-
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 -
JACC. Clinical Electrophysiology Sep 2020This study aimed to characterize the incidence, clinical characteristics, and electrocardiographic and electrophysiologic features of LVA VA in the absence of CAD and to...
OBJECTIVES
This study aimed to characterize the incidence, clinical characteristics, and electrocardiographic and electrophysiologic features of LVA VA in the absence of CAD and to describe the experience with catheter ablation (CA) in this group.
BACKGROUND
The left ventricular apex (LVA) is a well-described source of ventricular arrhythmias (VAs) in patients with coronary artery disease (CAD) and history of apical infarction but is a rare source of VA in the absence of CAD.
METHODS
Patients referred for CA of VA at our institution were retrospectively reviewed, and those with LVA VA in the absence of CAD were identified.
RESULTS
Of 3,710 consecutive patients undergoing VA ablation, CA of LVA VA was performed in 24 patients (20 with monomorphic ventricular tachycardia, 4 with premature ventricular contractions or nonsustained ventricular tachycardia; 18 men; mean age: 54 ± 15 years). These cases comprised 10 of 35 (29%) hypertrophic cardiomyopathy, 9 of 789 (1.2%) nonischemic cardiomyopathy, and 5 of 1,432 (0.4%) idiopathic VA ablation procedures. VA QRS morphology was predominantly right bundle with slurred upstroke and right superior frontal plane axis with precordial transition ≤V3. Epicardial ablation was performed in 14 of 24 (58%). After a median of 1 procedure (range 1 to 4) at this institution and median follow-up of 47 months (range 0-176), VA recurred in 1 patient (4%).
CONCLUSIONS
LVA VA in the absence of CAD is unusual and may occur in patients with hypertrophic cardiomyopathy or nonischemic cardiomyopathy or, rarely, in the absence of structural heart disease. It can be recognized by characteristic ECG features. CA of LVA VA is challenging; multiple procedures, including epicardial approaches, may be required to achieve VA control over long-term follow-up.
Topics: Catheter Ablation; Coronary Artery Disease; Heart Ventricles; Humans; Male; Middle Aged; Retrospective Studies; Tachycardia, Ventricular; Ventricular Premature Complexes
PubMed: 32972543
DOI: 10.1016/j.jacep.2020.04.021 -
Europace : European Pacing,... Mar 2020Pulsed field ablation (PFA) is a novel, non-thermal modality that selectively ablates myocardium with ultra-short electrical impulses while sparing collateral tissues....
AIMS
Pulsed field ablation (PFA) is a novel, non-thermal modality that selectively ablates myocardium with ultra-short electrical impulses while sparing collateral tissues. In a proof-of-concept study, the safety and feasibility of ventricular PFA were assessed using a prototype steerable, endocardial catheter.
METHODS AND RESULTS
Under general anaesthesia, the left and right ventricles of four healthy swine were ablated using the 12-Fr deflectable PFA catheter and a deflectable sheath guided by electroanatomic mapping. Using the study catheter, electrograms were recorded for each site and pre-ablation and post-ablation pacing thresholds (at 2.0 ms pulse width) were recorded in two of four animals. After euthanasia at 35.5 days, the hearts were submitted for histology. The PFA applications (n = 39) resulted in significant electrogram reduction without ventricular arrhythmias. In ablation sites where it was measured, the pacing thresholds increased by >16.8 mA in the right ventricle (3 sites) and >16.1 mA in the left ventricle (7 sites), with non-capture at maximum amplitude (20 mA) observable in 8 of 10 sites. Gross measurements, available for 28 of 30 ablation sites, revealed average lesion dimensions to be 6.5 ± 1.7 mm deep by 22.6 ± 4.1 mm wide, with a maximum depth and width of 9.4 mm and 28.6 mm, respectively. In the PFA lesions, fibrous tissue homogeneously replaced myocytes with a narrow zone of surrounding myocytolysis and no overlying thrombus. When present, nerve fascicles and vasculature were preserved within surrounding fibrosis.
CONCLUSION
We demonstrate that endocardial PFA can be focally delivered using this prototype catheter to create homogeneous, myocardium-specific lesions.
Topics: Animals; Arrhythmias, Cardiac; Catheter Ablation; Endocardium; Heart Ventricles; Myocardium; Swine; Tachycardia, Ventricular
PubMed: 31876913
DOI: 10.1093/europace/euz341 -
Revista Portuguesa de Cardiologia Nov 2021
Topics: Heart Ventricles; Humans; Tachycardia, Ventricular
PubMed: 34857161
DOI: 10.1016/j.repce.2021.10.023 -
Circulation. Arrhythmia and... Nov 2022Irreversible electroporation is an energy form utilizing high-voltage pulsed electric field, leading to cellular homeostasis disruption and cell death. Recently,...
BACKGROUND
Irreversible electroporation is an energy form utilizing high-voltage pulsed electric field, leading to cellular homeostasis disruption and cell death. Recently, irreversible electroporation has shown promising results for the treatment of cardiac arrhythmias. However, reversible and irreversible effects of pulsed electric field on cardiac myocytes remain poorly understood. Here, we evaluated the influence of a monophasic single electric pulse (EP) on the contractility, Ca homeostasis and recovery of cardiac myocytes.
METHODS
Isolated rat left ventricular myocytes were electroporated using single monophasic EP of different durations and voltages. Sarcomere length and intracellular Ca were simultaneously monitored for up to 20 minutes after EP application in Fura-2 loaded left ventricular myocytes. Lethal voltage thresholds were determined using 100 µs and 10 ms pulses and by discriminating cell orientation with respect to the electric field.
