Effect of esophageal cooling on ablation lesion formation in the left atrium: Insights from Ablation Index data in the IMPACT trial and clinical outcomes.

INTRODUCTION: The IMPACT study established the role of controlled esophageal cooling in preventing esophageal thermal injury during radiofrequency (RF) ablation for atrial fibrillation (AF). The effect of esophageal cooling on ablation lesion delivery and procedural and patient outcomes had not been previously studied. The objective was to determine the effect of esophageal cooling on the formation of RF lesions, the ability to achieve procedural endpoints, and clinical outcomes. METHODS: Participants in the IMPACT trial underwent AF ablation guided by Ablation Index (30 W at 350-400 AI posteriorly, 40 W at ≥450 AI anteriorly). A blinded 1:1 randomization assigned patients to the use of the ensoETM® device to keep esophageal temperature at 4°C during ablation or standard practice using a single-sensor temperature probe. Ablation parameters and clinical outcomes were analyzed. RESULTS: Procedural data from 188 patients were analyzed. Procedure and fluoroscopy times were similar, and all pulmonary veins were isolated. First-pass pulmonary vein isolation and reconnection at the end of the waiting period were similar in both randomized groups (51/64 vs. 51/68; p = 0.54 and 5/64 vs. 7/68; p = 0.76, respectively). Posterior wall isolation was also similar: 24/33 versus 27/38; p = 0.88. Ablation effect on tissue, measured in impedance drop, was no different between the two randomized groups: 8.6Ω (IQR: 6-11.8) versus 8.76Ω (IQR: 6-12.2; p = 0.25). Arrhythmia recurrence was similar after 12 months (21.1% vs. 24.1%; 95% CI: 0.38-1.84; HR: 0.83; p = 0.66). CONCLUSIONS: Esophageal cooling has been shown to be effective in reducing ablation-related thermal injury during RF ablation. This protection does not compromise standard procedural endpoints or clinical success at 12 months.

Randomized comparison of oesophageal protection with a temperature control device: results of the IMPACT study.

AIMS: Thermal injury to the oesophagus is an important cause of life-threatening complication after ablation for atrial fibrillation (AF). Thermal protection of the oesophageal lumen by infusing cold liquid reduces thermal injury to a limited extent. We tested the ability of a more powerful method of oesophageal temperature control to reduce the incidence of thermal injury. METHODS AND RESULTS: A single-centre, prospective, double-blinded randomized trial was used to investigate the ability of the ensoETM device to protect the oesophagus from thermal injury. This device was compared in a 1:1 randomization with a control group of standard practice utilizing a single-point temperature probe. In the protected group, the device maintained the luminal temperature at 4°C during radiofrequency (RF) ablation for AF under general anaesthesia. Endoscopic examination was performed at 7 days post-ablation and oesophageal injury was scored. The patient and the endoscopist were blinded to the randomization. We recruited 188 patients, of whom 120 underwent endoscopy. Thermal injury to the mucosa was significantly more common in the control group than in those receiving oesophageal protection (12/60 vs. 2/60; P = 0.008), with a trend toward reduction in gastroparesis (6/60 vs. 2/60, P = 0.27). There was no difference between groups in the duration of RF or in the force applied (P value range= 0.2-0.9). Procedure duration and fluoroscopy duration were similar (P = 0.97, P = 0.91, respectively). CONCLUSION: Thermal protection of the oesophagus significantly reduces ablation-related thermal injury compared with standard care. This method of oesophageal protection is safe and does not compromise the efficacy or efficiency of the ablation procedure.

Percutaneous management of lead-related cardiac perforation with limited use of computed tomography and cardiac surgery.

