Cryoballoon pulmonary vein isolation as first-line treatment of typical atrial flutter: long-term outcomes of the CRAFT trial.

BACKGROUND: CRAFT was an international, multicentre, randomised controlled trial across 11 sites in the United UK and Switzerland. Given the evidence that pulmonary vein triggers may be responsible for atrial flutter (AFL) as well as atrial fibrillation (AF), we hypothesised that cryoballoon pulmonary vein isolation (PVI) would provide greater symptomatic arrhythmia reduction than cavotricuspid isthmus (CTI) ablation, whilst also reducing the subsequent burden of AF. Twelve-month outcomes were previously reported. In this study, we report the extended outcomes of the CRAFT study to 36 months. METHODS: Patients with typical AFL and no evidence of AF were randomised 1:1 to cryoballoon PVI or radiofrequency CTI. All patients received an implantable loop recorder (ILR) for continuous cardiac rhythm monitoring. The primary outcome was time-to-symptomatic arrhythmia recurrence > 30 s. Secondary outcomes included time-to-first-AF episode ≥ 2 min. The composite safety outcome included death, stroke and procedural complications. RESULTS: A total of 113 patients were randomised to cryoballoon PVI (n = 54) or radiofrequency CTI ablation (n = 59). Ninety-one patients reconsented for extended follow-up beyond 12 months. There was no difference in the primary outcome between arms, with the primary outcome occurring in 12 PVI vs 11 CTI patients (HR 0.97; 95% CI 0.43-2.20; p = 0.994). AF ≥ 2 min was significantly less frequent in the PVI arm, affecting 26 PVI vs 36 CTI patients (HR 0.48; 95% CI 0.29-0.79; p = 0.004). The composite safety outcome occurred in 5 PVI and 6 CTI patients (p = 0.755). CONCLUSION: Cryoballoon PVI shows similar efficacy to radiofrequency CTI ablation in reducing symptomatic arrhythmia recurrence in patients presenting with isolated typical AFL but significantly reduces the occurrence of subsequent AF.

Coronary Guidewires in Temporary Cardiac Pacing and Assessment of Myocardial Viability: Current Perspectives and Future Directions.

Intracoronary guidewires used in percutaneous coronary intervention can also be configured to provide temporary ventricular pacing. Trans coronary electrophysiological parameters recorded by employing coronary guidewires may have a potential role in assessing myocardial viability and could provide a means to make an immediate on-table decision about revascularisation. To date, some small studies have demonstrated the safety of this technique in temporary cardiac pacing, but further research is required to refine this approach and establish its clinical utility in myocardial viability assessment. In this review we discuss the potential role of trans coronary electrophysiology in the assessment of myocardial viability.

Transcoronary electrophysiological parameters in patients undergoing elective and acute coronary intervention.

INTRODUCTION: Percutaneous coronary intervention is performed routinely in the management of myocardial infarction with obstructive coronary disease, but intervention to arteries supplying nonviable myocardium may be harmful. It is important therefore to establish myocardial viability, and there is an unmet need in current clinical practice for real time viability assessment to aid in decision making. Transcoronary pacing to assess myocardial electrophysiological parameters may be a novel viability assessment technique which could be used in this regard. METHODS: Coronary intervention was carried out according to standard departmental procedure with standard equipment. An exchange length coronary guidewire was passed into both target and reference coronary vessels and an over-the-wire balloon or microcatheter was used to insulate the guidewire and allow electrophysiological parameters to be assessed. Readings were obtained from all major epicardial vessels and substantial branches. At each position, an intracoronary electrocardiogram was recorded, and R wave amplitude was measured. Transcoronary pacing was then performed to establish threshold and impedance for each myocardial segment. A viability cardiac MRI scan was performed for each patient. A standard segmental model was used to determine viability in each segment using an 'infarct score' based on degree of late gadolinium enhancement. Studies were reported blinded to the electrical parameters obtained from the coronary guidewire. The primary outcome was the relationship between pacing threshold and myocardial segment infarct score. Secondary outcomes included the relationship between segmental infarct score and R wave height, and between segmental infarct score and pacing impedance. Data were collected on the feasibility of studying the coronary segments as well as safety. RESULTS: Sixty-five patients presenting with stable coronary artery disease or acute coronary syndromes to Leeds General Infirmary between September 2019 and August 2021 were included in the study. Electrophysiological parameters from segments with an infarct score of zero were obtained, with wide variances seen, with no significant difference in impedance or threshold in any territory. There was a significant difference in sensitivity for segments in the right coronary artery territory for both elective and acute patients. This likely relates to reduced myocardial mass in these territories. No significant association between infarct score and sensitivity, impedance or threshold were seen. CONCLUSION: This study has established intracoronary electrophysiological parameters in both normal myocardium and areas of myocardial scar. No reliable association was seen between impedance, threshold or R wave amplitude and degree of myocardial viability, contrasting with prior findings from our group and others. More work is therefore required to fully understand the role of transcoronary pacing in this setting.

