Brugada syndrome: a review and the role of epicardial ablation in management.

BACKGROUND: Brugada syndrome (BrS) is an inherited arrhythmogenic syndrome characterized by cove-shaped ST-segment elevation in leads V1-V3 and incomplete or complete right bundle branch block. BrS exhibits autosomal dominant inheritance with incomplete penetrance and a male predominance. It carries a significant risk of sudden cardiac death due to ventricular fibrillation (VF). MAIN BODY: Recent studies have highlighted the presence of epicardial fibrosis as a proarrhythmic substrate in BrS, revolutionizing our understanding of the disease's pathophysiology. Catheter ablation has emerged as a crucial intervention for symptomatic BrS patients experiencing recurrent episodes of ventricular tachycardia (VT) or VF. By potentially obviating the need for implantable cardioverter-defibrillator (ICD) implantation, epicardial ablation offers a promising therapeutic approach. CONCLUSION: This review emphasizes the significance of current evidence and ongoing research in shaping the role of epicardial ablation as a curative strategy in BrS management, highlighting its potential benefits and the necessity for further investigation.

Improving outcomes in single chamber leadless pacemakers: strategies for minimizing vascular complications.

BACKGROUND: Leadless pacemaker therapy is associated with a significant reduction in lead-related complication rate compared to conventional transvenous single chamber pacemaker therapy. However, a significant complication rate of 1.2% was observed in vascular access due to the use of large delivery femoral sheath (27Fr). The aim of this study was to evaluate the effectiveness of real-time ultrasound guidance and Z suture technique in reducing total and major vascular complications in leadless pacemaker therapy. METHOD: In this study, we performed a retrospective and prospective analysis of all adverse events associated with leadless pacemaker (Micra) implantation by two operators at a single tertiary center from December 2016 to December 2018. To mitigate the risk of vascular complications, all patients underwent real-time ultrasound-guided venipuncture for vascular access, as well as the application of a Z-suture technique for hemostasis at the end of the procedure. Data were collected on implant indications, implant procedure details, complications, and follow-up information. RESULTS: In this study, 45 patients with an age range of 24 to 94 years (mean 76 ± 14 years) were recruited, with 21 (46.6%) being female. The pacing indications for the patients included atrial fibrillation (24, 53.3%), vascular (7, 15.5%), infection (9, 20%), cognitive/frailty (3, 6.6%), and occupational (2, 4.4%). The implant procedures were performed under general anesthesia in 6 (13.3%) of the cases, and under local anesthesia and sedation in 39 (86.6%) of the cases. A single deployment was achieved in 43 (95.5%) of the patients, while 2 deployments were required in 2 (4.4%) of the patients. Notably, no vascular or major complications were reported in our cohort of patients. CONCLUSIONS: The results of this observational study indicate that incorporating real-time ultrasound guidance during venipuncture and the use of a Z-suture technique significantly reduce the occurrence of both total and major vascular complications associated with the implantation of leadless pacemaker. However, more robust and larger studies are required in order to confirm these results and implications for clinical practice.

Refractory hypertensive emergency associated with complete heart block resolved after permanent pacemaker implantation: A case report.

Severe hypertension sometimes improves with treatment of bradycardia but this phenomenon is under-reported. Here, an elderly gentleman with complete heart block and a hypertensive emergency was refractory to medical therapies and blood pressure only improved following pacemaker implantation. We discuss the possible mechanisms relating to heart rate and artificial pacing.

Deep Vein Thrombosis is Common After Cardiac Ablation and Pre-Procedural D-Dimer Could Predict Risk.

