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The degree of mineralization of TAH membranes in animals is directly related to the survival time of animals with a TAH. Large differences in mineralization of the membranes among individual animals have been observed. These differences can be explained by the simultaneous presence of infection on biomaterials (polyurethane) as well as by different levels of natural inhibitors of mineralization. No positive influence of applying sodium warfarin for the inhibition of the mineralization was observed.

The development of the adrenergic cardiac innervation was studied in premature dog fetuses, puppies and adult dogs by means of the formalin-induced fluorescence technique. A point-counting technique was used to evaluate the density of innervation. Two types of fluorescent profiles can be observed in the heart during development: (1) sprouting axons, and (2) beaded terminals. The axonal fluorescence disappears in adult neurons. A different morphology and a different time course of development enable to study separately the innervation of the myocardium (cardiomotor innervation) and that of the vessels (vasomotor innervation). The late prenatal innervation is very poor (0.1 hit). The first but very scant cardiomotor terminals appear in this period. A mature cardiomotor innervation is found in 4-month-old puppies [1.5 ± 0.3 (SD) hits]. The vasomotor innervation is shifted to the right. The development of beaded vascular terminals begins and matures 1–2 weeks later. The growing fluorescent axons reveal that the myocardium is supplied by axons of the cardiac plexus and of the perivascular nerves; the vascular wall on the other hand is supplied by the perivascular nerves only. The developmental, spatial and morphological differences in innervation suggest that two different types of neurons exist in the sympathetic ganglia: (1) neurons innervating the vessels (coronaromotor neurons), and (2) neurons innervating the myocardium (cardiomotor neurons).

Data concerning the effect of NO on the function and structure of the heart are controversial. We have studied two main questions: (i) Does the heart muscle reflect the hypertension induced by long-term inhibition of NO synthase? (ii) Since the arginine-NO pathway is also operative in the autonomic nervous system, the second goal was to ascertain the possible changes of the adrenergic nervous system in the heart after long-term NO synthase inhibition. Wistar rats were administered L-NAME in drinking water (50 mg/kg bw/day) for 8 weeks. Systolic blood pressure and heart rate were monitored weekly. The heart/body weight ratio were determined at the end of experiment. The adrenergic nerve terminals visualized by histochemistry were counted according to Haug's point counting method. Blood pressure increased significantly in L-NAME-treated rats. No changes were found in the heart rate. Heart/body weight ratio increased markedly. Surprisingly, the density of adrenergic nerve terminals did not alter accordingly. The density of adrenergic nerve terminals in the left ventricle and septum decreased but no significant changes were found in the left atrium and the right ventricle. Hypertension due to NO deficiency induced cardiac hypertrophy that was characterized by a decline in the density of adrenergic innervation of the overloaded left ventricle and septum.

The development of the adrenergic cardiac innervation was studied in premature dog fetuses, puppies and adult dogs by means of the formalin-induced fluorescence technique. A point-counting technique was used to evaluate the density of innervation. Two types of fluorescent profiles can be observed in the heart during development: (1) sprouting axons, and (2) beaded terminals. The axonal fluorescence disappears in adult neurons. A different morphology and a different time course of development enable to study separately the innervation of the myocardium (cardiomotor innervation) and that of the vessels (vasomotor innervation). The late prenatal innervation is very poor (0.1 hit). The first but very scant cardiomotor terminals appear in this period. A mature cardiomotor innervation is found in 4-month-old puppies [1.5 +/- 0.3 (SD) hits]. The vasomotor innervation is shifted to the right. The development of beaded vascular terminals begins and matures 1-2 weeks later. The growing fluorescent axons reveal that the myocardium is supplied by axons of the cardiac plexus and of the perivascular nerves; the vascular wall, on the other hand, is supplied by the perivascular nerves only. The developmental, spatial and morphological differences in innervation suggest that two different types of neurons exist in the sympathetic ganglia: (1) neurons innervating the vessels (coronaromotor neurons), and (2) neurons innervating the myocardium (cardiomotor neurons).

