51
|
Williams SE, O'Neill L, Roney CH, Julia J, Metzner A, Reißmann B, Mukherjee RK, Sim I, Whitaker J, Wright M, Niederer S, Sohns C, O'Neill M. Left atrial effective conducting size predicts atrial fibrillation vulnerability in persistent but not paroxysmal atrial fibrillation. J Cardiovasc Electrophysiol 2019; 30:1416-1427. [PMID: 31111557 PMCID: PMC6746623 DOI: 10.1111/jce.13990] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/01/2019] [Accepted: 05/17/2019] [Indexed: 11/30/2022]
Abstract
Background The multiple wavelets and functional re‐entry hypotheses are mechanistic theories to explain atrial fibrillation (AF). If valid, a chamber's ability to support AF should depend upon the left atrial size, conduction velocity (CV), and refractoriness. Measurement of these parameters could provide a new therapeutic target for AF. We investigated the relationship between left atrial effective conducting size (LAECS), a function of area, CV and refractoriness, and AF vulnerability in patients undergoing AF ablation. Methods and Results Activation mapping was performed in patients with paroxysmal (n = 21) and persistent AF (n = 18) undergoing pulmonary vein isolation. Parameters used for calculating LAECS were: (a) left atrial body area (A); (b) effective refractory period (ERP); and (c) total activation time (T). Global CV was estimated as √A/T. Effective atrial conducting size was calculated as LAECS=A/(CV×ERP). Post ablation, AF inducibility testing was performed. The critical LAECS required for multiple wavelet termination was determined from computational modeling. LAECS was greater in patients with persistent vs paroxysmal AF (4.4 ± 2.0 cm vs 3.2 ± 1.4 cm; P = .049). AF was inducible in 14/39 patients. LAECS was greater in AF‐inducible patients (4.4 ± 1.8 cm vs 3.3 ± 1.7 cm; P = .035, respectively). The difference in LAECS between inducible and noninducible patients was significant in patients with persistent (P = .0046) but not paroxysmal AF (P = .6359). Computational modeling confirmed that LAECS > 4 cm was required for continuation of AF. Conclusions LAECS measured post ablation was associated with AF inducibility in patients with persistent, but not paroxysmal AF. These data support a role for this method in electrical substrate assessment in AF patients.
Collapse
|
52
|
Sim I, Razeghi O, Karim R, Chubb H, Whitaker J, O'Neill L, Mukherjee RK, Roney CH, Razavi R, Wright M, O'Neill M, Niederer S, Williams SE. Reproducibility of Atrial Fibrosis Assessment Using CMR Imaging and an Open Source Platform. JACC Cardiovasc Imaging 2019; 12:2076-2077. [PMID: 31202748 DOI: 10.1016/j.jcmg.2019.03.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 02/20/2019] [Accepted: 03/16/2019] [Indexed: 11/26/2022]
|
53
|
O’Hare D, O’Neill L, O’Neill MD, Williams SE. Letter to the editor—pREVEntion and regReSsive Effect of weight-loss and risk factor modification on Atrial Fibrillation: the REVERSE-AF study. Europace 2019; 21:990. [DOI: 10.1093/europace/euz023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
54
|
Roney CH, Whitaker J, Sim I, O'Neill L, Mukherjee RK, Razeghi O, Vigmond EJ, Wright M, O'Neill MD, Williams SE, Niederer SA. A technique for measuring anisotropy in atrial conduction to estimate conduction velocity and atrial fibre direction. Comput Biol Med 2019; 104:278-290. [PMID: 30415767 PMCID: PMC6506689 DOI: 10.1016/j.compbiomed.2018.10.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/17/2018] [Accepted: 10/17/2018] [Indexed: 01/04/2023]
Abstract
BACKGROUND Cardiac conduction properties exhibit large variability, and affect patient-specific arrhythmia mechanisms. However, it is challenging to clinically measure conduction velocity (CV), anisotropy and fibre direction. Our aim is to develop a technique to estimate conduction anisotropy and fibre direction from clinically available electrical recordings. METHODS We developed and validated automated algorithms for estimating cardiac CV anisotropy, from any distribution of recording locations on the atrial surface. The first algorithm is for elliptical wavefront fitting to a single activation map (method 1), which works well close to the pacing location, but decreases in accuracy further from the pacing location (due to spatial heterogeneity in the conductivity and fibre fields). As such, we developed a second methodology for measuring local conduction anisotropy, using data from two or three activation maps (method 2: ellipse fitting to wavefront propagation velocity vectors from multiple activation maps). RESULTS Ellipse fitting to CV vectors from two activation maps (method 2) leads to an improved estimation of longitudinal and transverse CV compared to method 1, but fibre direction estimation is still relatively poor. Using three activation maps with method 2 provides accurate estimation, with approximately 70% of atrial fibres estimated within 20∘. We applied the technique to clinical activation maps to demonstrate the presence of heterogeneous conduction anisotropy, and then tested the effects of this conduction anisotropy on predicted arrhythmia dynamics using computational simulation. CONCLUSIONS We have developed novel algorithms for calculating CV and measuring the direction dependency of atrial activation to estimate atrial fibre direction, without the need for specialised pacing protocols, using clinically available electrical recordings.
