Publications
19 results found
Howard JP, Arnold AD, Ahmad Y, 2020, Bias, heterogeneity, and uncertainty in meta-analysis., Eur Heart J
Kaura A, Arnold AD, Vasileios P, et al., 2020, Prognostic significance of troponin level in 3,121 patients presenting with atrial fibrillation (The NIHR Health Informatics Collaborative TROP-AF study), Journal of the American Heart Association, Vol: 9, ISSN: 2047-9980
Background-—Patients presenting with atrial fibrillation (AF) often undergo a blood test to measure troponin, but interpretation of theresult is impeded by uncertainty about its clinical importance. We investigated the relationship between troponin level, coronaryangiography, and all-cause mortality in real-world patients presenting with AF.Methods and Results-—We used National Institute of Health Research Health Informatics Collaborative data to identify patients admitted between 2010 and 2017 at 5 tertiary centers in the United Kingdom with a primary diagnosis of AF. Peak troponin results 7 were scaled as multiples of the upper limit of normal. A total of 3121 patients were included in the analysis. Over a median followup of 1462 (interquartile range, 929–1975) days, there were 586 deaths (18.8%). The adjusted hazard ratio for mortality associatedwith a positive troponin (value above upper limit of normal) was 1.20 (95% CI, 1.01–1.43; P<0.05). Higher troponin levels were associated with higher risk of mortality, reaching a maximum hazard ratio of 2.6 (95% CI, 1.9–3.4) at 250 multiples of the upper limit of normal. There was an exponential relationship between higher troponin levels and increased odds of coronary angiography.The mortality risk was 36% lower in patients undergoing coronary angiography than in those who did not (adjusted hazard ratio, 0.61; 95% CI, 0.42–0.89; P=0.01).Conclusions-—Increased troponin was associated with increased risk of mortality in patients presenting with AF. The lower hazard ratio in patients undergoing invasive management raises the possibility that the clinical importance of troponin release in AF may be mediated by coronary artery disease, which may be responsive to revascularization.
Ahmad Y, Mortality after drug-eluting stents versus coronary artery bypass grafting for left main coronary artery disease: A meta-analysis of randomized controlled trials, European Heart Journal, ISSN: 0195-668X
Aims The optimal method of revascularization for patients with left main coronary artery disease (LMCAD) is controversial. Coronary artery bypass graft surgery (CABG) has traditionally been considered the gold standard therapy, and recent randomized trials comparing CABG with percutaneous coronary intervention (PCI) with drug-eluting stents (DES) have reported conflicting outcomes. We, therefore, performed a systematic review and updated meta-analysis comparing CABG to PCI with DES for the treatment of LMCAD.Methods and results We systematically identified all randomized trials comparing PCI with DES vs. CABG in patients with LMCAD. The primary efficacy endpoint was all-cause mortality. Secondary endpoints included cardiac death, myocardial infarction (MI), stroke, and unplanned revascularization. All analyses were by intention-to-treat. There were five eligible trials in which 4612 patients were randomized. The weighted mean follow-up duration was 67.1 months. There were no significant differences between PCI and CABG for the risk of all-cause mortality [relative risk (RR) 1.03, 95% confidence interval (CI) 0.81–1.32; P = 0.779] or cardiac death (RR 1.03, 95% CI 0.79–1.34; P = 0.817). There were also no significant differences in the risk of stroke (RR 0.74, 95% CI 0.35–1.50; P = 0.400) or MI (RR 1.22, 95% CI 0.96–1.56; P = 0.110). Percutaneous coronary intervention was associated with an increased risk of unplanned revascularization (RR 1.73, 95% CI 1.49–2.02; P < 0.001).Conclusion The totality of randomized clinical trial evidence demonstrated similar long-term mortality after PCI with DES compared with CABG in patients with LMCAD. Nor were there significant differences in cardiac death, stroke, or MI between PCI and CABG. Unplanned revascularization procedures were less common after CABG compared with PCI. These findings may inform clinica
Arnold A, Howard J, Chiew K, et al., 2019, Right ventricular pacing for hypertrophic obstructive cardiomyopathy: meta-analysis and meta-regression of clinical trials, European Heart Journal - Quality of Care and Clinical Outcomes, Vol: 5, Pages: 321-333, ISSN: 2058-5225
