Publications
212 results found
Mann I, Coyle C, Qureshi N, et al., 2019, Evaluation of a new algorithm for tracking activation during atrial fibrillation using multipolar catheters in humans, JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Vol: 30, Pages: 1464-1474, ISSN: 1045-3873
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- Citations: 7
Qureshi N, Kim S, Cantwell C, et al., 2019, Voltage during atrial fibrillation is superior to voltage during sinus rhythm in localizing areas of delayed enhancement on magnetic resonance imaging: An assessment of the posterior left atrium in patients with persistent atrial fibrillation, Heart Rhythm, Vol: 16, Pages: 1357-1367, ISSN: 1547-5271
BackgroundBipolar electrogram voltage during sinus rhythm (VSR) has been used as a surrogate for atrial fibrosis in guiding catheter ablation of persistent AF, but the fixed rate and wavefront characteristics present during sinus rhythm may not accurately reflect underlying functional vulnerabilities responsible for AF maintenance.ObjectivesWe hypothesized that given adequate temporal sampling, the spatial distribution of mean AF voltage (VmAF) should better correlate with delayed-enhancement MRI (MRI-DE) detected atrial fibrosis than VSR.MethodsAF was mapped (8s) during index ablation for persistent AF (20 patients) using a 20-pole catheter (660±28 points/map). Following cardioversion, VSR was mapped (557±326 points/map). Electroanatomic and MRI-DE maps were co-registered in 14 patients.Results(i) The time course of VmAF was assessed from 1-40 AF-cycles (∼8s) at 1113 locations. VmAF stabilized with sampling >4s (mean voltage error=0.05mV). (ii) Paired point analysis of VmAF from segments acquired 30s apart (3,667-sites, 15-patients), showed strong correlation (r=0.95, p<0.001). (iii) Delayed-enhancement (DE) was assessed across the posterior left atrial (LA) wall, occupying 33±13%. VmAF distributions (median[IQR]) were 0.21[0.14-0.35]mV in DE vs. 0.52[0.34-0.77]mV in Non-DE regions. VSR distributions were 1.34[0.65-2.48]mV in DE vs. 2.37[1.27-3.97]mV in Non-DE. A VmAF threshold of 0.35mV yielded sensitivity/specificity 75%/79% in detecting MRI-DE, compared with 63%/67% for VSR (1.8mV threshold).ConclusionThe correlation between low-voltage and posterior LA MRI-DE is significantly improved when acquired during AF vs. sinus rhythm. With adequate sampling, mean AF voltage is a reproducible marker reflecting the functional response to the underlying persistent AF substrate.
Shun-Shin MJ, Leong KMW, Ng FS, et al., 2019, Ventricular conduction stability test: a method to identify and quantify changes in whole heart activation patterns during physiological stress, EP-Europace, Vol: 21, Pages: 1422-1431, ISSN: 1099-5129
AIMS: Abnormal rate adaptation of the action potential is proarrhythmic but is difficult to measure with current electro-anatomical mapping techniques. We developed a method to rapidly quantify spatial discordance in whole heart activation in response to rate cycle length changes. We test the hypothesis that patients with underlying channelopathies or history of aborted sudden cardiac death (SCD) have a reduced capacity to maintain uniform activation following exercise. METHODS AND RESULTS: Electrocardiographical imaging (ECGI) reconstructs >1200 electrograms (EGMs) over the ventricles from a single beat, providing epicardial whole heart activation maps. Thirty-one individuals [11 SCD survivors; 10 Brugada syndrome (BrS) without SCD; and 10 controls] with structurally normal hearts underwent ECGI vest recordings following exercise treadmill. For each patient, we calculated the relative change in EGM local activation times (LATs) between a baseline and post-exertion phase using custom written software. A ventricular conduction stability (V-CoS) score calculated to indicate the percentage of ventricle that showed no significant change in relative LAT (<10 ms). A lower score reflected greater conduction heterogeneity. Mean variability (standard deviation) of V-CoS score over 10 consecutive beats was small (0.9 ± 0.5%), with good inter-operator reproducibility of V-CoS scores. Sudden cardiac death survivors, compared to BrS and controls, had the lowest V-CoS scores post-exertion (P = 0.011) but were no different at baseline (P = 0.50). CONCLUSION: We present a method to rapidly quantify changes in global activation which provides a measure of conduction heterogeneity and proof of concept by demonstrating SCD survivors have a reduced capacity to maintain uniform activation following exercise.
