Application Repetition and Electrode-Tissue-Contact Results in Deeper Lesions Using a Pulsed-Field Ablation Circular Variable Loop Catheter.

BACKGROUND: Pulsed field ablation (PFA) is a novel, myocardial-selective, non-thermal ablation modality used to target cardiac arrhythmias. Although prompt EGM signal disappearance is observed immediately after PFA application in the pulmonary veins, whether this finding results in adequate transmural lesions is unknown. STUDY AIM: If application repetition and catheter-tissue contact impact on lesion formation during PFA. METHODS: A circular loop PFA catheter was used to deliver repeated energy applications with various levels of contact-force. A benchtop vegetal potato model and a beating heart ventricular myocardial model were utilized to evaluate the impact of application repetition, contact force, and catheter repositioning on contiguity and lesion depth. Lesion development occurred over 18 hours in the vegetal model and over 6 hours in the porcine model. RESULTS: Lesion formation was found to be dependent on application repetition and contact. In porcine ventricles, single and multiple stacked applications led to a lesion depth of 3.5 ± 0.7 mm and 4.4 ± 1.3 mm, respectively (p =0.002). Furthermore, the greater the catheter-tissue contact, the more contiguous and deeper the lesions in the vegetal model (1.0±0.9 mm with no contact Vs. 5.4±1.4 mm with 30 g of force; p=.0001). CONCLUSION: PFA delivered via a circular catheter showed that both repetition and catheter contact led independently to deeper lesion formation. These findings indicate that endpoints for effective PFA ablation are more related to PFA biophysics than mere EGM attenuation.

Pulsed Field Ablation Index-Guided Ablation for Lesion Formation: Impact of Contact Force and Number of Applications in the Ventricular Model.

BACKGROUND: The effect of contact force (CF) on lesion formation is not clear during pulsed field ablation (PFA). The aim of this study was to evaluate the impact of CF, PFA, and their interplay through the PFA index (PF index) formula on the ventricular lesion size in swine. METHODS: PFA was delivered through the CF-sensing OMNYPULSE catheter. Predefined PFA applications (×3, ×6, ×9, and ×12) were delivered maintaining low (5-25 g), high (26-50 g), and very high (51-80 g) CFs. First, PFA lesions were evaluated on necropsy in 11 swine to investigate the impact of CF/PFA-and their integration in the PF index equation-on lesion size (study characterization). Then, 3 different PF index thresholds-300, 450, and 600-were tested in 6 swine to appraise the PF index accuracy to predict the ventricular lesion depth (study validation). RESULTS: In the study characterization data set, 111 PFA lesions were analyzed. CF was 32±17 g. The average lesion depth and width were 3.5±1.2 and 12.0±3.5 mm, respectively. More than CF and PFA dose alone, it was their combined effect to impact lesion depth through an asymptotically increasing relationship. Likewise, not only was the PF index related to lesion depth in the study validation data set (r2=0.66; P<0.001) but it also provided a prediction accuracy of the observed depth of ±2 mm in 69/73 lesions (95%). CONCLUSIONS: CF and PFA applications play a key role in lesion formation during PFA. Further studies are required to evaluate the best PFA ablation settings to achieve transmural lesions.

Antithrombotic Therapy for Patients Undergoing Cardiac Electrophysiological and Interventional Procedures: JACC State-of-the-Art Review.

Electrophysiological and interventional procedures have been increasingly used to reduce morbidity and mortality in patients experiencing cardiovascular diseases. Although antithrombotic therapies are critical to reduce the risk of stroke or other thromboembolic events, they can nonetheless increase the bleeding hazard. This is even more true in an aging population undergoing cardiac procedures in which the combination of oral anticoagulants and antiplatelet therapies would further increase the hemorrhagic risk. Hence, the timing, dose, and combination of antithrombotic therapies should be carefully chosen in each case. However, the maze of society guidelines and consensus documents published so far have progressively led to a hazier scenario in this setting. Aim of this review is to provide-in a single document-a quick, evidenced-based practical summary of the antithrombotic approaches used in different cardiac electrophysiology and interventional procedures to guide the busy clinician and the cardiac proceduralist in their everyday practice.