BACKGROUND: Cardiac implantable electronic device (CIED)-related perforation is uncommon but potentially lethal. Management typically includes the use of computed tomography (CT) scanning and often involves cardiac surgery. METHODS: Patients presenting to a single referral centre with CIED-related cardiac perforation between 2013 and 2019 were identified. Demographics, diagnostic modalities, the method of lead revision, and 30-day complications were examined. RESULTS: A total of 46 cases were identified; median time from implantation to diagnosis was 14 days (interquartile range = 4-50). Most were females (29/46, 63%), 9/46 (20%) had cancer, 18 patients (39%) used oral anticoagulants, and no patients had prior cardiac surgery. Active fixation was involved in 98% of cases; 9% involved an implantable cardioverter defibrillator lead. Thirty-seven leads perforated the right ventricle (apex: 24) and 9 punctured the right atrium (lateral wall: 5). Abnormal electrical parameters were noted in 95% of interrogated cases. Perforation was visualized in 41% and 6% of cases with chest X-ray (CXR) and transthoracic echocardiography, respectively. CXR revealed a perforation, gross lead displacement, or left-sided pleural effusion in 74% of cases. Pericardial effusion occurred in 26 patients (57%) of whom 11 (24%) developed tamponade, successfully drained percutaneously. Pre-extraction CT scan was performed in 19 patients but was essential in four cases. Transvenous lead revision (TLR) was successfully performed in all cases with original leads repositioned in six patients, without recourse to surgery. Thirty-day mortality and complications were low (0% and 26%, respectively). CONCLUSION: CT scanning provides incremental diagnostic value in a minority of CIED-related perforations. TLR is a safe and effective strategy.

Cardiac arrest following protamine administration: a case series.

AIMS: Protamine sulfate is commonly used to reverse the action of heparin after catheter ablation procedures. Serious protamine-related adverse effect is rare, but its recognition and appropriate management by electrophysiologists and intensivists is important. Direct ventricular fibrillation (VF) soon after a slow infusion of protamine has not been clearly described. METHODS AND RESULTS: We examined the records of all patients who suffered apparent adverse events after protamine administration in our electrophysiology lab from 2013 to 2018. We describe a series of three patients, all of whom suffered a precipitous fall in arterial pressure followed by VF within minutes after administration of protamine following ablation for atrial fibrillation. The same supplier of protamine was used in all three cases, but they were from different batches. Serum tryptase levels were measured in all cases, immediately post-cardiac arrest and at 2- and 6-h post-event. Immunoglobulin levels were not measured. Two patients recovered after aggressive supportive therapy; the third died despite similar support. CONCLUSION: We have encountered three cases of profound hypotension followed by VF soon after administration of protamine. Although protamine is safe in a large majority of patients, these adverse events have led our centre to exercise greater selectivity and caution in its use.

A study to assess a novel automated electrocardiogram technology in screening for atrial fibrillation.

INTRODUCTION: Atrial fibrillation is often asymptomatic and un-diagnosed in the community resulting in an increased risk of heart failure and stroke to those patients. We evaluated the effectiveness, tolerability, and accuracy of a novel six-channel electrocardiogram digital-health screening device, the RhythmPad, for the detection of atrial fibrillation. METHODS: Seven hundred and fifty-two participants attending the cardiology department were recruited. Two recordings were taken-a six-lead electrocardiogram using the RhythmPad device and a standard 12-lead electrocardiogram. Recorded traces were analyzed by two blinded cardiologists. The computer-generated automated diagnostic reports from both systems were also compared. Post-participation feedback was obtained from study participants using a three-part questionnaire. RESULTS: The sensitivity of the six-lead electrocardiogram compared to the 12-lead electrocardiogram, analyzed by two blinded cardiologists, for the detection of normal sinus rhythm was 95.9%, with a specificity of 97.2%. The sensitivity for the detection of atrial fibrillation using the six-lead ECG was 93.4%, with specificity 96.8%. The six-lead automated diagnostic report had a sensitivity and specificity of 97.5% and 98.6%, respectively, for correctly diagnosing normal sinus rhythm. For the correct diagnosis of atrial fibrillation, the six-lead automated diagnostic report had a sensitivity and specificity of 95.4% and 98.8%, respectively. A total of 95.4% of participants found RhythmPad to be comfortable, with only 0.5% preferring the 12-lead ECG device in comparison to six-lead ECG acquisitions. CONCLUSION: The RhythmPad digital health device and its automated diagnostic report were highly accurate in detecting atrial fibrillation when compared to a standard 12-lead electrocardiogram.

Initial clinical results with the ThermoCool® SmartTouch® Surround Flow catheter.

