BACKGROUND Ejection intraventricular pressure gradients are caused by the systolic force developed by the left ventricle (LV). By postprocessing color Doppler M-mode (CDMM) images, we can measure noninvasively the ejection intraventricular pressure difference (EIVPD) between the LV apex and the outflow tract. This study was designed to assess the value of Doppler-derived EIVPDs as noninvasive i...

Starr's formula for deriving stroke volume from pulse pressure, diastolic pressure, and age has been tested experimentally in a group of miscellaneous hospital patients. Nearly simultaneous measurements of stroke volume by the direct Fick method and of brachial arterial pressure by direct puncture were analyzed. The measured stroke volume frequently differed considerably from the values calcula...

PURPOSE Despite the increasing popularity of marathon running, there are no data on the responses of stroke volume (SV) and cardiac output (CO) to exercise in this context. We sought to establish whether marathon performance is associated with the ability to sustain high fractional use of maximal SV and CO (i.e, cardiac endurance) and/or CO, per meter (i.e., cardiac cost). METHODS We measured...

In this study, a new ensemble averaging technique was developed to measure cardiac output during treadmill exercise. Each dz/dt peak is used as a starting point for ensemble averaging, instead of the conventionally used R point of ECG, in order to prevent the peak dz/dt waveform (C point) to be smoothed, which results in increased dz/dtmax. When using the R point as a reference, time interval f...

We tested the hypothesis that cardiovascular responses to lower body positive pressure (LBPP) would be dependent on the posture of the subject and also on the background condition (rest or exercise). We measured heart rate (HR), mean arterial blood pressure (MAP), and cardiac stroke volume in eight subjects at rest and during cycle ergometer exercise (76 +/- 3 W) with and without LBPP (25, 50, ...

AIM Recent findings have challenged the belief that the cardiac output (CO) and oxygen consumption (VO(2) ) relationship is linear from rest to maximal exercise. The purpose of this study was to determine the CO and stroke volume (SV) response to a range of exercise intensities, 40-100% of VO(2max), during cycling. METHODS Ten well-trained cyclists performed a series of discontinuous exercise...

Studies carried out in 21 patients have shown for the first time that alternation of the pulse pressure in man can occur independently in either the greater or the lesser circulation without appearing in the other. Even when bilateral alternation exists, this cyclic variation may disappear in one circulation while persisting in the other. Mechanisms responsible for pulsus alternans, in particul...

The ventricular volume and function changes induced by the addition of 12 cm H2O of positive end-expiratory pressure (PEEP) during mechanical ventilation were studied in 11 patients with the adult respiratory distress syndrome. Cardiac output was measured by thermodilution and ventricular ejection fraction by the multiple gated equilibrated cardiac blood pool scintigraphy. Right and left end-di...

The velocity and acceleration of aortic blood flow were measured by means of a catheter velocity probe in 40 patients during routine diagnostic cardiac catheterization. Ten different variables were derived from the aortic velocity measurements, and their ability to discriminate between good and bad left ventricular (LV) function was tested. By means of eight conventional indices of LV function ...

Background In theory, movement of the septum contributes to left ventricular stroke volume (LVSV) if the movement is toward the left ventricle (LV) in systole. If the septum movement is toward the right ventricle (RV), as in dyssynchrony, the septal contribution to LVSV decreases. In patients with increased volume load of the RV the septum may move towards the RV and contribute to right ventric...