What training should psychiatrists have to interpret six- and 12-lead electrocardiograms?

To monitor for drug-related cardiac arrhythmias, psychiatrists regularly perform and interpret 12-lead (12L) and, increasingly often, six-lead (6L) electrocardiograms (ECGs). It is not known how training on this complex skill is updated or how well psychiatrists can interpret relevant arrhythmias on either device.We conducted an online survey and ECG interpretation test of cardiac rhythms relevant to psychiatrists.A total of 183 prescribers took part; 75% did not regularly update their ECG interpretation skills, and only 22% felt confident in interpreting ECGs. Most participants were able to recognise normal ECGs. For both 6L and 12L ECGs, the majority of participants were able to recognise abnormal ECGs, but fewer than 50% were able to correctly identify relevant arrhythmias (complete heart block and long QTc). A small number prescribed in the presence of potentially fatal arrhythmias. These findings suggest a need for mandatory ECG interpretation training to improve safe prescribing practice.

Imaging Real-Time Coronary Anatomy Using a Three-Dimensional Electrophysiology Mapping System.

The aim of this study is to evaluate the feasibility of creating fast three-dimensional maps of coronary arteries and to develop a bipolar coronary guidewire in vitro and determine whether it can be localised accurately within the model.A total of five patients were recruited, and EnSite Precision was utilised to create 3D coronary anatomy. A water bath to accommodate a 3D-printed coronary model was developed to test the performance of the bipolar angioplasty wire.Successful guidewire localisation and 3D reconstruction of coronary anatomy were achieved in all the cases. No complications. The bipolar wire was able to collect point clouds, and localisation of the distal tip was excellent when tested in the water bath.Our study demonstrates the feasibility and safety of utilising EAMS to collect coronary anatomy. Real-time tracking with a bipolar catheter is accurate when tested in vitro.

Cryoballoon Pulmonary Vein Isolation as First-Line Treatment for Typical Atrial Flutter.

OBJECTIVE: We aimed to compare cryoballoon pulmonary vein isolation (PVI) with standard radiofrequency cavotricuspid isthmus (CTI) ablation as first-line treatment for typical atrial flutter (AFL). METHODS: Cryoballoon Pulmonary Vein Isolation as First-Line Treatment for Typical Atrial Flutter was an international, multicentre, open with blinded assessment trial. Patients with CTI-dependent AFL and no documented atrial fibrillation (AF) were randomised to either cryoballoon PVI alone or radiofrequency CTI ablation. Primary efficacy outcome was time to first recurrence of sustained (>30 s) symptomatic atrial arrhythmia (AF/AFL/atrial tachycardia) at 12 months as assessed by continuous monitoring with an implantable loop recorder. Primary safety outcome was a composite of death, stroke, tamponade requiring drainage, atrio-oesophageal fistula, pacemaker implantation, serious vascular complications or persistent phrenic nerve palsy. RESULTS: Trial recruitment was halted at 113 of the target 130 patients because of the SARS-CoV-2 pandemic (PVI, n=59; CTI ablation, n=54). Median age was 66 (IQR 61-71) years, with 98 (86.7%) men. At 12 months, the primary outcome occurred in 11 (18.6%) patients in the PVI group and 9 (16.7%) patients in the CTI group. There was no significant difference in the primary efficacy outcome between the groups (HR 1.11, 95% CI 0.46 to 2.67). AFL recurred in six (10.2%) patients in the PVI arm and one (1.9%) patient in the CTI arm (p=0.116). Time to occurrence of AF of ≥2 min was significantly reduced with cryoballoon PVI (HR 0.46, 95% CI 0.25 to 0.85). The composite safety outcome occurred in four patients in the PVI arm and three patients in the CTI arm (p=1.000). CONCLUSION: Cryoballoon PVI as first-line treatment for AFL is equally effective compared with standard CTI ablation for preventing recurrence of atrial arrhythmia and better at preventing new-onset AF. TRIAL REGISTRATION NUMBER: NCT03401099.

Cardiac monitoring in memory clinics: national survey of UK practice.