ShunShin MJ, Miyazawa AA, Keene D, et al., 2019, How to deliver personalized Cardiac Resynchronization Therapy through the precise measurement of the acute hemodynamic response: insights from the iSpot trial, Journal of Cardiovascular Electrophysiology, Vol: 30, Pages: 1610-1619, ISSN: 1045-3873
IntroductionNew pacing technologies offer greater choice of left ventricular pacing sites and greater personalization of cardiac resynchronization therapy (CRT). The effects on cardiac function of novel pacing configurations are often compared using multi‐beat averages of acute hemodynamic measurements. In this analysis of the iSpot trial we explore whether this is sufficient.MethodsThe iSpot trial was an international, prospective, acute hemodynamic trial that assessed seven CRT configurations: Standard CRT, Multispot (posterolateral vein), and Multivein (anterior and posterior vein) pacing. Invasive and non‐invasive blood pressure, and LV dP/dtmax were recorded. Eight beats were recorded before and after an alternation from AAI to the tested pacing configuration and vice‐versa. Eight alternations were performed for each configuration at each of the 5 AV delays.Results25 patients underwent the full protocol of 8 alternations. Only 4 (16%) patients had a statistically significant >3mmHg improvement over conventional CRT configuration (posterolateral vein, distal electrode). However, if only one alternation was analyzed (standard multi‐beat averaging protocol), 15 (60%) patients falsely appeared to have a superior non‐conventional configuration. Responses to pacing were significantly correlated between the different hemodynamic measures: invasive SBP versus non‐invasive SBP r=0.82 (p<0.001); invasive SBP versus LV dP/dt r=0.57, r2=0.32 (p<0.001).ConclusionsCurrent standard multi‐beat acquisition protocols are unfortunately unable to prevent false impressions of optimality arising in individual patients. Personalization processes need to include distinct repeated transitions to the tested pacing configuration in addition to averaging multiple beats. The need is not only during research stages, but also during clinical implementation.
Luther V, Agarwal S, Chow A, et al., 2019, Ripple-AT study: A multicenter and randomized study comparing 3d mapping techniques during atrial tachycardia ablations, Circulation: Arrhythmia and Electrophysiology, Vol: 12, Pages: 1-13, ISSN: 1941-3084
BACKGROUND: Ripple mapping (RM) is an alternative approach to activation mapping of atrial tachycardia (AT) that avoids electrogram annotation. We tested whether RM is superior to conventional annotation based local activation time (LAT) mapping for AT diagnosis in a randomized and multicenter study. METHODS: Patients with AT were randomized to either RM or LAT mapping using the CARTO3v4 CONFIDENSE system. Operators determined the diagnosis using the assigned 3D mapping arm alone, before being permitted a single confirmatory entrainment manuever if needed. A planned ablation lesion set was defined. The primary end point was AT termination with delivery of the planned ablation lesion set. The inability to terminate AT with this first lesion set, the use of more than one entrainment manuever, or the need to crossover to the other mapping arm was defined as failure to achieve the primary end point. RESULTS: One hundred five patients from 7 centers were recruited with 22 patients excluded due to premature AT termination, noninducibility or left atrial appendage thrombus. Eighty-three patients (pts; RM=42, LAT=41) completed mapping and ablation within the 2 groups of similar characteristics (RM versus LAT: prior ablation or cardiac surgery n=35 [83%] versus n=35 [85%], P=0.80). The primary end point occurred in 38/42 pts (90%) in the RM group and 29/41pts (71%) in the LAT group (P=0.045). This was achieved without any entrainment in 31/42 pts (74%) with RM and 18/41 pts (44%) with LAT (P=0.01). Of those patients who failed to achieve the primary end point, AT termination was achieved in 9/12 pts (75%) in the LAT group following crossover to RM with entrainment, but 0/4 pts (0%) in the RM group crossing over to LAT mapping with entrainment (P=0.04). CONCLUSIONS: RM is superior to LAT mapping on the CARTO3v4 CONFIDENSE system in guiding ablation to terminate AT with the first lesion set and with reduced entrainment to assist diagnosis. CLINICAL TRIALS REGISTRATION: https:/
