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Sudden cardiac death (SCD) and arrhythmia represent a major worldwide public health problem, accounting for 15–20 % of all deaths. Early resuscitation and defibrillation remains the key to survival, yet its implementation and the access to public defibrillators remains poor, resulting in overall poor survival to patients discharged from hospital. Novel approaches employing smart technology may provide the solution to this dilemma. Though the majority of cases are attributable to coronary artery disease, a thorough search for an underlying cause in cases where the diagnosis is unclear is necessary. This enables better management of arrhythmia recurrence and screening of family members. The majority of cases of SCD occur in patients who do not have traditional risk factors for arrhythmia. New and improved large scale screening tools are required to better predict risk in the wider population who represent the majority of cases of SCD.

BackgroundDespite simpler regimens than vitamin K antagonists (VKAs) for stroke prevention in atrial fibrillation (AF), adherence (taking drugs as prescribed) and persistence (continuation of drugs) to direct oral anticoagulants are suboptimal, yet understudied in electronic health records (EHRs).ObjectiveWe investigated (1) time trends at individual and system levels, and (2) the risk factors for and associations between adherence and persistence.MethodsIn UK primary care EHR (The Health Information Network 2011–2016), we investigated adherence and persistence at 1 year for oral anticoagulants (OACs) in adults with incident AF. Baseline characteristics were analysed by OAC and adherence/persistence status. Risk factors for non-adherence and non-persistence were assessed using Cox and logistic regression. Patterns of adherence and persistence were analysed.ResultsAmong 36 652 individuals with incident AF, cardiovascular comorbidities (median CHA2DS2VASc[Congestive heart failure, Hypertension, Age≥75 years, Diabetes mellitus, Stroke, Vascular disease, Age 65-74 years, Sex category] 3) and polypharmacy (median number of drugs 6) were common. Adherence was 55.2% (95% CI 54.6 to 55.7), 51.2% (95% CI 50.6 to 51.8), 66.5% (95% CI 63.7 to 69.2), 63.1% (95% CI 61.8 to 64.4) and 64.7% (95% CI 63.2 to 66.1) for all OACs, VKA, dabigatran, rivaroxaban and apixaban. One-year persistence was 65.9% (95% CI 65.4 to 66.5), 63.4% (95% CI 62.8 to 64.0), 61.4% (95% CI 58.3 to 64.2), 72.3% (95% CI 70.9 to 73.7) and 78.7% (95% CI 77.1 to 80.1) for all OACs, VKA, dabigatran, rivaroxaban and apixaban. Risk of non-adherence and non-persistence increased over time at individual and system levels. Increasing comorbidity was associated with reduced risk of non-adherence and non-persistence across all OACs. Overall rates of ‘primary non-adherence’ (stopping after first prescription), ‘non-adherent non-persistence’ and ‘persistent adherence’ were 3.5%, 26.5% and 40.2%, differing across OACs.ConclusionsAdherence and persistence to OACs are low at 1 year with heterogeneity across drugs and over time at individual and system levels. Better understanding of contributory factors will inform interventions to improve adherence and persistence across OACs in individuals and populations.

This open-label, randomized trial assessed the safety of uninterrupted dabigatran versus warfarin in 635 patients undergoing ablation for atrial fibrillation. The incidence of major bleeding events was significantly lower with dabigatran than with warfarin (1.6% vs. 6.9%). Catheter ablation of atrial fibrillation is a well-established treatment for symptomatic atrial fibrillation. Guidelines have incorporated catheter ablation of symptomatic atrial fibrillation as a class 1 or 2 indication, depending on previous antiarrhythmic treatment and type of atrial fibrillation. 1 – 3 The most important complications associated with ablation of atrial fibrillation are periprocedural stroke or transient ischemic attack (TIA) and cardiac tamponade. 3 Systemic anticoagulation before, during, and after ablation is important in reducing the risk of periprocedural cerebrovascular events. 3 To minimize these risks, heparin should be administered during ablation to maintain an activated clotting time of more than 300 seconds. However, . . .

