The effect of digoxin on the contractility of transplanted heart.

The effects of digoxin on the contractility of orthotopically transplanted heart was studied in dogs. Intravenously administered digoxin produced a fall in the rate and output of the transplanted heart without any change in stroke volume, whereas the output of the intact heart was slightly improved due to a small increase of stroke volume. This difference was thought to be due to the action of digitalis which is mediated via the nervous pathways, which are interrupted in the transplanted heart.

Reduction of motion unsharpness in coronary angiography using rare-earth oxysulfide intensifying screens and green-sensitive X-ray film.

During cardiac cycle the coronary arteries move rapidly; the maximum velocity can exceed 400 mm/s. To eliminate the motion unsharpness, exposure times under ten milliseconds are necessary. Using new rare-earth oxysulfide intensifying screens and fast green sensitive X-ray film the exposure times can be reduced to as little as 2 milliseconds. Thus the motion unsharpness can be almost completely eliminated, producing enhanced resolution and better diagnostic accuracy.

The effects of beta-adrenergic agents on the contractility of transplanted canine heart.

The effects of isoprenaline and adrenalin on the myocardial contractility of transplanted heart were studied in 6 mongrel dogs which had undergone orthotopic cardiac transplantation. Isoprenaline and adrenaline produced a fall in end-diastolic and end-systolic volumes, and an increase in stroke volume, cardiac output and velocity of contraction when the heart rate was increased. Similar changes were observed in 4 mongrel dogs tested as controls, with the exception of a less pronounced increase of cardiac output after administration of isoprenaline and adrenalin and a fall in stroke volume associated with a higher acceleration of heart rate after administration of isoprenaline. These minor differences between the transplanted and intact heart were thought to be a reflexion of the increased blood volume following heart transplantation.

Pulmonary circulation in alpha1-antitrypsin deficiency investigated by cinedensigraphy.

The series consisted of eight cases of severe serum alpha1-antitrypsin deficiency (Piz homozygosity) and eight lung patients with a heterozygous level of the compound. The regional blood pulsation pattern in the lungs in the recumbent position was compared with the pattern in a group of normal controls using a cinedensigraphic device specially constructed for lung circulation studies. In the homozygous group, pulsation in the lower part of the lungs was significantly weakened to the benefit of the apical part. Individual variations occurred. The disturbance observed was not altered with oxygen breathing. This phenomenon is analogous to the redistribution of the blood flow demonstrated by scintigraphic methods. The heterozygous group did not differ significantly from the normal controls with regard to regional pulsation pattern.