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| 2. |
- Koulaouzidis, George, et al.
(författare)
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Prevalence of Noncalcified Coronary Plaque in Patients With Calcium Score of 0 : The Silent Enemy
- 2013
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Ingår i: Angiology. - : Sage Publications. - 0003-3197 .- 1940-1574. ; 64:3, s. 205-210
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Tidskriftsartikel (refereegranskat)abstract
- Noncalcified coronary artery plaques (NCAPs) are susceptible to rupture, resulting in coronary artery thrombosis. Using computer tomography coronary angiography (CTCA), we evaluated the prevalence and degree of stenosis caused by NCAP in patients without coronary artery calcification (CAC). A retrospective analysis of 447 symptomatic patients with 0 CAC score revealed negative CTCA in 400 (89.5%). Noncalcified coronary artery plaques were demonstrated in 47 (10.5%), with 4 presenting stenosis >50%. Patients with positive CTCA, compared to those with normal CTCA, had significantly higher mean age (56.2 years vs 50.6 years, P < .004) and higher pretest coronary artery disease (CAD) probability (26% vs 34%, P < .0001). Noncalcified coronary artery plaque was predominantly developed in the proximal segment of the left anterior descending artery. Noncalcified coronary artery plaque is present in up to 10% of patients with a CAC score of 0. Computer tomography coronary angiography could be of diagnostic value in symptomatic patients with multiple risk factors for CAD, even in the absence of CAC.
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| 3. |
- Charisopoulou, Dafni, et al.
(författare)
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Abnormal ventricular repolarization in long QT syndrome carriers is related to short left ventricular filling time and attenuated stroke volume response during exercise
- 2018
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Ingår i: Echocardiography. - : Wiley. - 0742-2822 .- 1540-8175. ; 35:8, s. 1116-1123
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Long QT syndrome (LQTS) carriers are characterized by abnormal ventricular repolarization, prolonged systole, and mechanical dispersion. Prolonged left ventricular (LV) systole has been shown to result in disproportionate shortening of LV filling in other conditions. The aim of this study was to assess LV filling, diastolic function, and stroke volume (SV) response to dynamic exercise, in a group of LQTS carriers.METHODS: Forty-seven LQTS carriers (45 ± 15 years, 20 symptomatic) and 35 healthy individuals underwent bicycle stress echocardiogram. Electrocardiographic and echocardiographic measurements were obtained at rest, peak exercise, and 4 minutes into recovery.RESULTS: Long QT syndrome carriers and controls did not differ in age, gender, heart rate, QRS duration, or LV ejection fraction. At rest, LQTS carriers had longer QTc and shorter filling time (FT). At peak exercise, QTc increased and remained longer than controls at recovery. A negative correlation was found between QTc and FT (r = -.398, P = .001) with greater fall in FT in LQTS carriers than in controls at peak exercise (-23% ± 10 vs +2% ± 3, P < .0001). FT correlated with SV (r = +.27, P = .001), which increased more in controls than in LQTS carriers (+32% ± 4 vs +2% ± 1, P < .05). These differences were more pronounced in symptomatic LQTS carriers who had shorter FT and smaller SV at peak exercise and during recovery compared to asymptomatics (P < .05).CONCLUSIONS: Long QT syndrome carriers have longer QTc, but also shorter FT. These disturbances worsen at peak exercise (particularly in symptomatics) compromising LV filling and SV, hence a potential pathomechanism for adverse events.
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| 4. |
- Charisopoulou, Dafni, et al.
(författare)
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Exercise Induced Worsening of Mechanical Heterogeneity and Diastolic Impairment in Long QT Syndrome
- 2021
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Ingår i: Journal of Clinical Medicine. - : MDPI. - 2077-0383. ; 10:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Electromechanical heterogeneities due to marked dispersion of ventricular repolarisation and mechanical function have been associated with symptoms in long QT syndrome (LQTS) patients.Aim: To examine the exercise response of longitudinal LV systolic and diastolic myocardial function and synchronicity in LQTS patients and its relationship with symptoms; Methods: Forty seven (age 45 ± 15 yrs, 25 female, 20 symptomatic) LQTS patients and 35 healthy individuals underwent an exercise test (Bruce protocol). ECG and echo parameters were recorded at rest, peak exercise (p.e.), and recovery.Results: LQTS patients had prolonged and markedly dispersed myocardial contraction, delayed early relaxation phase, and significantly decreased filling time at all exercise phases. Unlike controls, these electromechanical disturbances deteriorated further with exercise, during which additional decrease of the LV diastolic myocardial function and attenuated LV stroke volume were noted. Such abnormal responses to exercise were seen to a greater degree in symptomatic patients and in the LQT1 subgroup and improved with B-blocker therapy. Worsening myocardial contraction dispersion at p.e. was the strongest discriminator for previous clinical events, and its discriminating power excelled further by adding early relaxation delay.Conclusions: Electromechanical disturbances were shown to worsen during exercise in LQTS patients and were more pronounced in those with previous arrhythmic events.
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| 5. |
- Charisopoulou, Dafni, et al.