PURPOSE: Cardiac catheter ablations are an established treatment for supraventricular tachycardia (SVT) involving prolonged cannulation of the common femoral vein with multiple catheters. This study aimed to identify the risk of deep vein thrombosis (DVT) by studying the frequency of this complication after catheter ablation. METHODS: This was a prospective multi-centre cohort study of patients undergoing cardiac ablation for atrioventricular nodal re-entry tachycardia or right-sided accessory atrioventricular connection. Those taking anticoagulation or antiplatelet therapy prior to the procedure were excluded. Following the procedure, bilateral venous duplex ultrasonography from the popliteal vein to the inferior vena cava for DVT was undertaken at 24 hours and between 10 to 14 days. RESULTS: Eighty (80) patients (mean age 47.6 yrs [SD 13.4] with 67% female) underwent cardiac ablation (median duration 70 mins). Seven (7) patients developed acute DVT in either the femoral or external iliac vein of the intervention leg, giving a frequency of 8.8% (95% CI 3.6-17.2%). No thrombus was seen in the contralateral leg (p=0.023). An elevated D-dimer prior to the procedure was significantly more frequent in patients developing DVT (42.9% vs 4.1%, p=0.0081; OR 17.0). No other patient or procedural characteristics significantly influenced the risk of DVT. CONCLUSION: In patients without peri-procedural anticoagulation catheter ablation precipitated DVT in the catheterised femoral or iliac veins in 8.8% of patients. Peri-procedure prophylactic anticoagulation may be considered for all patients undergoing catheter ablation for SVT. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT03877770.

UBLED AF (Uninterrupted BLackpool EDoxaban vs Warfarin vs Rivaroxaban in Atrial Fibrillation/Flutter ablation) Study.

AIM: Catheter ablation in patients with atrial fibrillation (AF)/atrial flutter carries a risk of thromboembolism and major bleeding. In light of recent prospective trial data on the safety and efficacy of uninterrupted edoxaban in patients undergoing AF/flutter ablation, real-world Data was aimed for validation. METHODS: A total of 228 patients who underwent AF/atrial flutter ablation over 14 months at our centre were retrospectively analyzed. All patients received uninterrupted oral anticoagulation for at least 4 weeks prior to ablation and 3 months post-ablation. Both bleeding and thromboembolic events were assessed at 24 hours comparing patients on warfarin, rivaroxaban and edoxaban. RESULTS: Mean age of patients were 68.5 +/- 8 years in the warfarin group ( N =86), 63.4 +/- 10.6 years; in the edoxaban group ( N =63) and 62.3 +/- 11.6 years in the rivaroxaban group ( N =79). CHADSVASc scores were 2.43 +/- 1.34, 1.68 +/- 1.34 and 1.64 +/- 1.38 respectively. The mean left atrial sizes were 42.7 +/- 6.8 mm, 42.0 +/- 6 mm and 41.1 +/- 6.5 mm respectively. The study endpoint was death, acute thromboembolism or major bleeding. There was 1 pericardial effusion (1.2%) in the warfarin group, 1 pericardial effusion and 1 transient ischaemic attack (2.5%) in the rivaroxaban group and 1 pericardial effusion needing drainage (1.6%) in the edoxaban group. There were no significant differences in the study endpoints between groups. CONCLUSION: This real-world study demonstrated no significant difference in safety and efficacy between uninterrupted edoxaban, warfarin and rivaroxaban in patients undergoing AF/flutter ablation.

A 59-Year-Old Woman with Familial Brugada Syndrome and the c.664C>T Variant of the Sodium Voltage-Gated Channel Alpha Subunit 5 (SCN5A) Gene, Accompanied by Congenital Absence of the Right Coronary Artery, Patent Foramen Ovale, and Ischemic Stroke.

BACKGROUND Brugada syndrome is a rare inherited channelopathy that can lead to sudden cardiac death. The discovery of new variants of variable penetrance along with the current guidance for cascade family screening can be expected to lead to an increase in identified asymptomatic carriers of potentially causative mutations of channelopathies. A single coronary artery is a rare congenital anomaly of the coronary anatomy. We present a rare case of a 59-year-old woman with a family history of Brugada syndrome with the c.664C>T variant of the SCN5A gene, congenital absence of the right coronary artery, and patent foramen ovale. CASE REPORT We present a case of a patient with a family history of Brugada syndrome who tested positive for the SCN5A variant. The patient had no previous history of syncope or aborted sudden cardiac death. The patient had no features suggestive of Brugada type I ECG. An electrophysiology study was offered but the patient declined. She also complained of angina, and work-up with computed tomography coronary angiography revealed a congenital absence of the right coronary artery with no significant stenosis of the single left coronary artery. In the followup period, she suffered a stroke and was diagnosed with patent foramen ovale (PFO). She has been referred for PFO closure. CONCLUSIONS A rare case is reported of familial Brugada syndrome with absence of the right coronary artery and patent foramen ovale, which may have combined to increase this patient's risk for ischemic stroke.

Intermittent Loss of Telemetry Data: Lessons From a Leadless Pacemaker.

