We have examined the role of readmission of oxygen in the initiation of reperfusion-induced arrhythmias by separating readmission flow from readmission of oxygen on a temporal basis. Isolated rat hearts (n=12/group) were subjected to 10 minutes of global ischemia and reperfusion. In controls reperfused with aerobic perfusion medium, 100% of hearts developed ventricular tachycardia 1.48±0.78 seconds after reperfusion, and ventricular fibrillation occurred 13.47±2.91 seconds after reperfusion. Also in hearts reperfused with anoxic perfusion medium, 100% of hearts developed ventricular tachycardia 1.98±0.96 seconds after reperfusion, and ventricular fibrillation occurred 27.01±18.52 seconds after reperfusion. But the duration of the time from reperfusion to the onset of ventricular fibrillation were statistically differrent in these two groups (p<0.05). In conclusion anoxic reperfusion delayed ventricular fibrillation but prevent neither ventricular fibrillation nor ventricular tachycardia. This implies that oxygen-derived free radicals may play an important role in the initiation of reperfusion-induced arrhythmias, but are unneccessary for arrhythmogenesis.

This study was designed to evaluate the myocardial protection with observation of the monophasic action potential (MAP) which was recorded by suction electrode. Using the isolated working rabbit hearts, amplitude, duration of MAP at 50% repolarization level (MAPD₅₀), aortic flow and heart rate were measured after reperfusion. The comparative study obtained for all five groups under the following various conditions of the aortic cross clamping are stated as follows. Myocardial temperature were maintained at 20°C during aortic cross clamping. Group I was treated with St. Thomas' Hospital cardioplegic solution. The cardioplegic solution was infused every 20min during ischemia and kept at 20°C. The hearts of group I was divided into four sub-groups, all of which were infused with different concentration of diltiazem (D) in cardioplegia: group Ia D=0μg/ml (n=10), group Ib D=1μg/ml (n=5), group Ic D=5μg/ml (n=5). group Id D=10μg/ml (n=5), and in group II cardioplegic solution was not used. The amplitude of MAP following 30min working mode of reperfusion in group I showed a significantly higher recovery compared to those in group II. The MAPD₅₀ of MAP following 30min working mode of reperfusion in group I showed a significantly lower recovery compared to those in group II, and 10min Langendorff mode in group I a showed a significantly higher recovery compared to those in group Ib, group Ic and group Id. 20min working mode in group Ia and group Ib showed a significantly higher recovery compared to those in group Ic and group Id. The heart rate following 30min working mode of reperfusion in group Ia and group Ib showed a significantly higher recovery compared to those in group Ic and group Id. The aortic flow following 30min working mode of reperfusion in group Ia and group Ib showed a significantly higher recovery compared to those in group Ic, group Id and group II. We would like to conclude that the permeability of large amount of calcium across myocardial cell membrane seems to be depressed by diltiazem added to cardioplegia. But when the concentrations of diltiazem in cardioplegia was over 5μg/ml, it showed negative inotropic action and negative chronotropic action.

We have recently experienced a case of impending ruptured aneurysm of the common iliac artery associated with a gelatinous substance in the retroperitoneal space. A 69 year-old male had been diagnosed as a left common iliac aneurysm at another hospital by CTscan during the examination of lower abdominal pain. At the midnight of the day he admitted, the severity of pain gradually intensified. But there was no sign of anemia nor hypotension. Next morning CTscan showed low density left retroperitoneal mass. The patient underwent emergency laparotomy. The further inspection revealed about 600cm³ of gelatinous substance in left retroperitoneal space without the sign of aneurysmal rupture. A bifurcated graft replacement was performed. The low density mass was not recognized by CTscan done 42 days postoperatively. Electrolyte study of the gelatinous substance indicated its serous leakage through the impending ruptured aneurysm. Our present report constitutes a completely distinct variety of common iliac aneurysm, associated with a gelatinous substance in retroperitoneal space without a major rent of the aneurysmal wall.

A 63-year-old woman underwent coronary artery bypass grafting and mitral annuloplasty 4 years previously. She was readmitted owing to heart failure. Cardiac catheterization revealed worsened mitral regurgitation, although the internal thoracic artery (ITA) graft had good patency. Reoperation was performed by median resternotomy and continuous retrograde cardioplegia without clamping the ITA graft. The mitral valve had a perforation in the anterior leaflet, and was replaced by a 29mm Carbo-Medicus valve. The patient was discharged with transient myocardial ischemia. Although median resternotomy and continuous retrograde cardioplegia at reoperation provided on excellent view and myocardial protection, myocardial ischemia in the region perfused by the ITA graft may occur when the ITA graft cannot be clamped during continuous retrograde cardioplegia.

A 24-year-old woman had been injured in an automobile accident. The chest X-ray showed widening of the mediastinum and computed tomography showed mediastinal hematoma around the aortic arch. Aortic rupture was suspected, so we performed aortography, which revealed pseudoaneurysm of the descending aorta. Moreover, she also had splenic rupture and pelvic fracture. She underwent an emergency operation 4 hours after the accident. Medial tear of the descending aorta was replaced with a graft under temporary bypass without heparin. Simultaneously, splenectomy was performed. Her postoperative course was uneventful. We consider that temporary bypass without heparin is a useful method during repair of the descending aortic rupture due to trauma.