Sau A, Howard J, Al-Aidarous S, et al., 2019, Meta-analysis of randomized controlled trials of atrial fibrillation ablation with pulmonary vein isolation versus without, JACC: Clinical Electrophysiology, Vol: 5, Pages: 968-976, ISSN: 2405-5018
ObjectivesThis meta-analysis examined the ability of pulmonary vein isolation (PVI) to prevent atrial fibrillation in randomized controlled trials (RCTs) in which the patients not receiving PVI nevertheless underwent a procedure.BackgroundPVI is a commonly used procedure for the treatment of atrial fibrillation (AF), and its efficacy has usually been judged against therapy with anti-arrhythmic drugs in open-label trials. There have been several RCTs of AF ablation in which both arms received an ablation, but the difference between the treatment arms was inclusion or omission of PVI. These trials of an ablation strategy with PVI versus an ablation strategy without PVI may provide a more rigorous method for evaluating the efficacy of PVI.MethodsMedline and Cochrane databases were searched for RCTs comparing ablation including PVI with ablation excluding PVI. The primary efficacy endpoint was freedom from atrial fibrillation (AF) and atrial tachycardia at 12 months. A random-effects meta-analysis was performed using the restricted maximum likelihood estimator.ResultsOverall, 6 studies (610 patients) met inclusion criteria. AF recurrence was significantly lower with an ablation including PVI than an ablation without PVI (RR: 0.54; 95% confidence interval [CI]: 0.33 to 0.89; p 1⁄4 0.0147; I2 1⁄4 79.7%). Neither the type of AF (p 1⁄4 0.48) nor the type of non-PVI ablation (p 1⁄4 0.21) was a significant moderator of the effect size. In 3 trials the non-PVI ablation procedure was performed in both arms, whereas PVI was performed in only 1 arm. In these studies, AF recurrence was significantly lower when PVI was included (RR: 0.32; 95% CI: 0.14 to 0.73; p 1⁄4 0.007, I2 78%ConclusionIn RCTs where both arms received an ablation, and therefore an expectation amongst patients and doctors of benefit, being randomized to PVI had a striking effect, reducing AF recurrence by a half.
Whinnett Z, Sohaib SMA, Mason M, et al., 2019, Multicenter randomized controlled crossover trial comparing hemodynamic optimization against echocardiographic optimization of AV and VV delay of Cardiac Resynchronization Therapy: The BRAVO Trial, JACC: Cardiovascular Imaging, Vol: 12, Pages: 1407-1416, ISSN: 1936-878X
ObjectivesBRAVO (British Randomized Controlled Trial of AV and VV Optimization) is a multicenter, randomized, crossover, noninferiority trial comparing echocardiographic optimization of atrioventricular (AV) and interventricular delay with a noninvasive blood pressure method.BackgroundCardiac resynchronization therapy including AV delay optimization confers clinical benefit, but the optimization requires time and expertise to perform.MethodsThis study randomized patients to echocardiographic optimization or hemodynamic optimization using multiple-replicate beat-by-beat noninvasive blood pressure at baseline; after 6 months, participants were crossed over to the other optimization arm of the trial. The primary outcome was exercise capacity, quantified as peak exercise oxygen uptake. Secondary outcome measures were echocardiographic left ventricular (LV) remodeling, quality-of-life scores, and N-terminal pro–B-type natriuretic peptide.ResultsA total of 401 patients were enrolled, the median age was 69 years, 78% of patients were men, and the New York Heart Association functional class was II in 84% and III in 16%. The primary endpoint, peak oxygen uptake, met the criterion for noninferiority (pnoninferiority = 0.0001), with no significant difference between the hemodynamically optimized arm and echocardiographically optimized arm of the trial (mean difference 0.1 ml/kg/min). Secondary endpoints for noninferiority were also met for symptoms (mean difference in Minnesota score 1; pnoninferiority = 0.002) and hormonal changes (mean change in N-terminal pro–B-type natriuretic peptide -10 pg/ml; pnoninferiority = 0.002). There was no significant difference in LV size (mean change in LV systolic dimension 1 mm; pnoninferiority < 0.001; LV diastolic dimension 0 mm; pnoninferiority <0.001). In 30% of patients the AV delay identified as optimal was more than 20 ms from the nominal setting of 120 ms.ConclusionsOptimization of cardiac resynchronization therapy
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.