Sex-related differences in non-ischemic myocardial injury in the emergency department: A real-world perspective.

BACKGROUND: Myocardial injury is associated with adverse outcomes. No data are reported about sex differences in incidence and factors associated with myocardial injury in an emergency department (ED) setting from a real-world perspective. We aimed to assess whether sex plays a major role in the diagnosis of myocardial injury in the ED. METHODS: In this subanalysis of a retrospective study, patients presenting at the ED with at least one high-sensitivity cardiac troponin T (hs-cTnT) value and without acute coronary syndromes diagnosis were compared. RESULTS: 31,383 patients were admitted to the ED, 4660 had one hs-cTnT value, and 3937 were enrolled: 1943 females (49.4%) and 1994 males (50.6%). The diagnosis of myocardial injury was higher among men (36.8% vs. 32.9%, p < 0.01). Male sex was independently associated with myocardial injury. An older age, an elevated NT-proB-type Natriuretic Peptide and a lower estimated glomerular filtrate rate were independently associated with myocardial injury in both sexes. CONCLUSIONS: In the ED, from a real-world perspective, myocardial injury occurred more frequently in males, and it was associated with older age and the presence of cardiac, lung, and kidney disease but not higher hs-cTnT values.

Point-by-Point Pulsed Field Ablation Using a Multimodality Generator and a Contact Force-Sensing Ablation Catheter: Comparison With Radiofrequency Ablation in a Remapped Chronic Swine Heart.

BACKGROUND: Pulsed field ablation (PFA) has emerged as an alternative to radiofrequency ablation. However, data on focal point-by-point PFA are scarce. The aim of this study was to compare lesion durability and collateral damage between focally delivered unipolar/biphasic PFA versus radiofrequency in swine. METHODS: Eighteen swine were randomized to low-dose PFA, high-dose PFA, and radiofrequency using a multimodality generator. Radiofrequency delivered by market-available generator served as control group. A contact force-sensing catheter was used to focally deliver PFA/radiofrequency at the pulmonary veins and other predefined sites in the atria. Animals were remapped postprocedurally and 28 days postablation to test lesion durability followed by gross necroscopy and histology. RESULTS: All targeted sites were successfully ablated (contact force value, 13.9±4.1 g). Follow-up remapping showed persistent pulmonary vein isolation in all animals (100%) with lesion durability at nonpulmonary vein sites proven in most (98%). Regardless of the energy source used, the lesion size was similar across the study groups. Transmurality was achieved in 95% of targeted sites and 100% at pulmonary veins. On histology, PFA animals showed more mature scar formation than their radiofrequency counterpart without myocardial necrosis or inflammation. Finally, no sign of collateral damage was observed in any of the groups. CONCLUSIONS: In a randomized preclinical study, focally delivered unipolar/biphasic PFA guided by contact force values was associated with durable lesions on chronic remapping and with mature scar formation on histology without signs of collateral injury on necroscopy. Further studies are needed to investigate the long-term feasibility of this new approach to atrial fibrillation treatment.

Management of Atrial Arrhythmias After Lung Transplant.

The overall survival in patients undergoing lung transplantation is poor. Although postsurgical atrial arrhythmias seem to play a major role in the morbidity and mortality of this population, data regarding the clinical and interventional management of this complication are still controversial. Through a review of the literature in the field, we observed that not only the surgical technique is clearly arrhythmogenic, but the new administration of peri-procedure beta-blockers and amiodarone for arrhythmia prevention and treatment, respectively, seems harmful in these postsurgical patients. However, low-dose beta-blockers administered after surgery seem feasible in arrhythmia prevention in specific patient subgroups, and, aside from amiodarone, alternative antiarrhythmic agents can be safely and effectively used to treat symptomatic patients on top of adequate rate control. Finally, as to complex atrial arrhythmias occurring late after lung transplant surgery, radiofrequency catheter ablation seems a feasible treatment option. In light of this evidence and considering the absence of clear recommendations in the field, we suggest a practical approach that may help the clinician in the management of this postsurgical complication. However, as most of these considerations are drawn from small-sized and retrospective studies, more evidence is needed in the future to clarify which medical and interventional strategies may best treat these postsurgical arrhythmias and thus potentially improve the outcome of these frail patients.

