| 1. |
- Holmqvist, Fredrik, et al.
(författare)
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Interatrial conduction can be accurately determined using standard 12-lead electrocardiography: validation of P-wave morphology using electroanatomic mapping in man.
- 2008
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Ingår i: Heart Rhythm. - : Elsevier BV. - 1547-5271. ; 5:3, s. 413-418
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Different P-wave morphologies during sinus rhythm as displayed on standard ECGs have been postulated to correspond to differences in interatrial conduction. OBJECTIVE: The purpose of this study was to evaluate the hypothesis by comparing P-wave morphologies using left atrial activation maps. METHODS: Twenty-eight patients (mean age 49 +/- 9 years) admitted for ablation of paroxysmal atrial fibrillation were studied. Electroanatomic mapping of left atrial activation was performed at baseline during sinus rhythm with simultaneous recording of standard 12-lead ECG. Unfiltered signal-averaged P waves were analyzed to determine orthogonal P-wave morphology. The morphology was subsequently classified into one of three predefined types. All analyses were blinded. RESULTS: The primary left atrial breakthrough site was the fossa ovalis in 8 patients, Bachmann bundle in 18, and coronary sinus in 2. Type 1 P-wave morphology was observed in 9 patients, type 2 in 17, and type 3 in 2. Seven of eight patients with fossa ovalis breakthrough had type 1 P-wave morphology, 16 of 18 patients with Bachmann bundle breakthrough had type 2 morphology, and both patients with coronary sinus breakthrough had type 3 P-wave morphology. Overall, P-wave morphology criteria correctly identified the site of left atrial breakthrough in 25 (89%) of 28 patients. CONCLUSION: In the vast majority of patients, P-wave morphology derived from standard 12-lead ECG can be used to correctly identify the left atrial breakthrough site and the corresponding route of interatrial conduction.
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| 2. |
- Ji, Hong, et al.
(författare)
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TNFR1 mediates TNF-alpha-induced tumour lymphangiogenesis and metastasis by modulating VEGF-C-VEGFR3 signalling
- 2014
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Ingår i: Nature Communications. - : Nature Publishing Group: Nature Communications. - 2041-1723. ; 5:4944
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Tidskriftsartikel (refereegranskat)abstract
- Inflammation and lymphangiogenesis are two cohesively coupled processes that promote tumour growth and invasion. Here we report that TNF-alpha markedly promotes tumour lymphangiogenesis and lymphatic metastasis. The TNF-alpha-TNFR1 signalling pathway directly stimulates lymphatic endothelial cell activity through a VEGFR3-independent mechanism. However, VEGFR3-induced lymphatic endothelial cell tips are a prerequisite for lymphatic vessel growth in vivo, and a VEGFR3 blockade completely ablates TNF-alpha-induced lymphangiogenesis. Moreover, TNF-alpha-TNFR1-activated inflammatory macrophages produce high levels of VEGF-C to coordinately activate VEGFR3. Genetic deletion of TNFR1 (Tnfr1(-/-)) in mice or depletion of tumour-associated macrophages (TAMs) virtually eliminates TNF-alpha-induced lymphangiogenesis and lymphatic metastasis. Gain-of-function experiments show that reconstitution of Tnfr1(+/+) macrophages in Tnfr1(+/+) mice largely restores tumour lymphangiogenesis and lymphatic metastasis. These findings shed mechanistic light on the intimate interplay between inflammation and lymphangiogenesis in cancer metastasis, and propose therapeutic intervention of lymphatic metastasis by targeting the TNF-alpha-TNFR1 pathway.
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| 3. |
- Kongstad Rasmussen, Ole, et al.
(författare)
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Epicardial and endocardial dispersion of ventricular repolarization. A study of monophasic action potential mapping in healthy pigs.