Sau A, Howard J, Al-Aidarous S, et al., 2019, Efficacy of pulmonary vein isolation in preventing atrial fibrillation: meta-analysis of randomized controlled trials with an invasive control procedure, Annual Conference of the British-Cardiovascular-Society (BCS) - Digital Health Revolution, Publisher: BMJ Publishing Group, Pages: A31-A31, ISSN: 1355-6037
Introduction Pulmonary vein isolation (PVI) is a commonly used element in treatment of atrial fibrillation (AF) but has never been tested in an intentionally placebo (sham) controlled trial. Nevertheless there have been several randomized controlled trials (RCTs) in which both arms receive an ablation procedure but the only difference between treatment arms is inclusion or omission of PVI. As long as both doctor and patient have reason to believe that the procedures in both arms are effective, such RCTs could be an effective proxy for placebo controlled trials.Methods Medline and Cochrane databases were searched for RCTs comparing catheter ablation including PVI with left atrial ablation excluding PVI. The primary efficacy endpoint was freedom from AF/atrial tachycardia at 6 months. A random-effects meta-analysis was performed using the restricted maximum likelihood (REML) estimator.Results Overall, seven studies (909 patients) met inclusion criteria. Across the 7 trials, mean age was 57.3, 70.2% of participants were male. In four trials (352 patients) the non-PVI ablation procedure was performed in both arms, while PVI was performed in only one arm. The non-PVI ablation procedures were complex fractionated atrial electrogram ablation (2 studies), ganglionated plexi ablation (1 study) and focal impulse and rotor modulation (1 study). In these, AF recurrence was significantly lower when PVI was included (RR 0.48, 95% CI 0.26-0.90, I2 64.4%)In an analysis of all 7 studies, AF recurrence was significantly lower in ablation with an ablation strategy including PVI compared to one without PVI (Figure 1, RR 0.67, 95% CI 0.53-0.85, p = 0.001, I2 0%). Neither type of AF (persistent vs. paroxysmal, p=0.43) nor type of non-PVI ablation (p=0.35) were significant moderators of the effect size. A sensitivity analysis omitting each study in turn showed similar results to the primary analysis. In particular exclusion of the retracted OASIS trial showed results similar to the primar
Sharp A, Sohaib A, Shun-Shin M, et al., 2019, Improving haemodynamic optimization of cardiac resynchronization therapy for heart failure., Physiol Meas
Objective Optimization of cardiac resynchronization therapy using non-invasive haemodynamic parameters, produces reliable optima when performed at high atrial paced heart rates. Here we investigate whether this is a result of increased heart rate or atrial pacing itself. Approach 43 patients with cardiac resynchronization therapy underwent haemodynamic optimization of AV delay using non-invasive beat-to-beat systolic blood pressure in three states: rest (atrial-sensing, 66±11bpm), slow atrial pacing (73±12bpm), and fast atrial pacing (94±10bpm). A 20-patient subset underwent a fourth optimization, during exercise (80±11bpm). Main results Intraclass correlation coefficient (ICC, quantifying information content mean ±SE) was 0.20±0.02 for resting sensed optimization, 0.45± 0.03 for slow atrial pacing (p<0.0001 versus rest-sensed), and 0.52±0.03 for fast atrial pacing (p=0.12 versus slow-paced). 78% of the increase in ICC, from sinus rhythm to fast atrial pacing, is achieved by simply atrially pacing just above sinus rate. Atrial pacing increased signal (blood pressure difference between best and worst AV delay) from 6.5±0.6 mmHg at rest to 13.3±1.1 mmHg during slow atrial pacing (p<0.0001) and 17.2±1.3 mmHg during fast atrial pacing (p=0.003 versus slow atrial pacing). Atrial pacing reduced noise (average SD of systolic blood pressure measurements) from 4.9±0.4mmHg at rest to 4.1±0.3mmHg during slow atrial pacing (p=0.28). At faster atrial pacing the noise was 4.6±0.3mmHg (p=0.69 versus slow-paced, p=0.90 versus rest-sensed). In the exercise subgroup ICC was 0.14±0.02 (p=0.97 versus rest-sensed). Significance Atrial pacing, rather than the increase in heart rate, contributes to ~80% of the observed in
