Acute haemodynamic effects of ibopamine and dopamine on isovolumic relaxation.

The effects of intraduodenal ibopamine (a new orally active inotropic agent claimed to have haemodynamic effects similar to dopamine) on isovolumic relaxation were monitored for 90 min in eight closed-chest anaesthetized dogs. Dopamine and epinine (ibopamine active metabolite) were also infused at graded doses. After 15 min, ibopamine (12 mg/kg) shortened the time constant of isovolumic relaxation, and increased stroke volume and mean aortic pressure.

Microcomputer-aided diagnosis in cardiology. An expert system based on clinical and phono-mechanocardiographic data.

A knowledge-based consultation system capable of making multiple diagnoses in noninvasive cardiology is presented here. The system, expressly designed for a personal computer, is able to provide assistance in the diagnosis of 49 disease-entities. When tested in 52 retrospective cases (33 patients with one disease-entity, 17 with two, 2 with three), it made 39 correct diagnoses (75%).

Silent ischaemia in post-myocardial infarction patients submitted to physical training.

Recently, more attention has been focused on the detection and treatment of silent myocardial ischaemia. Electrocardiographic signs of exercise-induced asymptomatic myocardial ischaemia are very common findings among survivors of acute myocardial infarction. From data of our population we found that silent exercise-induced ischaemia is present in 15-20% of all patients, and that about half of the patients with exercise-induced ST-segment depression were free of symptoms.

Load dependence of isovolumic relaxation in intact heart: facts or artifacts?

In order to study the dependence of left ventricular isovolumic relaxation on preload, afterload, and contractility the effects of infusions of dextran, phenylephrine, and dobutamine were assessed in 10 closed chest anaesthetised dogs. Left ventricular and aortic pressures and left ventricular transverse diameters were measured by micromanometers and a tracking sonomicrometer. Isovolumic relaxation time constant was computed by two different single exponential models: the first (time constant Tw) assumed the horizontal asymptote as equal to zero, whereas the second (time constant Tl) assumed a variable asymptote (Pb).