We present the case of a 63-year-old female patient who presented to the pacemaker clinic for a scheduled interrogation of her leadless pacemaker. The device interrogation was suggestive of intermittent under-sensing with failure to pace. Connecting the electrocardiogram lead to the pacing system analyzer raised the suspicion of intermittent loss of telemetry data. (Level of Difficulty: Beginner.).

The primary prevention implantable cardioverter-defibrillator (ICD) during the COVID-19 pandemic.

During the recent 'first wave' of the COVID-19 pandemic, the National Health Service (NHS) has triaged planned services to create surge capacity. The primary prevention implantable cardioverter-defibrillator (ICD) was in a grey area of triage guidance, but it was suggested as a procedure that could be reasonably stopped. Recent reports have highlighted deaths of patients awaiting ICDs who may have been deferred during the pandemic. In our trust we reorganised our device service and continued to implant primary prevention ICDs during the 'first wave' and, here, report that most patients wished to proceed and underwent uncomplicated implantations. One patient later died from COVID-19, although the transmission site cannot be definitively concluded. With strict adherence to public health guidance and infection prevention strategies, we believe that ICD implantation can be performed safely during the pandemic, and this should be standard practice during subsequent surges.

Coronovirus Disease-2019 (COVID-19) Pandemic and Cardiac Electrophysiology: Guidance Protocol From a UK Tertiary Cardiac Center.

Since December 2019, the coronovirus disease-2019 (COVID-19) pandemic has resulted in more than 2,160,000 positive cases and more than 145,000 deaths until April 18, 2020. The pressure to the health services worldwide has been unprecedented. The redeployment of staff and resources to treat more efficiently COVID-19 cases along with the need to reduce disease transmission has affected the field of electrophysiology among many others. Amendments to clinical pathways are obligatory in this perspective to continue to provide the necessary health services to the people who need them, although at the same time, infection control and prevention are not compromised by inadvertent disease transmission or unnecessary use of resources. We aim to provide a guide of the logistic aspects of electrophysiology procedures derived from our tertiary cardiac center during the current COVID-19 pandemic.

Biventricular pacemaker therapy improves exercise capacity in patients with non-obstructive hypertrophic cardiomyopathy via augmented diastolic filling on exercise.

AIMS: Treatment options for patients with non-obstructive hypertrophic cardiomyopathy (HCM) are limited. We sought to determine whether biventricular (BiV) pacing improves exercise capacity in HCM patients, and whether this is via augmented diastolic filling. METHODS AND RESULTS: Thirty-one patients with symptomatic non-obstructive HCM were enrolled. Following device implantation, patients underwent detailed assessment of exercise diastolic filling using radionuclide ventriculography in BiV and sham pacing modes. Patients then entered an 8-month crossover study of BiV and sham pacing in random order, to assess the effect on exercise capacity [peak oxygen consumption (VO2 )]. Patients were grouped on pre-specified analysis according to whether left ventricular end-diastolic volume increased (+LVEDV) or was unchanged/decreased (-LVEDV) with exercise at baseline. Twenty-nine patients (20 male, mean age 55 years) completed the study. There were 14 +LVEDV patients and 15 -LVEDV patients. Baseline peak VO2 was lower in -LVEDV patients vs. +LVEDV patients (16.2 ± 0.9 vs. 19.9 ± 1.1 mL/kg/min, P = 0.04). BiV pacing significantly increased exercise ΔLVEDV (P = 0.004) and Δstroke volume (P = 0.008) in -LVEDV patients, but not in +LVEDV patients. Left ventricular ejection fraction and end-systolic elastance did not increase with BiV pacing in either group. This translated into significantly greater improvements in exercise capacity (peak VO2 + 1.4 mL/kg/min, P = 0.03) and quality of life scores (P = 0.02) in -LVEDV patients during the crossover study. There was no effect on left ventricular mechanical dyssynchrony in either group. CONCLUSION: Symptomatic patients with non-obstructive HCM may benefit from BiV pacing via augmentation of diastolic filling on exercise rather than contractile improvement. This may be due to relief of diastolic ventricular interaction. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT00504647.

First experience in quadripolar active fixation coronary sinus lead extraction: a case report.