- 2005
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Ingår i: Scandinavian Cardiovascular Journal. - : Informa UK Limited. - 1651-2006 .- 1401-7431. ; 39:6, s. 342-347
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. To investigate the total dispersion of ventricular repolarization of the epi- and endocardium. Design. Monophasic action potentials (MAP) were recorded from 211 +/- 54 (151-353) left and right ventricular epi- and endocardial sites during atrial pacing in 10 pigs using the CARTO system. The activation time (AT), MAP duration (MAPd) and end of repolarization time (EOR) were measured. Results. The total dispersion of AT, EOR and MAPd, defined as the maximal differences of these parameters over both the epi- and endocardium, were 57 +/- 10, 84 +/- 20, and 75 +/- 21 ms respectively and were significantly larger than the respective epi- and endocardial dispersions (p < 0.05). The epicardial dispersion of AT, EOR and MAPd of both the right and left ventricles were significantly larger than that of each ventricle alone (p < 0.02). Sternotomy did not affect these dispersion parameters. Conclusion. Detailed mapping of epicardial repolarization in vivo using the MAP mapping technique is feasible. Both the epi- and endocardium of the two ventricles contribute significantly to the total dispersion of repolarization.
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| 4. |
- Kongstad Rasmussen, Ole, et al.
(författare)
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Ventricular repolarization sequences on the epicardium and endocardium. Monophasic action potential mapping in healthy pigs
- 2012
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 45:1, s. 49-56
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Tidskriftsartikel (refereegranskat)abstract
- To investigate repolarization sequence, monophasic action potentials were recorded from a mean of 153 +/- 54 left and right ventricular epicardial and endocardial sites in 10 pigs using the CARTO mapping system (Biosense Webster, Waterloo, Belgium). The activation time and end-of-repolarization (EOR) time were measured and 3-dimensional maps of activation and repolarization sequences constructed. Results: In 8 of 9 pigs, both the activation and EOR times appeared first in the septum and last in the latero-basal areas on the endocardium, not on the epicardium. The EOR followed the activation sequence, both on the epicardium (in 8/9 pigs) and endocardium (in 8/8 pigs). The maximal EOR differences were 84 +/- 20 ms, whereas the local EOR differences between paired sites against each other on the tell ventricular epicardium and endocardium were 11 +/- 9 ms in the apex and 12 +/- 12 ms in the anterior wall. Conclusion: The EOR follows the activation sequence both on the epicardium and endocardium. The apico-basal gradients are predominant repolarization gradients, as compared with the epicardial-endocardial gradients. (C) 2012 Elsevier Inc. All rights reserved.
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| 6. |
- Xia, Yunlong, et al.
(författare)
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Activation recovery time measurements in evaluation of global sequence and dispersion of ventricular repolarization
- 2005
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 38:1, s. 28-35
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Activation recovery time (ART), defined as the time from the earliest ventricular activation time to the end of T wave on unipolar electrograms, has been used as an index of myocardial repolarization time. However, it is unknown whether the ART can be used to estimate the global sequence and dispersion of ventricular repolarization as determined by the monophasic action potential (MAP) mapping technique. Methods and Results: Endocardial MAPs and unipolar electrograms were simultaneously recorded using the CARTO system from 34 +/- 12 left (n = 6) or right (n = 9) ventricular sites in 12 patients. End-of-repolarization (EOR) times from the MAPs and ARTs from the unipolar electrograms were calculated, based on which 15 sets of 3-dimensional maps of global EOR sequence and ART sequence were reconstructed. The ART sequence was consistent with the EOR sequence in 14 of 15 maps. In the 473 paired measurements obtained, the differences between the ART and the EOR time were 2 +/- 22 milliseconds (NS). A significant positive correlation between the ART and the EOR time was found in all the maps (r = 0.58 +/- 0.22). Agreement analyses showed that the differences between these 2 measurements were almost all within the range of mean difference +/- 2 SD for each individual map and for all the 473 recordings. The global dispersion of ART was 79 +/- 35 milliseconds, as compared with that of EOR time of 78 +/- 35 milliseconds (NS). Conclusion: The ART from unipolar electrograms is a good estimate of EOR time measured from MAPs, suggesting the usefulness of the former in evaluation of global sequence and dispersion of ventricular repolarization.
