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Frontiers in Physiology 2024Electrocardiographic (ECG) features of left bundle branch (LBB) block (LBBB) can be observed in up to 20%-30% of patients suffering from heart failure with reduced...
BACKGROUND
Electrocardiographic (ECG) features of left bundle branch (LBB) block (LBBB) can be observed in up to 20%-30% of patients suffering from heart failure with reduced ejection fraction. However, predicting which LBBB patients will benefit from cardiac resynchronization therapy (CRT) or conduction system pacing remains challenging. This study aimed to establish a translational model of LBBB to enhance our understanding of its pathophysiology and improve therapeutic approaches.
METHODS
Fourteen male pigs underwent radiofrequency catheter ablation of the proximal LBB under fluoroscopy and ECG guidance. Comprehensive clinical assessments (12-lead ECG, bloodsampling, echocardiography, electroanatomical mapping) were conducted before LBBB induction, after 7, and 21 days. Three pigs received CRT pacemakers 7 days after LBB ablation to assess resynchronization feasibility.
RESULTS
Following proximal LBB ablation, ECGs displayed characteristic LBBB features, including QRS widening, slurring in left lateral leads, and QRS axis changes. QRS duration increased from 64.2 ± 4.2 ms to 86.6 ± 12.1 ms, and R wave peak time in V6 extended from 21.3 ± 3.6 ms to 45.7 ± 12.6 ms. Echocardiography confirmed cardiac electromechanical dyssynchrony, with septal flash appearance, prolonged septal-to-posterior-wall motion delay, and extended ventricular electromechanical delays. Electroanatomical mapping revealed a left ventricular breakthrough site shift and significantly prolonged left ventricular activation times. RF-induced LBBB persisted for 3 weeks. CRT reduced QRS duration to 75.9 ± 8.6 ms, demonstrating successful resynchronization.
CONCLUSION
This porcine model accurately replicates the electrical and electromechanical characteristics of LBBB observed in patients. It provides a practical, cost-effective, and reproducible platform to investigate molecular and translational aspects of cardiac electromechanical dyssynchrony in a controlled and clinically relevant setting.
PubMed: 38706948
DOI: 10.3389/fphys.2024.1385277 -
Europace : European Pacing,... Jun 2024Ablation of monomorphic ventricular tachycardia (MMVT) has been shown to reduce shock frequency and improve survival. We aimed to compare cause-specific risk factors for... (Comparative Study)
Comparative Study
Competing risks of monomorphic vs. non-monomorphic ventricular arrhythmias in primary prevention implantable cardioverter-defibrillator recipients: Global Electrical Heterogeneity and Clinical Outcomes (GEHCO) study.
AIMS
Ablation of monomorphic ventricular tachycardia (MMVT) has been shown to reduce shock frequency and improve survival. We aimed to compare cause-specific risk factors for MMVT and polymorphic ventricular tachycardia (PVT)/ventricular fibrillation (VF) and to develop predictive models.
METHODS AND RESULTS
The multicentre retrospective cohort study included 2668 patients (age 63.1 ± 13.0 years; 23% female; 78% white; 43% non-ischaemic cardiomyopathy; left ventricular ejection fraction 28.2 ± 11.1%). Cox models were adjusted for demographic characteristics, heart failure severity and treatment, device programming, and electrocardiogram metrics. Global electrical heterogeneity was measured by spatial QRS-T angle (QRSTa), spatial ventricular gradient elevation (SVGel), azimuth, magnitude (SVGmag), and sum absolute QRST integral (SAIQRST). We compared the out-of-sample performance of the lasso and elastic net for Cox proportional hazards and the Fine-Gray competing risk model. During a median follow-up of 4 years, 359 patients experienced their first sustained MMVT with appropriate implantable cardioverter-defibrillator (ICD) therapy, and 129 patients had their first PVT/VF with appropriate ICD shock. The risk of MMVT was associated with wider QRSTa [hazard ratio (HR) 1.16; 95% confidence interval (CI) 1.01-1.34], larger SVGel (HR 1.17; 95% CI 1.05-1.30), and smaller SVGmag (HR 0.74; 95% CI 0.63-0.86) and SAIQRST (HR 0.84; 95% CI 0.71-0.99). The best-performing 3-year competing risk Fine-Gray model for MMVT [time-dependent area under the receiver operating characteristic curve (ROC(t)AUC) 0.728; 95% CI 0.668-0.788] identified high-risk (> 50%) patients with 75% sensitivity and 65% specificity, and PVT/VF prediction model had ROC(t)AUC 0.915 (95% CI 0.868-0.962), both satisfactory calibration.