Feasibility of three-dimensional artificial intelligence algorithm integration with intracardiac echocardiography for left atrial imaging during atrial fibrillation catheter ablation.

AIMS: Intracardiac echocardiography (ICE) is a useful but operator-dependent tool for left atrial (LA) anatomical rendering during atrial fibrillation (AF) ablation. The CARTOSOUND FAM Module, a new deep learning (DL) imaging algorithm, has the potential to overcome this limitation. This study aims to evaluate feasibility of the algorithm compared to cardiac computed tomography (CT) in patients undergoing AF ablation. METHODS AND RESULTS: In 28 patients undergoing AF ablation, baseline patient information was recorded, and three-dimensional (3D) shells of LA body and anatomical structures [LA appendage/left superior pulmonary vein/left inferior pulmonary vein/right superior pulmonary vein/right inferior pulmonary vein (RIPV)] were reconstructed using the DL algorithm. The selected ultrasound frames were gated to end-expiration and max LA volume. Ostial diameters of these structures and carina-to-carina distance between left and right pulmonary veins were measured and compared with CT measurements. Anatomical accuracy of the DL algorithm was evaluated by three independent electrophysiologists using a three-anchor scale for LA anatomical structures and a five-anchor scale for LA body. Ablation-related characteristics were summarized. The algorithm generated 3D reconstruction of LA anatomies, and two-dimensional contours overlaid on ultrasound input frames. Average calculation time for LA reconstruction was 65 s. Mean ostial diameters and carina-to-carina distance were all comparable to CT without statistical significance. Ostial diameters and carina-to-carina distance also showed moderate to high correlation (r = 0.52-0.75) except for RIPV (r = 0.20). Qualitative ratings showed good agreement without between-rater differences. Average procedure time was 143.7 ± 43.7 min, with average radiofrequency time 31.6 ± 10.2 min. All patients achieved ablation success, and no immediate complications were observed. CONCLUSION: DL algorithm integration with ICE demonstrated considerable accuracy compared to CT and qualitative physician assessment. The feasibility of ICE with this algorithm can potentially further streamline AF ablation workflow.

Pseudo-pacemaker syndrome with prolonged PR interval: A narrative review.

Pseudo-pacemaker syndrome (PPMS) is a rare complication of first-degree atrio-ventricular (AV) block in which a very prolonged PR interval causes AV dyssynchrony and subsequent symptoms of hemodynamic instability in the absence of an implanted pacemaker. The aim of this manuscript was to describe a unique case of PPMS and to provide a comprehensive review of the topic to help clinicians in the diagnosis and management of this condition. Through systematic research on PubMed, Google Scholar, EBSCO, and Ovid MEDLINE and using the search strings "pseudo-pacemaker syndrome" and "symptomatic first-degree AV block," we identified 14 articles accounting for 17 cases of PPMS, including our case report. The most common age group for PPMS was middle-aged and young adults, with an average age of 47 years. Palpitations were the most common presenting symptom and four main etiologies of PPMS were identified, as follows: (1) Idiopathic PPMS with evidence of impaired conduction over the AV node (20% of cases), (2) PPMS associated with reversable inflammatory causes (13%) or (3) associated with iatrogenic surgical or interventional procedures leading to the permanent damage of the normal AV conduction system (20%), and, finally, (4) PPM related to dual AV nodal physiology (DAVNP) as a primary finding (27%) or occurring after fast or slow pathway ablation for treatment of AV nodal re-entrant tachycardia (AVNRT) (20%). Treatment should be patient-tailored and based on the specific etiology once identified. However, the treatment of PPMS due to DAVNP without AVNRT presentation is yet to be clarified.

