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Cardiac Electrophysiology Clinics Mar 2023The left ventricular summit corresponds to the epicardial side of the basal superior free wall, extending from the base of the left coronary aortic sinus. The summit... (Review)
Review
The left ventricular summit corresponds to the epicardial side of the basal superior free wall, extending from the base of the left coronary aortic sinus. The summit composes the floor of the compartment surrounded by the aortic root, infundibulum, pulmonary root, and left atrial appendage. The compartment is filled with thick adipose tissue, carrying the coronary vessels. Thus, the treatment of ventricular tachycardia originating from the summit is challenging, and three-dimensional understanding of this complicated region is fundamental. We revisit the clinical anatomy of the left ventricular summit with original images from the Wallace A. McAlpine collection.
Topics: Humans; Catheter Ablation; Heart Ventricles; Tachycardia, Ventricular; Arrhythmias, Cardiac; Coronary Vessels; Electrocardiography
PubMed: 36774131
DOI: 10.1016/j.ccep.2022.04.003 -
Heart Rhythm Dec 2023Patients with repaired tetralogy of Fallot (TOF) are at risk for ventricular tachycardia (VT) related to well-described anatomical isthmuses.
BACKGROUND
Patients with repaired tetralogy of Fallot (TOF) are at risk for ventricular tachycardia (VT) related to well-described anatomical isthmuses.
OBJECTIVE
The purpose of this study was to explore QRS morphology as an indicator of anatomical isthmus conduction.
METHODS
Patients with repaired TOF and complete right bundle branch block referred for transcatheter pulmonary valve replacement (PVR) or presenting with sustained VT underwent comprehensive 3-dimensional mapping in sinus rhythm. Electrocardiographic characteristics were compared to right ventricular (RV) activation and anatomical isthmus conduction properties.
RESULTS
Twenty-two patients (19 pre-pulmonary valve replacement and 3 clinical VT) underwent comprehensive 3-dimensional mapping (median 39 years; interquartile range [IQR] 27-48 years; 12 [55%] male). Septal RV activation (median 40 ms; IQR 34-46 ms) corresponded to the nadir in lead V and free wall activation (median 71 ms; IQR 64-81 ms) to the transition point in the upstroke of the R' wave. Patients with isthmus block between the pulmonary annulus and the ventricular septal defect patch and between the ventricular septal defect patch and the tricuspid annulus (when present), were more likely to demonstrate lower amplitude R' waves in lead V (5.8 mV vs 9.4 mV; P = .005), QRS fragmentation in lead V (15 [94%] vs 2 [13%]; P < .001), and terminal S waves in lead aVF (15 [94%] vs 6 [40%]; P < .001) than those with intact conduction. During catheter ablation, these QRS changes developed during isthmus block.
CONCLUSION
For patients with repaired TOF, the status of septal isthmus conduction was evident from sinus rhythm QRS morphology. Low-amplitude, fragmented R' waves in lead V and terminal S waves in the inferior leads were related to septal isthmus conduction abnormalities, providing a mechanistic link between RV activation and common electrocardiographic findings.
Topics: Humans; Male; Female; Tetralogy of Fallot; Heart Ventricles; Tachycardia, Ventricular; Arrhythmias, Cardiac; Heart Septal Defects, Ventricular; Electrocardiography
PubMed: 37598989
DOI: 10.1016/j.hrthm.2023.08.020 -
Journal of Electrocardiology 2022Accurate localization of premature ventricular contractions (PVC) focus is a prerequisite to successful catheter ablation.
BACKGROUND
Accurate localization of premature ventricular contractions (PVC) focus is a prerequisite to successful catheter ablation.
OBJECTIVE
The objective was to evaluate the software View Into Ventricular Onset (VIVO) accuracy at locating the anatomical origins for premature ventricular contractions. The VIVO device noninvasively creates a model of the patient's heart and torso, with exact locations of 12‑lead ECG electrodes, and applies a mathematical algorithm from surface signals to determine the origin of the arrhythmia. We sought to compare the agreement between VIVO-predicted locations to invasive electroanatomical mapping results.
METHODS
51 consecutive patients who presented for PVC ablations at the study centers were recruited. VIVO images were collected at baseline preprocedure and all patients underwent invasive electroanatomical activation mapping of the clinical arrhythmia. Pacing was performed in pre-specified locations in the right and/or left ventricle. The successful sites of ablation and the pacing locations were compared to VIVO predicted locations. The results were adjudicated by physician experts in a blinded fashion.
RESULTS
Seven patients were excluded from analyses. VIVO accurately identified the origin of the clinical premature ventricular contractions in 44/44 patients (100.00%). The accuracy in identifying the paced location for all patients (right and left sides of the heart) was 99.5% using the VIVO system. No adverse events were reported.
