to other available therapeutic options (e.g., quinidine in high-risk Brugada patients).
PubMed: 38673656
DOI: 10.3390/jcm13082384 -
Journal of Clinical Medicine Apr 2024: Catheter ablation in patients with ventricular arrhythmias (VA), such as ventricular tachycardias (VT) or frequent premature ventricular complexes (PVC), is...
: Catheter ablation in patients with ventricular arrhythmias (VA), such as ventricular tachycardias (VT) or frequent premature ventricular complexes (PVC), is increasingly considered an effective and safe therapy when performed in experienced centers. This study sought to determine acute success rates and complication rates of ablation procedures for patients with VA in a Swiss tertiary care center. All patients who underwent ablation therapy for VT and PVC at the University Heart Center in Zurich, Switzerland, between March 2012 and April 2017 were included in this analysis. A total of 120 patients underwent catheter ablation for VT and PVC (69 and 51, respectively). Seventy percent of patients were male, and the mean age was 55.3 years. The most common indication for ablation was high PVC burden (47.5%), followed by paroxysmal VT (38.3%), ICD shocks (23.3%), incessant VT (12.5%), electrical storm (7.5%), and syncope (3.3%). Acute success rates for VT and PVC ablations were 94.2% and 92.2%, respectively. Rates for complications (including major and minor) for VT and PVC were 10.1% and 7.8%, respectively. Complications occurred only in patients with structural heart disease; no complications were noted in structurally normal hearts. Our results suggest that catheter ablation for VT and PVC has high acute success rates with a reasonable risk for complications in the setting of tertiary care centers, comparable to those reported in other studies.
PubMed: 38673583
DOI: 10.3390/jcm13082310 -
Heart Rhythm Apr 2024Voltage mapping could identify the conducting channels potentially responsible for ventricular tachycardia (VT). Standard thresholds (0.5-1.5 mV) were established using...
BACKGROUND
Voltage mapping could identify the conducting channels potentially responsible for ventricular tachycardia (VT). Standard thresholds (0.5-1.5 mV) were established using bipolar catheters. No thresholds have been analyzed with high-density mapping catheters. In addition, channels identified by cardiac magnetic resonance (CMR) has been proven to be related with VT.
OBJECTIVE
The purpose of this study was to analyze the diagnostic yield of a personalized voltage map using CMR to guide the adjustment of voltage thresholds.
METHODS
All consecutive patients with scar-related VT undergoing ablation after CMR (from October 2018 to December 2020) were included. First, personalized CMR-guided voltage thresholds were defined systematically according to the distribution of the scar and channels. Second, to validate these new thresholds, a comparison with standard thresholds (0.5-1.5 mV) was performed. Tissue characteristics of areas identified as deceleration zones (DZs) were recorded for each pair of thresholds. In addition, the relation of VT circuits with voltage channels was analyzed for both maps.
RESULTS
Thirty-two patients were included [mean age 66.6 ± 11.2 years; 25 (78.1%) ischemic cardiomyopathy]. Overall, 52 DZs were observed: 44.2% were identified as border zone tissue with standard cutoffs vs 75.0% using personalized voltage thresholds (P = .003). Of the 31 VT isthmuses detected, only 35.5% correlated with a voltage channel with standard thresholds vs 74.2% using adjusted thresholds (P = .005). Adjusted cutoff bipolar voltages that better matched CMR images were 0.51 ± 0.32 and 1.79 ± 0.71 mV with high interindividual variability (from 0.14-1.68 to 0.7-3.21 mV).
CONCLUSION
Personalized voltage CMR-guided personalized voltage maps enable a better identification of the substrate with a higher correlation with both DZs and VT isthmuses than do conventional voltage maps using fixed thresholds.
PubMed: 38670249
DOI: 10.1016/j.hrthm.2024.04.074 -
Journal of Cardiovascular Development... Apr 2024Heart failure (HF) represents a significant global health challenge that is still responsible for increasing morbidity and mortality despite advancements in... (Review)
Review
Heart failure (HF) represents a significant global health challenge that is still responsible for increasing morbidity and mortality despite advancements in pharmacological treatments. This review investigates the effectiveness of non-pharmacological interventions in the management of HF, examining lifestyle measures, physical activity, and the role of some electrical therapies such as catheter ablation, cardiac resynchronization therapy (CRT), and cardiac contractility modulation (CCM). Structured exercise training is a cornerstone in this field, demonstrating terrific improvements in functional status, quality of life, and mortality risk reduction, particularly in patients with HF with reduced ejection fraction (HFrEF). Catheter ablation for atrial fibrillation, premature ventricular beats, and ventricular tachycardia aids in improving left ventricular function by reducing arrhythmic burden. CRT remains a key intervention for selected HF patients, helping achieve left ventricular reverse remodeling and improving symptoms. Additionally, the emerging therapy of CCM provides a novel opportunity for patients who do not meet CRT criteria or are non-responders. Integrating non-pharmacological interventions such as digital health alongside specific medications is key for optimizing outcomes in HF management. It is imperative to tailor approaches to individual patients in this diverse patient population to maximize benefits. Further research is warranted to improve treatment strategies and enhance patient outcomes in HF management.
PubMed: 38667740
DOI: 10.3390/jcdd11040122 -
Europace : European Pacing,... May 2024Stereotactic arrhythmia radioablation (STAR) is a treatment option for recurrent ventricular tachycardia/fibrillation (VT/VF) in patients with structural heart disease...
Stereotactic arrhythmia radioablation (STAR) is a treatment option for recurrent ventricular tachycardia/fibrillation (VT/VF) in patients with structural heart disease (SHD). The current and future role of STAR as viewed by cardiologists is unknown. The study aimed to assess the current role, barriers to application, and expected future role of STAR. An online survey consisting of 20 questions on baseline demographics, awareness/access, current use, and the future role of STAR was conducted. A total of 129 international participants completed the survey [mean age 43 ± 11 years, 25 (16.4%) female]. Ninety-one (59.9%) participants were electrophysiologists. Nine participants (7%) were unaware of STAR as a therapeutic option. Sixty-four (49.6%) had access to STAR, while 62 (48.1%) had treated/referred a patient for treatment. Common primary indications for STAR were recurrent VT/VF in SHD (45%), recurrent VT/VF without SHD (7.8%), or premature ventricular contraction (3.9%). Reported main advantages of STAR were efficacy in the treatment of arrhythmias not amenable to conventional treatment (49%) and non-invasive treatment approach with overall low expected acute and short-term procedural risk (23%). Most respondents have foreseen a future clinical role of STAR in the treatment of VT/VF with or without underlying SHD (72% and 75%, respectively), although only a minority expected a first-line indication for it (7% and 5%, respectively). Stereotactic arrhythmia radioablation as a novel treatment option of recurrent VT appears to gain acceptance within the cardiology community. Further trials are critical to further define efficacy, patient populations, as well as the appropriate clinical use for the treatment of VT.
Topics: Humans; Female; Male; Tachycardia, Ventricular; Adult; Middle Aged; Ventricular Fibrillation; Radiosurgery; Health Care Surveys; Electrophysiologic Techniques, Cardiac; Recurrence; Treatment Outcome; Practice Patterns, Physicians'; Cardiologists; Cardiac Electrophysiology
PubMed: 38666444
DOI: 10.1093/europace/euae110