Outcomes of catheter ablation of atrial tachyarrhythmia guided exclusively by activation mapping.

INTRODUCTION: Complex atrial tachyarrhythmias (CATs) are commonly observed in patients with prior catheter ablation or cardiac surgery. These arrhythmias are challenging to map and ablate. Historically, entrainment mapping was utilized to characterize CAT. With the advent of high-definition mapping (HDM), full visualization of the CAT circuit is possible which may obviate the need for entrainment mapping. METHODS: We sought to investigate the outcomes of catheter ablation of CAT guided only by HDM. Consecutive patients who underwent CAT ablation from 2017 to 2021 were included in our study (excluding right atrial tachyarrhythmias). Patients were sorted by the type of mapping performed. Group I consisted of patients where HDM alone was utilized with no attempt of entrainment. Group II consisted of patients where both entrainment and HDM were utilized. RESULTS: A total of 67 patients were included in our study, with 40 patients in HDM group (I) and 27 patients in entrainment group (II). No statistically significant difference regarding 1-year freedom from atrial arrhythmias was found between the two groups (80% vs 77.8%, p = 0.819). Four CATs were terminated by entrainment during procedure versus none in the HDM-only group (p = 0.011). CONCLUSIONS: CAT ablation with HDM alone yielded similar 1-year freedom from atrial arrhythmias compared to ablation with HDM and entrainment. Entrainment combined with HDM was associated with higher undesired CAT interruption rate. Further validation is needed with randomized control trials.

Cryoablation of para-Hisian and mid-septal accessory pathways: long-term outcomes of a specific stepwise cryoablation protocol.

BACKGROUND: Although cryoablation (CA) of septally located accessory pathways (APs) is an established treatment for Wolff-Parkinson-White Syndrome, its major limitation is the lack of data regarding long-term follow-up (FU). The present study sought to investigate long-term outcomes of a specific CA protocol targeting para-Hisian (P-H) and mid-septal (M-S) APs. METHODS: Twenty-six patients who previously underwent CA of PH or MS APs from 2004 to 2014, were prospectively considered to receive a FU during 2021. All subjects received an outpatient control visit, performing an exercise stress test and a 24-h ECG Holter monitoring. RESULTS: Acute success was achieved in 22 patients (85%). One case of recurrence was reported at short-term FU. Long-term FU, performed after a mean time of 150±37 months, did not show ventricular preexcitation recurrences, with a success rate of 81%, and without late adverse events. Symptoms reduction (12% vs. 96%, P<.001) and lower rates of antiarrhythmic drug use (12% vs. 62%, P<.001) were observed at long term-FU with respect to baseline. This clinical outcome was detected also among patients who underwent unsuccessful CA at baseline. CONCLUSIONS: Our CA protocol confirmed remarkable safety and efficacy throughout a long-term FU. Significant clinical improvement in terms of antiarrhythmic therapy discontinuation and symptoms reduction was also shown among patients who experienced acute failure of CA.

Pathophysiology of Atypical Atrial Flutters.

Atypical atrial flutters are complex supraventricular arrhythmias that share different pathophysiological aspects in common. In most cases, the arrhythmogenic substrate is essentially embodied by slow-conducting areas eliciting re-entrant circuits. Although atrial scarring seems to promote slow conduction, these arrhythmias may occur even in the absence of structural heart disease. To set out the ablation strategy in this setting, three-dimensional mapping systems have proved invaluable over the last decades, helping the cardiac electrophysiologist understand the electrophysiological complexity of these circuits and easily identify critical areas amenable to effective catheter ablation.

Mapping and Ablation of Atypical Atrial Flutters.