AimsRight ventricular pacing for left ventricular outflow tract gradient reduction in hypertrophic obstructive cardiomyopathy remains controversial. We undertook a meta-analysis for echocardiographic and functional outcomes.Methods and resultsThirty-four studies comprising 1135 patients met eligibility criteria. In the four blinded randomized controlled trials (RCTs), pacing reduced gradient by 35% [95% confidence interval (CI) 23.2–46.9, P < 0.0001], but there was only a trend towards improved New York Heart Association (NYHA) class [odds ratio (OR) 1.82, CI 0.96–3.44; P = 0.066]. The unblinded observational studies reported a 54.3% (CI 44.1–64.6, P < 0.0001) reduction in gradient, which was a 18.6% greater reduction than the RCTs (P = 0.0351 for difference between study designs). Observational studies reported an effect on unblinded NYHA class at an OR of 8.39 (CI 4.39–16.04, P < 0.0001), 450% larger than the OR in RCTs (P = 0.0042 for difference between study designs). Across all studies, the gradient progressively decreased at longer follow durations, by 5.2% per month (CI 2.5–7.9, P = 0.0001).ConclusionRight ventricular pacing reduces gradient in blinded RCTs. There is a non-significant trend to reduction in NYHA class. The bias in assessment of NYHA class in observational studies appears to be more than twice as large as any genuine treatment effect.
Keene D, Arnold A, Jastrzębski M, et al., 2019, His bundle pacing, learning curve, procedure characteristics, safety, and feasibility: Insights from a large international observational study, Journal of Cardiovascular Electrophysiology, Vol: 30, Pages: 1984-1993, ISSN: 1045-3873
BackgroundHis‐bundle pacing (HBP) provides physiological ventricular activation. Observational studies have demonstrated the techniques feasibility however, data has come from a limited number of centres.ObjectivesWe set out to explore contemporary global practise in HBP focusing on learning curve, procedural characteristics and outcomes.MethodsThis is a retrospective, multi‐centre observational study of patients undergoing attempted HBP at seven centres. Pacing indication, fluoroscopy time, HBP thresholds and lead re‐intervention and deactivation rates were recorded. Where centres had systematically recorded implant success rates from the outset, these were collated.Results529 patients underwent attempted HBP during the study period (2014‐19) with mean follow‐up of 217±303 days. Most implants were for bradycardia indications.In the three centres with systematic collation of all attempts, overall implant success rate was 81% which improved to 87% after completion of 40 cases.All seven centres reported data on successful implants. Mean fluoroscopy time was 11.7±12.0 minutes, His‐bundle capture threshold at implant was 1.4±0.9V at 0.8±0.3 ms and was 1.3±1.2V at 0.9±0.2ms at last device check.HBP lead re‐intervention or deactivation (for lead displacement or rise in threshold) occurred in 7.5% of successful implants.There was evidence of a learning curve: fluoroscopy time and HBP capture threshold reduced with greater experience, plateauing after ~30‐50 cases.ConclusionWe found that it is feasible to establish a successful HBP program, using the currently available implantation tools. For physicians who are experienced at pacemaker implantation the steepest part of the learning curve appears to be over the first 30‐50 cases.
Pucci N, Kwan CH, Yates DC, et al., 2019, Effect of Fields Generated Through Wireless Power Transfer on Implantable Biomedical Devices, Pages: 160-164
© 2019 IEEE. This paper assesses the safety of pacemakers when exposed to the electromagnetic (EM) field generated by high frequency inductive power transfer (HF-IPT) systems. It includes both simulation and experimental results, showing temperature variations to ensure conformity with the EN standards, changes in detected lead impedance and determining whether EM field strength can affect the operating mode of the device. This is the first time the interaction between 6.78MHz, 100W HF-IPT systems and pacemaker devices was tested up to distances of 5 cm to 10 cm, Temporary decrease of detected lead's impedance and interruption of communications are the most relevant effects recorded through in-vitro tests. No permanent alteration of the device's operation was recorded, indicating good early stage evidence of safety for pacemaker users in proximity of this new emerging technology.