AIMS AND METHOD: People diagnosed with dementia are often started on acetylcholinesterase inhibitors (AChEIs). As AChEIs can be associated with cardiac side-effects, an electrocardiogram (ECG) is sometimes requested before treatment. Previous work has suggested there is little consensus as to when or how ECGs should be obtained. This can create inconsistent practice, with patient safety, economic and practical repercussions. We surveyed 305 UK memory clinic practitioners about prescribing practice. RESULTS: More than 84% of respondents completed a pulse and cardiac history before prescribing AChEIs. Opinion was divided as to who should fund and conduct ECGs. It was believed that obtaining an ECG causes patients inconvenience and delays treatment. Despite regularly interpreting ECGs, 76% of respondents did not update this clinical skill regularly. CLINICAL IMPLICATIONS: The variation in practice observed has service-level and patient implications and raises potential patient safety concerns. Implementing national guidelines or seeking novel ways of conducting cardiac monitoring could help standardise practice.

An unusual cause of a haemothorax following pacemaker implantation: A case report.

Background: Haemothoraces are a reported but extremely rare complication of pacemaker implantation. Haemothoraces can be a consequence of lead perforation through the right ventricle (RV) and pericardium into the pleural space, direct lung or vascular injury during access. Case summary: A 72-year-old woman presented 24 h after a pacemaker implantation with chest pain and shortness of breath. Computed tomography of the chest confirmed perforation of the RV lead into the left pleural cavity with a large left sided haemothorax. Following percutaneous drainage of the left sided haemothorax, the patient became haemodynamically unstable necessitating emergent sternotomy. During surgery, the extra-cardiac portion of the pacing lead was cut, the RV repaired and a large haematoma evacuated from the left pleural space. Despite this, the patient remained hypotensive, and further exploration showed a bleeding intercostal artery that had been lacerated by the pacing lead. This was treated by electrocautery, and the patient's haemodynamic status improved. The RV lead remnant was removed transvenously via the subclavian vein, and the patient was left with a single chamber atrial pacemaker. Discussion: Prompt recognition of RV lead perforation and its associated sequalae, often utilising multi-modality imaging, is vital to enable transfer to a centre with cardiac surgical expertise. In this case, the perforating RV lead lacerated an intercostal artery, and this was only identified at the time of surgery. In order to minimize the risk of perforation, multiple fluoroscopic views should be used, and care should be taken during helix deployment.

Clinical validation and evaluation of a novel six-lead handheld electrocardiogram recorder compared to the 12-lead electrocardiogram in unselected cardiology patients (EVALECG Cardio).

Aims: Handheld electrocardiogram (ECG) monitors are increasingly used by both healthcare workers and patients to diagnose cardiac arrhythmias. There is a lack of studies validating the use of handheld devices against the standard 12-lead ECG. The Kardia 6L is a novel handheld ECG monitor which can produce a 6-lead ECG. In this study, we compare the 6L ECG against the 12-lead ECG. Methods and results: A prospective study consisting of unselected cardiac inpatients and outpatients at Leeds Teaching Hospital NHS Trust. All participants had a 12- and 6-lead ECGs. All ECG parameters were analysed by using a standard method template for consistency between independent observers. Electrocardiograms from the recorders were compared by the following statistical methods: linear regression, Bland-Altman, receiver operator curve, and kappa analysis. There were 1015 patients recruited. The mean differences between recorders were small for PR, QRS, cardiac axis, with receiver operator analysis area under the curve (AUC) of >80%. Mean differences for QT and QTc (between recorders) were also small, with AUCs for QT leads of >75% and AUCs for QTc leads of >60%. Key findings from Bland-Altman analysis demonstrate overall an acceptable agreement with few outliers instances (<6%, Bland-Altman analysis). Conclusion: Several parameters recorded by the Kardia 6L (QT interval in all six leads, rhythm detection, PR interval, QRS duration, and cardiac axis) perform closely to the gold standard 12-lead ECG. However, that consistency weakens for left ventricular hypertrophy, QRS amplitudes (Lead I and AVL), and ischaemic changes.

Cardiac Pacing Training in Africa: Endorsed by the Africa Heart Rhythm Association (AFHRA): JACC International.

The field of pacing in Africa has evolved in an uncoordinated way across the continent with significant variation in local expertise, cost, and utilization. There are many countries where pacemaker services do not meet one-hundredth of the national demand. Regional, national, and institutional standards for pacemaker qualification and credentials are lacking. This paper reviews the current needs for bradycardia pacing and evaluates what standards should be set to develop pacemaker services in a resource-constrained continent, including the challenges and opportunities of capacity building and training as well as standards for training programs (training prerequisites, case volumes, program content, and evaluation).

