571 results found
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
Kaura A, Panoulas V, Glampson B, et al., 2019, UNEXPECTED INVERTED U-SHAPED RELATIONSHIP BETWEEN TROPONIN LEVEL AND MORTALITY EXPLAINED BY REVASCULARIZATION IN BOTH PATIENTS WITH AND WITHOUT ACUTE CORONARY SYNDROME (TROP-RISK STUDY), 68th Annual Scientific Session and Expo of the American-College-of-Cardiology (ACC), Publisher: ELSEVIER SCIENCE INC, Pages: 1086-1086, ISSN: 0735-1097
Kaura A, Hartley A, Panoulas V, et al., 2019, HSCRP PREDICTS MORTALITY BEYOND TROPONIN IN 102,337 PATIENTS WITH SUSPECTED ACUTE CORONARY SYNDROME IN THE UK NATIONAL INSTITUTE FOR HEALTH RESEARCH CRP-RISK STUDY, 68th Annual Scientific Session and Expo of the American-College-of-Cardiology (ACC), Publisher: ELSEVIER SCIENCE INC, Pages: 10-10, ISSN: 0735-1097
Rajkumar CA, Suh WM, Francis DP, 2019, Upcoding of Clinical Information to Meet Appropriate Use Criteria for Percutaneous Coronary Intervention., Circ Cardiovasc Qual Outcomes, Vol: 12
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., Europace
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.
Howard J, Fisher L, Shun-Shin M, et al., Cardiac rhythm device identification using neural networks, JACC: Clinical Electrophysiology, 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.
Seligman H, Shun-Shin M, Vasireddy A, et al., Fractional flow reserve derived from microcatheters versus standard pressure wires: a stenosis-level meta-analysis, Open Heart, ISSN: 2053-3624
Aims: To determine the agreement between sensor-tipped microcatheter (MC) and pressure wire (PW) derived Fractional Flow Reserve (FFR). Methods and results: Studies comparing FFR obtained from MC (FFRMC, Navvus Microcatheter System, ACIST Medical Systems, Minnesota, USA) versus standard PW (FFRPW) were identified and a meta-analysis of numerical and categorical agreement was performed. The relative levels of drift and device failure of MC and PW systems from each study were assessed. Six studies with 440 lesions (413 patients) were included. The mean overall bias between FFRMC and FFRPW was -0.029 (FFRMC lower). Bias and variance were greater for lesions with lower FFRPW (p <0.001). Using a cut-off of 0.80, 18% of lesions were re-classified by FFRMC versus FFRPW (with 15% being false-positives). The difference in reported drift between FFRPW and FFRMC was small. Device failure was more common with MC than PW (7.1% versus 2%). Conclusion: FFRMC systematically overestimates lesion severity, with increased bias in more severe lesions. Using FFRMC changes revascularisation guidance in approximately 1 out of every 5 cases. Pressure wire drift was similar between systems. Device failure was higher with MC.
Arnold A, Keene D, Howard J, et al., Quantification of electro-mechanical coupling to prevent inappropriate implantable cardioverter defibrillator shocks, JACC: Clinical Electrophysiology, 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.
Francis DP, Nallamothu BK, 2019, PCI Guided by Fractional Flow Reserve at 5 Years., N Engl J Med, Vol: 380
Al-Lamee RK, Nowbar AN, Francis DP, 2019, Percutaneous coronary intervention for stable coronary artery disease, HEART, Vol: 105, Pages: 11-19, ISSN: 1355-6037
Arnold AD, Shun-Shin MJ, 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
Hartley A, Shah M, Nowbar AN, et al., 2018, CHRISTMAS 2018: LOOK BEFORE YOU LEAP Key opinion leaders' guide to spinning a disappointing clinical trial result, BMJ-BRITISH MEDICAL JOURNAL, Vol: 363, ISSN: 1756-1833
Broyd CJ, Rigo F, Nijjer S, et al., 2018, Regression of left ventricular hypertrophy provides an additive physiological benefit following treatment of aortic stenosis: Insights from serial coronary wave intensity analysis, ACTA PHYSIOLOGICA, Vol: 224, ISSN: 1748-1708
Kim M-Y, Sikkel MB, Hunter RJ, et al., 2018, A novel approach to mapping the atrial ganglionated plexus network by generating a distribution probability atlas, JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Vol: 29, Pages: 1624-1634, ISSN: 1045-3873
Sacchi S, Dhutia NM, Shun-Shin MJ, et al., 2018, Doppler assessment of aortic stenosis: a 25-operator study demonstrating why reading the peak velocity is superior to velocity time integral, EUROPEAN HEART JOURNAL-CARDIOVASCULAR IMAGING, Vol: 19, Pages: 1380-1389, ISSN: 2047-2404
Ferreira-Martins J, Howard J, Al-Khayatt B, et al., 2018, Outcomes of paroxysmal atrial fibrillation ablation studies are affected more by study design and patient mix than ablation technique, JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Vol: 29, Pages: 1471-1479, ISSN: 1045-3873
Al-Lamee R, Howard JP, Shun-Shin MJ, et al., 2018, Fractional Flow Reserve and Instantaneous Wave-Free Ratio as Predictors of the Placebo-Controlled Response to Percutaneous Coronary Intervention in Stable Single-Vessel Coronary Artery Disease: Physiology-Stratified Analysis of ORBITA, CIRCULATION, Vol: 138, Pages: 1780-1792, ISSN: 0009-7322