(författare)
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Exercise worsening of electromechanical disturbances : a predictor of arrhythmia in long QT syndrome
- 2019
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Ingår i: Clinical Cardiology. - : Wiley Periodicals, Inc.. - 0160-9289 .- 1932-8737. ; 42:2, s. 235-240
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Tidskriftsartikel (refereegranskat)abstract
- Background; Electromechanical (EM) coupling heterogeneity is significant in long QT syndrome (LQTS), particularly in symptomatic patients; EM window (EMW) has been proposed as an indicator of interaction and a better predictor of arrhythmia than QTc. Hypothesis To investigate the dynamic response of EMW to exercise in LQTS and its predictive value of arrhythmia.Methods: Forty-seven LQTS carriers (45 +/- 15 years, 20 with arrhythmic events), and 35 controls underwent exercise echocardiogram. EMW was measured as the time difference between aortic valve closure on Doppler and the end of QT interval on the superimposed electrocardiogram (ECG). Measurements were obtained at rest, peak exercise (PE) and 4 minutes into recovery.Results: Patients did not differ in age, gender, heart rate, or left ventricular ejection fraction but had a negative resting EMW compared with controls (-42 +/- 22 vs 17 +/- 5 ms, P < 0.0001). EMW became more negative at PE (-89 +/- 43 vs 16 +/- 7 ms, P = 0.0001) and recovery (-65 +/- 39 vs 16 +/- 6 ms, P = 0.001) in patients, particularly the symptomatic, but remained unchanged in controls. PE EMW was a stronger predictor of arrhythmic events than QTc (AUC:0.765 vs 0.569, P < 0.001). B-blockers did not affect EMW at rest but was less negative at PE (BB: -66 +/- 21 vs no-BB: -113 +/- 25 ms, P < 0.001). LQT1 patients had worse PE EMW negativity than LQT2.Conclusion: LQTS patients have significantly negative EMW, which worsens with exercise. These changes are more pronounced in patients with documented arrhythmic events and decrease with B-blocker therapy. Thus, EMW assessment during exercise may help improve risk stratification and management of LQTS patients.
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| 6. |
- Charisopoulou, Dafni, et al.
(författare)
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Reversed Apico-Basal Myocardial Relaxation Sequence During Exercise in Long QT Syndrome Mutations Carriers With History of Previous Cardiac Events
- 2022
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Ingår i: Frontiers in Physiology. - : Frontiers Media S.A.. - 1664-042X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Recent echocardiography studies in inherited long QT syndrome (LQTS) have shown left ventricular (LV) myocardial relaxation disturbances to follow markedly prolonged and dispersed mechanical contraction. Aim: We used speckle-tracking echocardiography to assess disturbances in LV myocardial relaxation sequence during exercise and their relationship to symptoms. Methods: Forty seven LQTS patients (45 ± 15 years, 25 female and 20 symptomatic, LVEF: 65 ± 6%) and 35 controls underwent exercise echocardiogram using Bruce protocol. ECG and echo parameters were recorded at rest, peak exercise (p.e.) and recovery. Results: Between patients and controls there were no differences in age, gender, HR or LVEF. At p.e, patients had longer time to LV longitudinal ESR (tESR) at all three LV segments; basal (p < 0.0001), mid- cavity (p = 0.03) and apical (p = 0.03) whereas at rest such difference was noted only at base (p = 0.0007). Patients showed reversed apico-basal relaxation sequence (ΔtESRbase–apex) with early relaxation onset occurring later at base than at apex, both at rest (49 ± 43 vs. –29 ± 19 ms, p < 0.0001) and at p.e. (46 ± 38 vs. –40 ± 22 ms, p < 0.0001), particularly in symptomatic patients (69 ± 44 vs. 32 ± 26, p < 0.0007). ΔtESRbase–apex correlated with longer QTc interval, lower ESR and attenuated LV stroke volume. Conclusion: LQTS patients show reversed longitudinal relaxation sequence, which worsens with exercise, particularly in those with previous cardiac events.
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| 7. |
- Henein, Michael, et al.
(författare)
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Heart valve calcification
- 2022. - 1
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Ingår i: Cardiovascular calcification. - Cham : Springer. - 9783030815158 - 9783030815141 ; , s. 33-44
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Bokkapitel (refereegranskat)abstract
- This chapter focuses on the calcification of heart valves. The extent of valve calcification may vary from mild sclerosis with no effects on valve function to the development of leaflets calcification which causes valve dysfunction. It is well known that valve calcification is associated with conventional atherosclerosis risk factors. The valve calcification process can be classified into 2 phases: an early initiation phase dominated by valve tissue injury, lipid deposition, and inflammation, with many similarities to atherosclerosis and a later propagation phase where pro-calcific and pro-osteogenic factors drive disease progression. The best method for assessing the extent of valve calcification is cardiac CT applying the Agatston score which is used for assessing the coronary artery calcification. Echocardiography could assess valve calcification but in a semiquantitative way. Although observational studies showed a potential beneficial effect of statins on aortic stenosis severity, further randomised controlled trials and a meta analysis have failed to confirm these results. Recognition of valve calcification is clinically important as it has a strong predictive value of future clinical events.
