ISSN:0009-7330    

出版商:OVID    

年代:1956

数据来源: OVID

摘要:

A study of the transmission of early premature contractions between atria and ventricles and in the retrograde direction in the dog heart suggests the existence of two parallel A-V conduction pathways communicating with each other over one or more branches. The evidence is based on the excessive delay of very early premature responses in traversing the node, suggesting that a slowly conducting pathway recovers earlier than the normal “fast” pathway; on the echoing back to the chamber of origin of early premature responses; and on ventricular electrograms of “abnormal” configuration obtained during early premature responses. These observations and the hypothesis to which they lead provide a natural explanation for reciprocal rhythm and nodal paroxysmal tachycardia.

ISSN:0009-7330    

出版商:OVID    

年代:1956

数据来源: OVID

摘要:

Placental transfer of radioactive C14-digitoxin was investigated in four pregnant women. The concentration of the labeled drug and its metabolic products in the various fetal organs was determined. Less than 1 per cent of the administered glycoside was detected in the fetus as unchanged digitoxin and less than 3.5 per cent as its metabolites. The fetal heart and kidney of 11 to 12 weeks gestation had the highest concentrations. However, at near term the fetal liver, gallbladder and intestine had somewhat similar concentrations. Metabolic conversion of the cardiac glycoside by fetal liver as well as biliary excretion is indicated from the tissue distribution data.

ISSN:0009-7330    

出版商:OVID    

年代:1956

数据来源: OVID

摘要:

Comparative studies of left atrial electrokymograms, left atrial pressure tracings, and pulmonary wedge pressure tracings were made in dogs with experimental mitral insufficiency or stenosis. Typical patterns were found in pure insufficiency or stenosis. A remarkable coincidence was found between pressure tracings and electrokymograms of the left atrium.

ISSN:0009-7330    

出版商:OVID    

年代:1956

数据来源: OVID

摘要:

Cardiac arrest was produced by coronary perfusion of potassium chloride in hypothermic dogs during sinus rhythm and during ventricular fibrillation. Resuscitation of rhythmic beats was facilitated by injection of hypertonic glucose when the ventricles responded to a light tap (responsive phase).

ISSN:0009-7330    

出版商:OVID    

年代:1956

数据来源: OVID

摘要:

A method has been developed by which flow to each lung, as well as pulmonary artery and left atrial pressures can be measured and varied at will. Vascular resistances were determined over a wide range of these variables. Both pressures have a marked effect on vascular resistances; the higher either pressure, the lower the resistances. This effect is most marked at low levels of pressure and flow. The absolute levels of the pressures, by affecting vascular distension, are major determinants of pulmonary vascular resistance.

ISSN:0009-7330    

出版商:OVID    

年代:1956

数据来源: OVID

摘要:

The possibility of measuring pulmonary blood flow in patients with central arteriovenous shunts utilizing the initial portion of indicator-dilution curves was explored in 16 patients by comparing these values for pulmonary blood flow with determinations by the direct Fick method. A good correlation between Fick and indicator-dilution values was obtained, and no systematic differences were demonstrated. The standard deviation of the differences between Fick and dye values was in the order of 20 to 25 per cent.

ISSN:0009-7330    

出版商:OVID    

年代:1956

数据来源: OVID

摘要:

Cholesterol feeding studies revealed that the wide variability of cholesteremic response of rabbits is in part sex determined. Male rabbits display lower cholesterol levels both before and after cholesterol feeding. Estradiol treatment of selected rabbits fed cholesterol augmented their cholesteremic response; testosterone treatment had an opposite effect. Ovariectomy lowered while orchidectomy augmented the cholesteremic response of rabbits fed cholesterol; castration tended to diminish the wide variability of cholesteremic response previously observed among intact rabbits.

ISSN:0009-7330    

出版商:OVID    

年代:1956

数据来源: OVID

摘要:

Preferential right-to-left shunting of inferior vena caval blood and left-to-right shunting of right-lung blood has been demonstrated to occur in experimental atrial septal defects in dogs as in the congenital defects in human beings. Existence of these preferential shunts proves that uniform mixing of blood does not occur in either atrium.

ISSN:0009-7330    

出版商:OVID    

年代:1956

数据来源: OVID

摘要:

A standard method is described which gives reproducible blood volume values for rats and their various organs and tissues.

ISSN:0009-7330    

出版商:OVID    

年代:1956

数据来源: OVID