| 1. |
- Almer, Jakob, et al.
(författare)
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Ischemic QRS prolongation as a biomarker of severe myocardial ischemia.
- 2016
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 49:2, s. 139-147
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies have shown that QRS prolongation is a sign of depressed collateral flow and increased rate of myocardial cell death during coronary occlusion. The aims of this study were to evaluate ischemic QRS prolongation as a biomarker of severe ischemia by establishing the relationship between prolongation and collateral flow experimentally in a dog model, and test if the same pattern of ischemic QRS prolongation occurs in man.
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| 2. |
- Almer, Jakob, et al.
(författare)
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Prevalence of manual Strauss LBBB criteria in patients diagnosed with the automated Glasgow LBBB criteria.
- 2015
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 48:4, s. 558-564
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Tidskriftsartikel (refereegranskat)abstract
- About one-third of patients undergoing cardiac resynchronization therapy because of left bundle branch block (LBBB) and heart failure do not improve. Strauss et al. have developed strict criteria to more accurately define complete LBBB in this patient group. The aim of this study was to investigate the prevalence of the manual application of the Strauss criteria for LBBB (QRS≥140ms in men, ≥130ms in women, along with mid-QRS notching/slurring) in consecutive patients who have been diagnosed with LBBB by the automated Glasgow criteria (QRS≥120ms).
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| 3. |
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| 5. |
- Floyd, James S, et al.
(författare)
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Effects of ischemic preconditioning and arterial collateral flow on ST-segment elevation and QRS complex prolongation in a canine model of acute coronary occlusion.
- 2009
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Ingår i: Journal of electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 42:1, s. 19-26
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: During acute myocardial infarction, both ST elevation and QRS distortion on the initial electrocardiogram (ECG) have been correlated with poorer prognosis. Studies in dogs and humans suggest that these ECG markers provide information about myocardial protection from both collateral blood flow and ischemic preconditioning. METHODS: In a protocol designed to precondition the heart with ischemia, we examined both ST-segment elevation and QRS complex prolongation in lead II of the ECG in 23 mongrel dogs during the first and fourth episode of 5 minutes of left circumflex artery occlusion. Myocardial collateral flow was measured during each of these episodes by injection of radioactive microspheres 2.5 minutes into the episode of ischemia. RESULTS: During ischemia, the degree of elevation of the ST segments was reduced markedly in hearts preconditioned with ischemia and/or in hearts with the greatest amounts of collateral arterial flow. During the first episode of ischemia, the ST segments increased to a similar extent in severe and moderate ischemia, but less in hearts in which the ischemia was mild. However, marked QRS prolongation was present only in hearts with severe ischemia, and decreased when the hearts were preconditioned. In addition, large ischemic beds exhibited the most marked QRS prolongation, whereas small but even severely ischemic beds showed little or no change in QRS duration. CONCLUSION: Both ST elevation and QRS prolongation are reduced by the presence of collateral flow and ischemic preconditioning. The QRS complex merits further study as an important marker of the degree of myocardial protection during human acute myocardial ischemia/infarction.
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| 6. |
- Hakacova, Nina, et al.
(författare)
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Aspects of Left Ventricular Morphology Outperform Left Ventricular Mass for Prediction of QRS Duration
- 2010
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Ingår i: Annals of Noninvasive Electrocardiology. - 1082-720X. ; 15:2, s. 124-129
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Tidskriftsartikel (refereegranskat)abstract
- Methods: The study population of healthy adult volunteers was divided into a sample for development of a prediction model (n = 63) and a testing sample (n = 30). Magnetic resonance imaging data were used to assess anatomical characteristics of the left ventricle: the angle between papillary muscles (PMA), the length of the left ventricle (LVL) and left ventricular mass (LVM). Twelve-lead electrocardiogram (ECG) was used for measurement of the QRS duration. Multiple linear regression analysis was used to develop a prediction model to estimate the QRS duration. The accuracy of the prediction model was assessed by comparing predicted with measured QRS duration in the test set. Results: The angle between PMA and the length of the LVL were statistically significant predictors of QRS duration. Correlation between QRS duration and PMA and LVL was r = 0.57, P = 0.0001 and r = 0.45, P = 0.0002, respectively. The final model for prediction of the QRS was: QRS(Predicted) = 97 + (0.35 x LVL) - (0.45 x PMA). The predicted and real QRS duration differed with median 1 ms. Conclusions: The model for prediction of QRS duration opens the ability to predict case-specific normal QRS duration. This knowledge can have clinical importance, when determining the normality on case-specific basis. Ann Noninvasive Electrocardiol 2010;15(2):124-129.
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| 7. |
- Hakacova, Nina, et al.
(författare)
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Comprehensive echocardiographic imaging of atrioventricular valves in children with atrioventricular septal defect : Accuracy of 2D and 3D imaging and reasons for disagreement
- 2019
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Ingår i: The Anatolian Journal of Cardiology. - 2149-2263. ; 21:4, s. 214-221
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To compare the accuracy and reasons for disagreement of two-dimensional (2D) and three-dimensional (3D) echocardiography findings in the assessment of the atrioventricular valve complex in patients with atrioventricular septal defect. METHODS: A total of 20 children (mean age 8 months) with atrioventricular septal defect were enrolled prospectively into this study. The accuracy of and the reasons for disagreement in the assessment of the atrioventricular valve features were analyzed between 2D and 3D echocardiography and surgical findings. RESULTS: We found that in assessing the Rastelli type and the extension of the inferior leaflet into the right ventricle, 3D echocardiography was more accurate compared to 2D echocardiography. In all other features, 2D and 3D echocardiography showed similar accuracy. A significant reason for inaccuracy by both echo modalities was that the technique itself could not visualize the feature, although the image quality was considered to be adequate. In most cases, where it was not possible to visualize the atrioventricular feature by 2D, it was possible by 3D, and vice versa. CONCLUSION: The accuracy of 2D and 3D echocardiography and understanding the potential reasons for disagreements in assessing the atrioventricular valve complex with 2D and 3D can guide the use of those two techniques when combining them in the clinical practice.