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| 8. |
- Henein, Michael Y., et al.
(författare)
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The natural history of coronary calcification : a meta-analysis from St Francis and EBEAT trials
- 2013
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Ingår i: International Journal of Cardiology. - : Elsevier. - 0167-5273 .- 1874-1754. ; 168:4, s. 3944-3948
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND AIM: Coronary artery calcium score (CACs) is an established quantitative tool for assessing subclinical atherosclerosis. The aim of this study was to assess in a meta-analysis model the natural history and reproducibility of CACs measurements obtained from St Francis and EBEAT trials.METHODS: We analysed data from 649 individuals: 443 on placebo with 2year follow-up from St Francis trial (Study A) and 209 on 10mg atorvastatin with 1year follow-up of EBEAT trial (Study B). Total CACs and that in the left coronary artery (LCA) branches, left main stem (LMS), left anterior descending (LAD), left circumflex (Cx) and right coronary artery (RCA) were analysed. In view of the wide CACs spectrum, data were logarithmically transformed before the analyses and mixed model analysis was used to evaluate the change of CACs over time.RESULTS: The overall agreement between the two measurements was fairly good, showing a small but significant increase in CAC: 68% of the group as a whole presented an increase in CACs, 23% of the cohort had negligible change in CACs of <10% irrespective of the baseline CACs; and the remaining 10% showed a fall in CACs. Both studies showed similar patterns. The analysis of individual coronary arteries showed significantly higher variability of measurements in the RCA than in the LCA. Males had higher baseline CACs than females, but the rate of progression was not different between genders, irrespectively of age and baseline score.CONCLUSION: The natural history of CACs was overtime progression in the majority of subjects, irrespective of gender. The higher variability in RCA measurements could be related to the low baseline CACs or exaggerated movement of the right side atrioventricular ring, whereas those for LCA branches are influenced by the branch allocation of the CACs. Large changes to and from zero, might be related to technical limitations.
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| 9. |
- Iakovidis, Dimitris K., et al.
(författare)
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Robotic validation of visual odometry for wireless capsule endoscopy
- 2016
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Ingår i: IST 2016 - 2016 IEEE International Conference on Imaging Systems and Techniques, Proceedings. - 9781509018178 ; , s. 83-87
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Konferensbidrag (refereegranskat)abstract
- Wireless capsule endoscopy (WCE) is the prime diagnostic modality for the small-bowel. It consists in a swallowable color camera that enables the visual detection and assessment of abnormalities, without patient discomfort. The localization of the capsule is currently performed in the 3D abdominal space using radiofrequency (RF) triangulation. However, this approach does not provide sufficient information for the localization of the capsule, and therefore for the localization of the detected abnormalities, within the gastrointestinal (GI) lumen. To cope with this problem, we have recently proposed a method for visual tracking of the capsule endoscope (CE). It is based solely on visual features extracted from the captured images during the journey of the CE in the GI tract, enabling therefore visual odometry. Due to lack of ex-vivo or in-vivo ground truth data, the feasibility of that method was assessed using relative measurements in an image-based simulation experiment. In this paper, we make one step forward towards the assessment of the absolute localization capabilities of visual odometry using a calibrated in-vitro experimental setup. The obtained results validate the feasibility of the proposed approach, highlight the difficulty of this complex problem, and reveal the challenges ahead.
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| 10. |
- Koulaouzidis, Anastasios, et al.
(författare)
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Novel experimental and software methods for image reconstruction and localization in capsule endoscopy
- 2018
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Ingår i: Endoscopy International Open. - : Georg Thieme Verlag KG. - 2364-3722 .- 2196-9736. ; 6:2, s. 205-210
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Tidskriftsartikel (refereegranskat)abstract
- Background and study aims : Capsule endoscopy (CE) is invaluable for minimally invasive endoscopy of the gastrointestinal tract; however, several technological limitations remain including lack of reliable lesion localization. We present an approach to 3D reconstruction and localization using visual information from 2D CE images.Patients and methods : Colored thumbtacks were secured in rows to the internal wall of a LifeLike bowel model. A PillCam SB3 was calibrated and navigated linearly through the lumen by a high-precision robotic arm. The motion estimation algorithm used data (light falling on the object, fraction of reflected light and surface geometry) from 2D CE images in the video sequence to achieve 3D reconstruction of the bowel model at various frames. The ORB-SLAM technique was used for 3D reconstruction and CE localization within the reconstructed model. This algorithm compared pairs of points between images for reconstruction and localization.Results: As the capsule moved through the model bowel 42 to 66 video frames were obtained per pass. Mean absolute error in the estimated distance travelled by the CE was 4.1 ± 3.9 cm. Our algorithm was able to reconstruct the cylindrical shape of the model bowel with details of the attached thumbtacks. ORB-SLAM successfully reconstructed the bowel wall from simultaneous frames of the CE video. The "track" in the reconstruction corresponded well with the linear forwards-backwards movement of the capsule through the model lumen.Conclusion: The reconstruction methods, detailed above, were able to achieve good quality reconstruction of the bowel model and localization of the capsule trajectory using information from the CE video and images alone.
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