[Criteria for the evaluation of myocardial contractility of the hypertrophied and insufficient heart. II]

[Hemodynamics, left ventricular volumes and compliance in 167 patients with congenital and acquired heart disease (author's transl)]

In 167 patients with congenital and acquired heart disease (ventricular septum defect (VSD), atrial septum defect (ASD), mitral stenosis (MS), mitral insufficiency (MI), combined mitral stenosis and insufficiency (MV) aortic stenosis (AS), aortic insufficiency (AI), combined aortic stenosis and insufficiency (AV), idiopathic hypertrophic subaortic stenosis (HOK) hemodynamic measures (arterial pressure, right and left heart pressures, cardiac output, cardiac index, stroke volume, cardiac work), left ventricular volumes (endiastolic volume, endsystolic volume, ejection fraction, regurgitant flow) and diastolic pressure-volume relationships (on the basis of diastolic pressure-volume changes) were determined during routine right and left heart catheterization and left ventriculography. 1...

Experimental hyperthyroidism III: Contractile responses to propranolol of the intact heart and of the isolated ventricular myocardium

The effect of propranolol on cardiac mechanics and haemodynamics was examined on isolated papillary muscle as well as in situ in the closed thorax in euthyroid and hyperthyroid cats. Under propranolol there occurred on isolated papillary muscle significant decreases of muscle contraction, contraction velocity, isometric tension rise velocity and load and velocity values of simultaneously determined force-velocity relations. The 50% decrease of the values found was demonstrable at ca. 5--8 mu/ml for euthyroidal muscles, at 0.3--0.5 mug/ml for hyperthyroidal muscles. Contractility indices determined in situ (dp/dtmax, VCEmax, extrapolated Vmax) showed in hyperthyroidism at equal propranolol concentration a decrease about twice as great as in euthyroidism. The findings, showing a raised responsiveness of the ventricular myocardium in experimental hyperthyroidism to the negative inotropic effect of propranolol are discussed with regard to the therapeutic use of propranolol in hyperthyroidism.

Experimental hyperthyroidism I. Hemodynamics and contractility in situ

The influence of experimental hyperthyroidism (intraperitoneal injection of crystalline L-thyroxine 1 mg/kg/day, 8-18 days) on cardiac mechanics in contractility in situ were studied in 30 hyperthyroid cats and compared with an euthyroid control group (n equals 30). 1. In hyperthyroidism left ventricular weight was considerably increased. Hypertrophy in hyperthyroidism represents a special case of myocardial hypertrophy, associated with an increase of myocardial performance. 2. Heart rate, systolic pressure, cardiac index, external cardiac work and tension time index were increased by 60-180 per cent. 3. Indices of contractility (dp/dtmax, t-dp/dtmax, dp/dtmax/IP) as well as isovolumetric force velocity relationships and VCE-max and Vmax demonstrated a considerable increase of contractility. Maximum rate isovolumetric pressure fall was increased by 120 per cent. Experimental hyperthyroidism is characterized by hypercirculation associated with increases of pressure, volume and velocity factors. The results are discussed with regards to the effects of increased cardiac mechanics on myocardial energy balance.