The influence of calcium concentration in the bathing solution on the force-velocity relations of the isolated, electrically excited cat papillary muscle was examined. Shortening velocity was directly measured at minimum loads by unloading or load clamping the muscle from the preload (at the length, Lmax, where maximum active tension was developed) to 0 (zero-load clamp), 2, 5, 10, and 15% of t...

This study was undertaken to evaluate the cardiac dimensions and various indices of myocardial function, determined by echocardiography, in a group of 12 infants with congenital hypothyroidism. Left ventricular systolic and diastolic dimensions, posterior wall thickness, enddiastolic and systolic volumes were all significantly lower in the hypothyroid infants compared with 25 normal infants of ...

Forty-five symptomatic patients with aortic regurgitation underwent graded treadmill exercise testing before operation. Twenty-seven patients (group A) could not complete stage I of the National Institutes of Health exercise protocol because of limiting symptoms (exercise duration < 22.5 minutes); 18 patients (group B) completed this stage without limiting symptoms (exercise duration > 22.5 min...

Improved global or segmental wall motion following revascularization suggests potential reversibility of ischemic left ventricular dysfunction in coronary artery disease (CAD). This study evaluates the effectiveness of post-extra systolic potentiation (PESP) to detect latent residual contractile function. Quantitative left ventriculography was performed in 15 patients with CAD (including seven ...

Improved global or segmental wall motion following revascularization suggests potential reversibility of ischemic left ventricular dysfunction in coronary artery disease (CAD). This study evaluates the effectiveness of post-extra systolic potentiation (PESP) to detect latent residual contractile function. Quantitative left ventriculography was performed in 15 patients with CAD (including seven ...

The level of cardiac compensation in valvular disease was studied by relating echocardiographic and cardiac catheterization measurements. Three groups -- compensated, intermediately compensated, and decompensated -- were defined according to the left ventricular angiographic pattern and cardiac output. The echocardiographic ejection indices, percent left ventricular minor diameter shortening, e...

Improved global or segmental wall motion following revascularization suggests potential reversibility of ischemic left ventricular dysfunction in coronary artery disease (CAD). This study evaluates the effectiveness of post-extra systolic potentiation (PESP) to detect latent residual contractile function. Quantitative left ventriculography was performed in 15 patients with CAD (including seven ...

Myocarditis, the principal cause of dilated cardiomyopathy and heart failure in young adults, is associated with autoimmunity to human cardiac α-myosin (hCAM) and the DR4 allele of human major histocompatibility II (MHCII). We developed an hCAM-induced myocarditis model in human HLA-DR4 transgenic mice that lack all mouse MHCII genes, demonstrating that immunization for 3weeks significantly inc...

OBJECTIVE The M-mode-derived left ventricular shortening fraction is incorporated into most of the paediatric oncology protocols for monitoring of cardiotoxicity. This study tested the hypothesis that alteration of left ventricular myocardial deformation and mechanical dyssynchrony may occur in asymptomatic children after anthracycline therapy despite having left ventricular shortening fraction...