Collapse
|
55
|
Gould J, Klis M, Porter B, Sieniewicz BJ, Sidhu BS, Claridge S, Williams SE, Shetty A, O’Neill M, Gill J, Rinaldi CA. Transvenous lead extraction in patients with cardiac resynchronization therapy devices is not associated with increased 30-day mortality. Europace 2018; 21:928-936. [DOI: 10.1093/europace/euy290] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/14/2018] [Indexed: 12/30/2022] Open
|
56
|
Williams SE, Harrison JL, Chubb H, Whitaker J, Kiedrowicz R, Rinaldi CA, Cooklin M, Wright M, Niederer S, O'Neill MD. Local activation time sampling density for atrial tachycardia contact mapping: how much is enough? Europace 2018; 20:e11-e20. [PMID: 28379525 PMCID: PMC5834039 DOI: 10.1093/europace/eux037] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 02/12/2017] [Indexed: 11/25/2022] Open
Abstract
Aims Local activation time (LAT) mapping forms the cornerstone of atrial tachycardia diagnosis. Although anatomic and positional accuracy of electroanatomic mapping (EAM) systems have been validated, the effect of electrode sampling density on LAT map reconstruction is not known. Here, we study the effect of chamber geometry and activation complexity on optimal LAT sampling density using a combined in silico and in vivo approach. Methods and results In vivo 21 atrial tachycardia maps were studied in three groups: (1) focal activation, (2) macro-re-entry, and (3) localized re-entry. In silico activation was simulated on a 4×4cm atrial monolayer, sampled randomly at 0.25–10 points/cm2 and used to re-interpolate LAT maps. Activation patterns were studied in the geometrically simple porcine right atrium (RA) and complex human left atrium (LA). Activation complexity was introduced into the porcine RA by incomplete inter-caval linear ablation. In all cases, optimal sampling density was defined as the highest density resulting in minimal further error reduction in the re-interpolated maps. Optimal sampling densities for LA tachycardias were 0.67 ± 0.17 points/cm2 (focal activation), 1.05 ± 0.32 points/cm2 (macro-re-entry) and 1.23 ± 0.26 points/cm2 (localized re-entry), P = 0.0031. Increasing activation complexity was associated with increased optimal sampling density both in silico (focal activation 1.09 ± 0.14 points/cm2; re-entry 1.44 ± 0.49 points/cm2; spiral-wave 1.50 ± 0.34 points/cm2, P < 0.0001) and in vivo (porcine RA pre-ablation 0.45 ± 0.13 vs. post-ablation 0.78 ± 0.17 points/cm2, P = 0.0008). Increasing chamber geometry was also associated with increased optimal sampling density (0.61 ± 0.22 points/cm2 vs. 1.0 ± 0.34 points/cm2, P = 0.0015). Conclusion Optimal sampling densities can be identified to maximize diagnostic yield of LAT maps. Greater sampling density is required to correctly reveal complex activation and represent activation across complex geometries. Overall, the optimal sampling density for LAT map interpolation defined in this study was ∼1.0–1.5 points/cm2.