CONCLUSION
We developed and validated models to predict the competing risks of MMVT or PVT/VF that could inform procedural planning and future randomized controlled trials of prophylactic ventricular tachycardia ablation.
CLINICAL TRIAL REGISTRATION
URL:www.clinicaltrials.gov Unique identifier:NCT03210883.
Topics: Humans; Defibrillators, Implantable; Female; Male; Tachycardia, Ventricular; Middle Aged; Retrospective Studies; Primary Prevention; Risk Factors; Risk Assessment; Aged; Ventricular Fibrillation; Treatment Outcome; Electric Countershock; Electrocardiography; Catheter Ablation; Time Factors; Death, Sudden, Cardiac
PubMed: 38703375
DOI: 10.1093/europace/euae127 -
Mitral Annular Disjunction in the Context of Mitral Valve Prolapse: Identifying the At-Risk Patient.JACC. Cardiovascular Imaging Apr 2024Mitral annular disjunction (MAD), a separation between the left atrium/mitral valve annulus and the left ventricular myocardium, is frequently seen in patients with... (Review)
Review
Mitral annular disjunction (MAD), a separation between the left atrium/mitral valve annulus and the left ventricular myocardium, is frequently seen in patients with arrhythmic mitral valve prolapse. Although an association exists between MAD and ventricular arrhythmias, little is known regarding the identification of individuals at high risk. Multimodality imaging including echocardiography, computed tomography, cardiac magnetic resonance, and positron emission tomography can play an important role in both the diagnosis and risk stratification of MAD. Due to a paucity of data, clinical decision making in a patient with MAD is challenging and remains largely empirical. Although MAD itself can be corrected surgically, the prevention and treatment of associated arrhythmias may require medical therapy, catheter ablation, and an implantable cardioverter-defibrillator. Prospective data are required to define the role of implantable cardioverter-defibrillators, targeted catheter ablation, and surgical correction in selected, at-risk patients.
PubMed: 38703174
DOI: 10.1016/j.jcmg.2024.03.006 -
Revista Portuguesa de Cardiologia :... May 2024Atrial fibrillation (AF) and heart failure (HF) often coexist. AF catheter ablation improves left ventricular ejection fraction (LVEF), but its impact varies between...
INTRODUCTION AND OBJECTIVES
Atrial fibrillation (AF) and heart failure (HF) often coexist. AF catheter ablation improves left ventricular ejection fraction (LVEF), but its impact varies between patients. We aimed to identify predictors of LVEF improvement in HF patients with impaired LVEF undergoing AF ablation.
METHODS
We conducted a retrospective single-center study in HF patients with LVEF <50% undergoing AF catheter ablation between May 2016 and May 2022. The primary endpoint was the LVEF recovery rate ('responders'). Secondary endpoints were one-year safety and effectiveness. We also aimed to validate a prediction model for LVEF recovery.
RESULTS
The study included 100 patients (79% male, median age 60 years, 70% with probable tachycardia-induced cardiomyopathy [TIC], mean LVEF 37%, 29% with paroxysmal AF). After a median follow-up of 12 months after catheter ablation, LVEF improved significantly (36±10% vs. 53±10%, p<0.001), with an 82% responder rate. A suspected diagnosis of TIC (OR 4.916 [95% CI 1.166-20.732], p=0.030), shorter QRS duration (OR 0.969 [95% CI 0.945-0.994], p=0.015), and smaller left ventricle (OR 0.893 [95% CI 0.799-0.999], p=0.049) were independently associated with LVEF improvement. Freedom from any documented atrial arrhythmia was 86% (64% under antiarrhythmic drugs), and the rate of adverse events was 2%. The prediction model had a good discriminative performance (AUC 0.814 [95% CI 0.681-0.947]).
CONCLUSION
In AF patients with HF and impaired LVEF, suspected TIC, shorter QRS duration, and smaller LV diameter were associated with LVEF recovery following AF catheter ablation.