Atypical atrial flutters are complex, hard-to-manage atrial arrhythmias. Catheter ablation has progressively emerged as a successful treatment option with a remarkable role played by irrigated-tip catheters and 3D electroanatomic mapping systems. However, despite the improvement of these technologies, the ablation results may be still suboptimal due to the progressive atrial substrate modification occurring in diseased hearts. Hence, a patient-tailored approach is required to improve the long-term success rate in this scenario, aiming at achieving specific procedure end points and detecting any potential arrhythmogenic substrate in each patient.

Atypical Cases of Typical Atrial Flutter? A Case Study.

Ablation of typical atrial flutter has a high safety and efficacy profile, but hidden pitfalls may be encountered. In some cases, a longer cycle length with isoelectric lines is associated with a different or more complex arrhythmogenic substrate, which may be missed if conduction block of the cavotricuspid isthmus is performed in the absence of the clinical arrhythmia. Prior surgery may have consistently modified the atrial substrate and complex or multiple arrhythmias associated with an isthmus-dependent circuit can be encountered. In these cases, electroanatomic mapping is useful to guide the procedure and plan an appropriate ablation strategy.

High-Sensitivity Cardiac Troponin T and the Diagnosis of Cardiovascular Disease in the Emergency Room: The Importance of Combining Cardiovascular Biomarkers with Clinical Data.

Background. Nowadays, it is still not possible to clinically distinguish whether an increase in high-sensitivity cardiac troponin (hs-cTn) values is due to myocardial injury or an acute coronary syndrome (ACS). Moreover, predictive data regarding hs-cTnT in an emergency room (ER) setting are scarce. This monocentric retrospective study aimed to improve the knowledge and interpretation of this cardiac biomarker in daily clinical practice. Methods. Consecutive adult patients presenting at the ER and hospitalized with a first abnormal hs-cTnT value (≥14 ng/L) were enrolled for 6 months. The baseline hs-cTnT value and the ensuing changes and variations were correlated with the clinical presentation and the type of diagnosis. Subsequently, multivariable models were built to assess which clinical/laboratory variables most influenced hospital admissions in the investigated population analyzed according to the final reason for hospitalization: (1) cardiovascular vs. non-cardiovascular diagnosis, and (2) ACS vs. non-ACS one. Results. A total of 4660 patients were considered, and, after a first screening, 4149 patients were enrolled. Out of 4129 patients, 1555 (37.5%) had a first hs-cTnT ≥14 ng/L, and 1007 (65%) were hospitalized with the following types of diagnosis: ACS (182; 18%), non-ACS cardiovascular disease (337; 34%) and non-cardiovascular disease (487; 48%). Higher hs-cTnT values and significant hs-cTnT variations were found in the ACS group (p < 0.01). The mean percentage of variation was higher in patients with ACS, intermediate in those with non-ACS cardiovascular disease, and low in those with non-cardiovascular disease (407.5%, 270.6% and 12.4%, respectively). Only syncope and CRP (OR: 0.08, 95% CI: 0.02−0.39, p < 0.01 and OR: 0.9988, 95% CI: 0.9979−0.9998, p = 0.02, respectively) or CRP (OR: 0.9948, 95% CI: 0.9908−0.9989, p = 0.01) and NT-proBNP (OR: 1.0002, 95% CI: 1.0000−1.0004, p = 0.02) were independent predictors of a cardiovascular disease diagnosis. On the other hand, only chest pain (OR: 22.91, 95% CI: 3.97−132.32, p < 0.01) and eGFR (OR: 1.04, 95% CI: 1.004−1.083, p = 0.03) were associated with the ACS diagnosis. Conclusions. Differently from the investigated biomarkers, in this study, only clinical variables predicted hospitalizations in different patients' subgroups.

Procedural Feasibility and Long-Term Efficacy of Catheter Ablation of Atypical Atrial Flutters in a Wide Spectrum of Heart Diseases: An Updated Clinical Overview.