Collapse
|
57
|
Gould J, Klis M, Porter B, Sidhu BS, Sieniewicz BJ, Williams SE, Teall T, Webb J, Shetty A, Gill J, Rinaldi CA. Predictors of mortality and outcomes in transvenous lead extraction for systemic and local infection cohorts. Pacing Clin Electrophysiol 2018; 42:73-84. [DOI: 10.1111/pace.13542] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 10/16/2018] [Accepted: 10/30/2018] [Indexed: 11/26/2022]
|
58
|
Chubb H, Lal K, Kiedrowicz R, Karim R, Williams SE, Harrison J, Whitaker J, Wright M, Razavi R, O’Neill M. The value of ablation parameter indices for predicting mature atrial scar formation in humans: An in vivo assessment using cardiac magnetic resonance imaging. J Cardiovasc Electrophysiol 2018; 30:67-77. [DOI: 10.1111/jce.13754] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 09/05/2018] [Accepted: 09/13/2018] [Indexed: 12/26/2022]
|
59
|
Mukherjee RK, Williams SE, Niederer SA, O'Neill MD. Atrial Fibrillation Ablation in Patients with Heart Failure: One Size Does Not Fit All. Arrhythm Electrophysiol Rev 2018; 7:84-90. [PMID: 29967679 DOI: 10.15420/aer.2018.11.3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Atrial fibrillation (AF) is common in patients with heart failure and is associated with poorer clinical outcomes compared with patients with heart failure alone. Recent evidence has challenged previous treatment paradigms in which rate control was considered equivalent to rhythm control in this population. Catheter ablation has emerged as a safe and effective treatment strategy in selected patients and overcomes the issues of limited efficacy and drug toxicities associated with pharmacological rhythm control. Numerous studies have explored the benefits of catheter ablation in patients with heart failure, but these have included heterogeneous patient cohorts and variable ablation strategies. This state-of-the-art review explores the evidence from these trials and examines the need for tailored, patient-specific strategies for AF ablation in patients with heart failure.
Collapse
|
60
|
Williams SE, Linton NWF, Niederer S, O'Neill MD. Simultaneous display of multiple three-dimensional electrophysiological datasets (dot mapping). Europace 2018; 19:1743-1749. [PMID: 27702855 PMCID: PMC5834094 DOI: 10.1093/europace/euw190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/30/2016] [Indexed: 11/14/2022] Open
Abstract
Aims Complex ablation procedures are supported by accurate representation of an increasing variety of electrophysiological and imaging data within electroanatomic mapping systems (EMS). This study aims to develop a novel method for representing multiple complementary datasets on a single cardiac chamber model. Validation of the system and its application to both atrial and ventricular arrhythmias is examined. Methods and results Dot mapping was conceived to display multiple datasets by utilizing quantitative surface shading to represent one dataset and finely spaced dots to represent others. Dot positions are randomized within triangular (surface meshes) or tetrahedral (volumetric meshes) simplices making the approach directly transferrable to contemporary EMS. Test data representing uniform electrical activation (n = 10) and focal scarring (n = 10) were used to test dot mapping data perception accuracy. User experience of dot mapping with atrial and ventricular clinical data is evaluated. Dot mapping ensured constant screen dot density for regions of uniform dataset values, regardless of user manipulation of the cardiac chamber. Perception accuracy of dot mapping was equivalent to colour mapping for both propagation direction (1.5 ± 1.8 vs. 4.8 ± 5.3°, P = 0.24) and focal source localization (1.1 ± 0.7 vs. 1.4 ± 0.5 mm, P = 0.88). User acceptance testing revealed equivalent diagnostic accuracy and display fidelity when compared with colour mapping. Conclusion Dot mapping provides the unique ability to display multiple datasets from multiple sources on a single cardiac chamber model. The visual combination of multiple datasets may facilitate interpretation of complex electrophysiological and imaging data.
