During hypoxic heart failure, inorganic phosphate (Pi) accumulates. We report the effects of Pi on force development and on myofibrillar ATPase-activity of human skinned atrial fibers, both at normal and at reduced levels of Mg-ATP. Pi (10 mM) depressed force production at maximal calcium activation (pCa 4.3) by about 40%. At higher pCa values (pCa 5.6), force inhibition was even more pronounced, but at low concentrations of Mg-ATP (10 microM), Pi was less effective. In contrast to contractile force, myofibrillar ATPase was only inhibited by about 10% at pCa 4.3, whereas it could be inhibited by 40-50% at submaximal calcium activation (pCa 5.6). As Pi inhibited contractile force more than ATPase activity, the ratio of ATPase-activity to force (tension cost) was increased by inorganic phosphate. ATPase-activity and tension cost were significantly reduced by lowering Mg-ATP concentration to 10 microM, whereas contractile force was less affected. Pi did not affect ATPase under these conditions at 10 mM Mg-ATP. Pi also shifted the calcium-force relationship towards higher Ca++ concentrations, that is, it decreased calcium sensitivity. In contrast, the calcium sensitivity of myofibrillar ATPase was less affected. These findings suggest that inorganic phosphate may affect the myocardium by altering crossbridge kinetics rather than the calcium affinity of troponin-C. Because of its inhibitory effect on myofibrillar ATPase, inorganic phosphate may be partly cardioprotective in the hypoxic myocardium. However, this "energy sparing' effect is probably offset by the greater "tension cost' that decreases the "efficiency' of tension maintenance in the presence of inorganic phosphate.

Adenosine Triphosphatases↗

PubMedDate not supplied

Rethrombosis analysed in reference to anticoagulant therapy.

Of 1,103 re-examinations on femoro-popliteal operations, 485 in reference to anticoagulant therapy could be more closely analyzed. A very significant difference was found on relapse occlusions with or without Coumadin in relation to the disease stage. A significant difference could not be proven between the frequency of occlusion and the type of operation with or without Coumadin. After correction of chronic occlusions the indication for an anticoagulant therapy is poor distal outflow and stage III or IV disease.

Arterial Occlusive Diseases↗

PubMedDate not supplied

[Pulmonary pressure-flow relationship following pulmonary microembolism: preventive therapy with heparin and acetylsalicylic acid/dipyridamole].

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Animals↗

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Technique of implantation and removal of balloon catheters for the intra-aortic balloon counter pulsation.

During recent years, intra-aortic balloon counterpulsation has become the treatment of choice in patients suffering from left ventricular power failure following cardiac operations. In our clinic IABP became necessary in 55 patients out of 1873 patients operated with heart lung machine during the period under study. The patients were studied in two groups. In Group I the intra aortic balloon counter pulsation was started only after there was no response to pharmacological agents, which often included high doses of catecholamines and vasoconstrictors. The mortality in this group was 74%. The second group consisted of patients treated since 1975. In this group, the counter pulsation was started early before ventricular damage was irreversible. In this group the survival was 52%. In addition we have paid careful attention to the technique of implantation of the balloon catheter, thrombosis prophylaxis during the counter pulsation and removal of any possible thrombi in proximal and distal segments to the arteriotomy with the help of Fogarty catheters together with the closure of the arteriotomy with a vein patch. The technique described has resulted in almost no peripheral vascular complications.

Aorta↗