BACKGROUND: The Attain Stability Quadripolar 4798 lead is a relatively new quadripolar active fixation coronary sinus (CS) lead. No cases of extraction of a chronically implanted 4798 lead have been published to date. CASE SUMMARY: A 52-year-old man with a history of previous cardiac resynchronization therapy pacemaker (CRT-P) insertion and atrioventricular node ablation presented to our institution with a pocket infection 69 weeks after implantation. Directed intravenous antibiotic therapy was commenced and an extraction was performed the following day. Extraction of the right atrial and right ventricular leads was simple and achieved with gentle manual traction. Extraction of the CS lead was more difficult. Significant traction was required due to the formation of adhesions inside the CS but extraction of the lead was eventually successful without complication. Specialized extraction equipment was not required. A new contralateral CRT-P device was implanted, and the patient was discharged home. He remains well at 3 months of follow-up. DISCUSSION: We present the first case of extraction of a chronically implanted active fixation Attain Stability Quadripolar lead. Our experience demonstrates that this has been performed successfully without specialist tools and with preservation of the CS branch. Significant adhesion was noted at the site of active fixation, however. Potential difficulty with this lead's extraction should therefore be considered when contemplating its use.

Bradyarrhythmias for the Internist.

In this article, the authors review the different types of sinus node and atrioventricular node diseases that lead to bradyarrhythmias with their associated symptoms, the diagnostic investigations needed to assess the degree of disease, and the therapeutic management, including the indications for permanent pacing.

The use of a single chamber leadless pacemaker for the treatment of cardioinhibitory vasovagal syncope.

BACKGROUND: The use of pacemakers in the treatment of cardioinhibitory vasovagal syncope is controversial with a mixed message from the limited evidence base. Single chamber leadless pacemakers have been shown to be an effective alternative option to conventional pacemakers. OBJECTIVE: This study examines the use of leadless pacemakers in a cardioinhibitory vasovagal population in the United Kingdom. METHODS: Observational data on 32 patients implanted with the Micra Transcatheter Pacemaker System for vasovagal syncope are presented. Data was collected on implant indications, implant procedure and follow up data from 12 centres across the United Kingdom that had elected to use a Micra leadless pacemaker in this patient population. RESULTS: 32 patients aged 37 ±â€¯14 years (range 18 to 64 years) with 62% of the patients being female were recruited to the study. Vasovagal syncope was diagnosed clinically and with the support of Holter monitoring, tilt table testing and implantable loop recorders. The duration of symptoms was 8 ±â€¯8 yrs. with an average frequency of syncope being 4 ±â€¯6 times/year. The Micra pacemaker was successfully implanted in all patients with a major complication rate of 3.1%. Patients were followed up for 404 ±â€¯237 days (range 63-928 days). At follow up 28 (87%) patients were free from symptoms. CONCLUSIONS: This observational study suggests that the use of a single chamber leadless pacemaker in the treatment of cardioinhibitory vasovagal syncope might be a reasonable clinical option.

Uninterrupted edoxaban vs. vitamin K antagonists for ablation of atrial fibrillation: the ELIMINATE-AF trial.

AIMS: Edoxaban is a direct factor Xa inhibitor approved for stroke prevention in atrial fibrillation (AF). Uninterrupted edoxaban therapy in patients undergoing AF ablation has not been tested. METHODS AND RESULTS: The ELIMINATE-AF trial, a multinational, multicentre, randomized, open-label, parallel-group study, was conducted to assess the safety and efficacy of once-daily edoxaban 60 mg (30 mg in patients indicated for dose reduction) vs. vitamin K antagonists (VKAs) in AF patients undergoing catheter ablation. Patients were randomized 2:1 to edoxaban vs. VKA. The primary endpoint (per-protocol population) was time to first occurrence of all-cause death, stroke, or International Society of Thrombosis and Haemostasis-defined major bleeding during the period from the end of the ablation procedure to end of treatment (90 days). Overall, 632 patients were enrolled, 614 randomized, and 553 received study drug and underwent ablation; 177 subjects underwent brain magnetic resonance imaging to assess silent cerebral infarcts. The primary endpoint (only major bleeds occurred) was observed in 0.3% (1 patient) on edoxaban and 2.0% (2 patients) on VKA [hazard ratio (95% confidence interval): 0.16 (0.02-1.73)]. In the ablation population (modified intent-to-treat population including patients with ablation), the primary endpoint was observed in 2.7% of edoxaban (N = 10) and 1.7% of VKA patients (N = 3) between start of ablation and end of treatment. There were one ischaemic and one haemorrhagic stroke, both in patients on edoxaban. Cerebral microemboli were detected in 13.8% (16) patients who received edoxaban and 9.6% (5) patients in the VKA group (nominal P = 0.62). CONCLUSION: Uninterrupted edoxaban therapy represents an alternative to uninterrupted VKA treatment in patients undergoing AF ablation.