Collapse
|
61
|
Chubb H, Aziz S, Karim R, Sohns C, Razeghi O, Williams SE, Whitaker J, Harrison J, Chiribiri A, Schaeffter T, Wright M, O’Neill M, Razavi R. Optimization of late gadolinium enhancement cardiovascular magnetic resonance imaging of post-ablation atrial scar: a cross-over study. J Cardiovasc Magn Reson 2018; 20:30. [PMID: 29720202 PMCID: PMC5932811 DOI: 10.1186/s12968-018-0449-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 04/04/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Cardiovascular magnetic resonance (CMR) imaging may be used to visualize post-ablation atrial scar (PAAS), and three-dimensional late gadolinium enhancement (3D LGE) is the most widely employed technique for imaging of chronic scar. Detection of PAAS provides a unique non-invasive insight into the effects of the ablation and may help guide further ablation procedures. However, there is evidence that PAAS is often not detected by CMR, implying a significant sensitivity problem, and imaging parameters vary between leading centres. Therefore, there is a need to establish the optimal imaging parameters to detect PAAS. METHODS Forty subjects undergoing their first pulmonary vein isolation procedure for AF had detailed CMR assessment of atrial scar: one scan pre-ablation, and two scans post-ablation at 3 months (separated by 48 h). Each scan session included ECG- and respiratory-navigated 3D LGE acquisition at 10, 20 and 30 min post injection of a gadolinium-based contrast agent (GBCA). The first post-procedural scan was performed on a 1.5 T scanner with standard acquisition parameters, including double dose (0.2 mmol/kg) Gadovist and 4 mm slice thickness. Ten patients subsequently underwent identical scan as controls, and the other 30 underwent imaging with a reduced, single, dose GBCA (n = 10), half slice thickness (n = 10) or on a 3 T scanner (n = 10). Apparent signal-to-noise (aSNR), contrast-to-noise (aCNR) and imaging quality (Likert Scale, 3 independent observers) were assessed. PAAS location and area (%PAAS scar) were assessed following manual segmentation. Atrial shells with standardised %PAAS at each timepoint were then compared to ablation lesion locations to assess quality of scar delineation. RESULTS A total of 271 3D acquisitions (out of maximum 280, 96.7%) were acquired. Likert scale of imaging quality had high interobserver and intraobserver intraclass correlation coefficients (0.89 and 0.96 respectively), and showed lower overall imaging quality on 3 T and at half-slice thickness. aCNR, and quality of scar delineation increased significantly with time. aCNR was higher with reduced, single, dose of GBCA (p = 0.005). CONCLUSION 3D LGE CMR atrial scar imaging, as assessed qualitatively and quantitatively, improves with time from GBCA administration, with some indices continuing to improve from 20 to 30 min. Imaging should be performed at least 20 min post-GBCA injection, and a single dose of contrast should be considered. TRIAL REGISTRATION Trial registry- United Kingdom National Research Ethics Service 08/H0802/68 - 30th September 2008.