Keene D, Shun-Shin M, Arnold A, et al., 2019, Quantification of Electromechanical Coupling to Prevent Inappropriate Implantable Cardioverter-Defibrillator Shocks, JACC: Clinical Electrophysiology, Vol: 5, Pages: 705-715, ISSN: 2405-500X
Objective To test specialised processing of laser Doppler signals for discriminating ventricular fibrillation(VF) from common causes of inappropriate therapies.BackgroundInappropriate ICD therapies remain a clinically important problem associated with morbidity and mortality.Tissue perfusion biomarkers, to assist automated diagnosis of VF, suffer the vulnerability of sometimes mistaking artefact and random noise for perfusion, which could lead to shocks being inappropriately withheld. MethodsWe developed a novel processing algorithm that combines electrogram data and laser Doppler perfusion monitoring, as a method for assessing circulatory status. We recruited 50 patients undergoing VF induction during ICD implantation. We recorded non-invasive laser Doppler and continuous electrograms, during both sinus-rhythm and VF. For each patient we simulated two additional scenarios that may lead to inappropriate shocks: ventricular-lead fracture and T-wave oversensing. We analysed the laser Doppler using three methods for reducing noise: (i)Running Mean, (ii)Oscillatory Height, (iii)a novel quantification of Electro-Mechanical coupling which gates laser Doppler against electrograms. We additionally tested the algorithm during exercise induced sinus tachycardia.ResultsOnly the Electro-mechanical coupling algorithm found a clear perfusion cut-off between sinus rhythm and VF (sensitivity and specificity 100%). Sensitivity and specificity remained 100% during simulated lead fracture and electrogram oversensing. (AUC: Running Mean 0.91, Oscillatory Height 0.86, Electro-Mechanical Coupling 1.00). Sinus tachycardia did not cause false positives.ConclusionsQuantifying the coupling between electrical and perfusion signals increases reliability of discrimination between VF and artefacts that ICDs may interpret as VF. Incorporating such methods into future ICDs may safely permit reductions of inappropriate shocks.
Howard J, Fisher L, Shun-Shin M, et al., 2019, Cardiac rhythm device identification using neural networks, JACC: Clinical Electrophysiology, Vol: 5, Pages: 576-586, ISSN: 2405-5018
BackgroundMedical staff often need to determine the model of a pacemaker or defibrillator (cardiac rhythm devices) quickly and accurately. Current approaches involve comparing a device’s X-ray appearance with a manual flow chart. We aimed to see whether a neural network could be trained to perform this task more accurately.Methods and ResultsWe extracted X-ray images of 1676 devices, comprising 45 models from 5 manufacturers. We developed a convolutional neural network to classify the images, using a training set of 1451 images. The testing set was a further 225 images, consisting of 5 examples of each model. We compared the network’s ability to identify the manufacturer of a device with those of cardiologists using a published flow-chart.The neural network was 99.6% (95% CI 97.5 to 100) accurate in identifying the manufacturer of a device from an X-ray, and 96.4% (95% CI 93.1 to 98.5) accurate in identifying the model group. Amongst 5 cardiologists using the flow-chart, median manufacturer accuracy was 72.0% (range 62.2% to 88.9%), and model group identification was not possible. The network was significantly superior to all of the cardiologists in identifying the manufacturer (p < 0.0001 against the median human; p < 0.0001 against the best human).ConclusionsA neural network can accurately identify the manufacturer and even model group of a cardiac rhythm device from an X-ray, and exceeds human performance. This system may speed up the diagnosis and treatment of patients with cardiac rhythm devices and it is publicly accessible online.
