The feasibility of using continuous on-line recording of intraventricular electrical impedance to measure ventricular stroke volume was assessed in 12 patients at cardiac catheterization with a multielectrode impedance catheter and a 1.3 kHz measuring current of 4 ,A. Stroke volumes determined by electrical impedance were compared with stroke volumes determined by the thermodilution technique i...

The flow of blood through the cardiovascular system depends on basic principles of liquid flow in tubes elucidated by Bernoulli and Poiseuille. The elementary equations are described involving pressures related to velocity, acceleration/deceleration, gravity, and viscous resistance to flow (Bernoulli-Poiseuille equation). The roles of vascular diameter and number of branches are emphasized. In ...

Ilemodynamic and echocardiographic measurements were obtained in 15 patients prior to cardioversion and immediately, one, three, and five hours after ca ,dioversion of atrial fibrillation to normal sinus rhythm1z4. j ve hours after cardioversion, there was improvement in cardiac index (P < 0.005), in stroke index (P <0.005)1and i11 stroke work index (P < 04)25), but no significant change in hea...

The goal of elucidating the biophysical and physiological basis of pressure-flow relations in the microcirculation has been a recurring theme since the first observations of capillary blood flow in living tissues. At the birth of the Microcirculatory Society, seminal observations on the heterogeneous distribution of blood cells in the microvasculature and the rheological properties of blood in ...

• Large animals have been used on numerous occasions by investigators pioneering in the field of cardiovascular research. The first recorded measurement of arterial blood pressure was made in the horse by Stephen Hales in .1733. Cardiac catheterization was first performed in a horse by Chauveau and Marey in 1861. One of the earliest applications of the Fick principle to the measurement of cardi...

The organization of goal-directed movements is a process central to the relationship between brain and behavior. In The Neural and Behavioral Organization of GoalDirected Movements, the author describes the cooperation between the neurological and musculoskeletal systems which produces mechanical movement. By nature, the subject is an interesting mixture of basic neurophysiology and abstract ps...

a high cardiac output and a lower than normal total peripheral resistance. It was our feeling, based on this original work, that this pattern might be an early phase or a benign type of essential hypertension. This is a report of the first follow-up study done on a group of such labile hypertensive patients in whom the hemodynamics and clinical status have been studied over a period of 50 month...