Collapse
|
62
|
Whitaker J, Fish J, Harrison J, Chubb H, Williams SE, Fastl T, Corrado C, Van Zaen J, Gibbs J, O’Neill L, Mukherjee R, Rittey D, Thorsten J, Donskoy E, Sohal M, Rajani R, Niederer S, Wright M, O’Neill MD. Lesion Index–Guided Ablation Facilitates Continuous, Transmural, and Durable Lesions in a Porcine Recovery Model. Circ Arrhythm Electrophysiol 2018; 11:e005892. [DOI: 10.1161/circep.117.005892] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 02/22/2018] [Indexed: 11/16/2022]
|
63
|
O'Neill M, Williams SE. Measure What Can Be Measured: Multimodal Examination of the Atrial Fibrillation Substrate. JACC Clin Electrophysiol 2018; 4:69-71. [PMID: 29600787 DOI: 10.1016/j.jacep.2017.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 11/16/2017] [Indexed: 12/01/2022]
|
64
|
Chubb H, Karim R, Roujol S, Nuñez-Garcia M, Williams SE, Whitaker J, Harrison J, Butakoff C, Camara O, Chiribiri A, Schaeffter T, Wright M, O’Neill M, Razavi R. The reproducibility of late gadolinium enhancement cardiovascular magnetic resonance imaging of post-ablation atrial scar: a cross-over study. J Cardiovasc Magn Reson 2018; 20:21. [PMID: 29554919 PMCID: PMC5858144 DOI: 10.1186/s12968-018-0438-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 02/19/2018] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Cardiovascular magnetic resonance (CMR) imaging has been used to visualise post-ablation atrial scar (PAAS), generally employing a three-dimensional (3D) late gadolinium enhancement (LGE) technique. However the reproducibility of PAAS imaging has not been determined. This cross-over study is the first to investigate the reproducibility of the technique, crucial for both future research design and clinical implementation. METHODS Forty subjects undergoing first time ablation for atrial fibrillation (AF) had detailed CMR assessment of PAAS. Following baseline pre-ablation scan, two scans (separated by 48 h) were performed at three months post-ablation. Each scan session included 3D LGE acquisition at 10, 20 and 30 min post administration of gadolinium-based contrast agent (GBCA). Subjects were allocated at second scan post-ablation to identical imaging parameters ('Repro', n = 10), 3 T scanner ('3 T', n = 10), half-slice thickness ('Half-slice', n = 10) or half GBCA dose ('Half-gad', n = 10). PAAS was compared to baseline scar and then reproducibility was assessed for two measures of thresholded scar (% left atrial (LA) occupied by PAAS (%LA PAAS) and Pulmonary Vein Encirclement (PVE)), and then four measures of non-thresholded scar (point-by-point assessment of PAAS, four normalisation methods). Thresholded measures of PAAS were evaluated against procedural outcome (AF recurrence). RESULTS A total of 271 3D acquisitions (out of maximum 280, 96.7%) were acquired. At 20 and 30 min, inter-scan reproducibility was good to excellent (coefficient of variation at 20 min and 30 min: %LA PAAS 0.41 and 0.20; PVE 0.13 and 0.04 respectively for 'Repro' group). Changes in imaging parameters, especially reduced GBCA dose, reduced inter-scan reproducibility, but for most measures remained good to excellent (ICC for %LA PAAS 0.454-0.825, PVE 0.618-0.809 at 30 min). For non-thresholded scar, highest reproducibility was observed using blood pool z-score normalisation technique: inter-scan ICC 0.759 (absolute agreement, 'Repro' group). There was no significant relationship between indices of PAAS and AF recurrence. CONCLUSION PAAS imaging is a reproducible finding. Imaging should be performed at least 20 min post-GBCA injection, and a blood pool z-score should be considered for normalisation of signal intensities. The clinical implications of these findings remain to be established in the absence of a simple correlation with arrhythmia outcome. TRIAL REGISTRATION United Kingdom National Research Ethics Service 08/H0802/68 - 30th September 2008.