AIM: The Biosense Webster ThermoCool® SmartTouch® Surround Flow (STSF) catheter is a recently developed ablation catheter incorporating Surround Flow (SF) technology to ensure efficient cooling and force sensing to quantify tissue contact. In our unit, it superseded the ThermoCool® SF catheter from the time of its introduction in May 2015. METHODS AND RESULTS: Procedure-related data were collected prospectively for the first 100 ablation procedures performed in our department using the STSF catheter. From a database of 654 procedures performed in our unit using the SF catheter, we selected one to match each STSF procedure, matching for procedure type, operator experience, patient age, and gender. The groups were well matched for patient age, gender, and procedure type. Procedure duration was similar in both groups (mean 225.5 vs. 221.4 min, IQR 106.5 vs. 91.5, P = 0.55), but fluoroscopy duration was shorter in the STSF group (mean 25.8 vs. 30.0, IQR 19.6 vs. 18.5, P = 0.03). No complication occurred in the STSF group. Complications occurred in two cases in the SF group (one pericardial effusion requiring drainage and one need for permanent pacing). Complete procedural success was achieved in 98 cases in the STSF group and 94 cases in the SF group (P = 0.15). The composite endpoint of procedure failure or acute complication was less common in the STSF group (2 vs. 8, P = 0.05). CONCLUSION: The STSF catheter is safe and effective in treating a range of arrhythmias. Compared with the SF catheter, it shows a trend towards improved safety-efficacy balance.

Benefits of a quadripolar left ventricular lead in patients undergoing cardiac resynchronization therapy with underlying myocardial scar.

We present a case of a 76-year-old man with ischemic cardiomyopathy. Cardiac magnetic resonance imaging demonstrated severe left ventricular (LV) impairment with possibility of scar formation. Cardiac resynchronization therapy was employed with the aid of a novel quadripolar LV lead. The quadripolar LV lead can be programmed for 10 different pacing configurations, allowing the electrophysiologist freedom to optimize the vector around scar and also avoid phrenic nerve stimulation without the requirement of LV lead repositioning.

Correct dosing, adherence and persistence of DOACs in atrial fibrillation and chronic kidney disease: a systematic review and meta-analysis.

BACKGROUND: Chronic kidney disease (CKD) and atrial fibrillation (AF) are increasing in prevalence globally and share common risk factors.Our aim was to characterise real-world evidence on direct oral anticoagulant (DOAC) prescribing for people with AF and CKD, in terms of adherence, persistence and renal dose titration. METHODS: PubMed, EMBASE and CINAHL were searched from inception to June 2022. Our search terms included a combination of Medical Subject Headings (MeSH) terms and keywords including 'atrial fibrillation', 'chronic kidney disease', 'adherence', 'persistence', 'direct oral anticoagulants' and 'dosing'. Data extraction and quality assessment were undertaken by two reviewers independently. Meta-analyses for pooled estimates were performed using DerSimonian and Laird random-effects models. Age, sex, diabetes, hypertension and heart failure were chosen as variables of interest. RESULTS: From 19 studies, a total of 252 117 patients were included with CKD and AF. Meta-analysis was only possible in seven studies with 128 406 patients, five on DOAC dose titration and two on adherence. There were insufficient studies on persistence. Our meta-analysis of dosing showed that 68% of patients with CKD and AF had correct dosing. There was no evidence to show any association between correct DOAC dosing and variables of interest. Overall, 67% of patients were DOAC adherent. CONCLUSION: Adherence and correct dosing of DOACs were suboptimal compared with other medications in the pooled studies with respect to CKD and AF. Thus, further research is required as the lack of generalisation of findings is a rate-limiting factor for improved DOAC management in AF and CKD. PROSPERO REGISTRATION NUMBER: CRD;42022344491.

The management of cardiovascular disease risk in patients with rheumatoid arthritis.