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| 8. |
- Hakacova, Nina, et al.
(författare)
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Computer-based rhythm diagnosis and its possible influence on nonexpert electrocardiogram readers.
- 2012
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 45, s. 18-22
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Systems providing computer-based analysis of the resting electrocardiogram (ECG) seek to improve the quality of health care by providing accurate and timely automatic diagnosis of, for example, cardiac rhythm to clinicians. The accuracy of these diagnoses, however, remains questionable. OBJECTIVES: We tested the hypothesis that (a) 2 independent automated ECG systems have better accuracy in rhythm diagnosis than nonexpert clinicians and (b) both systems provide correct diagnostic suggestions in a large percentage of cases where the diagnosis of nonexpert clinicians is incorrect. METHODS: Five hundred ECGs were manually analyzed by 2 senior experts, 3 nonexpert clinicians, and automatically by 2 automated systems. The accuracy of the nonexpert rhythm statements was compared with the accuracy of each system statement. The proportion of rhythm statements when the clinician's diagnoses were incorrect and the systems instead provided correct diagnosis was assessed. RESULTS: A total of 420 sinus rhythms and 156 rhythm disturbances were recognized by expert reading. Significance of the difference in accuracy between nonexperts and systems was P = .45 for system A and P = .11 for system B. The percentage of correct automated diagnoses in cases when the clinician was incorrect was 28% ± 10% for system A and 25% ± 11% for system B (P = .09). CONCLUSION: The rhythm diagnoses of automated systems did not reach better average accuracy than those of nonexpert readings. The computer diagnosis of rhythm can be incorrect in cases where the clinicians fail in reaching the correct ECG diagnosis.
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| 9. |
- Hedén, Bo, et al.
(författare)
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A modified Anderson-Wilkins electrocardiographic acuteness score for anterior or inferior myocardial infarction.
- 2003
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Ingår i: American Heart Journal. - 1097-6744. ; 146:5, s. 797-803
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Tidskriftsartikel (refereegranskat)abstract
- Background Optimal treatment of acute myocardial infarction (AMI) depends on the duration of the ischemia. The Anderson Wilkins (AW) electrocardiographic acuteness score has been shown to complement the historical timing in estimating the time interval from acute thrombotic coronary occlusion in patients presenting with chest pain and evolving myocardial infarction. The purposes of this study were to (1) compare the distributions of the previously developed AW acuteness score in a training population with either anterior or inferior AMI and (2) propose modifications to the formula to achieve distributions similar to the observed distributions of historical times from onset of pain. Methods Two hundred three and 177 patients were included as training and testing population, respectively. All patients had an anterior or an inferior AMI and were without confounding factors on the electrocardiogram. Results The training population had similar distributions of historical times from onset of pain, but differences in distributions of AW acuteness scores, between patients with anterior and inferior AMI (P<.0001). Eighty percent of the inferior AMI group had the highest possible AW acuteness score. Modification of a Q-wave criterion from &GE;30 to &GE;20 ms resulted in similar distributions in patients with anterior and inferior AMI both in the training and an independent testing population. Conclusions These results suggest that a modified AW acuteness score using a lower Q-wave duration criterion provides similar AMI timing information in patients with anterior and inferior locations. Clinical use of the AW acuteness score will only be practical if the calculation is automated
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| 10. |
- Low, Liying, et al.
(författare)
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The comparative relationships between locations of the papillary muscles and electrophysiologic QRS axis in patients with atrioventricular septal defect and common as opposed to separate orifices in the valve guarding the common atrioventricular junction
- 2017
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Ingår i: Cardiology in the Young. - 1047-9511. ; 27:2, s. 261-266
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Tidskriftsartikel (refereegranskat)abstract
- Background: Knowledge regarding factors that influence deviation of the QRS axis is important when seeking to differentiate between physiological and pathological changes. We hypothesised that, in contrast to those patients with an atrioventricular septal defect and common atrioventricular junction permitting only atrial shunting, those associated with ventricular shunting would show no relationship between the positions of the papillary muscles and the degree of the leftward deviation of the QRS axis. Methods: We compared the positions of endocardial origin of the papillary muscles, and the frontal plane QRS axis, in patients with atrioventricular septal defects and common atrioventricular junction permitting exclusively atrial as opposed to atrial and ventricular shunting. Results: We analysed 18 patients with atrial and ventricular shunting and 23 patients with exclusively atrial shunting. The correlation coefficient between the ratio of distances of the papillary muscles from the mid-septum and the amount of leftward deviation in the frontal plane QRS axis was 0.1 (p=0.4) in those with ventricular shunting and 0.26 (p=0.01) in those with exclusively atrial shunting. Conclusions: In contrast to patients with the so-called primum form of atrioventricular septal defect, in whom the locations of the papillary muscles correlate with the degree of QRS axis, such relationships are lacking in patients with defects permitting both atrial and ventricular shunting. It may be, therefore, that the presence of ventricular shunting and/or their younger age causes pressure overload, which negates the leftward QRS forces caused by the abnormally positioned papillary muscles.
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