Collapse
|
65
|
O'Neill M, Williams SE. How should contact force be used for catheter ablation of atrial fibrillation? J Cardiovasc Electrophysiol 2018; 29:393-394. [PMID: 29377405 DOI: 10.1111/jce.13442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 01/22/2018] [Indexed: 12/01/2022]
|
66
|
Sammut EC, Villa ADM, Di Giovine G, Dancy L, Bosio F, Gibbs T, Jeyabraba S, Schwenke S, Williams SE, Marber M, Alfakih K, Ismail TF, Razavi R, Chiribiri A. Prognostic Value of Quantitative Stress Perfusion Cardiac Magnetic Resonance. JACC Cardiovasc Imaging 2017; 11:686-694. [PMID: 29153572 PMCID: PMC5952817 DOI: 10.1016/j.jcmg.2017.07.022] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 07/15/2017] [Accepted: 07/20/2017] [Indexed: 02/06/2023]
Abstract
OBJECTIVES This study sought to evaluate the prognostic usefulness of visual and quantitative perfusion cardiac magnetic resonance (CMR) ischemic burden in an unselected group of patients and to assess the validity of consensus-based ischemic burden thresholds extrapolated from nuclear studies. BACKGROUND There are limited data on the prognostic value of assessing myocardial ischemic burden by CMR, and there are none using quantitative perfusion analysis. METHODS Patients with suspected coronary artery disease referred for adenosine-stress perfusion CMR were included (n = 395; 70% male; age 58 ± 13 years). The primary endpoint was a composite of cardiovascular death, nonfatal myocardial infarction, aborted sudden death, and revascularization after 90 days. Perfusion scans were assessed visually and with quantitative analysis. Cross-validated Cox regression analysis and net reclassification improvement were used to assess the incremental prognostic value of visual or quantitative perfusion analysis over a baseline clinical model, initially as continuous covariates, then using accepted thresholds of ≥2 segments or ≥10% myocardium. RESULTS After a median 460 days (interquartile range: 190 to 869 days) follow-up, 52 patients reached the primary endpoint. At 2 years, the addition of ischemic burden was found to increase prognostic value over a baseline model of age, sex, and late gadolinium enhancement (baseline model area under the curve [AUC]: 0.75; visual AUC: 0.84; quantitative AUC: 0.85). Dichotomized quantitative ischemic burden performed better than visual assessment (net reclassification improvement 0.043 vs. 0.003 against baseline model). CONCLUSIONS This study was the first to address the prognostic benefit of quantitative analysis of perfusion CMR and to support the use of consensus-based ischemic burden thresholds by perfusion CMR for prognostic evaluation of patients with suspected coronary artery disease. Quantitative analysis provided incremental prognostic value to visual assessment and established risk factors, potentially representing an important step forward in the translation of quantitative CMR perfusion analysis to the clinical setting.
Collapse
|
67
|
Williams SE, Leonard-Jones H, Sim I, Rizvi M, Jogiya R, Mehta P. 132The prevalence of upgrade to biventricular pacing after bradycardia pacing is less than 2%: a 12-year series of over 750 patients from a ‘real world’ district general cohort. Europace 2017. [DOI: 10.1093/europace/eux283.125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
68
|
Williams SE, Linton N, O'Neill L, Harrison J, Whitaker J, Mukherjee R, Rinaldi CA, Gill J, Niederer S, Wright M, O'Neill M. The effect of activation rate on left atrial bipolar voltage in patients with paroxysmal atrial fibrillation. J Cardiovasc Electrophysiol 2017; 28:1028-1036. [PMID: 28639747 PMCID: PMC5639376 DOI: 10.1111/jce.13282] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 06/05/2017] [Accepted: 06/12/2017] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Bipolar voltage is used during electroanatomic mapping to define abnormal myocardium, but the effect of activation rate on bipolar voltage is not known. We hypothesized that bipolar voltage may change in response to activation rate. By examining corresponding unipolar signals we sought to determine the mechanisms of such changes. METHODS AND RESULTS LA extrastimulus mapping was performed during CS pacing in 10 patients undergoing first time paroxysmal atrial fibrillation ablation. Bipolar and unipolar electrograms were recorded using a PentaRay catheter (4-4-4 spacing) and indifferent IVC electrode, respectively. An S1S2 pacing protocol was delivered with extrastimulus coupling interval reducing from 350 to 200 milliseconds. At each recording site (119 ± 37 per LA), bipolar peak-to-peak voltage, unipolar peak to peak voltage and activation delay between unipole pairs was measured. Four patterns of bipolar voltage/extrastimulus coupling interval curves were seen: voltage attenuation with plateau voltage >1 mV (48 ± 15%) or <1 mV (22 ± 15%), and voltage unaffected by coupling interval with plateau voltage >1 mV (17 ± 10%) or <1 mV (13 ± 8%). Electrograms showing bipolar voltage attenuation were associated with significantly greater unipolar voltage attenuation at low (25 ± 28 mV/s vs. 9 ± 11 mV/s) and high (23 ± 29 mV/s vs. 6 ± 12 mV/s) plateau voltage sites (P < 0.001). There was a small but significant increase in conduction delay between unipole pairs at sites showing bipolar voltage attenuation (P = 0.026). CONCLUSIONS Bipolar electrogram voltage is dependent on activation rate at a significant proportion of sites. Changes in unipolar voltage and timing underlie these effects. These observations have important implications for use of voltage mapping to delineate abnormal atrial substrate.
