During acute altitude exposure tachycardia increases cardiac output (Q) thus preserving systemic O2 delivery. Within days of acclimatization, however, Q normalizes following an unexplained reduction in stroke volume (SV). To investigate whether the altitude-mediated reduction in plasma volume (PV) and hence central blood volume (CBV) is the underlying mechanism we increased/decreased CBV by mea...

We investigated how parameters describing the heart and the arterial system contribute to the systolic and diastolic pressures (Ps and Pd, respectively) and stroke volume (SV). We have described the heart by the varying-elastance model with six parameters and the systemic arterial tree by the three-element windkessel model, leading to a total of nine parameters. Application of dimensional analy...

During incremental exercise, stroke volume (SV) plateaus at 40-50% of maximal exercise capacity. In healthy individuals, left ventricular (LV) twist and untwisting ("LV twist mechanics") contribute to the generation of SV at rest, but whether the plateau in SV during incremental exercise is related to a blunting in LV twist mechanics remains unknown. To test this hypothesis, nine healthy young ...

OBJECTIVES This study investigated the accuracy of mitral inflow quantification using biplane transesophageal echocardiography. BACKGROUND Mitral stroke volume can be reliably quantified by transthoracic Doppler echocardiography, but previous studies involving monoplane transesophageal echocardiography have yielded mixed results. METHODS Thirty patients without mitral regurgitation were pro...

The immediate effect of contrast medium injection on left ventricular (LV) volume, stroke volume (SV) and ejection fraction (EF) was evaluated from postoperative LV biplane cineangiograms of 10 patients with 4-6 epicardial markers placed at the time of coronary artery surgery. After calibrating marker distances with respect to volume (r = 0.97-0.99) over one cardiac cycle for each patient, regr...

BACKGROUND Decreased left ventricle ejection fraction (LVEF) is a predictor of poor late outcome in patients with mitral regurgitation (MR). The relationship between pre-operative forward stroke volume (SV) and right heart parameters and perioperative outcome in patients with MR has been little studied. METHODS Forty patients with severe organic MR, unsuitable for mitral valve repair, who und...

background: echocardiography is the most common test used for the evaluation of aortic regurgitation (ar). however, the role of echocardiography as an available and inexpensive method in the quantification of ar by the left ventricle to right ventricle stroke volume ratio (lv/rv sv ratio) has not been completely investigated. methods: between june 2005 and december 2007, 132 consecutive patient...

Background Heart failure (HF) is a condition characterized by increased filling pressures in the left ventricle due to altered cardiopulmonary blood flow. However, there are no clinically available non-invasive quantitative methods to measure filling pressures in HF. The pulmonary blood volume variation (PBVV) indexed to stroke volume (SV) by cardiac magnetic resonance (CMR) could be a novel no...

BACKGROUND The objective of this study was to test whether non-invasive assessment of respiratory stroke volume variation (ΔrespSV) by oesophageal Doppler monitoring (ODM) can predict fluid responsiveness during surgery in a mixed population. The predictive value of ΔrespSV was evaluated using a grey zone approach. METHODS Ninety patients monitored using ODM who required i.v. fluids to expand...

AIMS This study investigated the relationship between right ventricular (RV) structure and function and survival in idiopathic pulmonary arterial hypertension (IPAH). METHODS AND RESULTS In 64 patients, cardiac magnetic resonance, right heart catheterization, and the six-minute walk test (6MWT) were performed at baseline and after 1-year follow-up. RV structure and function were analysed as p...