RESULTS
Electroporation led to an immediate increase in intracellular Ca which was dependent upon the voltage delivered to the cell. Intermediate-voltage EP (140 V, 100 µs) increased sarcomere shortening, Ca transient amplitude, and diastolic Ca level measured 1 minute post-EP. Although sarcomere shortening returned to pre-EP level within 5 minutes, Ca transient amplitude decreased further below pre-EP level and diastolic Ca level remained elevated within 20 minutes post-EP. Spontaneous contractions were observed after sublethal EP application but their frequency decreased progressively within 20 minutes. Lethal EP voltage threshold was lower in myocytes oriented perpendicular than parallel to the electric field using 100 µs pulses while an opposite effect was found using 10 ms pulses.
CONCLUSIONS
Sublethal EP affected rat left ventricular myocytes contractility and disrupted Ca homeostasis as a function of the EP voltage. Moreover, EP-induced lethality was preceded by a large increase in intracellular Ca and was dependent upon the EP duration, amplitude and left ventricular myocytes orientation with respect to the electric field. These findings provide new insights into the effect of pulsed electric field on cardiac myocytes.
Topics: Rats; Animals; Myocytes, Cardiac; Calcium; Heart Ventricles; Electroporation; Homeostasis
PubMed: 36306333
DOI: 10.1161/CIRCEP.122.011131 -
JACC. Clinical Electrophysiology Jan 2022
Topics: Catheter Ablation; Heart Ventricles; Humans; Microbubbles
PubMed: 35057979
DOI: 10.1016/j.jacep.2021.08.013 -
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 -
Journal of Cardiovascular... Jul 2018
Topics: Heart Ventricles; Humans; Tachycardia, Ventricular
PubMed: 29771455
DOI: 10.1111/jce.13633 -
Current Cardiology Reviews Aug 2014Percutaneous pericardial access for epicardial mapping and ablation of ventricular arrhythmias has expanded considerably in recent years. After its description in... (Review)
Review
Percutaneous pericardial access for epicardial mapping and ablation of ventricular arrhythmias has expanded considerably in recent years. After its description in patients with Chagas disease, the technique has provided relevant information on the arrhythmia substrate in other cardiomyopathies and has improved the results of ablation procedures in various clinical settings. Electrocardiographic criteria proposed for the recognition of the epicardial origin of ventricular tachycardias are mainly based on analysis of the first QRS components. Ventricular activation at the epicardium has a slow initial component reflecting the transmural activation and influenced by the absence of Purkinje system in the epicardium. Various parameters (pseudodelta wave, intrinsicoid deflection and shortest RS interval) of these initial intervals predict an epicardial origin in patients with scar-related ventricular tachycardias with right bundle branch block morphology. Using the same concept, the maximum deflection index was defined for the location of idiopathic epicardial tachycardias remote from the aortic root. Electrocardiogram criteria based on the morphology of the first component of the QRS (q wave in lead I) have been proposed in patients with nonischemic cardiomyopathy. All these criteria seem to be substrate-specific and have several limitations. Other information, including type of underlying heart disease, previous failed endocardial ablation, and evidence of epicardial scar on magnetic resonance imaging, can help to plan the ablation procedure and decide on an epicardial approach.
Topics: Arrhythmias, Cardiac; Cardiomyopathies; Catheter Ablation; Electrocardiography; Endocardium; Epicardial Mapping; Heart Ventricles; Humans; Myocardial Infarction; Pericardium; Tachycardia, Ventricular; Ventricular Dysfunction, Right
PubMed: 24827797
DOI: 10.2174/1573403x10666140514103047 -
Pacing and Clinical Electrophysiology :... Apr 2022Catheter ablation of papillary muscle ventricular arrhythmias (PM-VAs) has been associated with unsatisfactory results. Features that may affect acute and long-term...
BACKGROUND
Catheter ablation of papillary muscle ventricular arrhythmias (PM-VAs) has been associated with unsatisfactory results. Features that may affect acute and long-term procedural outcomes are not well established.
OBJECTIVE
To systematically review the available data in the literature assessing efficacy and safety of PM-VAs catheter ablation.
METHODS
An online search of PubMed, Cochrane Registry, Web of Science, Scopus and EMBASE libraries (from inception to March 1, 2021) was performed, in addition to manual screening. Twenty-one observational noncontrolled case-series were considered eligible for the systematic review, including 536 patients.
RESULTS
Postero-medial PM harbored 60.8% of PM-VAs, while antero-lateral PM and right ventricular PMs 34.9% and 4.3% of cases, respectively. The mean acute success rate of the index ablation procedure was 88.1% (95% CI 82.8% to 91.9%, p < .001, I 0%). After a mean follow-up period of 15.5 ± 17.4 months, pooled long-term arrhythmia-free rate was 69.2%, while the pooled long-term success rate after multiple ablation procedure was 84.9%. Overall, procedure complications occurred in nine patients (1.7%) and no procedure-related deaths were reported. The use of intracardiac echocardiography (ICE) as well as contact force sensing (CFS) and irrigated catheters during ablation was associated with higher rates of arrhythmia-freedom at long-term follow-up.
CONCLUSIONS
Catheter ablation is an effective and safe strategy for PM-VAs, with an acute success rate of 88.1%, a long-term success rate of 69.2%, with a relatively low procedural complication rate. The use of ICE, irrigated catheters and catheters with CFS capability was associated with higher rates of arrhythmia-freedom at long-term follow-up.
Topics: Catheter Ablation; Heart Ventricles; Humans; Papillary Muscles; Tachycardia, Ventricular; Treatment Outcome; Ventricular Premature Complexes
PubMed: 35147225
DOI: 10.1111/pace.14462