CONCLUSIONS
VIVO is a novel noninvasive system that could be used to help guide ablation procedures with a high degree of accuracy. The VIVO algorithm is easy to use and may be useful in the workflow for ventricular arrhythmia ablation.
Topics: Catheter Ablation; Electrocardiography; Heart Ventricles; Humans; Prospective Studies; Tachycardia, Ventricular; Ventricular Premature Complexes
PubMed: 35220047
DOI: 10.1016/j.jelectrocard.2022.02.007 -
Circulation. Arrhythmia and... Oct 2022Pulsed-field ablation (PFA) is a nonthermal energy with higher selectivity to myocardial tissue in comparison to radiofrequency ablation (RFA). We compared the effects...
BACKGROUND
Pulsed-field ablation (PFA) is a nonthermal energy with higher selectivity to myocardial tissue in comparison to radiofrequency ablation (RFA). We compared the effects of PFA and RFA on heterogeneous ventricular scar in a swine model of healed infarction.
METHODS
In 9 swine, myocardial infarction was created by balloon occlusion of the left anterior descending artery. After a survival period of 8 to 10 weeks, ablation with PFA or RFA was performed at infarct border zones identified by abnormal electrograms. In the PFA group (4 swine), ablation was performed with a lattice catheter (Sphere-9, Affera, Inc). In the RFA group (5 swine), ablation was performed using a 3.5-mm tip catheter (Thermocool ST-SF; Biosense Webster). To further investigate the effect of RFA on temperature development in scar tissue, intramyocardial temperature was measured in healthy and infarcted myocardium using an ex vivo bath model.
RESULTS
A total of 11 PFA and 15 RFA lesions were created at infarct border zones with heterogeneous scar. PFA produced uniform and well-demarcated lesions exhibiting irreversible injury characterized by cardiomyocyte death, contraction bands, and lymphocytic infiltration. This effect of PFA extended from the subendocardium through collagen and fat to the epicardial layers. In contrast, the effect of RFA is less uniform and largely limited to the subendocardium with minimal effect on viable myocardium deeper to separating layers of collagen and fat. PFA produced deeper and more transmural lesions (6.4 [interquartile range, 5.5-7.5) versus 5.4 [interquartile range, 4.8-5.9]), 72% versus 30%, respectively; ≤0.02 for each comparison). The limited effect of RFA on viable myocardium at deeper infarct layers was related to a lower intramyocardial maximal temperature compared with healthy myocardium (=0.01).
CONCLUSIONS
PFA may be advantageous for ablation in ventricular scar, producing lesions that unlike RFA are not limited to the subendocardium, but also eliminate viable myocardium separated from the catheter by collagen and fat.
Topics: Swine; Animals; Cicatrix; Catheter Ablation; Heart Ventricles; Radiofrequency Ablation; Myocardial Infarction
PubMed: 36194542
DOI: 10.1161/CIRCEP.122.011209 -
Texas Heart Institute Journal Jun 2020This retrospective study evaluated the feasibility of surgical endoepicardial linear ablation for ventricular tachycardia in patients with postinfarction left...
This retrospective study evaluated the feasibility of surgical endoepicardial linear ablation for ventricular tachycardia in patients with postinfarction left ventricular aneurysm. Sixty-four patients with multivessel coronary artery disease and left ventricular aneurysm but no mural thrombosis of the aneurysm or valve disease were treated at our institution from March 2012 through July 2015. All underwent off-pump coronary artery bypass grafting and left ventricular aneurysm repair by linear plication. Twenty-three patients (35.9%) had ventricular tachycardia and underwent surgical endoepicardial linear ablation on the beating heart guided by epicardial substrate mapping with the Carto 3 system. The remaining 41 patients (64.1%) composed the no-ablation group. The effectiveness of surgical linear ablation in the ablation group was evaluated. Safety and clinical outcomes were evaluated and compared between the groups. The ventricular tachycardia recurrence rate in the ablation group was 17.4% in the immediate postoperative period and 23.8% at last follow-up (39 ± 21 mo). Early (<30-d) mortality rates were 8.7% in the ablation group and 4.9% in the no-ablation group (P=0.41); the respective late mortality rates were 19.1% and 18% (P=0.70). Multivariate Cox regression analysis indicated that preoperatively poor left ventricular function was an independent risk factor for early and late death in both groups. The groups were similar in terms of the need for postoperative mechanical circulatory support, intensive care unit stay, and cumulative survival rate. We conclude that, for carefully selected candidates, surgical endoepicardial linear ablation combined with off-pump coronary artery bypass grafting and left ventricular aneurysm linear plication is a feasible treatment for ventricular tachycardia with postinfarction left ventricular aneurysm.
