BACKGROUND High-intensity ultrasound pulses intermittently triggered from an ECG signal can interact with circulating contrast agent microbubbles to produce myocardial cavitation microlesions of potential therapeutic value. In this study, the timing of therapy pulses relative to the ECG R wave was investigated to identify the optimal time point for tissue reduction therapy with regard to both t...

We investigate the behaviour of a dynamic fluid-structure interaction model of a chorded polyurethane mitral valve prosthesis, focusing on the effects on valve dynamics of including descriptions of the bending stiffnesses of the valve leaflets and artificial chordae tendineae. Each of the chordae is attached at one end to the valve annulus and at the other to one of two chordal attachment point...

Background: Cardiac dysfunction due to chronic anemia and hemosiderosis are the major causes of death among patients with thalassemia intermedia. This study was performed to compare the cardiac function in thalassemia intermedia patients with normal subjects by means of echocardiography. Materials and Methods: This was a case-control study performed on 22 patients affected by thalassemia int...

To cite: Gillebert TC, De Pauw M, Timmermans F. Heart 2013, 99, 55–64. The concepts related to diastolic function were developed by muscle physiologists and by cardiologists with a strong background in physics (cardiac mechanics and fluid dynamics). These scientists described left ventricular (LV) material properties in terms of pressures and volumes, and their mutual relation. When a given vol...

Titin, a giant protein spanning half the sarcomere, is responsible for passive and restoring forces in cardiac myofilaments during sarcomere elongation and compression, respectively. In addition, titin has been implicated in the length-dependent activation that occurs in the stretched sarcomere, during the transition from diastole to systole. The purpose of this study was to investigate the rol...

Diastolic dysfunction contributes significantly to the clinical syndrome of congestive heart failure in the settings of both preserved and impaired left ventricular (LV) systolic function.1,2 Over the past 20 years, the clinical diagnosis of diastolic dysfunction has been based largely on echocardiographic Doppler parameters of LV filling.3 The most important limitation of these parameters is t...

This article presents a new method for measuring longitudinal strain in a short-axis section of the heart using harmonic phase magnetic resonance imaging (HARP-MRI). The heart is tagged using 1-1 SPAMM at end-diastole with tag surfaces parallel to a short-axis imaging plane. Two or more images are acquired such that the images have different phase encodings in a direction orthogonal to the imag...

A central problem in biomechanical studies of personalized human left ventricular (LV) modelling is to estimate material properties from in vivo clinical measurements. In this work we evaluate the passive myocardial mechanical properties inversely from the in vivo LV chamber pressure-volume and strain data. The LV myocardium is described using a structure-based orthotropic Holzapfel-Ogden const...

We study the phase-synchronization properties of systolic and diastolic arterial pressure in healthy subjects. We find that delays in the oscillatory components of the time series depend on the frequency bands that are considered, in particular we find a change of sign in the phase shift going from the very low frequency band to the high frequency band. This behavior should reflect a collective...

Cardiac resynchronization therapy (CRT) has been shown to improve quality of life, increase cardiac output, enhance functional class, and reduce mortality in patients with cardiomyopathy and mechanical dyssynchrony. For pacemaker-dependent patients, the addition of a left ventricular (LV) lead most often leads to a reduction of QRS morphology of 30%, compared with right ventricular pacing alone...