Atypical atrial flutters (AAFL) are difficult-to-manage atrial arrhythmias, yet potentially amenable to effective radiofrequency catheter ablation (CA). However, data on CA feasibility are only sparingly reported in the literature in different clinical settings, such as AAFL related to surgical correction of congenital heart disease. The aim of this review was to provide an overview of the clinical settings in which AAFL may occur to help the cardiac electrophysiologist in the prediction of the tachycardia circuit location before CA. Moreover, the role and proper implementation of cutting-edge technologies in this setting were investigated as well as which procedural and clinical factors are associated with long-term failure to maintain sinus rhythm (SR) to find out which patients may, or may not, benefit from this procedure. Not only different surgical and non-surgical scenarios are associated with peculiar anatomical location of AAFL, but we also found that CA of AAFL is generally feasible. The success rate may be as low as 50% in surgically corrected congenital heart disease (CHD) patients but up to about 90% on average after pulmonary vein isolation (PVI) or in patients without structural heart disease. Over the years, the progressive implementation of three-dimensional mapping systems and high-density mapping tools has also proved helpful for ablation of these macro-reentrant circuits. However, the long-term maintenance of SR may still be suboptimal due to the progressive electroanatomic atrial remodeling occurring after cardiac surgery or other interventional procedures, thus limiting the likelihood of successful ablation in specific clinical settings.

Hypertension and Arrhythmias: A Clinical Overview of the Pathophysiology-Driven Management of Cardiac Arrhythmias in Hypertensive Patients.

Because of demographic aging, the prevalence of arterial hypertension (HTN) and cardiac arrhythmias, namely atrial fibrillation (AF), is progressively increasing. Not only are these clinical entities strongly connected, but, acting with a synergistic effect, their association may cause a worse clinical outcome in patients already at risk of ischemic and/or haemorrhagic stroke and, consequently, disability and death. Despite the well-known association between HTN and AF, several pathogenetic mechanisms underlying the higher risk of AF in hypertensive patients are still incompletely known. Although several trials reported the overall clinical benefit of renin-angiotensin-aldosterone inhibitors in reducing incident AF in HTN, the role of this class of drugs is greatly reduced when AF diagnosis is already established, thus hinting at the urgent need for primary prevention measures to reduce AF occurrence in these patients. Through a thorough review of the available literature in the field, we investigated the basic mechanisms through which HTN is believed to promote AF, summarising the evidence supporting a pathophysiology-driven approach to prevent this arrhythmia in hypertensive patients, including those suffering from primary aldosteronism, a non-negligible and under-recognised cause of secondary HTN. Finally, in the hazy scenario of AF screening in hypertensive patients, we reviewed which patients should be screened, by which modality, and who should be offered oral anticoagulation for stroke prevention.

Ventricular arrhythmias and ARNI: is it time to reappraise their management in the light of new evidence?

The remarkable scientific progress in the treatment of patients with heart failure (HF) and reduced ejection fraction (HFrEF) has more than halved the risk of sudden cardiac death (SCD) in this setting. However, SCD remains one of the major causes of death in this patient population. Beyond the acknowledged role of beta blockers and inhibitors of the renin-angiotensin-aldosterone system (RAAS), a new class of drugs, the angiotensin receptor neprilysin inhibitors (ARNI), proved to reduce the overall cardiovascular mortality and, more specifically, the risk of SCD in HFrEF patients. The mechanism by which ARNI may reduce the mortality connected with harmful ventricular arrhythmias is not utterly clear. A variety of direct and indirect mechanisms have been suggested, but a favorable left ventricular reverse remodeling seems to play a key role in this setting. Furthermore, the well-known protective effect of implantable cardioverter-defibrillator (ICD) has been debated in HFrEF patients with non-ischemic cardiomyopathy (NICM) arguing against the role of primary prevention ICD in this setting, particularly when ARNI therapy is considered. The purpose of this review was to provide insights into the SCD mechanisms involved in HFrEF patients together with the current role of electrical therapies and new drug agents in this setting. Graphical abstract.