Key Points Patients with both atrial fibrillation (AF) and heart failure (HF) present unique diagnostic and management challenges No randomized trial has demonstrated that pharmacological rhythm control confers a reduction in mortality compared with rate control in patients with both AF and HF Studies of highly selected populations of patients with both AF and HF indicate that, in the short term, AF ablation improves symptoms of HF, functional capacity, and left ventricular function Randomized, controlled trials to evaluate hard clinical outcomes of AF ablation in patients with both AF and HF are currently in progress Atrial fibrillation (AF) and heart failure (HF) are evolving epidemics with increasing global prevalence. HF is known to promote AF, but how AF exacerbates or even causes HF is uncertain. In this Review, Ling and colleagues present the current understanding of the epidemiology and pathophysiology of AF–HF, and the roles of pharmacological and interventional therapies in the management of patients with this comorbidity. Atrial fibrillation (AF) and heart failure (HF) are evolving epidemics, together responsible for substantial human suffering and health-care expenditure. Ageing, improved cardiovascular survival, and epidemiological transition form the basis for their increasing global prevalence. Although we now have a clear picture of how HF promotes AF, gaps remain in our knowledge of how AF exacerbates or even causes HF, and how the development of HF affects the outcome of patients with AF. New data regarding HF with preserved ejection fraction and its unique relationship with AF suggest a possible role for AF in its aetiology, possibly as a trigger for ventricular fibrosis. Deciding on optimal treatment strategies for patients with both AF and HF is increasingly difficult, given that results from trials of pharmacological rhythm control are arguably obsolete in the age of catheter ablation. Restoring sinus rhythm by catheter ablation seems successful in the medium term and improves HF symptoms, functional capacity, and left ventricular function. Long-term studies to examine the effect on rates of stroke and death are ongoing. Guidelines continue to evolve to keep pace with this rapidly changing field.

National electronic health records (EHR) are increasingly used for research but identifying disease cases is challenging due to differences in information captured between sources (e.g. primary and secondary care). Our objective was to provide a transparent, reproducible model for integrating these data using atrial fibrillation (AF), a chronic condition diagnosed and managed in multiple ways in different healthcare settings, as a case study. Potentially relevant codes for AF screening, diagnosis, and management were identified in four coding systems: Read (primary care diagnoses and procedures), British National Formulary (BNF; primary care prescriptions), ICD-10 (secondary care diagnoses) and OPCS-4 (secondary care procedures). From these we developed a phenotype algorithm via expert review and analysis of linked EHR data from 1998 to 2010 for a cohort of 2.14 million UK patients aged ≥ 30 years. The cohort was also used to evaluate the phenotype by examining associations between incident AF and known risk factors. The phenotype algorithm incorporated 286 codes: 201 Read, 63 BNF, 18 ICD-10, and four OPCS-4. Incident AF diagnoses were recorded for 72,793 patients, but only 39.6% (N = 28,795) were recorded in primary care and secondary care. An additional 7,468 potential cases were inferred from data on treatment and pre-existing conditions. The proportion of cases identified from each source differed by diagnosis age; inferred diagnoses contributed a greater proportion of younger cases (≤ 60 years), while older patients (≥ 80 years) were mainly diagnosed in SC. Associations of risk factors (hypertension, myocardial infarction, heart failure) with incident AF defined using different EHR sources were comparable in magnitude to those from traditional consented cohorts. A single EHR source is not sufficient to identify all patients, nor will it provide a representative sample. Combining multiple data sources and integrating information on treatment and comorbid conditions can substantially improve case identification.

Background: Left ventricular systolic dysfunction (LVSD) can improve after catheter ablation (CA) in many patients with AF. However, prospective prediction of response can be challenging. The aim of this study was, therefore, to perform a systematic literature review of features associated with improvement in left ventricular ejection fraction (LVEF) in patients with AF and LVSD undergoing first CA. Method: Systematic search of Ovid MEDLINE, Embase and Cochrane Library databases up to 24 January 2024, for studies involving adult patients with LVSD receiving treatment for AF. The focus was on research articles and clinical trials reporting features associated with changes in LVEF following CA. The review followed PRISMA guidelines. Results: A total of 789 unique articles were reviewed and 20 were included in the systematic review. Sixty-nine per cent (range, 54–79%) of included patients met the criteria for responder status, which were based on LVEF improvement (usually an increase in LVEF >10% or to >50% at follow-up). Baseline surrogates of myocardial fibrosis on MRI (R2=−0.67), electroanatomical mapping (R2=−0.93) and biochemical surrogates have shown the strongest association with LVEF change. Left atrium and LV chamber size, diastolic dysfunction ECG-based parameters and a known heart failure aetiology have shown prognostic value independently and in combination. Discussion: Imaging, clinical and ECG-based surrogates of LV fibrosis may be pre-CA markers of LVEF improvement in patients with AF and LVSD. However, the confounding effect of procedural outcomes should be considered. A composite risk stratification tool would have clinical utility in risk stratification and patient selection; however, prospective studies are needed.

