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The authors present an account of thrombosis of the superior vena cava which developed in two patients with permanent cardiac pacing and led to the development of superior vena cava syndrome. The cause was loosening of the impaired stimulating electrode from fixation and its penetration into the superior vena cava with subsequent formation of a thrombus on the bare surface of the spiral. Contemporary therapeutic procedures are reviewed.

The authors give an account of their experience with the problem of assessment of ionized calcium (Ca2+) in clinical work. To assess Ca2+ they use an ICA 2 analyzer of Radiometer Co. Copenhagen which makes it possible to assess concurrently the Ca2+ concentration at a given pH (Ca2+/act. pH), pH and Ca2+ calculated for pH 7.4 (Ca2+/pH 7.4) in capillary and venous blood. The authors confirmed the significant difference between Ca2+/act. pH in venous and capillary blood which is due to the pH and they did not find a significant difference in Ca2+/pH 7.4 in venous and capillary blood. They found that the specimens of capillary blood can be kept in capillaries in the refrigerator at +4 degrees C for four hours without a significant changes of the Ca2+/act.pH level. During subsequent time intervals, i.e. after 24, 48 and 72 hours following collection of the blood sample, there is a significant rise of Ca2+/act.pH due in particular to a significant drop of the pH of the blood samples. The Ca2+/pH 7.4. concentration in capillary blood does not change throughout the 72-hour follow up period. The authors provided also evidence that slight physical strain (30 min. walk on flat ground) does not cause significant changes in the concentration of capillary Ca2+/act.pH nor of Ca2+/pH 7.4 due to the three-minute compression of the arm by the tonometer cuff with a pressure equal to the diastolic blood pressure of the examined subject. The reported results make simpler and more accurate assessment of Ca2+ in clinical and ambulatory practice possible.

An important advance in the diagnosis of arrhythmias as the cause of syncopes is the introduction of intracardiac electrocardiography and diagnostic electric stimulation known at present as clinical cardiac electrophysiology. The author examined a group of 70 patients with syncopes and divided them into two sub-groups. The first group comprised 46 patients examined by means of a hisogram and assessment of the recovery period of the sinus node and the second group 24 patients where the examination comprised in addition programmed stimulation of the right atrium and ventricle. In the first group the examination explained the cause of syncopes in arrhythmia in 22 patients (48%), in the second group in 12 patients (50%). In the entire group the invasive technique proved useful in 34 patients (49%). Based on the results of tests a therapeutic procedure was selected--implantation of a pacemaker or medicamentous antiarrhythmic therapy.