INTRODUCTION: Rheumatoid Arthritis (RA) is a chronic inflammatory disorder associated with an increased incidence and prevalence of cardiovascular disease (CVD), including myocardial infarction and heart failure. In addition to traditional risk factors, evidence suggests inflammation is critical to the pathophysiology of both conditions. Despite the association being well-recognised, challenges remain in managing cardiovascular risk in RA. AREAS COVERED: This manuscript analyses the association between CVD and RA and explores the limitations in evaluating cardiovascular risk in RA with available risk assessment tools. The authors review the optimal management of traditional risk factors such as hypertension and dyslipidaemia and contemporary risk factors such as inflammation and analyse the cardiovascular impact of RA medications. EXPERT OPINION: Analysis points to the critical role of inflammation in the pathogenesis of RA and CVD. It is well established that conventional disease-modifying anti-rheumatic drugs (DMARDs) improve cardiovascular outcomes; however, underlying risk often remains underappreciated. The authors suggest there remains an opportunity to improve mortality and morbidity with the early recognition and of at-risk populations and the timely initiation of appropriate cardiovascular and anti-inflammatory medications. More research is necessary into the role that imaging may play in stratifying risk and in the longer-term cardiovascular impact of biological DMARDs.

A Chronicle of Hybrid Atrial Fibrillation Ablation Therapy: From Cox Maze to Convergent.

The burden of AF is increasing in prevalence and healthcare resource usage in the UK and worldwide. It can result in impaired quality of life for affected patients, as well as increased risk of stroke, heart failure and mortality. A holistic, integrated approach to AF management is recommended, which may include a focus on reducing risk factors and on medical management with anticoagulation and anti-arrhythmic drugs. There are also various ablation strategies that may be considered when anti-arrhythmic drugs fail to alleviate symptoms and reduce AF burden. These ablation techniques range from standalone percutaneous endocardial catheter ablation to open surgical ablation procedures concomitant with cardiac surgery. More recently, hybrid ablation that combines aspects of both surgical and electrophysiologically targeted ablation has been described. This article reviews the evolution of ablation strategies, beginning with the origin of the Cox maze IV procedure and continuing to the recent hybrid convergent approach, and provides a summary of the associated outcomes.

The Convergent Ablation and AtriClip Exclusion of the Left Atrial Appendage in Long-Standing Persistent Atrial Fibrillation.

We here present a case of a 54-year-old man with longstanding persistent atrial fibrillation refractory to direct current electrical cardioversion who underwent a concurrent convergent ablation and Atriclip exclusion of left atrial appendage. His preoperative echocardiography revealed dilated 5.8 cm left atrium with a normal left ventricular ejection fraction of 50%. Transmural isolation of pulmonary veins was performed through a subxiphoid approach, and 3 left-sided video-assisted thoracoscopic surgery ports were utilised to occlude the base of the left atrium appendage with the Atriclip device. A peri-operative transoesophageal echocardiogram confirmed left atrium appendage base occlusion, and the patient was in sinus rhythm after having a single 200 kJ direct current cardioversion shock. The postoperative period was uneventful, and the patient was discharged with preprocedural anticoagulant after 24 hours of the procedure and advised to come for follow up after 3 months.

Localisation of SCN10A gene product Na(v)1.8 and novel pain-related ion channels in human heart.

We have shown that the gene SCN10A encoding the sodium channel Na(v)1.8 is a susceptibility factor for heart block and serious ventricular arrhythmia. Since Na(v)1.8 is known to be present in nerve fibres that mediate pain, it may be related to both cardiac pain and dysrhythmia. The localisation of Na(v)1.8 and other key nociceptive ion channels, including Na(v)1.7, Na(v)1.9, capsaicin receptor TRPV1, and purinergic receptor P2X(3), have not been reported in human heart. The aim of this study was to determine the distribution of Na(v)1.8, related sodium and other sensory channels in human cardiac tissue, and correlate their density with sympathetic nerves, regenerating nerves (GAP-43), and vascularity. Human heart atrial appendage tissues (n = 13) were collected during surgery for valve disease. Tissues were investigated by immunohistology using specific antibodies to Na(v)1.8 and other markers. Na(v)1.8 immunoreactivity was detected in nerve fibres and fascicles in the myocardium, often closely associated with small capillaries. Na(v)1.8 nerve fibres per mm(2) correlated significantly with vascular markers. Na(v)1.8-immunoreactivity was present also in cardiomyocytes with a similar distribution pattern to that seen with connexins, the specialised gap junction proteins of myocardial intercalated discs. Na(v)1.5-immunoreactivity was detected in cardiomyocytes but not in nerve fibres. Na(v)1.7, Na(v)1.9, TRPV1, P2X(3)/P2X(2), and GAP43 positive nerve fibres were relatively sparse, whereas sympathetic innervation and connexin43 were abundant. We conclude that sodium channel Na(v)1.8 is present in sensory nerves and cardiomyocytes of human heart. Na(v)1.8 and other pain channels provide new targets for the understanding and treatment of cardiac pain and dysrhythmia.