Imaging, biomarker and invasive assessment of diffuse left ventricular myocardial fibrosis in atrial fibrillation.

BACKGROUND: Using cardiovascular magnetic resonance imaging (CMR), it is possible to detect diffuse fibrosis of the left ventricle (LV) in patients with atrial fibrillation (AF), which may be independently associated with recurrence of AF after ablation. By conducting CMR, clinical, electrophysiology and biomarker assessment we planned to investigate LV myocardial fibrosis in patients undergoing AF ablation. METHODS: LV fibrosis was assessed by T1 mapping in 31 patients undergoing percutaneous ablation for AF. Galectin-3, coronary sinus type I collagen C terminal telopeptide (ICTP), and type III procollagen N terminal peptide were measured with ELISA. Comparison was made between groups above and below the median for LV extracellular volume fraction (ECV), followed by regression analysis. RESULTS: On linear regression analysis LV ECV had significant associations with invasive left atrial pressure (Beta 0.49, P = 0.008) and coronary sinus ICTP (Beta 0.75, P < 0.001), which remained significant on multivariable regression. CONCLUSION: LV fibrosis in patients with AF is associated with left atrial pressure and invasively measured levels of ICTP turnover biomarker.

P wave indices, heart rate variability and anthropometry in a healthy South Asian population.

BACKGROUND: South Asians have a low prevalence of atrial fibrillation (AF) in comparison with White Europeans despite a higher burden of hypertension, diabetes mellitus and coronary artery disease. The reason for this disparity is unclear but may relate to electrophysiological or structural differences within the atria or variations in autonomic function. We aimed to assess these areas using a range of non-invasive cardiac investigations. METHODS: A prospective cohort study was performed on 200 South Asian and 200 Caucasian healthy volunteers aged 18-40 years. All subjects underwent electrocardiography (ECG), echocardiography and anthropometric measurements. Eighty subjects in each cohort underwent 24 hour ambulatory ECG and fifty subjects in each cohort underwent exercise testing. RESULTS: Compared with White Europeans, South Asians were of a smaller height with lower lean body mass and smaller left atrial size. They had reduced P wave dispersion and P wave terminal force in lead V1. South Asians had a lower burden of supraventricular ectopy. They had a higher mean heart rate and South Asian males had lower heart rate variability, suggestive of sympathetic predominance. Exercise capacity was lower in South Asians. CONCLUSIONS: South Asians have differences in left atrial size, P wave indices, burden of supraventricular ectopy, heart rate, heart rate variability and anthropometric measurements. These differences may relate to variations in atrial morphology, atrial electrophysiology and autonomic function and might help to explain why South Asians are less susceptible to developing AF.

Multicentre randomised trial comparing contact force with electrical coupling index in atrial flutter ablation (VERISMART trial).

INTRODUCTION: Electrical coupling index (ECI) and contact force (CF) have been developed to aid lesion formation during catheter ablation. ECI measures tissue impedance and capacitance whilst CF measures direct contact. The aim was to determine whether the presence of catheter / tissue interaction information, such as ECI and CF, reduce time to achieve bidirectional cavotricuspid isthmus block during atrial flutter (AFL) ablation. METHODS: Patients with paroxysmal or persistent AFL were randomised to CF visible (range 5-40g), CF not visible, ECI visible (change of 12%) or ECI not visible. Follow-up occurred at 3 and 6 months and included a 7 day ECG recording. The primary endpoint was time to bidirectional cavotricuspid isthmus block. RESULTS: 114 patients were randomised, 16 were excluded. Time to bidirectional block was significantly shorter when ECI was visible (median 30.0 mins (IQR 31) to median 10.5mins (IQR 12) p 0.023) versus ECI not visible. There was a trend towards a shorter time to bidirectional block when CF was visible. Higher force was applied when CF was visible (median 9.03g (IQR 7.4) vs. 11.3g (5.5) p 0.017). There was no difference in the acute recurrence of conduction between groups. The complication rate was 2%, AFL recurrence was 1.1% and at 6 month follow-up, 12% had atrial fibrillation. CONCLUSION: The use of tissue contact information during AFL ablation was associated with reduced time taken to achieve bidirectional block when ECI was visible. Contact force data improved contact when visible with a trend towards a reduction in the procedural endpoint. ClinicalTrials.gov trial identifier: NCT02490033.