THAT THE catechol amines or cardiac sympathetic nerve stimulation will increase the vigor of ventricular contraction has been established." Further, it is now known that the ventricle will contract more forcefully from any given filling pressure under these influences." The early studies of Anrep and other more recent studies" indicate that a changed myocardial extensibility cannot, of itself, ...

The relation of the Doppler transmitral flow velocity profile to left ventricular loading conditions and diastolic properties remains poorly described. We studied seven adult mongrel dogs with an open-chest right heart bypass model in which left atrial pressure, representing preload, was varied by controlling blood flow into the pulmonary artery and left ventricular systolic pressure, represent...

Arterial pulse pressure has been widely used as surrogate of stroke volume, for example, in the guidance of fluid therapy. However, recent experimental investigations suggest that arterial pulse pressure is not linearly proportional to stroke volume. However, mechanisms underlying the relation between the two have not been clearly understood. The goal of this study was to elucidate how arterial...

AUTHORS' SYNOPSIS In dogs the effects of acute myocardial infarction (AMI) on right and left heart pressure relationships were studied. Right atrial pressure was a poor predictor of left heart pressures. Pulmonary artery end-diastolic, left atrial, and left ventricular end-diastolic pressures tended to equalize in normals (except with tachycardia) and after AMI. In a previously scarred left ven...

BACKGROUND The effects of volatile anesthetics on left atrial function in vivo have not been described. The authors tested the hypothesis that desflurane, sevoflurane, and isoflurane alter left atrial mechanics evaluated with invasively derived pressure-volume relations. METHODS Barbiturate-anesthetized dogs (n = 24) were instrumented for measurement of aortic, left atrial, and left ventricul...

BACKGROUND Desflurane and sevoflurane have negative inotropic effects. The current study investigated whether these effects resulted in an altered left ventricular response to increased cardiac load and affected length-dependent regulation of myocardial function. Length-dependent regulation of myocardial function refers to the ability of the heart to improve its performance when preload is incr...

We investigated the effects of nifedipine on left ventricular diastolic function in 17 asymptomatic or minimally symptomatic patients with hypertrophic cardiomyopathy by simultaneously measuring left ventricular pressure and volume with a catheter-tipped manometer and biplane cineangiography. Studies were performed before and 20 minutes after sublingual administration of nifedipine (20 mg). Hea...