Lewis AJM, Foley P, Whinnett Z, et al., 2019, His bundle pacing: a new strategy for physiological ventricular activation, Journal of the American Heart Association : Cardiovascular and Cerebrovascular Disease, Vol: 8, Pages: e010972-e010972, ISSN: 2047-9980
The specialized fibers of the His‐Purkinje system are essential for the maintenance of the coordinated, synchronous ventricular contraction via endocardial to epicardial and apical to basal electrical activation. The right ventricle has been the most commonly used site to deliver artificial pacemaker stimuli since the 1950s, although pacing from both right ventricular (RV) apical and septal positions causes ventricular dyssynchrony, which is in turn associated with deleterious consequences including impaired myocardial perfusion,1 mitral and tricuspid regurgitation,2 an increased risk of atrial fibrillation, and systolic contractile dysfunction.3 As a result, the risk of hospitalization for heart failure was strikingly increased in patients receiving a higher proportion of ventricular pacing in the DAVID (Dual Chamber and VVI Implantable Defibrillator) trial 4, 5 and MOST (Mode Selection Trial)6 alongside an increased risk of ventricular tachycardia/fibrillation.7 Current guidelines8 and pacemaker algorithms9 therefore promote the minimization of right ventricular pacing wherever possible; however, excessive restriction of RV pacing with, for example, long atrioventricular delays impairs atrioventricular synchrony, increasing the risk of atrioventricular block at higher atrial rates and predisposing to mitral regurgitation. Furthermore, current strategies for the reduction of RV pacing have not improved clinical outcomes.10
Burri H, Keene D, Whinnett Z, et al., 2019, Device Programming for His Bundle Pacing, CIRCULATION-ARRHYTHMIA AND ELECTROPHYSIOLOGY, Vol: 12, ISSN: 1941-3149
Leong KMW, Ng FS, Jones S, et al., 2019, Prevalence of spontaneous type I ECG pattern, syncope, and other risk markers in sudden cardiac arrest survivors with Brugada syndrome, PACE - Pacing and Clinical Electrophysiology, Vol: 42, Pages: 257-264, ISSN: 0147-8389
IntroductionA spontaneous type I electrocardiogram (ECG) pattern and/or unheralded syncope are conventionally used as risk markers for primary prevention of sudden cardiac arrest/death (SCA/SCD) in Brugada syndrome (BrS). In this study, we determine the prevalence of conventional and newer markers of risk in those with and without previous aborted SCA events.MethodsAll patients with BrS were identified at our institute. History of symptoms was obtained from medical tests or from interviews. Other markers of risk were also obtained, such as presence of (1) spontaneous type I pattern, (2) fractionated QRS (fQRS), (3) early repolarization (ER) pattern, (4) late potentials on signal‐averaged ECG (SAECG), and (5) response to programmed electrical stimulation.ResultsIn 133 patients with Bars, 10 (7%) patients (mean age = 39 ± 11 years; nine males) were identified with a previous ventricular fibrillation/ventricular tachycardia episode (n = 8) or requiring cardio‐pulmonary resuscitation (n = 2). None of these patients had a prior history of syncope before their SCA event. Only two (20%) patients reported a history of palpitations or dizziness. None had apneic breathing and three (30%) patients had a family history of SCA. From their ECGs, a spontaneous pattern was only found in one (10%) of these patients. Further, 10% of patients had fQRS, 17% had late potentials on SAECG, 20% had deep S waves in lead I, and 10% had an ER pattern in the peripheral leads. No significant differences were observed in the non‐SCA group.ConclusionThe majority of BrS patients with previous aborted SCA events did not have a spontaneous type I and/or prior history of syncope. Conventional and newer markers of risk appear to only have limited ability to predict SCA.