Collapse
|
69
|
Lough KJ, Byrd KM, Spitzer DC, Williams SE. Closing the Gap: Mouse Models to Study Adhesion in Secondary Palatogenesis. J Dent Res 2017; 96:1210-1220. [PMID: 28817360 DOI: 10.1177/0022034517726284] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Secondary palatogenesis occurs when the bilateral palatal shelves (PS), arising from maxillary prominences, fuse at the midline, forming the hard and soft palate. This embryonic phenomenon involves a complex array of morphogenetic events that require coordinated proliferation, apoptosis, migration, and adhesion in the PS epithelia and underlying mesenchyme. When the delicate process of craniofacial morphogenesis is disrupted, the result is orofacial clefting, including cleft lip and cleft palate (CL/P). Through human genetic and animal studies, there are now hundreds of known genetic alternations associated with orofacial clefts; so, it is not surprising that CL/P is among the most common of all birth defects. In recent years, in vitro cell-based assays, ex vivo palate cultures, and genetically engineered animal models have advanced our understanding of the developmental and cell biological pathways that contribute to palate closure. This is particularly true for the areas of PS patterning and growth as well as medial epithelial seam dissolution during palatal fusion. Here, we focus on epithelial cell-cell adhesion, a critical but understudied process in secondary palatogenesis, and provide a review of the available tools and mouse models to better understand this phenomenon.
Collapse
|
70
|
O’Neill L, Harrison J, O’Neill M, Williams SE. Response to letter: ‘Bear tracks hypothesis: from atrial fibrillation to atrial fibrosis syndrome in stroke risk assessment’. Expert Rev Cardiovasc Ther 2017; 15:563. [DOI: 10.1080/14779072.2017.1355240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
71
|
O'Neill L, Harrison J, O'Neill M, Williams SE. Clinical, electrophysiological and imaging predictors of atrial fibrillation ablation outcome. Expert Rev Cardiovasc Ther 2017; 15:289-305. [PMID: 28267401 DOI: 10.1080/14779072.2017.1303378] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
INTRODUCTION Significant technological advances for catheter ablation of atrial fibrillation (AF) have occurred over the last decade, with a consequent increase in numbers of patients referred for AF ablation worldwide. Despite this, long-term success rates, particularly in those with persistent AF, remain modest. The patient population presenting for AF ablation are heterogeneous with regard to age, type of AF and presence of associated cardiovascular disease. Improved understanding of factors predicting response to AF ablation may therefore help to improve patient selection for ablation procedures. Areas covered: This review outlines the clinical, electrophysiological and imaging predictors of response to radiofrequency ablation for AF in contemporary practice. Recently developed scoring systems incorporating these parameters are examined, as are factors identified thus far which may predict the outcome of cryoballoon ablation. Expert commentary: Traditional clinical factors associated with ablation outcomes serve as surrogates rather than direct measures of the underlying arrhythmia substrate. An improved understanding of this substrate could improve the prediction of response to radiofrequency ablation. Continued development of methods for characterising the arrhythmia substrate, including atrial cardiac magnetic resonance imaging and invasive voltage mapping, may inform patient risk assessment and help guide selection for catheter ablation on an increasingly individualistic basis.
Collapse
|
72
|
Chubb H, Williams SE, Whitaker J, Harrison JL, Razavi R, O'Neill M. Cardiac Electrophysiology Under MRI Guidance: an Emerging Technology. Arrhythm Electrophysiol Rev 2017; 6:85-93. [PMID: 28845235 DOI: 10.15420/aer.2017.1.2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
MR-guidance of electrophysiological (EP) procedures offers the potential for enhanced arrhythmia substrate assessment, improved procedural guidance and real-time assessment of ablation lesion formation. Accurate device tracking techniques, using both active and passive methods, have been developed to offer an interface similar to electroanatomic mapping platforms, and MR-compatible EP equipment continues to be developed. Progress to clinical implementation of these technically complex fields has been relatively slow over the last 10 years, but recent developments have led to successful clinical experience. However, further advances, particularly in harnessing the full imaging potential of CMR, are required to realise the mainstream adoption of this powerful guidance modality.
