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J F Spann

Publications and source records attributed to J F Spann.

125 records · Page 7Linked to original sources
PubMed1967

Influence of the thyroid state on the intrinsic contractile properties and energy stores of the myocardium.

The intrinsic contractile properties of isolated cat papillary muscles and myocardial high energy phosphate stores were examined at three levels of thyroid activity and correlated with hemodynamic measurements in the intact animal. In addition, the relationship of thyroid state to endogenous norepinephrine stores and myocardial responsiveness to certain inotropic interventions were studied. In muscles from hyperthyroid cats, the velocity of shortening and the rate of tension development were markedly augmented, while duration of active state was decreased, compared to euthyroid muscles. These findings occurred in the presence and absence of intact norepinephrine stores and over a wide range of temperature and contraction frequency. The opposite changes occurred in muscles from hypothyroid cats. Isometric tension was slightly higher in muscles from hyperthyroid and lower in muscles from hypothyroid cats. The inotropic response to both norepinephrine and strophanthidin varied inversely with the level of thyroid state and allowed all three groups of muscles to reach a common ceiling of isometric tension regardless of thyroid state. Creatine phosphate and adenosine triphosphate stores were intact at all three levels of thyroid state. Thus, the level of thyroid activity profoundly affects the intrinsic contractile state of cardiac muscle, independent of both norepinephrine stores and alterations in high energy phosphate stores, and, in addition, modifies the responsiveness of cardiac muscle to inotropic agents.

Adenosine Triphosphate↗
PubMedDate not supplied

Left ventricular diastolic filling abnormalities in left anterior descending disease.

Reduced left ventricular diastolic filling (DF) has been noted in coronary disease (CD) patients with normal left ventricular systolic function (NLVF). However, previous studies have included patients with regional wall disease, hypertension, or left ventricular hypertrophy. In the absence of these factors, only a subgroup of patients who had greater than 75% luminal obstruction of the left anterior descending artery (LAD) demonstrated DF abnormalities. Using 60 frames/sec biplane contrast ventriculography, we evaluated the left ventricular filling curve and its derivative in 21 patients with normal coronary arteries and NLVF (group 1), 17 CD patients with NLVF and no LAD disease (group 2), and 18 patients with LAD disease and NLVF (group 3). The peak filling rate (PFR) as end diastolic volumes/sec (EDV/S) was reduced in group 3 patients (group 3: 3.00 +/- 0.51 EDV/S vs group 1: 3.59 +/- 0.84 EDV/S, p less than .05; and group 2: 3.61 +/- 0.91 EDV/S, p less than .05). There was marked overlap in the PFR's between the normal and LAD group. DF may be normal in CD patients with NLVF in the absence of LAD disease. LAD patients have abnormal DF, but these abnormalities lack predictive valve.

Adult↗