We evaluated the effect of adenosine upon mechanisms sustaining persistent AF through analysis of contact electrograms and ECGI mapping. Persistent AF patients undergoing catheter ablation were included. ECGI maps and cycle length (CL) measurements were recorded in the left and right atrial appendages and repeated following boluses of 18 mg of intravenous adenosine. Potential drivers (PDs) were defined as focal or rotational activations completing ≥ 1.5 revolutions. Distribution of PDs was assessed using an 18 segment biatrial model. 46 patients were enrolled. Mean age was 63.4 ± 9.8 years with 33 (72%) being male. There was no significant difference in the number of PDs recorded at baseline compared to adenosine (42.1 ± 15.2 vs 40.4 ± 13.0; p = 0.417), nor in the number of segments harbouring PDs, (13 (11-14) vs 12 (10-14); p = 0.169). There was a significantly higher percentage of PDs that were focal in the adenosine maps (36.2 ± 15.2 vs 32.2 ± 14.4; p < 0.001). There was a significant shortening of CL in the adenosine maps compared to baseline which was more marked in the right atrium than left atrium (176.7 ± 34.7 vs 149.9 ± 27.7 ms; p < 0.001 and 165.6 ± 31.7 vs 148.3 ± 28.4 ms; p = 0.003). Adenosine led to a small but significant shortening of CL which was more marked in the right than left atrium and may relate to shortening of refractory periods rather than an increase in driver burden or distribution. Registered on Clinicaltrials.gov: NCT03394404.

High-frequency ultrasound imaging can provide exquisite visualizations of tissue to guide minimally invasive procedures. Here, we demonstrate that an all-optical ultrasound transducer, through which light guided by optical fibers is used to generate and receive ultrasound, is suitable for real-time invasive medical imaging in vivo . Broad-bandwidth ultrasound generation was achieved through the photoacoustic excitation of a multiwalled carbon nanotube-polydimethylsiloxane composite coating on the distal end of a 300-μm multi-mode optical fiber by a pulsed laser. The interrogation of a high-finesse Fabry–Pérot cavity on a single-mode optical fiber by a wavelength-tunable continuous-wave laser was applied for ultrasound reception. This transducer was integrated within a custom inner transseptal needle (diameter 1.08 mm; length 78 cm) that included a metallic septum to acoustically isolate the two optical fibers. The use of this needle within the beating heart of a pig provided unprecedented real-time views (50 Hz scan rate) of cardiac tissue (depth: 2.5 cm; axial resolution: 64 μm) and revealed the critical anatomical structures required to safely perform a transseptal crossing: the right and left atrial walls, the right atrial appendage, and the limbus fossae ovalis. This new paradigm will allow ultrasound imaging to be integrated into a broad range of minimally invasive devices in different clinical contexts. All-optical ultrasound imaging demonstrated in vivo A fiber optic ultrasound transducer integrated within a surgical needle provides useful images for guiding invasive heart surgery. Malcolm Finlay, Adrien Desjardins, and co-authors at the University College London developed the device and tested it during cardiac transseptal puncture of a swine's heart. They generated real-time views of cardiac tissue with a 50 Hz scan rate and centimeter-scale imaging depths. The scheme involved optical generation of ultrasound with photoacoustic excitation of a multiwalled carbon nanotube–polymer composite coating applied to the distal end of a multimode optical fiber. Ultrasound detection was performed using a second optical fiber with a high-finesse Fabry–Perot cavity. This new paradigm will allow ultrasound imaging to be integrated into a broad range of minimally invasive devices in different clinical contexts.

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. 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. 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. 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.

Collateral tissue injury and the inflammatory process that follows cause vasodilatation, endothelial permeability, and leucocyte recruitment leading to further pulmonary damage, hypoxaemia and cardiovascular stress.3,4 Several recent studies have demonstrated a deleterious impact on the cardiovascular system including acute myocardial injury, acute myocarditis, cardiomyopathies, arrhythmias, sudden cardiac death and cardiac arrest.5,6 Angiotensin-converting enzyme 2 (ACE2) acts as a host receptor, facilitating entry of the SARS-CoV-2 infection into human cells, and is expressed in lung alveolar epithelial, heart, vascular and gastrointestinal tract cells.7,8 Even though it is not certain at this time, ACE2 host receptor involvement may account for the clinical presentations with cardiovascular complications, such as myocarditis, arrhythmia and cardiogenic shock. [...]extremely raised D-dimer levels are found in patients affected with COVID-19, with a substantial proportion affected with venous and arterial thromboembolism.13,15 There is no clear evidence as to whether all patients with the combination of severe COVID-19, new-onset AF and very high D-dimer would benefit from therapeutic anticoagulation irrespective of CHA2DS2VASc score due to the additional risk of thromboembolism associated with COVID-19. [...]either dose reduction or monitoring of plasma levels is essential to minimise the risk of bleeding.16–18 There is a small amount of emerging literature on the incidence of ventricular arrhythmias. COVID-19 can also cause diarrhoea, malabsorption, acute kidney injury and electrolyte imbalance, which may pose a risk of ventricular and atrial arrhythmias.21–23 In addition, there is an increased risk of MI during the acute phase in patients with cardiac comorbidities, secondary to supply/demand imbalance, plaque rupture, severe hypoxia causing myocyte necrosis or arterial embolism due to hypercoagulable state, which can trigger malignant ventricular arrhythmias.24–26 Risk of Sudden Cardiac Death There are no specific data on patients with channelopathies or inherited cardiomyopathies and COVID-19.