Persistent Atrial Fibrillation: The Role of Left Atrial Posterior Wall Isolation and Ablation Strategies.

Atrial fibrillation (AF) is a global disease with rapidly rising incidence and prevalence. It is associated with a higher risk of stroke, dementia, cognitive decline, sudden and cardiovascular death, heart failure and impairment in quality of life. The disease is a major burden on the healthcare system. Paroxysmal AF is typically managed with medications or endocardial catheter ablation to good effect. However, a large proportion of patients with AF have persistent or long-standing persistent AF, which are more complex forms of the condition and thus more difficult to treat. This is in part due to the progressive electro-anatomical changes that occur with AF persistence and the spread of arrhythmogenic triggers and substrates outside of the pulmonary veins. The posterior wall of the left atrium is a common site for these changes and has become a target of ablation strategies to treat these more resistant forms of AF. In this review, we discuss the role of the posterior left atrial wall in persistent and long-standing persistent AF, the limitations of current endocardial-focused treatment strategies, and future perspectives on hybrid epicardial-endocardial approaches to posterior wall isolation or ablation.

Hybrid Convergent Procedure for the Treatment of Persistent and Long-standing Persistent Atrial Fibrillation.

Recent advances have been made in AF treatment, including the role of early rhythm control and landmark clinical trials using ablation therapy. However, some treatment gaps remain, including the creation of durable lesions outside the pulmonary veins and effective treatment of longstanding persistent AF. A novel epicardial-endocardial ablation approach - the hybrid convergent procedure - was developed to combine surgical and catheter ablation techniques into a collaborative, multidisciplinary approach to managing AF. In this review, the authors discuss recently published data on hybrid convergent ablation, including results of the CONVERGE clinical trial, in the context of current challenges to treatment of persistent and long-standing persistent AF. The review also aims to provide perspective on outstanding questions and future directions in this area.

Contact force sensing in ablation of ventricular arrhythmias using a 56-hole open-irrigation catheter: a propensity-matched analysis.

PURPOSE: The effect of adding contact force (CF) sensing to 56-hole tip irrigation in ventricular arrhythmia (VA) ablation has not been previously studied. We aimed to compare outcomes with and without CF sensing in VA ablation using a 56-hole radiofrequency (RF) catheter. METHODS: A total of 164 patients who underwent first-time VA ablation using Thermocool SmartTouch Surround Flow (TC-STSF) catheter (Biosense-Webster, Diamond Bar, CA, USA) were propensity-matched in a 1:1 fashion to 164 patients who had first-time ablation using Thermocool Surround Flow (TC-SF) catheter. Patients were matched for age, gender, cardiac aetiology, ejection fraction and approach. Acute success, complications and long-term follow-up were compared. RESULTS: There was no difference between procedures utilising either TC-SF or TC-STSF in acute success (TC-SF: 134/164 (82%), TC-STSF: 141/164 (86%), p = 0.3), complications (TC-SF: 11/164 (6.7%), TC-STSF: 11/164 (6.7%), p = 1.0) or VA-free survival (TC-SF: mean arrhythmia-free survival time = 5.9 years, 95% CI = 5.4-6.4, TC-STSF: mean = 3.2 years, 95% CI = 3-3.5, log-rank p = 0.74). Fluoroscopy time was longer in normal hearts with TC-SF (19 min, IQR: 14-30) than TC-STSF (14 min, IQR: 8-25; p = 0.04). CONCLUSION: Both TC-SF and TC-STSF catheters are safe and effective in treating VAs. The use of CF sensing catheters did not improve safety or acute and long-term outcomes, but reduced fluoroscopy time in normal heart VA.