PubMed: 38701967
DOI: 10.1016/j.repc.2024.02.008 -
Current Cardiology Reports May 2024Percutaneous radiofrequency (RF) catheter ablation is an established strategy to prevent ventricular tachycardia (VT) recurrence and ICD shocks. Yet delivery of durable... (Review)
Review
PURPOSE OF REVIEW
Percutaneous radiofrequency (RF) catheter ablation is an established strategy to prevent ventricular tachycardia (VT) recurrence and ICD shocks. Yet delivery of durable lesion sets by means of traditional unipolar radiofrequency ablation remains challenging, and left ventricular transmurality is rarely achieved. Failure to ablate and eliminate functionally relevant areas is particularly common in deep intramyocardial substrates, e.g. septal VT and cardiomyopathies. Here, we aim to give a practical-orientated overview of advanced and emerging RF ablation technologies to target these complex VT substrates. We summarize recent evidence in support of these technologies and share experiences from a tertiary VT centre to highlight important "hands-on" considerations for operators new to advanced RF ablation strategies.
RECENT FINDINGS
A number of innovative and modified radiofrequency ablation approaches have been proposed to increase energy delivery to the myocardium and maximize RF lesion dimensions and depth. These include measures of impedance modulation, combinations of simultaneous unipolar ablations or true bipolar ablation, intramyocardial RF delivery via wires or extendable RF needles and investigational linear or spherical catheter designs. Recent new clinical evidence for the efficacy and safety of these investigational technologies and strategies merits a re-evaluation of their role and clinic application for percutaneous VT ablations. Complexity of substrates targeted with percutaneous VT ablation is increasing and requires detailed preprocedural imaging to characterize the substrate to inform the procedural approach and selection of ablation technology. Depending on local experience, options for additional and/or complementary interventional treatments should be considered upfront in challenging substrates to improve the success rates of index procedures. Advanced RF technologies available for clinical VT ablations include impedance modulation via hypotonic irrigation or additional dispersive patches and simultaneous unipolar as well as true bipolar ablation. Promising investigational RF technologies involve an extendable needle RF catheter, intramyocardial RF delivery over intentionally perforated wires as well as a variety of innovative ablation catheter designs including multipolar linear, spherical and partially insulated ablation catheters.
Topics: Humans; Tachycardia, Ventricular; Catheter Ablation; Equipment Design
PubMed: 38700597
DOI: 10.1007/s11886-024-02048-z -
Journal of the American Heart... May 2024Previous studies have shown that women with hypertrophic obstructive cardiomyopathy (HCM) have worse long-term outcomes irrespective of intervention. However, the... (Comparative Study)
Comparative Study
BACKGROUND
Previous studies have shown that women with hypertrophic obstructive cardiomyopathy (HCM) have worse long-term outcomes irrespective of intervention. However, the outcomes of patients undergoing alcohol septal ablation (ASA) based on sex have not been described. Hence, this study aimed to evaluate pressure changes and long-term mortality in patients with HCM undergoing ASA based on sex.
METHODS AND RESULTS
This is a single-center retrospective study evaluating hemodynamic changes and long-term mortality in patients with HCM treated with ASA according to sex. A total of 259 patients were included (aged 68.4±11.9 years, 62.2% women). Women had higher age and baseline pressures at the time of ASA, with a greater percent reduction in mean left atrial pressure (men versus women: 2.2% versus 15.9%, respectively; =0.02). Women had better survival (median survival rate of men versus women: 8.6 versus 12.5 years, respectively; =0.011). On Cox multivariable regression, predictors of mortality were age (per group change <60 years, 61-70 years, 71-80 years, and >80 years; hazard ratio [HR], 1.45 [95% CI, 1.10-1.91], =0.008), female sex (HR, 0.59 [95% CI, 0.35-0.99], =0.048), chronic kidney disease (HR, 1.88 [95% CI, 1.06-3.33], =0.031), and left ventricular outflow tract gradient reduction ≤86% (HR, 1.91 [95% CI, 1.14-3.19], =0.014).
CONCLUSIONS
Women with HCM undergoing ASA are older and have higher left-sided baseline pressures compared with men yet have better survival. Further studies exploring the mechanisms of differential outcomes according to sex in patients with HCM undergoing ASA are needed.
