This study was designed to evaluate the left ventricular systolic synchronization in patients implanted with dual-chamber DDD mode cardiac pacemakers by real-time three-dimensional echocardiography (RT3DE). Twenty patients implanted with DDD mode cardiac pacemakers for 12 months and 20 healthy subjects underwent RT3DE. This method provided left ventricular end-diastolic volume (LEDV), left vent...

Septal systolic motion is towards the left ventricle (LV) in healthy hearts. Patients with pulmonary regurgitation (PR) and right ventricular (RV) volume overload have systolic septal motion toward the RV. This may affect the longitudinal contribution from atrioventricular plane displacement (AVPD) and septal and lateral contribution to stroke volume (SV). The study aimed to quantify these cont...

The purpose of this study was to evaluate right ventricular (RV) loading and cardiac output changes, by using the thermodilution technique, during the mechanical ventilatory cycle. Fifteen critically ill patients on mechanical ventilation, with 5 cmH(2)O of positive end-expiratory pressure, mean respiratory frequency of 18 breaths/min, and mean tidal volume of 708 ml, were studied with help of ...

AIMS This study aimed to evaluate ventricular diastolic properties using three-dimensional echocardiography and tissue Doppler imaging at rest and during exercise in heart failure with preserved ejection fraction (HFpEF) patients with borderline evidence of diastolic dysfunction at rest. METHODS AND RESULTS Results obtained from 52 HFpEF patients (left ventricular ejection fraction ≥ 50%) ide...

Abbreviations: A wave late-filling wave; CW continuouswave; dP/dtmax positive maximum first derivative of pressure, corrected for time; Ea arterial elastance; E/A ratio of the early and rapid-filling wave to the late-filling wave; E wave early and rapid-filling wave; LA left atrium atrial; LAP left atrial pressure; LV left ventricle/ventricular; LVEDA left ventricular end-diastolic area; LVEDP ...

Aorta effectively buffers cardiac pulsatile fluctuation generated from the left ventricular (LV) which could be a mechanical force to high blood flow and low-resistance end-organs such as the brain. A dynamic orthostatic challenge may evoke substantial cardiac pulsatile fluctuation via the transient increases in venous return and stroke volume (SV). Particularly, this response may be greater in...

The OBJECTIVE was to estimate the left ventricular stroke volume calculated using Reuleaux triangle formula, and compare with parameters obtained from measurements in ventricle outflow tract. METHODS AND MATERIALS. A prospective cross-sectional study of dimensions tract (LVOT), aortic valve, velocity-time integral (VTI) carried out, followed by calculation LVOT valve 36 patients receiving renal...

A method for estimating the stroke volume (SV) from the systolic area of a single-channel record of the central aortic pressure has been tested in 12 anesthetized open-chest dogs. The formula used was SV = K>Psa-(l + Ts/Td), where Psa is the area under the systolic part of the curve above end-diastolic pressure, Ts and Td are the durations of systole and diastole, respectively, and K is an arbi...

Pericardial constraint and ventricular interaction influence left ventricular (LV) performance when preload is high. However, it is unclear if these constraining forces modulate LV filling when the heart is unloaded, such as during upright posture, in humans. Fifty healthy individuals underwent right heart catheterization to measure pulmonary capillary wedge (PCWP) and right atrial pressure (RA...

This study determined whether the decline in stroke volume (SV) during prolonged exercise is related to an increase in heart rate (HR) and/or an increase in cutaneous blood flow (CBF). Seven active men cycled for 60 min at approximately 57% peak O2 uptake in a neutral environment (i.e., 27 degrees C, <40% relative humidity). They received a placebo control (CON) or a small oral dose (i.e., appr...