The remnant stumps of the atria in six calves surviving with the artificial TNS-Brno II methacrylate heart for up to 5 months were examined by means of the Bodian silver-impregnating technique and by the formalin-induced fluorescence technique visualizing noradrenaline in monoaminergic nerve terminals. The degeneration of the nerve terminal system detected in animals surviving for 2 days and 1 week was followed by regeneration of the vegetative nerve system in four animals surviving for greater than 1 month. Moreover, thick myelinated nerves afferent in character were detected within the atrium of one animal surviving for 5 months.

Causes of the death of four animals from the total of eight were technical failures (diaphragm perforations, disconnection of the quick-connector, and a failure of the supply of electric current which could not be prevented). Causes of the death of the remaining four animals were embolisation in the brain stem, embolisation in the superior mesenteric artery leading to diffuse peritonitis, ruptures of aorta and hemocoagulation disorder causing fatal gastrointestinal bleeding.

A 150-day experiment in a calf with an implanted total artificial heart, TNS-BRNO-II, is described. The Czechoslovak TAH-BRNO-II device is a hybrid; the outer housing is made of polymethylmethacrylate, the moving parts of segmented polyurethane. The blood flow through the device after the surgery gradually increased from 7 L/min to 12 L/min by the end of the experiment. Atrial pressures were automatically maintained at the same level, about one kPa on both sides. The left systolic time was automatically derived from the pump emptying phase; the right systolic time was maintained between 40% and 50%. After the surgery, normal values of blood gases, stabilization of respiratory activity, and normalization of gastrointestinal functions were reached very soon. Anticoagulant therapy was performed during the whole experiment, with several periods of increased bleeding tendency. The clinical state of the calf was essentially physiological until the 94th day of the experiment, when acute bronchopneumonia, with a high fever, over 41°C, initiated a series of complications (pseudomembranous enterocolitis, followed by sepsis lenta). The fatal complication was sudden impairment of the coagulation mechanisms on the 149th to 150th day of the experiment. This was the basic reason for the subsequent death of the animal, caused by acute cerebral anemic anoxia, which could not be prevented by immediate therapeutic procedures. In spite of these complications, the clinical state of this calf was relatively good until the end of the experiment. Autopsy revealed minimal thromboembolization at the valves. The outer surface of the diaphragm was covered with pseudoneointimal deposits and the inlet orifices were free of pannus or other connective tissue crescents. Macroscopic signs of infection were not seen, but bacteriological cultivation from internal organs confirmed Klebsiella infection. The state of the device at the time of autopsy, with simultaneous undisturbed function of the control and driving unit, showed the possibility of still longer survival.

The influence of previous pharmacotherapy or intra-aortic balloon counterpulsation (with thiamine infusion) on the effectiveness of reperfusion of the left anterior descending (LAD) coronary artery after 150 minutes of occlusion has been studied in dogs. The infarct size was determined by morphometric method 20 hours after the onset of ischaemia. Reperfusion 150 minutes after the occlusion of the LAD coronary artery resulted in a smaller infarct; however, no protective effect from pharmacological or mechanical heart support during the period of ischaemia was observed.

To determine whether haemodynamic effective support of the failing heart can prevent spontaneous irreversible ventricular fibrillation (IVF) after experimental cardiogenic shock, 63 open chest dogs were assigned randomly into four groups--two control groups (combined heart failure--CHF) and two MCHSS-treated (combined heart failure and non-pulsatile bypass with intraaortic counterpulsation). The CHF was produced by occlusion of the anterior descending coronary artery (group I) or the left circumflex coronary artery (group II) and by an artificial shunt between the pulmonary artery and right atrium. IVF were observed in 10 out of 22 control dogs (group I) and im 17 out of 21 control dogs (group II). In the 20 dogs with the CHF (10 animals in each group) the MCHSS was performed in the course of two hours. During the heart support no IVF were observed in any of the dogs. The difference between the incidence of IVF in the control and treated animals is statistically significant (Chi square = 21.9767 greater than Chi square 0.005).

