Vectorcardiography

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Mikael Dellborg - One of the best experts on this subject based on the ideXlab platform.

  • Computerized Vectorcardiography Telemetry: A New Device for Continuous Multilead ST‐Segment Monitoring of Ambulatory Patients. A Preliminary Report
    Annals of Noninvasive Electrocardiology, 2002
    Co-Authors: Bjarne L. Nørgaard, Kristian Thygesen, Claus Sørensen, Thomas Larsen, Mikael Dellborg
    Abstract:

    Background: Continuous Vectorcardiography ST-segment monitoring has become a well-established method in the surveillance of patients with acute myocardial ischemia. However, immobility of the Vectorcardiography technique prevents monitoring of patients during ambulatory activities. Computerized Vectorcardiography telemetry (CVT) with the capacity of real-time ST-segment analysis has been developed in an attempt to overcome this shortcoming. Recent data, however, indicate that changes in body position occasionally lead to pseudo-ischemic ST-segment changes during continuous ST-segment monitoring. Aims: This report describes the technical features of the CVT system, presents clinical examples using CVT, and assesses the influence of changes in body position on ST-vector magnitude (ST-VM) during CVT, respectively. Methods: Clinical cases involving CVT are presented. The influence of changing body position during CVT monitoring was evaluated on 24 patients with suspected acute coronary syndromes, i.e., unstable angina or acute myocardial infarction. Each patient performed a specific body positional schedule. Results: We present three discrete clinical cases where CVT provided early and valuable evidence of ongoing myocardial ischemia. The consequences of different recumbent and ambulatory body positions on ST-VM during CVT monitoring appear to be limited. Conclusion: Computerized Vectorcardiography telemetry is a promising new tool for disclosing residual myocardial ischemic activity during the mobilization phase of patients with acute coronary syndromes. The clinical value of CVT needs further investigation in future trials. A.N.E. 2002;7(3):204–210

  • Comparison of continuous Vectorcardiography and continuous 12-lead electrocardiography of patients with unstable coronary artery disease: do they identify the same population?
    Coronary Artery Disease, 2001
    Co-Authors: Tomas Jernberg, Lars Wallentin, Bertil Lindahl, Putte Abrahamsson, Mikael Dellborg
    Abstract:

    Comparison of continuous Vectorcardiography and continuous 12-lead electrocardiography of patients with unstable coronary artery disease : do they identify the same population?

  • Positional changes of spatial QRS- and ST-segment variables in normal subjects: implications for continuous Vectorcardiography monitoring during myocardial ischemia.
    Journal of Electrocardiology, 2000
    Co-Authors: Bjarne L. Nørgaard, Birthe M. Rasmussen, Mikael Dellborg, Kristian Thygesen
    Abstract:

    Abstract Electrocardiographic QRS- and ST-segment changes are to beexpected during changes in body posture. We prospectively analyzed the influence of changes in body position on continuous Vectorcardiography monitoring of QRS-vector difference (QRS-VD) and ST change-vector magnitude (STC-VM) according to the currently used criteria of myocardial ischemia in 21 normal subjects. Fifteen (71%)and 6 (29%) subjects had significant positional QRS-VD and STC-VM changes, respectively. Vectorcardiography changes were most frequent and pronounced in the left lateral position. An alternative to the existing criterion of ischemia is proposed to improve the specificity of STC-VM. Subjects with positional QRS-VD changes had higher mean STC-VM values as compared with those without such changes. Otherwise no characteristics among those with positional Vectorcardiography changes could be identified. There was no statistically significant association between positional QRS-VD and STC-VM changes ( R = .13, P = .57). We conclude that the clinical use of QRS-VD in its present form for continuous Vectorcardiography monitoring of myocardial ischemia seems to be of limited practical value, because of the presence of frequent “pseudo- ischemic” changes. STC-VM seems to have a significant potential of continuous Vectorcardiography monitoring. However, an indicator of body position change or even an algorithm enabling on-line correction for positional Vectorcardiography changes seems to be essential to improve the accuracy of this technique in identifying myocardial ischemia.

  • Diagnosis of acute myocardial infarction in patients with chronic left bundle-branch block. Standard 12-lead ECG compared to dynamic Vectorcardiography.
    Scandinavian Cardiovascular Journal, 1999
    Co-Authors: Peter Eriksson, Gunnar Gunnarsson, Mikael Dellborg
    Abstract:

    Standard 12-lead electrocardiogram (ECG) criteria were evaluated and compared with dynamic Vectorcardiography for diagnosing acute myocardial infarction in 33 patients with chronic left bundle-branch block. In 14 patients a clinical diagnosis of acute myocardial infarction was made, but it was found that none of the seven most promising ECG criteria suggested in the literature could alone or in combination diagnose acute myocardial infarction. QRS vector difference evolution showed the same kind of pattern as that for patients with narrow QRS-complex. By using a predefined specific pattern, a diagnostic accuracy of 79% was achieved. The results indicate that dynamic Vectorcardiography is a better tool for diagnosing and monitoring acute myocardial infarction in patients with left bundle-branch block than standard 12-lead ECGs taken on admission and after 12-24 h.

  • Dynamic Vectorcardiography for early diagnosis of acute myocardial infarction compared with 12-lead electrocardiogram. BIOMACS Study Group.
    Coronary Artery Disease, 1996
    Co-Authors: Gunnar Gustafsson, Mikael Dellborg, Bertil Lindahl, Lars Wallentin
    Abstract:

    Dynamic Vectorcardiography for early diagnosis of acute myocardial infarction compared to 12-lead ECG

M Dellborg - One of the best experts on this subject based on the ideXlab platform.