Pucci N, Kwan CH, Yates DC, et al., 2019, Effect of Fields Generated Through Wireless Power Transfer on Implantable Biomedical Devices, IEEE MTT-S Wireless Power Transfer Conference (WPTC) / IEEE PELS Workshop on Emerging Technologies - Wireless Power (WoW) / Wireless Power Week Conference, Publisher: IEEE, Pages: 160-164
Gyimah D, Arnold AD, Whinnett ZI, 2019, The Scientific Rationale of Artificial Pacing, HEART OF THE MATTER: KEY CONCEPTS IN CARDIOVASCULAR SCIENCE, Editors: Terracciano, Guymer, Publisher: SPRINGER INTERNATIONAL PUBLISHING AG, Pages: 105-119, ISBN: 978-3-030-24218-3
Reddy RK, Cullen BN, Arnold AD, et al., 2019, Cell-Based Tachyarrhythmias and Bradyarrhythmias, HEART OF THE MATTER: KEY CONCEPTS IN CARDIOVASCULAR SCIENCE, Editors: Terracciano, Guymer, Publisher: SPRINGER INTERNATIONAL PUBLISHING AG, Pages: 87-103, ISBN: 978-3-030-24218-3
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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.
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
Kyriacou A, Rajkumar CA, Pabari P, et al., 2018, Distinct impacts of heart rate and right atrial-pacing on left atrial mechanical activation and optimal AV delay in CRT, Pacing and Clinical Electrophysiology, Vol: 41, Pages: 959-966, ISSN: 0147-8389
AbstractBackgroundControversy exists regarding how atrial activation mode and heart rate affect optimal AV delay in cardiac resynchronisation therapy. We studied these questions using high‐reproducibility haemodynamic and echocardiographic measurements.Methods20 patients were hemodynamically optimized using non‐invasive beat‐to‐beat blood pressure at rest (62±11 bpm), during exercise (80±6 bpm) and at 3 atrially‐paced rates: 5, 25 and 45 bpm above rest, denoted Apaced,r+5, Apaced,r+25 and Apaced,r+45 respectively. Left atrial myocardial motion and transmitral flow were timed echocardiographically.ResultsDuring atrial‐sensing, raising heart rate shortened optimal AV delay by 25±6 ms (p < 0.001). During atrial pacing, raising heart rate from Apaced,r+5 to Apaced,r+25 shortened it by 16±6 ms; Apaced,r+45 shortened it 17±6 ms further (p < 0.001).In comparison to atrial‐sensed activation, atrial pacing lengthened optimal AV delay by 76±6 ms (p < 0.0001) at rest, and at ∼20 bpm faster, by 85±7 ms (p < 0.0001), 9±4 ms more (p = 0.017). Mechanically, atrial pacing delayed left atrial contraction by 63±5 ms at rest and by 73±5 ms (i.e. by 10±5 ms more, p < 0.05) at ∼20 bpm faster.Raising atrial rate by exercise advanced left atrial contraction by 7±2 ms (p = 0.001). Raising it by atrial pacing did not (p = 0.2).ConclusionsHemodynamic optimal AV delay shortens with elevation of heart rate. It lengthens on switching from atrial‐sensed to atrial‐paced at the same rate, and echocardiography shows this sensed‐paced difference in optima results from a sensed‐paced difference in atrial electromechanical delay.The reason for the widening of the sensed‐paced difference in AV optimum may be physiological stimuli (e.g. adrenergic drive) advancing left atrial contraction during exercise but not with fast atrial pacing.
