[An emulsion of fluorocarbons as a protective agent against myocardial ischemia]. / Emul'siia ftoruglerodov kak sredstvo protivoishemicheskoi zashchity miokarda.

Acute myocardial ischemia was induced by reducing the lumen of the anterior descending branch of the left coronary artery in 32 mongrel dogs. Following 60 min of ischemia, 16 animals were infused perfluorine carbon emulsion (10 ml/kg) and 16 were given saline. Alteration in hemodynamics, myocardial contractility, coronary blood flow, as well as pH and pO2 in the ischemic area were examined. The analysis of the results showed that carbon tetrafluoride emulsion, in contrast to saline, substantially increased coronary blood flow and oxygen supply in the ischemic area decreased myocardial ischemic and reperfusion lesion, improved hemodynamic parameters and myocardial contractility.

[Study of spontaneous acetylcholine-dependent tachyarrhythmias using isolated specimens of the right canine atrium by bilateral mapping of the spread of excitation]. / Issledovanie spontannykh atsetilkholinzavisimykh takhiaritmii na izolirovannykh preparatakh pravogo predserdiia sobaki metodom dvustoronnego kartografirovaniia rasprostraneniia vozbushdeniia.

The authors examined tachycardias induced by administering acetylcholine (AC), 1-2 micrograms into the artery of sinus node (ASN) of an isolated specimen of the canine right atrium, which had spontaneous automatism. Bilateral multielectrode mapping was employed. The episodes of tachycardia occurred during AC-induced arrest of sinus rhythm. In 81% of the cases, episodes of arrhythmia consisted of 2-3 beats, in 19%, 6-150 beats. The mapping revealed a focal picture of activation during short-term episodes of arrhythmia and transition from a focal type of activation to the re-entry in most cases of "prolonged" episodes. With this, excitation circulation might be detected only on one side of the specimen, in the presence of the focal activation picture, on the other. Focus-re-entry transition is proposed to be caused by a mechanism associated with heterogeneous refractoriness of atrial tissue.