Topics: Humans; Cardiomyopathy, Hypertrophic; Female; Male; Aged; Retrospective Studies; Ethanol; Middle Aged; Sex Factors; Ablation Techniques; Aged, 80 and over; Treatment Outcome; Heart Septum; Risk Factors; Time Factors; Age Factors
PubMed: 38700034
DOI: 10.1161/JAHA.123.032553 -
Europace : European Pacing,... May 2024Arrhythmia-induced cardiomyopathy (AiCM) represents a subtype of acute heart failure (HF) in the context of sustained arrhythmia. Clear definitions and management...
AIMS
Arrhythmia-induced cardiomyopathy (AiCM) represents a subtype of acute heart failure (HF) in the context of sustained arrhythmia. Clear definitions and management recommendations for AiCM are lacking. The European Heart Rhythm Association Scientific Initiatives Committee (EHRA SIC) conducted a survey to explore the current definitions and management of patients with AiCM among European and non-European electrophysiologists.
METHODS AND RESULTS
A 25-item online questionnaire was developed and distributed among EP specialists on the EHRA SIC website and on social media between 4 September and 5 October 2023. Of the 206 respondents, 16% were female and 61% were between 30 and 49 years old. Most of the respondents were EP specialists (81%) working at university hospitals (47%). While most participants (67%) agreed that AiCM should be defined as a left ventricular ejection fraction (LVEF) impairment after new onset of an arrhythmia, only 35% identified a specific LVEF drop to diagnose AiCM with a wide range of values (5-20% LVEF drop). Most respondents considered all available therapies: catheter ablation (93%), electrical cardioversion (83%), antiarrhythmic drugs (76%), and adjuvant HF treatment (76%). A total of 83% of respondents indicated that adjuvant HF treatment should be started at first HF diagnosis prior to antiarrhythmic treatment, and 84% agreed it should be stopped within six months after LVEF normalization. Responses for the optimal time point for the first LVEF reassessment during follow-up varied markedly (1 day-6 months after antiarrhythmic treatment).
CONCLUSION
This EHRA Survey reveals varying practices regarding AiCM among physicians, highlighting a lack of consensus and heterogenous care of these patients.
Topics: Humans; Arrhythmias, Cardiac; Female; Male; Cardiomyopathies; Middle Aged; Adult; Europe; Surveys and Questionnaires; Stroke Volume; Health Care Surveys; Anti-Arrhythmia Agents; Practice Patterns, Physicians'; Ventricular Function, Left; Catheter Ablation; Cardiologists
PubMed: 38693772
DOI: 10.1093/europace/euae112 -
Circulation. Arrhythmia and... Jun 2024Conventional focal radiofrequency catheters may be modified to enable multiple energy modalities (radiofrequency or pulsed field [PF]) with the benefit of contact force...
BACKGROUND
Conventional focal radiofrequency catheters may be modified to enable multiple energy modalities (radiofrequency or pulsed field [PF]) with the benefit of contact force (CF) feedback, providing greater flexibility in the treatment of arrhythmias. Information on the impact of CF on lesion formation in PF ablations remains limited.
METHODS
An in vivo study was performed with 8 swine using an investigational dual-energy CF focal catheter with local impedance. Experiment I: To evaluate atrial lesion formation, contiguity, and width, a point-by-point approach was used to create an intercaval line. The distance between the points was prespecified at 4±1 mm. Half of the line was created with radiofrequency energy, whereas the other half utilized PF (single 2.0 kV application with a proprietary waveform). Experiment II: To evaluate single application lesion dimensions with a proprietary waveform, discrete ventricular lesions were performed with PFA (single 2.0 kV application) with targeted levels of CF: low, 5 to 15 g; medium, 20 to 30 g; and high, 35 to 45 g. Following 1 week of survival, animals underwent endocardial/epicardial remapping, and euthanasia to enable histopathologic examination.
RESULTS
Experiment I: Both energy modalities resulted in a complete intercaval line of transmural ablation. PF resulted in significantly wider lines than radiofrequency: minimum width, 14.9±2.3 versus 5.0±1.6 mm; maximum width, 21.8±3.4 versus 7.3±2.1 mm, respectively; <0.01 for each. Histology confirmed transmural lesions with both modalities. Experiment II: With PF, lesion depth, width, and volume were larger with higher degrees of CF (depth: r=0.82, <0.001; width: r=0.26, =0.052; and volume: r=0.55, <0.001), with depth increasing at a faster rate than width. The mean depths were as follows: low (n=17), 4.3±1.0 mm; medium (n=26), 6.4±1.2 mm; and high (n=14), 9.1±1.4 mm.