Shun-Shin M, Arnold A, Keene D, et al., 2018, The magnitude of LV activation time reduction with His bundle pacing over biventricular pacing in LBBB predicts the incremental improvement in acute cardiac function, European-Society-of-Cardiology Congress, Publisher: OXFORD UNIV PRESS, Pages: 385-385, ISSN: 0195-668X
Arnold AD, Shun-Shin MJ, Sohaib A, et al., 2018, Automated, high-precision echocardiographic and haemodynamic assessment of the effect of atrioventricular interval during right ventricular pacing in obstructed hypertrophic cardiomyopathy, European-Society-of-Cardiology Congress, Publisher: OXFORD UNIV PRESS, Pages: 729-729, ISSN: 0195-668X
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.
Jackson T, Lenarczyk R, Sterlinski M, et al., 2018, Left ventricular scar and the acute hemodynamic effects of multivein and multipolar pacing in cardiac resynchronization, IJC Heart and Vasculature, Vol: 19, Pages: 14-19, ISSN: 2352-9067
BackgroundWe sought to determine whether presence, amount and distribution of scar impacts the degree of acute hemodynamic response (AHR) with multisite pacing.Multi-vein pacing (MVP) or multipolar pacing (MPP) with a multi-electrode left ventricular (LV) lead may offer benefits over conventional biventricular pacing in patients with myocardial scar.MethodsIn this multi-center study left bundle branch block patients underwent an hemodynamic pacing study measuring LV dP/dtmax. Patients had cardiac magnetic resonance scar imaging to assess the effect of scar presence, amount and distribution on AHR.Results24 patients (QRS 171 ± 20 ms) completed the study (83% male). An ischemic etiology was present in 58% and the mean scar volume was 6.0 ± 7.0%. Overall discounting scar, MPP and MVP showed no significant AHR increase compared to an optimized “best BiV” (BestBiV) site. In a minority of patients (6/24) receiver-operator characteristic analysis of scar volume (cut off 8.48%) predicted a small AHR improvement with MPP (sensitivity 83%, specificity 94%) but not MVP. Patients with scar volume > 8.48% had a MPP-BestBiV of 3 ± 6.3% vs. −6.4 ± 7.7% for those below the cutoff. There was a significant correlation between the difference in AHR and scar volume for MPP-BestBiV (R = 0.49, p = 0.02) but not MVP-BestBiV(R = 0.111, p = 0.62). The multielectrode lead positioned in scar predicted MPP AHR improvement (p = 0.04).ConclusionsMultisite pacing with MPP and MVP shows no AHR benefit in all-comers compared to optimized BestBiV pacing. There was a minority of patients with significant scar volume in relation to the LV site that exhibited a small AHR improvement with MPP.
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
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
Luther V, Qureshi N, Lim PB, et al., 2018, Isthmus sites identified by Ripple Mapping are usually anatomically stable: A novel method to guide atrial substrate ablation?, Journal of Cardiovascular Electrophysiology, Vol: 29, Pages: 404-411, ISSN: 1045-3873
BACKGROUND: Postablation reentrant ATs depend upon conducting isthmuses bordered by scar. Bipolar voltage maps highlight scar as sites of low voltage, but the voltage amplitude of an electrogram depends upon the myocardial activation sequence. Furthermore, a voltage threshold that defines atrial scar is unknown. We used Ripple Mapping (RM) to test whether these isthmuses were anatomically fixed between different activation vectors and atrial rates. METHODS: We studied post-AF ablation ATs where >1 rhythm was mapped. Multipolar catheters were used with CARTO Confidense for high-density mapping. RM visualized the pattern of activation, and the voltage threshold below which no activation was seen. Isthmuses were characterized at this threshold between maps for each patient. RESULTS: Ten patients were studied (Map 1 was AT1; Map 2: sinus 1/10, LA paced 2/10, AT2 with reverse CS activation 3/10; AT2 CL difference 50 ± 30 ms). Point density was similar between maps (Map 1: 2,589 ± 1,330; Map 2: 2,214 ± 1,384; P = 0.31). RM activation threshold was 0.16 ± 0.08 mV. Thirty-one isthmuses were identified in Map 1 (median 3 per map; width 27 ± 15 mm; 7 anterior; 6 roof; 8 mitral; 9 septal; 1 posterior). Importantly, 7 of 31 (23%) isthmuses were unexpectedly identified within regions without prior ablation. AT1 was treated following ablation of 11/31 (35%) isthmuses. Of the remaining 20 isthmuses, 14 of 16 isthmuses (88%) were consistent between the two maps (four were inadequately mapped). Wavefront collision caused variation in low voltage distribution in 2 of 16 (12%). CONCLUSIONS: The distribution of isthmuses and nonconducting tissue within the ablated left atrium, as defined by RM, appear concordant between rhythms. This could guide a substrate ablative approach.