Collapse
|
73
|
Chubb H, Williams SE, Whitaker J, Harrison JL, Razavi R, O’Neill M. Cardiac Electrophysiology Under MRI Guidance: an Emerging Technology. Arrhythm Electrophysiol Rev 2017. [DOI: 10.15420/aer.2017:1:2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
MR-guidance of electrophysiological (EP) procedures offers the potential for enhanced arrhythmia substrate assessment, improved procedural guidance and real-time assessment of ablation lesion formation. Accurate device tracking techniques, using both active and passive methods, have been developed to offer an interface similar to electroanatomic mapping platforms, and MR-compatible EP equipment continues to be developed. Progress to clinical implementation of these technically complex fields has been relatively slow over the last 10 years, but recent developments have led to successful clinical experience. However, further advances, particularly in harnessing the full imaging potential of CMR, are required to realise the mainstream adoption of this powerful guidance modality.
Collapse
|
74
|
Demos KE, Hart CN, Sweet LH, Mailloux KA, Trautvetter J, Williams SE, Wing RR, McCaffery JM. Partial sleep deprivation impacts impulsive action but not impulsive decision-making. Physiol Behav 2016; 164:214-9. [PMID: 27267950 DOI: 10.1016/j.physbeh.2016.06.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 06/02/2016] [Accepted: 06/03/2016] [Indexed: 10/21/2022]
Abstract
Sleep deprivation may lead to increased impulsivity, however, previous literature has focused on examining effects of total sleep deprivation (TSD) rather than the more common condition, partial sleep deprivation (PSD) or 'short sleep'. Moreover, it has been unclear whether PSD impacts impulse-related cognitive processes, and specifically if it differentially affects impulsive action versus impulsive decision-making. We sought to determine if short compared to long sleep (6 vs. 9h/night) impacts impulsive action via behavioral inhibition (Go/No-Go), and/or impulsive decision-making processes of risk taking (Balloon Analogue Risk Task [BART]) and preferences for immediate over delayed rewards (Delay Discounting). In a within-subject design, 34 participants (71% female, mean age=37.0years, SD=10.54) were assigned to four consecutive nights of 6h/night (short sleep) and 9h/night (long sleep) in their own home in random counterbalanced order. Sleep was measured via wrist-worn actigraphs to confirm adherence to the sleep schedules (mean short sleep=5.9h, SD=0.3; mean long sleep=8.6h, SD=0.3, p<0.001). The Go/No-Go, BART, and Delay Discounting tasks were completed following both sleep conditions. Participants had more inhibition errors on the Go/No-Go task after short (mean false alarms=19.79%, SD=14.51) versus long sleep (mean=15.97%, SD=9.51, p=0.039). This effect was strongest in participants reporting longer habitual time in bed (p=0.04). There were no differences in performance following long- versus short-sleep for either delay discounting or the BART (p's>0.4). Overall, these results indicate that four days of PSD diminishes behavioral inhibition abilities, but may not alter impulsive decision-making. These findings contribute to the emerging understanding of how partial sleep deprivation, currently an epidemic, impacts cognitive ability. Future research should continue to explore the connection between PSD and cognitive functions, and ways to minimize the occurrence and negative consequences of short sleep.
Collapse
|
75
|
Harrison JL, Sohns C, Linton NW, Karim R, Williams SE, Rhode KS, Gill J, Cooklin M, Rinaldi CA, Wright M, Schaeffter T, Razavi RS, O'Neill MD. Response to letter from Bisbal et al regarding, "Repeat left atrial catheter ablation: cardiac magnetic resonance prediction of endocardial voltage and gaps in ablation lesion sets". Circ Arrhythm Electrophysiol 2015; 8:754-5. [PMID: 26082535 DOI: 10.1161/circep.115.003117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|