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| 9. |
- Xia, Yunlong
(författare)
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Global sequence and dispersion of ventricular repolarization: In vivo validation of non-invasive parameters using monophasic action potential mapping technique
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The purposes are to validate the noninvasive parameters, QT interval, QT dispersion, Tpeak-Tend interval, and the activation recovery time (ART) for estimation of global dispersion of ventricular repolarization (DVR), and to investigate the changes of repolarization sequence and DVR by altered ventricular pacing sites. The material consisted of 12 patients (Study I) and two series healthy pigs with 10 in each (Studies II and III; Studies IV and V). In Study I, endocardial MAPs and unipolar electrograms were recorded using the CARTO system in 12 patients. End of repolarization (EOR) times from the MAPs and ARTs from the unipolar electrograms were acquired and 3-dimensional maps of global EOR and ART were reconstructed. The ART sequence was consistent with that of EOR and no significant diffence was found between EOR times and ART. A significant, positive correlation between the ART and the EOR time was also found in all maps. These findings suggest the usefulness of the ART in evaluation of global sequence and dispersion of ventricular repolarization. In Studies II and III, MAP mapping was performed over both the ventricular endo- and the epicardium using the CARTO system in 10 open-chest pigs, from which the EOR times over the epi- (EORepi), endocardium (EORendo) and over both (EORtotal) were obtained- 12-lead ECG were recorded simultaneously. The QTpeak intervals were significantly smaller than the maximal EORepi. No significant difference was found between the maximal QTend interval and the maximal EORendo, between the maximal QTend interval and the maximal EORtotal nor between the minimal QTpeak interval and the minimal EORtotal, which suggests that not only the transmural gradients, but also the apico-basal repolarization gradients contribute to the genesis of the T wave. In addition, the maximal Tpeak-Tend intervals were consistent with the dispersion of EOR-total, and significantly correlated with the dispersion of EOR-total. However, the mean Tpeak-Tend intervals, and Tpeak-Tend intervals from lead II and V5 were all significantly smaller than and poorly correlated with the dispersion of EOR-total, as were the QTpeak and QTend dispersions. These findings suggest that the maximal Tpeak-Tend interval may be used as a noninvasive estimate of the global DVR, but not the QTpeak and QTend dispersions, nor the mean Tpeak-Tend interval and that from a single lead. In Studies IV and V, global MAPs were recorded from the ventricular endocardium during right atrial (RA), RV apex endocardial (RVEndo) and LV laterobasal epicardial (LVEpi) pacing in 10 pigs, with ECG simultaneously recorded. During RA pacing, the EOR sequence followed the AT sequence in both ventricles. Strikingly, the EOR sequence was also consistent with the AT sequence in both ventricles during RVEndo and LVEpi pacing, even though the mapping was performed after an abrupt change of the pacing site. In all maps, there was a negative correlation between the MAP duration and the AT and a positive correlation between the EOR time and the AT under each pacing protocol. These findings suggest the importance of activation sequence in governing repolarization patterns. Significant changes in repolarization from an altered activation sequence may happen within a few hours in vivo, implying that electrical remodeling of the ventricles may be rapidly induced by altered activation sequence. In addition, the global dispersion of EOR times during LVEpi pacing was significantly greater than those during RA and RVEndo pacing, whereas no significant difference was found between those during RA and RVEndo pacing. In addition, the QT intervals, QT dispersion and Tpeak-Tend intervals during LVEpi pacing were all significantly greater than those during RA and RVEndo pacing These findings provide in vivo evidence supporting the involvement of increased DVR in the incidence of malignant ventricular arrhythmias in a subgroup of patients with biventricular pacing.
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