Impact of Voltage Mapping to Guide Whether to Perform Ablation of the Posterior Wall in Patients With Persistent Atrial Fibrillation.

BACKGROUND: Fibrosis as a substrate for atrial fibrillation (AF) has been shown in numerous preclinical models. Voltage mapping enables in vivo assessment of scar in the left atrium (LA), which can be targeted with catheter ablation. OBJECTIVE: We hypothesized that using the presence or absence of low voltage to guide ablation beyond pulmonary vein antral isolation (PVAI) will improve atrial arrhythmia (AF/AT)-free survival in persistent AF. METHODS AND RESULTS: Single-center retrospective analysis of 2 AF ablation strategies: (1) standard ablation (SA) versus (2) voltage-guided ablation (VGA). PVAI was performed in both groups. With SA, additional lesions beyond PVAI were performed at the discretion of the operator. With VGA, additional lesions to isolate the LA posterior wall were performed if voltage mapping of this region in sinus rhythm showed scar (LA voltage < 0.5 mV). AF-/AT-free endpoint was defined as no sustained AF/AT seen off antiarrhythmic medications after a 2-month postablation blanking period. Seventy-six patients underwent SA and 65 underwent VGA. Patients were well matched for comorbidities, LVEF, and left atrial size. Posterior wall ablation was performed in 57% of patient with SA compared to 42% with VGA. VGA ablation increased 1-year AF-/AT-free survival in patients when compared to SA (80% vs. 57%; P = 0.005). In a multivariate analysis, VGA was the only independent predictor of AF-/AT-free survival (hazard ratio of 0.30; P = 0.002). CONCLUSIONS: The presence of LA posterior wall scar may be an important ablation target in persistent AF. A prospective randomized trial is needed to confirm these data.

Improvement in cardiac energetics by perhexiline in heart failure due to dilated cardiomyopathy.

OBJECTIVES: The aim of this study was to determine whether short-term treatment with perhexiline improves cardiac energetics, left ventricular function, and symptoms of heart failure by altering cardiac substrate utilization. BACKGROUND: Perhexiline improves exercise capacity and left ventricular ejection fraction (LVEF) in patients with heart failure (HF). (31)P cardiac magnetic resonance spectroscopy can be used to quantify the myocardial phosphocreatine/adenosine triphosphate ratio. Because improvement of HF syndrome can improve cardiac energetics secondarily, we investigated the effects of short-term perhexiline therapy. METHODS: Patients with systolic HF of nonischemic etiology (n = 50, 62 ± 1.8 years of age, New York Heart Association functional class II to IV, LVEF: 27.0 ± 1.44%) were randomized to receive perhexiline 200 mg or placebo for 1 month in a double-blind fashion. Clinical assessment, echocardiography, and (31)P cardiac magnetic resonance spectroscopy were performed at baseline and after 1 month. A substudy of 22 patients also underwent cross-heart blood sampling at completion of the study to quantify metabolite utilization. RESULTS: Perhexiline therapy was associated with a 30% increase in the phosphocreatine/adenosine triphosphate ratio (from 1.16 ± 0.39 to 1.51 ± 0.51; p < 0.001) versus a 3% decrease with placebo (from 1.36 ± 0.31 to 1.34 ± 0.31; p = 0.37). Perhexiline therapy also led to an improvement in New York Heart Association functional class compared with placebo (p = 0.036). Short-term perhexiline therapy did not change LVEF. Cross-heart measures of cardiac substrate uptake and respiratory exchange ratio (which reflects the ratio of substrates used) did not differ between patients who received perhexiline versus placebo. CONCLUSIONS: Perhexiline improves cardiac energetics and symptom status with no evidence of altered cardiac substrate utilization. No change in LVEF is seen at this early stage. (Metabolic Manipulation in Chronic Heart Failure; NCT00841139).