Topics: Body Surface Potential Mapping; Catheter Ablation; Endocardium; Female; Follow-Up Studies; Heart Aneurysm; Heart Ventricles; Humans; Male; Middle Aged; Myocardial Infarction; Retrospective Studies; Tachycardia, Ventricular
PubMed: 32997773
DOI: 10.14503/THIJ-18-6615 -
Journal of Cardiovascular... Sep 2023This study aimed to identify the characteristics of unipolar and bipolar electrogram (UniEGM and BiEGM) in guiding successful ablation of premature ventricular...
INTRODUCTION
This study aimed to identify the characteristics of unipolar and bipolar electrogram (UniEGM and BiEGM) in guiding successful ablation of premature ventricular contractions (PVCs) originating from the free wall of the ventricular aspect of the tricuspid annulus (TA). We hypothesized that the negative concordance pattern (NCP) on the onset of UniEGM and BiEGM, together with the least value of the difference between the earliest BiEGM and UniEGM dV/dTmax, might improve the accuracy of conventional mapping.
METHODS AND RESULTS
Thirty consecutive patients who underwent successful catheter ablation from February 2018 to July 2021 were retrospectively analyzed. The BiEGM and UniEGM for successful ablation sites were compared with those for non-successful ablation sites. Among the 30 patients, 30 successful and 26 nonsuccessful ablation sites were compared. The earliest activation time of the BiEGM (BiEGMoneset-QRS) was 25 ± 6 ms for the successful ablation sites and 21 ± 6 ms for the nonsuccessful ablation sites (p = .47). The value of the difference in the earliest BiEGM and UniEGM dV/dTmax differed between successful and nonsuccessful ablation sites (6.4 ± 3.6 ms vs. 10.4 ± 6.8 ms). NCP was observed at 90.0% and 42.3% of the successful and nonsuccessful ablation sites, respectively. Alignment of NCP and BiEGMonset-UniEGM ≤6 ms was applied as the mapping criterion for successful PVC suppression (73.1% sensitivity and 87.7% specificity). The area under the receiver-operating characteristic curve for this cutoff was 0.85.
CONCLUSION
Mapping based on an NCP at the onset of the BiEGM and UniEGM and the least difference value of the earliest BiEGM and UniEGM dV/dTmax had an excellent predictive value for successful ablation. These strategies may reduce the number of radiofrequency catheter ablation (RFCA) applications for free-wall tricuspid annular PVCs.
Topics: Humans; Ventricular Premature Complexes; Retrospective Studies; Heart Ventricles; Catheter Ablation; ROC Curve
PubMed: 37632286
DOI: 10.1111/jce.16042 -
Circulation. Arrhythmia and... Mar 2022Right ventricular outflow tract (RVOT) is a common source of ventricular tachycardia, which often requires ablation. However, the mechanisms underlying the RVOT's unique...
BACKGROUND
Right ventricular outflow tract (RVOT) is a common source of ventricular tachycardia, which often requires ablation. However, the mechanisms underlying the RVOT's unique arrhythmia susceptibility remain poorly understood due to lack of detailed electrophysiological and molecular studies of the human RVOT.
METHODS
We conducted optical mapping studies in 16 nondiseased donor human RVOT preparations subjected to pharmacologically induced adrenergic and cholinergic stimulation to evaluate susceptibility to arrhythmias and characterize arrhythmia dynamics.
RESULTS
We found that under control conditions, RVOT has shorter action potential duration at 80% repolarization relative to the right ventricular apical region. Treatment with isoproterenol (100 nM) shortened action potential duration at 80% repolarization and increased incidence of premature ventricular contractions (=0.003), whereas acetylcholine (100 μM) stimulation alone had no effect on action potential duration at 80% repolarization or premature ventricular contractions. However, acetylcholine treatment after isoproterenol stimulation reduced the incidence of premature ventricular contractions (=0.034) and partially reversed action potential duration at 80% repolarization shortening (=0.029). Immunolabeling of RVOT (n=4) confirmed the presence of cholinergic marker VAChT (vesicular acetylcholine transporter) in the region. Rapid pacing revealed RVOT susceptibility to both concordant and discordant alternans. Investigation into transmural arrhythmia dynamics showed that arrhythmia wave fronts and phase singularities (rotors) were relatively more organized in the endocardium than in the epicardium (=0.006). Moreover, there was a weak but positive spatiotemporal autocorrelation between epicardial and endocardial arrhythmic wave fronts and rotors. Transcriptome analysis (n=10 hearts) suggests a trend that MAPK (mitogen-activated protein kinase) signaling, calcium signaling, and cGMP-PKG (protein kinase G) signaling are among the pathways that may be enriched in the male RVOT, whereas pathways of neurodegeneration may be enriched in the female RVOT.