CONCLUSIONS
Using the same focal point CF-sensing catheter, a novel PF ablation waveform with a single application resulted in transmural atrial lesions that were significantly wider than radiofrequency. Lesion depth showed a significant positive correlation with CF with depths of 6.4 mm at moderate CF.
Topics: Animals; Catheter Ablation; Equipment Design; Cardiac Catheters; Swine; Heart Atria; Models, Animal; Sus scrofa; Heart Ventricles
PubMed: 38690671
DOI: 10.1161/CIRCEP.123.012723 -
European Heart Journal. Case Reports Apr 2024The left ventricular (LV) summit has anatomical limitations, so the detailed mapping is difficult. Therefore, the mechanism of ventricular tachycardia (VT) originating...
Bipolar radiofrequency ablation for re-entrant ventricular tachycardia of right bundle branch block and left bundle branch block morphologies with the common slow conduction zone at the left ventricular summit: a case report.
BACKGROUND
The left ventricular (LV) summit has anatomical limitations, so the detailed mapping is difficult. Therefore, the mechanism of ventricular tachycardia (VT) originating from the LV summit is not well understood.
CASE SUMMARY
A 70-year-old man had VTs with right bundle branch block (VT1 and VT3) and left bundle branch block (VT2) morphologies originating from the left ventricular summit (LV summit). During the VT2 and VT3, fragmented potentials, which occurred earlier than the QRS onset, were recorded from bipolar electrodes of a catheter at the anterior intraventricular vein (AIV). By pacing from right ventricular apex, constant and progressive fusion were observed. During the entrainment pacing, the fragmented potentials in the AIV catheter were activated orthodromically and those in the His bundle were activated antidromically. In addition, there were two components of the ventricular electrogram at the LV summit area with the interval of more than 100 ms during the VTs. We performed bipolar radiofrequency ablation between the LV endocardium and AIV, and the VTs became non-inducible.
DISCUSSION
Non-sustained VT/premature ventricular contraction originating from LV summit is generally considered to occur due to abnormal automaticity or triggered activity. In contrast, using entrainment technique, we demonstrated that the VTs with multiple morphologies were sustained with a re-entrant mechanism. Fragmentated potentials recorded in the AIV catheter were activated orthodromically with the entrainment pacing, indicating the slowly conducting isthmus. The intramural VT substrate was also suggested with a prolonged conduction time between the two ventricular components during the VTs.
PubMed: 38690559
DOI: 10.1093/ehjcr/ytae191 -
European Heart Journal. Case Reports Apr 2024Ventricular arrhythmias are a significant cause of morbidity and mortality in patients with ischaemic heart disease. When pharmacologic therapies, catheter ablation...
BACKGROUND
Ventricular arrhythmias are a significant cause of morbidity and mortality in patients with ischaemic heart disease. When pharmacologic therapies, catheter ablation (CA), and implantable cardioverter defibrillator (ICD) are ineffective, stellate ganglion blockade (SGB), sympathectomy, and renal sympathetic denervation are considered. However, they are invasive for patients with high bleeding risk. We present a case of successfully recovering from haemodynamically unstable ventricular tachycardia (VT) storm with stellate ganglion phototherapy (SGP) in a non-invasive manner.
CASE SUMMARY
A 73-year-old male presented to the emergency department with chief complaint of general malaise, resulting from VT storm associated with ischaemic cardiomyopathy. He had a history of CA and implantation of ICD. Despite multiple electrical cardioversions, pharmacologic therapies, and deep sedation with mechanical circulatory support (MCS), VT storm was not controlled. Thereafter, we irradiated the patient's neck with SGP to inhibit sympathetic neurological activity, which suppressed VT storm and dramatically improved his haemodynamic status.
DISCUSSION
It has been reported that SGP is an alternative to SGB for refractory VT storm. Stellate ganglion phototherapy was easy and non-invasive to perform because we just irradiated the patient's neck with the near-infrared light for 5 min per day. If conventional therapies are ineffective in suppressing VT storm, SGP may be considered as a next step, especially for patients with high bleeding risk. However, since the effect of a single SGP lasts only 1-2 days, it should be performed as a bridge therapy to CA or sympathectomy. Stellate ganglion phototherapy may be effective in suppressing VT storm that requires MCS devices.
PubMed: 38690554
DOI: 10.1093/ehjcr/ytae177