The influence of Ca2+ and Nitroprusside on the opening kinematics of the mitral valve

During a cardiac cycle the cardiac walls change between contracted and relaxed and the valves open and close in response to pressure changes. This master thesis is a study of the changes in heart movement pattern caused by intravenous injections of Ca2+ or Nitroprusside. At Stanford University radiopaque markers have been surgically implanted in the walls and in the mitral valve of ovine hearts and 3D coordinates for each marker have been constantly measured during the cardiac cycle. By using MatLab, the volume and pressure of the left ventricle and several parameters related to the opening kinematics of the mitral valve have been analyzed…


1 Introduction
1.1 Aims of this Master Thesis
2 Anatomy and Physiology
2.1 Anatomy
2.2 Physiology
2.2.1 The Cardiac Conduction System
2.2.2 Volumes in the Heart
2.2.3 Cardiac Muscle Contraction and its Dependence on Ca2+
2.2.4 The Effect of Sodium Nitroprusside (NIP) on the Heart
2.2.5 The Frank-Starling Mechanism (Length-Dependent Activa-tion)
3 Material
3.1 Data Acquisition
3.2 Parameter Calculations
4 Method
4.1 Setting the Interval
4.2 Parameter Investigation
4.3 Statistics
4.4 End-Systolic Pressure-Volume Relationship (ESPVR)
4.5 Volume of the Left Ventricle (LVV)
4.6 Distance Between Two Markers
4.7 Defining Moment of Opening
4.7.1 Method 1 – Mean Moment of Opening
4.7.2 Method 2 – Moment of Opening for one Animal
4.8 Movement Pattern of the Leaflets
4.8.1 Curvature (κ) in the xy-plane
4.8.2 Angles Between Leaflet Markers and Septal-Lateral Axis
4.8.3 Angular Velocity for Marker 34 around Marker 32, dα/dt
5 Results
5.1 End-Systolic Pressure-Volume Ratio, ESPVR
5.2 Left Ventricular Pressure (LVP)
5.3 Left Ventricular Volume (LVV)
5.4 Size and Shape of the Mitral Annulus
5.5 Distance Between Leaflet Edges, D3435
5.5.1 Maximum Distance Between Leaflet Edges, max D3435
5.6 Maximum Pressure Drop (-dP/dt|max)
5.7 Movement of the Leaflets
5.8 Curvature (κ) in the xy-plane
5.9 Leaflet Angles, θi
5.10 Angular Velocity (dα/dt)
6 Discussion
6.1 Conclusions
6.1.1 Ca2+
6.1.2 Nitroprusside
6.2 Circumstances that have to be Taken into Account and Alternative Methods
7 Future Work
7.1 3D Curvature
7.2 Average Flow Velocity Through the Mitral Valve
7.3 Papillary Muscle Markers and the Role of Chordae
7.4 New Marker Array
7.5 Volume Depletion

Author: Oom, Charlotte

Source: Linkoping University

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