  • heparin is more effective than inogatran a low molecular weight thrombin inhibitor in suppressing ischemia and recurrent angina in unstable coronary disease thrombin inhibition in myocardial ischemia trim study group
    American Journal of Cardiology, 1998
    Co-Authors: K Andersen, M Dellborg
    Abstract:

    Thrombin has been suggested as one of the main pharmacologic targets in unstable coronary syndromes. Electrocardiographic signs of ischemia during continuous monitoring convey prognostic information in these patients. This study assessed the anti-ischemic and clinical effects of the novel low-molecular weight thrombin inhibitor inogatran in patients with unstable angina and non-Q-wave infarction without persistent ST-segment elevation on hospital admission. Within 24 hours of the last episode of chest pain, 324 patients were randomized to 72 hours of treatment with inogatran or heparin. Continuous ST-segment analysis with computerized Vectorcardiography was used to monitor ischemia for 24 hours. The occurrence of cardiac events during the first 7 days were studied and compared with ischemic episodes during the initial 24 hours. The heparin-treated patients had less episodes of ischemia (ST vector magnitude [ST-VM]: 1 +/- 2.6 vs 2 +/- 4.5, p < 0.001 and ST change vector magnitude [STC-VM]: 3 +/- 4.7 vs 6 +/- 7.6, p < 0.001) than the patients receiving inogatran. This was paralleled by a lower incidence of the combined end point of death, nonfatal infarction, refractory or recurrent angina during the first 7 days for the heparin-treated patients (35%) compared with the inogatran-treated patients (50%) (p < 0.05). Patients who had episodes of ischemia in spite of anti-ischemic therapy were at increased risk of all events studied. Heparin is more effective than inogatran in suppressing myocardial ischemia and clinical events at short-term follow-up. Continuous ST-segment monitoring with Vectorcardiography identifies nonresponders who are at an increased level of risk.

  • Key factors in the identification of the high-risk patient with unstable coronary artery disease: clinical findings, resting 12-lead electrocardiogram, and continuous electrocardiographic monitoring.
    The American journal of cardiology, 1997
    Co-Authors: M Dellborg, K Andersen
    Abstract:

    This article reviews a range of methods for identifying high-risk patients with unstable coronary artery disease, including clinical evaluation, the resting 12-lead electrocardiogram, continuous Vectorcardiography, and a combined risk evaluation using continuous Vectorcardiography and measurement of troponin-T. Clinical evaluation is not very accurate for identifying high-risk patients and modern techniques have not been fully validated in clinical trials. The combination of continuous Vectorcardiography and biochemical monitoring is a very powerful method of identifying both very high- and very low-risk patients and may be increasingly used in the future.

K Andersen - One of the best experts on this subject based on the ideXlab platform.

  • heparin is more effective than inogatran a low molecular weight thrombin inhibitor in suppressing ischemia and recurrent angina in unstable coronary disease thrombin inhibition in myocardial ischemia trim study group
    American Journal of Cardiology, 1998
    Co-Authors: K Andersen, M Dellborg
    Abstract:

    Thrombin has been suggested as one of the main pharmacologic targets in unstable coronary syndromes. Electrocardiographic signs of ischemia during continuous monitoring convey prognostic information in these patients. This study assessed the anti-ischemic and clinical effects of the novel low-molecular weight thrombin inhibitor inogatran in patients with unstable angina and non-Q-wave infarction without persistent ST-segment elevation on hospital admission. Within 24 hours of the last episode of chest pain, 324 patients were randomized to 72 hours of treatment with inogatran or heparin. Continuous ST-segment analysis with computerized Vectorcardiography was used to monitor ischemia for 24 hours. The occurrence of cardiac events during the first 7 days were studied and compared with ischemic episodes during the initial 24 hours. The heparin-treated patients had less episodes of ischemia (ST vector magnitude [ST-VM]: 1 +/- 2.6 vs 2 +/- 4.5, p < 0.001 and ST change vector magnitude [STC-VM]: 3 +/- 4.7 vs 6 +/- 7.6, p < 0.001) than the patients receiving inogatran. This was paralleled by a lower incidence of the combined end point of death, nonfatal infarction, refractory or recurrent angina during the first 7 days for the heparin-treated patients (35%) compared with the inogatran-treated patients (50%) (p < 0.05). Patients who had episodes of ischemia in spite of anti-ischemic therapy were at increased risk of all events studied. Heparin is more effective than inogatran in suppressing myocardial ischemia and clinical events at short-term follow-up. Continuous ST-segment monitoring with Vectorcardiography identifies nonresponders who are at an increased level of risk.

  • Key factors in the identification of the high-risk patient with unstable coronary artery disease: clinical findings, resting 12-lead electrocardiogram, and continuous electrocardiographic monitoring.
    The American journal of cardiology, 1997
    Co-Authors: M Dellborg, K Andersen
    Abstract:

    This article reviews a range of methods for identifying high-risk patients with unstable coronary artery disease, including clinical evaluation, the resting 12-lead electrocardiogram, continuous Vectorcardiography, and a combined risk evaluation using continuous Vectorcardiography and measurement of troponin-T. Clinical evaluation is not very accurate for identifying high-risk patients and modern techniques have not been fully validated in clinical trials. The combination of continuous Vectorcardiography and biochemical monitoring is a very powerful method of identifying both very high- and very low-risk patients and may be increasingly used in the future.

Peter Lundin - One of the best experts on this subject based on the ideXlab platform.

Sven V. Eriksson - One of the best experts on this subject based on the ideXlab platform.