CONCLUSIONS
Human RVOT electrophysiology is characterized by shorter action potential duration relative to the right ventricular apical region. Cholinergic right ventricular stimulation attenuates the arrhythmogenic effects of adrenergic stimulation, including increase in frequency of premature ventricular contractions and shortening of wavelength. Right ventricular arrhythmia is characterized by positive spatial-temporal autocorrelation between epicardial-endocardial arrhythmic wave fronts and rotors that are relatively more organized in the endocardium.
Topics: Acetylcholine; Adrenergic Agents; Cardiac Electrophysiology; Cholinergic Agents; Electrocardiography; Female; Heart Ventricles; Human Rights; Humans; Isoproterenol; Male; Pericardium; Tachycardia, Ventricular; Ventricular Premature Complexes
PubMed: 35238622
DOI: 10.1161/CIRCEP.121.010630 -
Cardiovascular Research Jun 2022Recent developments in imaging, mapping, and ablation techniques have shown that the epicardial region of the heart is a key player in the occurrence of ventricular... (Review)
Review
Recent developments in imaging, mapping, and ablation techniques have shown that the epicardial region of the heart is a key player in the occurrence of ventricular arrhythmic events in several cardiac diseases, such as Brugada syndrome, arrhythmogenic cardiomyopathy, or dilated cardiomyopathy. At the atrial level as well, the epicardial region has emerged as an important determinant of the substrate of atrial fibrillation, pointing to common underlying pathophysiological mechanisms. Alteration in the gradient of repolarization between myocardial layers favouring the occurrence of re-entry circuits has largely been described. The fibro-fatty infiltration of the subepicardium is another shared substrate between ventricular and atrial arrhythmias. Recent data have emphasized the role of the epicardial reactivation in the formation of this arrhythmogenic substrate. There are new evidences supporting this structural remodelling process to be regulated by the recruitment of epicardial progenitor cells that can differentiate into adipocytes or fibroblasts under various stimuli. In addition, immune-inflammatory processes can also contribute to fibrosis of the subepicardial layer. A better understanding of such 'electrical fragility' of the epicardial area will open perspectives for novel biomarkers and therapeutic strategies. In this review article, a pathophysiological scheme of epicardial-driven arrhythmias will be proposed.
Topics: Atrial Fibrillation; Brugada Syndrome; Catheter Ablation; Heart Atria; Heart Ventricles; Humans; Myocardium
PubMed: 34152392
DOI: 10.1093/cvr/cvab213 -
Pacing and Clinical Electrophysiology :... Jun 2022Sonic shockwaves (SSW) can cause cardiac pacing. This observation first came to notice with the early urologic lithotripters and later with the cumulative use of... (Review)
Review
Sonic shockwaves (SSW) can cause cardiac pacing. This observation first came to notice with the early urologic lithotripters and later with the cumulative use of shockwaves to treat calcified coronary lesions. There have been multiple observations of cardiac pacing and tachyarrhythmias occurring during SSW delivery using the Shockwave Intravascular Lithotripsy system. The underlying mechanism of cardiac cell depolarization by SSW is still under debate. At the end of the last decade, we are witnessing this technology in electrophysiology with the WiSE-CRT system that uses sonic waves to synchronize the ventricles and novel shockwave ablation catheters that can treat tachyarrhythmia foci with minor collateral damage.
Topics: Cardiac Electrophysiology; Cardiac Resynchronization Therapy; Catheters; Electrophysiologic Techniques, Cardiac; Heart Ventricles; Humans; Ultrasonics
PubMed: 35466403
DOI: 10.1111/pace.14513 -
Cardiac Electrophysiology Clinics Jun 2021Catheter ablation is the most effective treatment option for idiopathic ventricular arrhythmias. Intracardiac echocardiography (ICE) has been increasingly used during... (Review)
Review
Catheter ablation is the most effective treatment option for idiopathic ventricular arrhythmias. Intracardiac echocardiography (ICE) has been increasingly used during ablation procedures, allowing real-time visualization of cardiac anatomy, and improving our understanding of the relationships between different cardiac structures. In this article we review the adjuvant role of ICE to guide mapping and ablation of ventricular arrhythmias in the structurally normal heart.
Topics: Arrhythmias, Cardiac; Catheter Ablation; Echocardiography; Heart Ventricles; Humans; Surgery, Computer-Assisted
PubMed: 33990271
DOI: 10.1016/j.ccep.2021.03.010