The present chapter is a report of the current status of our testing of total artificial heart (TAH) implants in over 50 calves. Our 50th TAH experiment was performed with the calf Hasan; the experiment lasted 150 days. The TAH used in this experiment was TNS-BRNO-II, made of polymethylmethacrylate with polyurethane diaphragm and valves. Basic physiological functions normalized very soon after surgery. Blood flow through the device gradually increased from 7.5 to 11.5–12.5 liter/min at the end of the experiment. Central venous pressure (CVP) increased to 2.0–2.5 kPa in later months; atrial pressures were automatically maintained at the same level, ca. 1 kPa on both sides during the whole experiment. Anticoagulant therapy kept the prothrombin time two- to threefold above normal. The experiment was terminated by a sudden impairment of the blood coagulation mechanism, marked GI bleeding, and acute cerebral anemic anoxia. Autopsy revealed no thrombi at the artificial valves; there was thick pseudo-neointima in the outer portion of the diaphragm; inlet orifices were clean, without traces of pannus on either side. There were no signs of infection of organs detectable by the autopsy, but bacteriological examination revealed Klebsiella infection. Another experiment with the TAH, no. 51, was started immediately after experiment no. 50 was terminated. The calf, named Dalibor, recovered very quickly from surgery and anesthesia; about 3 weeks after surgery, basic physiological functions were stabilized , and during the subsequent course there were no problems in postoperative care. The calf was anticoagulated with warfarin (Coumadin®) until the 102nd day when slight GI bleeding occurred, and the administration of warfarin was interrupted. Only antiaggregation therapy with dipyridamole (Curantyl®) and aspirin was used from that time. Dalibor survived for 142 days in full health and died of accidental causes. During the calf s survival period, its CVP oscillated between 3 and 2.8 kPa, and blood flow through the TAH averaged 13 liter/min. The technical equipment used in both these experiments functioned without the slightest disturbance. In both experiments, the internal milieu of the calves showed absolute adaptation and normalization of all basic parameters, especially in the second calf, Dalibor. A third calf, no. 52, Samson, of this group survived 104 days; the cause of death was diaphragm leakage in the right-hand pump. The longest survival to date was achieved in calf no. 53, Florian, which survived 155 days; the cause of death was microthrombembolization in the CNS. The last calf of this group, no. 54, Waldemar, survived 31 days; the experiment was terminated because of a thrombembolism into the superior mesenteric artery. The mean survival of our five calves that lived longer than 1 month was 116 days. During their survival time, the basic physiological functions of all of these animals were fully normalized; the calves gained weight, and their condition was very good. These facts have documented excellent adaptation of these animals to the TAH. The control and driving unit used in our experiments with the TAH is an apparatus produced in our institute and designated Chirasist TN 3.

A study was carried out of a therapy supporting the anaerobic glycolysis and coronary perfusion of ischemic myocardium and preserving its potassium and magnesium contents, which consisted in combined administration of hyaluronidase, glucose, insulin, Tris, methoxamine, and potassium and magnesium aspartate. The drugs were administered to Beagle dogs between 30 minutes and 20 hours after the ligation of the left anterior descending coronary artery. The size of infarction was determined by the Nachlas method, which is based on the detection of activities of dehydrogenases in heart slices. Treated animals showed a reduced infarction size (p less than 0.001). The evidence of the favourable effect of the therapy used was brought also by hemodynamic measurements. The heart rate was slower (p less than 0.02) and the mean arterial blood pressure was higher (p less than 0.001) in treated animals than in control ones (as evaluated at the end of the experimental period). Significant correlation between the infarction size and the heart rate on the one hand and the mean arterial pressure on the other hand was found (r = 0.59, p less than 0.01; r=--0.47, p less than 0.05, respectively).