Ambulatory Impedance Cardiography (eBook)

Ambulatory ImpedanceCardiography 2
Preface 5
Contents 7
List of Abbreviations 10
1 Introduction 12
1.1…The Importance of Monitoring Transient Changes 12
1.2…Non-invasive Recording of the Cardiac Parameters and its Significance 13
1.3…Ambulatory Monitoring and Implementations of it 13
1.4…Ambulatory Monitoring Using Impedance Cardiography Signals 14
References 15
2 Impedance Cardiography 17
2.1…Bioimpedance Measurement: Applications and Importance 17
2.2…Electrical Properties of the Biological Tissues 18
2.3…Tissue as a Conductor 19
2.4…Frequency and Current Values 20
2.5…Bioimpedance Measurement Methods 21
2.5.1 Biopolar and Tetrapolar Method 21
2.5.2 Alternating Constant-Current Source 21
2.5.3 Receiving Unit 22
2.5.4 Demodulation Unit 22
2.5.5 Automatic Balance Systems 23
2.6…Electrodes Types and Topography 23
2.6.1 Band Electrodes, Spot Electrodes and Mixed Spot/Band Electrodes 23
2.6.2 Other Solutions 24
2.7…Signal Description and Analysis 25
2.7.1 Impedance Cardiography Traces 25
2.7.2 Characteristic Points on Impedance Cardiography Curves 25
2.7.3 Characteristic Periods in Impedance Cardiography 27
2.7.4 Hemodynamic Indices 28
2.7.5 The Influence of Breathing 30
2.7.6 The Origin of the Impedance Cardiography Signals 31
2.7.7 The Methods of Stroke Volume Calculation 33
Nyboer Formula 33
Kubicek Formula 34
Sramek Formula 34
Sramek-Bernstein Formula 35
TaskForce Monitor Method 36
PhysioFlow Method 36
2.7.8 Blood Resistivity Impact 38
2.8…Signal Conditioning 38
2.8.1 Ensemble Averaging Method 39
2.8.2 Large-Scale Ensemble Averaging Method 40
2.9…Technical Aspects of ICG-Limitations, Errors and Patients’ Safety 40
2.10…Modifications of ICG, and Other Impedance Techniques 41
2.11…Physiological and Clinical Applications of Impedance Cardiography 41
2.12…Conclusions 42
References 43
3 Ambulatory Impedance Cardiography 48
3.1…The Idea of Ambulatory Impedance Cardiography 48
3.2…ReoMonitor: The Research System 49
3.2.1 The Ambulatory Recorder 50
3.2.2 The Analogue Unit 50
3.2.3 The Digital Unit 52
3.2.4 The User Interface 53
3.2.5 Software for Hemodynamics Parameters Calculations 54
3.3…VU-AMS: The Vrije Universiteit Ambulatory Monitoring System 56
3.4…MW1000A: The MindWare System 58
3.5…PhysioFlow Enduro System 58
3.6…AIM-8-V3: Wearable Cardiac Performance Monitor 60
3.7…Ambulatory Impedance Cardiograph: AZCG 62
3.8…Other Systems 63
References 64
4 Validation of the Ambulatory Impedance Cardiography Method 66
4.1…Introduction 66
4.2…Validation using Reference Methods 67
4.2.1 Background and Motivation 67
4.2.2 Experimental Studies 68
4.2.3 Results of the Own Experimental Studies 69
Stroke Volume 69
Ejection Time 70
Pre-ejection Period 72
4.2.4 Discussion and Conclusions 72
4.3…The Quality of the Ambulatory Impedance Cardiography Recordings 73
4.3.1 Background and Motivation 73
4.3.2 Experimental Studies 74
4.3.3 Results of the Experimental Studies 75
4.3.4 Discussion and Conclusions 76
References 78
5 Clinical and Physiological Applications of Impedance Cardiography Ambulatory Monitoring 81
5.1…Introduction 81
5.2…Atrial Fibrillation 82
5.3…Ventricular Extrasystole Beats (VEB) Monitoring 86
5.4…Ambulatory ICG and Pacemaker Monitoring 90
5.4.1 Cardiac Pacing Optimisation 90
5.4.2 Pacemaker Syndrome Detection 92
5.5…Cardiac Parameters Monitoring During the Tilt Test 94
5.6…Other Applications 99
References 101
6 Final Conclusions and Future Directions 107
6.1…Prospects for Impedance Ambulatory Monitoring 107
6.2…Clinical Importance of the Ambulatory Impedance Cardiography Monitoring 108
References 109
Appendix 111
Ambulatory Impedance Cardiography System: Reomonitor 111
The Vrije Universiteit Ambulatory Monitoring System: Specifications and Features 112
The MindWare MW1000A System: Specification and Features 114
The PhysioFlow Enduro System: Specification and Features 115
AIM-8-V3 Wearable Cardiac Performance Monitor 116
Ambulatory Impedance Cardiograph: AZCG 117
The Useful Links to Ambulatory Monitoring and Impedance Cardiography Web Pages 118
Index 119