Arnold AD, Vijayaraman P, 2019, His bundle pacing: The road ahead: An editorial commentary on “Updates on His Bundle Pacing: The Road More Traveled Lately” by Fatima M Ezzeddine MD & Gopi Dandamudi MD FHRS, Trends in Cardiovascular Medicine, ISSN: 1050-1738
Arnold A, Shun-Shin M, Keene D, et al., 2018, His resynchronization versus biventricular pacing in patients with heart failure and left bundle branch block, Journal of the American College of Cardiology, Vol: 72, Pages: 3112-3122, ISSN: 0735-1097
Background His bundle pacing is a new method for delivering cardiac resynchronization therapy (CRT).Objectives The authors performed a head-to-head, high-precision, acute crossover comparison between His bundle pacing and conventional biventricular CRT, measuring effects on ventricular activation and acute hemodynamic function.Methods Patients with heart failure and left bundle branch block referred for conventional biventricular CRT were recruited. Using noninvasive epicardial electrocardiographic imaging, the authors identified patients in whom His bundle pacing shortened left ventricular activation time. In these patients, the authors compared the hemodynamic effects of His bundle pacing against biventricular pacing using a high-multiple repeated alternation protocol to minimize the effect of noise, as well as comparing effects on ventricular activation.Results In 18 of 23 patients, left ventricular activation time was significantly shortened by His bundle pacing. Seventeen patients had a complete electromechanical dataset. In them, His bundle pacing was more effective at delivering ventricular resynchronization than biventricular pacing: greater reduction in QRS duration (−18.6 ms; 95% confidence interval [CI]: −31.6 to −5.7 ms; p = 0.007), left ventricular activation time (−26 ms; 95% CI: −41 to −21 ms; p = 0.002), and left ventricular dyssynchrony index (−11.2 ms; 95% CI: −16.8 to −5.6 ms; p < 0.001). His bundle pacing also produced a greater acute hemodynamic response (4.6 mm Hg; 95% CI: 0.2 to 9.1 mm Hg; p = 0.04). The incremental activation time reduction with His bundle pacing over biventricular pacing correlated with the incremental hemodynamic improvement with His bundle pacing over biventricular pacing (R = 0.70; p = 0.04).Conclusions His resynchronization delivers better ventricular resynchronization, and greater improvement in hemodynamic parameters, than biventricular pacing.
Ahmad Y, Howard J, Arnold A, et al., 2018, Reply: Assessing the quality of evidence supporting patent foramen ovale closure over medical therapy after cryptogenic stroke, European Heart Journal, Vol: 39, Pages: 3620-3620, ISSN: 1522-9645
This commentary refers to ‘Assessing the quality of evidence supporting patent foramen ovale closure over medical therapy after cryptogenic stroke’, by W.F. McIntyre et al., doi:10.1093/eurheartj/ehy496.
Keene D, Arnold A, Shun-Shin MJ, et al., 2018, Rationale and design of the randomized multicentre His Optimized Pacing Evaluated for Heart Failure (HOPE-HF) trial, ESC Heart Failure, Vol: 5, Pages: 965-976, ISSN: 2055-5822
AIMS: In patients with heart failure and a pathologically prolonged PR interval, left ventricular (LV) filling can be improved by shortening atrioventricular delay using His-bundle pacing. His-bundle pacing delivers physiological ventricular activation and has been shown to improve acute haemodynamic function in this group of patients. In the HOPE-HF (His Optimized Pacing Evaluated for Heart Failure) trial, we are investigating whether these acute haemodynamic improvements translate into improvements in exercise capacity and heart failure symptoms. METHODS AND RESULTS: This multicentre, double-blind, randomized, crossover study aims to randomize 160 patients with PR prolongation (≥200 ms), LV impairment (EF ≤ 40%), and either narrow QRS (≤140 ms) or right bundle branch block. All patients receive a cardiac device with leads positioned in the right atrium and the His bundle. Eligible patients also receive a defibrillator lead. Those not eligible for implantable cardioverter defibrillator have a backup pacing lead positioned in an LV branch of the coronary sinus. Patients are allocated in random order to 6 months of (i) haemodynamically optimized dual chamber His-bundle pacing and (ii) backup pacing only, using the non-His ventricular lead. The primary endpoint is change in exercise capacity assessed by peak oxygen uptake. Secondary endpoints include change in ejection fraction, quality of life scores, B-type natriuretic peptide, daily patient activity levels, and safety and feasibility assessments of His-bundle pacing. CONCLUSIONS: Hope-HF aims to determine whether correcting PR prolongation in patients with heart failure and narrow QRS or right bundle branch block using haemodynamically optimized dual chamber His-bundle pacing improves exercise capacity and symptoms. We aim to complete recruitment by the end of 2018 and report in 2020.
