Ventricular pump

It is characterized by severe, persisting pain, shock and hypotension with possible development of arrhythmias and is due to severe depression of systolic cardiac performance, systolic arterial pressure is below 80 mm Hg, low cardiac index, ventricular filling pressure is elevated and pulmonary edema may or may not be evident. The most frequent cause is infarction involving more than fourty percent of the left ventricular myocardiam, leading to a severe reduction in left ventricular contractility contradictively and failure of the left ventricular pump. 

Prinzen FW, Peschar M. Relation between the pacing induced sequence of activation and left ventricular pump function in animals. Pacing Clin Electrophysiol 2002 25(pt l) 484-98. 

The first case study of this chapter outlines the development of a model of left ventricular pumping. The model is devised from canine experiments and represents the left ventricle as a time, volume, and outflow-dependent pressure generator. In the course of model development, a new analytical method of measuring ventricular elastance emerges, with the potential of clarifying issues with previous elastance measurements. One application is a slight model expansion to study the cardiac pump theory of cardiopulmonary resuscitation (CPR). 

Sagawa, K. 1987. The ventricular pressure-volume diagram revisited. Circ. Res. 43 677-687. Campbell, K.B., Ringo, J.A., Knowlen, G., Kirkpatrick, R., and Schmidt, S.L. 1986. Validation of optional elastance-resistance left ventricular pump models. Am. J. Physiol. 251 H382-H397. 

Sagawa K. 1967. Analysis of the ventricular pumping capacity as a function of input and output pressure loads. In E.B. Reeve and A.C. Guyton (Eds.), Physical Bases of Circulatory Transport, pp. 141-149, Philadelphia, W.B. Saunders. 

Intra-aortic balloon piunps A balloon catheter inserted in the descending aorta and alternately inflated and deflated timed to the EKG in order to assist the ventricular pumping. 

FIGURE 54.5 Schematic diagram of left ventricular pressure-volume loops (a) End-systolic pressure-volume relation (ESPVR), end-diastolic pressure-volume relation (EDPVR) and stroke work. The three P-V loops show the effects of changes in preload and afterload, (b) Time-varying elastance approximation of ventricular pump function (see text). 

FIGURE 1.8 Electrical analog model to simulate atrial and ventricular pumping. Variable capacitances simulate the muscle contractions, and the filling and emptying through the ventricle can be simulated by a series of inductance and... 

The circulatory fluid is ejected by an electropneumatically driven ventricular pump. Downstream of the pump, an aortic valve assembly is located two different models have been built in order to offer lateral or frontal view of the prosthesis movements. Suitable stent adapters allow to test prostheses of different type and size. The aorta is a variable compliance rubber tube. Through a rigid conduit the fluid is conveyed to the laminar flow assembly which controls peripheral resistances. Aortic compliance and peripheral resistances are hydropneumatically controlled. The fluid, passing through a venous reservoir open to atmospheric pressure, reaches the left atrium. This is a rigid wall chamber in which a hydropneumatic system relates cardiac output to venous return, reproducing Frank--Starling s Law. Between atrium and ventricle there is another valve test assembly which allows to test mitral valves. 

Prophylactic Temporary Pacemaker Insertion. Approximately 1% of patients with acute myocardial infarction develop a Type n second-degree AV block. Although this rhythm is often tolerated hemodynamically, because there can be sudden progression to complete AV block, temporary pacing should be considered. New bundle-branch block (BBB) has been associated with an 18% risk of transient complete AV block (9-11). The development of BBB usually signifies an extensive infarction, typically involving the anterior wall. Death in these patients usually results from left ventricular pump failure, although 9% of deaths have been attributable to complete AV block (9). 

Figure 4. Equilibrium diagram for ventriculo-arterial coupling. See Figure 3 legend for explanation of the Ees and curves. Points 1 to 5 indicate equilibria between the ventricular pump performance and arterial impedance property under various conditions discussed in text. The ventricule is assumed to contract at a fixed end-diastolic volume of 35 ml...

Ghista DN and Ray G (1980) Cardiac assessment mechanics Left Ventricular mechanocardiography, a new approach to noninvasive intrinsic assessment of left ventricular pumping efficiency. Med Biol Eng Comput 18 344-352... 

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