Ahmad Y, Götberg M, Cook C, et al., 2018, Coronary Hemodynamics in Patients With Severe Aortic Stenosis and Coronary Artery Disease Undergoing Transcatheter Aortic Valve Replacement: Implications for Clinical Indices of Coronary Stenosis Severity., JACC Cardiovasc Interv, Vol: 11, Pages: 2019-2031
OBJECTIVES: In this study, a systematic analysis was conducted of phasic intracoronary pressure and flow velocity in patients with severe aortic stenosis (AS) and coronary artery disease, undergoing transcatheter aortic valve replacement (TAVR), to determine how AS affects: 1) phasic coronary flow; 2) hyperemic coronary flow; and 3) the most common clinically used indices of coronary stenosis severity, instantaneous wave-free ratio and fractional flow reserve. BACKGROUND: A significant proportion of patients with severe aortic stenosis (AS) have concomitant coronary artery disease. The effect of the valve on coronary pressure, flow, and the established invasive clinical indices of stenosis severity have not been studied. METHODS: Twenty-eight patients (30 lesions, 50.0% men, mean age 82.1 ± 6.5 years) with severe AS and coronary artery disease were included. Intracoronary pressure and flow assessments were performed at rest and during hyperemia immediately before and after TAVR. RESULTS: Flow during the wave-free period of diastole did not change post-TAVR (29.78 ± 14.9 cm/s vs. 30.81 ± 19.6 cm/s; p = 0.64). Whole-cycle hyperemic flow increased significantly post-TAVR (33.44 ± 13.4 cm/s pre-TAVR vs. 40.33 ± 17.4 cm/s post-TAVR; p = 0.006); this was secondary to significant increases in systolic hyperemic flow post-TAVR (27.67 ± 12.1 cm/s pre-TAVR vs. 34.15 ± 17.5 cm/s post-TAVR; p = 0.02). Instantaneous wave-free ratio values did not change post-TAVR (0.88 ± 0.09 pre-TAVR vs. 0.88 ± 0.09 post-TAVR; p = 0.73), whereas fractional flow reserve decreased significantly post-TAVR (0.87 ± 0.08 pre-TAVR vs. 0.85 ± 0.09 post-TAVR; p = 0.001). CONCLUSIONS: Systolic and hyperemic coronary flow increased significantly post-TAVR; consequently, hyperemic indices that include systole underestimated coronary stenosis severity in patients with severe AS. Flow during the wave-free pe
Ahmad Y, Gotberg M, Cook C, et al., 2018, Coronary Hemodynamics in Patients With Severe Aortic Stenosis and Coronary Artery Disease Undergoing Transcatheter Aortic Valve Replacement Implications for Clinical Indices of Coronary Stenosis Severity, JACC-CARDIOVASCULAR INTERVENTIONS, Vol: 11, Pages: 2019-2031, ISSN: 1936-8798
Ahmad Y, Howard J, Arnold A, et al., 2018, Reply to: 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: 0195-668X
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: 966-977, ISSN: 2055-5822
Cook C, Ahmad Y, Howard J, et al., 2018, Predicting angina-limited exercise capacity using coronary physiology, 30th Annual Symposium on Transcatheter Cardiovascular Therapeutics (TCT), Publisher: ELSEVIER SCIENCE INC, Pages: B42-B42, ISSN: 0735-1097
Ahmad Y, Gotberg M, Cook C, et al., 2018, Coronary pressure and flow in patients with severe aortic stenosis and coronary artery disease undergoing TAVI: implications for clinical indices of coronary stenosis severity, 30th Annual Symposium on Transcatheter Cardiovascular Therapeutics (TCT), Publisher: ELSEVIER SCIENCE INC, Pages: B4-B4, ISSN: 0735-1097
Cook CM, Ahmad Y, Howard JP, et al., 2018, Impact of Percutaneous Revascularization on Exercise Hemodynamics in Patients With Stable Coronary Disease, JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, Vol: 72, Pages: 970-983, ISSN: 0735-1097
Kyriacou A, Rajkumar CA, Pabari PA, et al., 2018, Distinct impacts of heart rate and right atrial-pacing on left atrial mechanical activation and optimal AV delay in CRT, PACE-PACING AND CLINICAL ELECTROPHYSIOLOGY, Vol: 41, Pages: 959-966, ISSN: 0147-8389
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
Ahmad Y, Gotberg M, Malik IS, et al., 2018, Coronary haemodynamics in patients with severe aortic stenosis and coronary artery disease undergoing TAVI: implications for clinical indices of coronary stenosis severity, European-Society-of-Cardiology Congress, Publisher: OXFORD UNIV PRESS, Pages: 22-23, ISSN: 0195-668X
Arnold AD, Howard JP, Ahmad Y, et al., 2018, Right ventricular pacing for LVOT gradient reduction in hypertrophic obstructive cardiomyopathy: a meta-analysis and meta-regression of clinical trials, EUROPEAN HEART JOURNAL, Vol: 39, Pages: 728-728, ISSN: 0195-668X
Accad M, Francis D, 2018, Does evidence based medicine adversely affect clinical judgment?, BMJ, Vol: 362
Francis DP, Al-Lamee R, 2018, Percutaneous coronary intervention for stable angina in ORBITA Reply, LANCET, Vol: 392, Pages: 28-30, ISSN: 0140-6736
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