Sharma PS, Naperkowski A, Bauch TD, et al., 2018, Permanent His Bundle Pacing for Cardiac Resynchronization Therapy in Patients With Heart Failure and Right Bundle Branch Block, CIRCULATION-ARRHYTHMIA AND ELECTROPHYSIOLOGY, Vol: 11, ISSN: 1941-3149
Murray MI, Arnold A, Younis M, et al., 2018, Cryoballoon versus radiofrequency ablation for paroxysmal atrial fibrillation: a meta-analysis of randomized controlled trials, Clinical Research in Cardiology, Vol: 107, Pages: 658-669, ISSN: 1861-0684
Objective: The aim of this study was to evaluate the clinical efficacy and safety outcomes of the treatment with cryoballoon (CB) compared to the treatment with traditional irrigated radiofrequency ablation (RF) for pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (pAF) and refractory to antiarrhythmic drug therapy (AAD). Design: We conducted a systemic review to find and include more than two randomized controlled trials (RCTs) with at least 20 patients in each of the CB and RF groups. Thereafter, we performed a meta-analysis to compare the treatment with CB and RF in primary outcomes including 1 year free from AF, complications and re-ablation procedures. Additionally, we evaluated procedure time and fluoroscopy duration in both groups. Risk of bias in the individual studies and across studies was assessed using Cochrane methods. Data extraction and synthesis: Two reviewers extracted study data and assessed risk of bias. Primary outcome data were extracted from the time point 1 year after the procedure. The random-effects model was used to calculate the odds ratio with 95% confidence interval. Data sources: Data sources utilized were PubMed and CENTRAL databases up to 16 June 2016. Eligibility criteria for selecting studies: Included studies were RCTs in adults with pAF and refractory to AAD in which CB therapy, including 1st and 2nd generation CB, was compared to the traditional irrigated RF therapy. Clinical outcomes assessed in each RCT were 1 year AF-free survival, complication rates, re-ablations, fluoroscopy time and procedure time. Results: The systematic review identified four randomized controlled trials that reported on comparative clinical outcomes involving 1284 patients. Our meta-analysis demonstrated that CB ablation had a non-significant higher success rate than RF therapy (OR 1.13; 95% CI 0.72–1.77). However, our study showed a relatively higher rate of complications in the CB group (OR 1.20; 95% CI 0.58–2.
Arnold A, Ali N, Keene D, et al., 2018, Authors' Reply: His Bundle Pacing: A New Frontier in the Treatment of Heart Failure, ARRHYTHMIA & ELECTROPHYSIOLOGY REVIEW, Vol: 7, Pages: 218-219, ISSN: 2050-3369
Ali N, Keene D, Arnold A, et al., 2018, His bundle pacing: a new frontier in the treatment of heart failure, Arrhythmia & electrophysiology review, Vol: 7, Pages: 103-110, ISSN: 2050-3369
Biventricular pacing has revolutionised the treatment of heart failure in patients with sinus rhythm and left bundle branch block; however, left ventricular-lead placement is not always technically possible. Furthermore, biventricular pacing does not fully normalise ventricular activation and, therefore, the ventricular resynchronisation is imperfect. Right ventricular pacing for bradycardia may cause or worsen heart failure in some patients by causing dyssynchronous ventricular activation. His bundle pacing activates the ventricles via the native His-Purkinje system, resulting in true physiological pacing, and, therefore, is a promising alternate site for pacing in bradycardia and traditional CRT indications in cases where it can overcome left bundle branch block. Furthermore, it may open up new indications for pacing therapy in heart failure, such as targeting patients with PR prolongation, but a narrow QRS duration. In this article we explore the physiology, technology and potential roles of His bundle pacing in the prevention and treatment of heart failure.