Combined epicardial and endocardial ablation for atrial fibrillation: Best practices and guide to hybrid convergent procedures.

The absence of strategies to consistently and effectively address nonparoxysmal atrial fibrillation by nonpharmacological interventions has represented a long-standing treatment gap. A combined epicardial/endocardial ablation strategy, the hybrid Convergent procedure, was developed in response to this clinical need. A subxiphoid incision is used to access the pericardial space facilitating an epicardial ablation directed at isolation of the posterior wall of the left atrium. This is followed by an endocardial ablation to complete isolation of the pulmonary veins and for additional ablation as needed. Experience gained with the hybrid Convergent procedure during the last decade has led to the development and adoption of strategies to optimize the technique and mitigate risks. Additionally, a surgical and electrophysiology "team" approach including comprehensive training is believed critical to successfully develop the hybrid Convergent program. A recently completed randomized clinical trial indicated that this ablation strategy is superior to an endocardial-only approach for patients with persistent atrial fibrillation. In this review, we propose and describe best practice guidelines for hybrid Convergent ablation on the basis of a combination of published data, author consensus, and expert opinion. A summary of clinical outcomes, emerging evidence, and future perspectives is also given.

Human connexin31.9, unlike its orthologous protein connexin30.2 in the mouse, is not detectable in the human cardiac conduction system.

In the human heart connexin(Cx)40, Cx43 and Cx45-containing gap junctional channels electrically couple cardiomyocytes, forming a functional syncytium. In the mouse heart, additionally, Cx30.2-containing gap junctions have been detected in the atrioventricular node where they are implicated, together with Cx45, in impulse delay. However, whether the human ortholog of Cx30.2, Cx31.9, is expressed in the human heart has not previously been investigated. We therefore generated Cx31.9 specific antibodies to test for the expression of Cx31.9 in the human heart. These antibodies recognized the Cx31.9 protein in HeLaCx31.9 transfectants by immunofluorescence and immunoblot analyses. However, we did not find punctate Cx31.9 specific immunofluorescence signals in the working myocardium or in the impulse generation and conduction system of adult or fetal human heart. Complementary immunoblot analyses did not reveal Cx31.9 protein in the adult atrial or ventricular myocardium. We conclude that the Cx31.9 protein, unlike its counterpart in the mouse, is not expressed in detectable quantities and is thus unlikely to contribute to the impulse generation and conduction system or the working myocardium of the human heart.

Short-term pacing in the mouse alters cardiac expression of connexin43.

BACKGROUND: Cardiac insults such as ischemia, infarction, hypertrophy and dilatation are often accompanied by altered abundance and/or localization of the connexin43 gap junction protein, which may predispose towards arrhythmic complications. Models of chronic dyssynchronous cardiac activation have also been shown to result in redistribution of connexin43 in cardiomyocytes. We hypothesized that alterations in connexin43 expression and localization in the mouse heart might be induced by ventricular pacing over a short period of time. RESULTS: The subdiaphragmatic approach was used to pace a series of wild type mice for six hours before the hearts were removed for analysis. Mice were paced at 10-15% above their average anesthetized sinus rate and monitored to ensure 1:1 capture. Short-term pacing resulted in a significant reduction in connexin43 mRNA abundance, a partial redistribution of connexin43 from the sarcolemma to a non-sarcolemmal fraction, and accumulation of ubiquitinated connexin43 without a significant change in overall connexin43 protein levels. These early pacing-induced changes in connexin43 expression were not accompanied by decreased cardiac function, prolonged refractoriness or increased inducibility into sustained arrhythmias. CONCLUSION: Our data suggest that short-term pacing is associated with incipient changes in the expression of the connexin43 gap junction, possibly including decreased production and a slowed rate of degradation. This murine model may facilitate the study of early molecular changes induced by pacing and may ultimately assist in the development of strategies to prevent gap junction remodeling and the associated arrhythmic complications of cardiac disease.