Leong KMW, chow J-J, Ng FS, et al., 2017, Comparison of the Prognostic Usefulness of the European Society of Cardiology and American Heart Association/American College of Cardiology Foundation Risk Stratification Systems for Patients With Hypertrophic Cardiomyopathy, American Journal of Cardiology, Vol: 121, Pages: 349-355, ISSN: 0002-9149
Implantable cardio-defibrillators (ICDs) have proven benefit in preventing sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HC), making risk stratification essential. Data on the predictive accuracy on the European Society of Cardiology (ESC) risk scoring system has been conflicting. We independently evaluated the ESC risk scoring system in our cohort of HC patients from a large tertiary centre and compared this to previous guidance by the American College of Cardiology Foundation and Heart Association (ACCF/AHA). Risk factor profiles, 5-year SCD risk estimates and ICD recommendations as defined by the ACCF/AHA and ESC guidelines, were retrospectively ascertained for 288 HC patients with and without SCD or equivalent events at our centre. In the SCD group (n=14), a significantly higher proportion of patients would not have met the criteria for an ICD implant using the ESC scoring algorithm than ACCF/AHA guidance (43%vs7%, p=0.029). In those without SCD events (n=274), a larger proportion of individuals not requiring an ICD was identified using the ESC risk score model compared to the ACCF/AHA model (82%vs57%; p<0.0001). Based on risk stratification criteria alone, 5 more individuals with a previously aborted SCD event would not have received an ICD with the ESC risk model than the ACCF/AHA risk model. In conclusion, we found that the current ESC scoring system potentially leaves more high-risk patients unprotected from sudden death in our cohort of patients.
Leong KMW, Ng FS, Roney C, et al., 2017, Repolarization abnormalities unmasked with exercise in sudden cardiac death survivors with structurally normal hearts, Journal of Cardiovascular Electrophysiology, Vol: 29, Pages: 115-126, ISSN: 1045-3873
BACKGROUND: Models of cardiac arrhythmogenesis predict that non-uniformity in repolarization and/or depolarization promotes ventricular fibrillation and is modulated by autonomic tone, but this is difficult to evaluate in patients. We hypothesize that such spatial heterogeneities would be detected by non-invasive ECG imaging (ECGi) in sudden cardiac death (SCD) survivors with structurally normal hearts under physiological stress. METHODS: ECGi was applied to 11 SCD survivors, 10 low-risk Brugada Syndrome patients (BrS) and 10 controls undergoing exercise treadmill testing. ECGi provides whole heart activation maps and > 1200 unipolar electrograms over the ventricular surface from which global dispersion of activation recovery interval (ARI) and regional delay in conduction were determined. These were used as surrogates for spatial heterogeneities in repolarization and depolarization. Surface ECG markers of dispersion (QT and Tpeak-end intervals) were also calculated for all patients for comparison. RESULTS: Following exertion, the SCD group demonstrated the largest increase in ARI dispersion compared to BrS and control groups (13±8 ms vs 4±7 ms vs 4±5 ms; p = 0.009), with baseline dispersion being similar in all groups. In comparison, surface ECG markers of dispersion of repolarisation were unable to discriminate between the groups at baseline or following exertion. Spatial heterogeneities in conduction were also present following exercise but were not significantly different between SCD survivors and the other groups. CONCLUSION: Increased dispersion of repolarization is apparent during physiological stress in SCD survivors and is detectable with ECGi but not with standard ECG parameters. The electrophysiological substrate revealed by ECGi could be the basis of alternative risk-stratification techniques. This article is protected by copyright. All rights reserved.
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