Arnold AD, Shun-Shin MJ, Keene D, et al., 2018, His bundle pacing can overcome left bundle branch block to produce greater improvements in acute haemodynamic function and ventricular activation than biventricular pacing, Heart Rhythm Society Scientific Sessions, Publisher: Elsevier, Pages: S40-S41, ISSN: 1547-5271
Ahmad Y, Howard J, Arnold A, et al., 2018, Patent foramen ovale closure versus medical therapy for cryptogenic stroke: a meta-analysis of randomised controlled trials, European Heart Journal, Vol: 39, Pages: 1638-1649, ISSN: 1522-9645
BackgroundThe efficacy of patent foramen ovale (PFO) closure for cryptogenic stroke has been controversial. We undertook a meta-analysis of randomised controlled trials (RCTs) comparing device closure with medical therapy to prevent recurrent stroke for patients with PFO.Methods and ResultsWe systematically identified all RCTs comparing device closure to medical therapy for cryptogenic stroke in patients with PFO. The primary efficacy endpoint was recurrent stroke, analysed on an intention-to-treat basis. The primary safety endpoint was new onset atrial fibrillation (AF). 5 studies (3440 patients) were included. 1829 patients were randomised to device closure and 1611 to medical therapy. Across all patients, PFO closure was superior to medical therapy for prevention of stroke (HR 0.32, 95% CI 0.13 to 0.82, p=0.018, I2 = 73.4%). The risk of AF was significantly increased with device closure (RR 4.54, 95% CI 2.17 to 9.48, p<0.001, heterogeneity I2 = 22.9%). In patients with large shunts, PFO closure was associated with a significant reduction in stroke (HR 0.33, 95% CI 0.16 to 0.72, p=0.005), whilst there was no significant reduction in stroke in patients with a small shunt (HR 0.90, 95% CI 0.50 to 1.60, p=0.712). There was no effect from the presence or absence of an atrial septal aneurysm on outcomes (p=0.994).ConclusionIn selected patients with cryptogenic stroke, PFO closure is superior to medical therapy for the prevention of further stroke: this is particularly true for patients with moderate-to-large shunts. Guidelines should be updated to reflect this.
Ahmad Y, Demir O, Rajkumar CA, et al., 2018, Optimal antiplatelet strategy after transcatheter aortic valve implantation: a meta-analysis, Open Heart, Vol: 5, ISSN: 2053-3624
Objective International guidelines recommend the use of dual antiplatelet therapy (DAPT) after transcatheter aortic valve implantation (TAVI). The recommended duration of DAPT varies between guidelines. In this two-part study, we (1) performed a structured survey of 45 TAVI centres from around the world to determine if there is consensus among clinicians regarding antiplatelet therapy after TAVI; and then (2) performed a systematic review of all suitable studies (randomised controlled trials (RCTs) and registries) to determine if aspirin monotherapy can be used instead of DAPT.Methods A structured electronic survey regarding antiplatelet use after TAVI was completed by 45 TAVI centres across Europe, Australasia and the USA. A systematic review of TAVI RCTs and registries was then performed comparing DAPT duration and incidence of stroke, bleeding and death. A variance weighted least squared metaregression was then performed to determine the relationship of antiplatelet therapy and adverse events.Results 82.2% of centres routinely used DAPT after TAVI. Median duration was 3 months. 13.3% based their practice on guidelines. 11 781 patients (26 studies) were eligible for the metaregression. There was no benefit of DAPT over aspirin monotherapy for stroke (P=0.49), death (P=0.72) or bleeding (P=0.91).Discussion Aspirin monotherapy appears to be as safe and effective as DAPT after TAVI.
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