Assessment of left ventricular function by a power index: an intraoperative study

Summary To investigate whether left ventricular performance can be described independent of loading conditions, twelve patients underwent intraoperatively two cineangiographies of the left ventricle with simultaneous pressure recordings. The first ventriculography was performed with ejecting left ventricle without assistance by the extracorporeal circulation. The second one was performed with ejecting left ventricle partially unloaded by the extracorporeal circulation. Myocardial perfusion pressure (mean aortic pressure) was held constant. Due to this procedure marked decreases in preload (end-diastolic wall stress: –54%) and modest changes in afterload (mean systolic wall stress: –23%) were achieved. End-diastolic volume index was reduced from 84 ml/m² to 57 ml/m², whereas end-systolic volume index decreased slightly from 33 ml/m² to 29 ml/m². Left ventricular end-diastolic pressure decreased from 12 mm Hg to 7 mm Hg, while peak pressure remained nearly unchanged. Usual parameters of ejection phase (EF, V_mw) as well as power per wall volume (PW) were markedly affected by unloading. In contrast to these parameters, the power index (PI), i.e., the ratio of power per wall volume and enddiastolic wall stress, remained unchanged when left ventricular preload was reduced: PI under control: 5.2±1.8 sec^–1; PI under unloading: 5.2±1.5 sec^–1.This power index can easily be determined from routine angiographies. It may provide a new approach to the assessment of left ventricular function in man.Supported by Deutsche Forschungsgemeinschaft, Sonderforschungsbereich 30     

Ruptured cerebral aneurysms associated with arterial occlusion

Seven cases of ruptured cerebral aneurysm associated with an occlusion of a large cerebral artery are reported. All seven patients had never suffered from ischemic cerebrovascular disease before the aneurysmal rupture. All nine aneurysms, including the two unruptured ones, arose on the artery serving as an important collateral pathway, and eight of the nine were found in locations where saccular aneurysms are known to occur infrequently. The role of hemodynamic factors in the pathogenesis of these aneurysms is stressed.     

Double eyelid surgery in singapore

Between March 1978 and April 1980, the author performed 400 consecutive double eyelid operations in Singapore using Dexon sutures. The results, including various characteristics of the patients, are outlined. There were few complications, and results were good or satisfactory in 98.5% (394) of the cases.     

Menièresche Krankheit und Akustikusneurinom

Summary It is questionable whether a hydrops endolymphaticus can develop on the basis of an acousticus-neurinoma. Histological evidence is also lacking. The fact that an acousticus-neurinoma can very rarely lead to the classical symptoms of Menière's disease has practical consequences. If a significant decrease in caloric function and an asymmetry in the inner ear ducts exist, a meato-cisternography is indicated. In the meato-cisternogramme typical filling defects are found; but also in 50% of the patients with Menière's disease, certain types of filling defects are seen. This observation suggests that perhaps other pathological processes in the inner ear duct provoke symptoms similar to those of Menière's disease. In our patient material we have indications that isolated intrameatal liquor circulation disturbances and intrameatal angioma are much more often associated with the clinical symptoms of Menière's disease than an acousticus neurinoma.

     

The effect of pharmacologically increased blood pressure on brain circulation

Summary The cerebral angiograms of patients with cerebrovascular diseases, head injury and intracranial tumours obtained under normal and pharmacologically increased blood pressure were compared. Changes in cerebral blood flow, circulation time and arterial diameter were examined. CBF was measured by a semiquantitative densitometric method, arterial diameter by a split-image focusing technique.The majority of patients with normal angiograms showed a virtually constant CBF and circulation time, while there was a slight constriction of the arteries. The functional tests during cerebral angiography revealed disturbances of autoregulation in patients with acute cerebrovascular diseases or with intracranial tumours.

---

Zusammenfassung An Patienten mit normalen und pathologischen angiographischen Befunden wurden Serienangiogramme bei normalem und medikamentös gesteigertem Blutdruck durchgeführt. Die Auswertung der Angiogramme erfolgte hinsichtlich Strömungsgröße, Gefäßdurchmesser und Zirkulationszeit. Die Durchströmung wurde mit Hilfe einer semiquantitativen densitometrischen Methode bestimmt. Die Messung des Gefäßdurchmessers erfolgte mit einem Schnittbilddickenmesser.Die meisten Patienten zeigten bei Blutdrucksteigerung eine Konstanthaltung der Strömung und der Zirkulationszeiten, während sich die Arterien meßbar kontrahierten. Bei Patienten mit frischen cerebrovasculären Insulten und Hirntumoren ließen sich mit den angiographischen Belastungstesten Störungen der Autoregulation nachweisen.

     

Catecholamine-induced vasodilator metabolite release from guinea-pig hearts is not due to increased myocardial activity

Guinea-pig isolated hearts were perfused in series, the donor heart perfusate supplying the recipient heart. Isoprenaline increased the rate and force of contraction and oxygen consumption of donor hearts and produced a coronary vasodilatation. This was accompanied by the release of vasodilator metabolite as demonstrated by vasodilatation of the recipient heart, the -adrenoceptors of which were antagonized by propranolol. During arrest of donor hearts by either carbachol or application of a fibrillating current, isoprenaline still released vasodilator metabolite and increased oxygen consumption but without changes in rate or tension. This release was prevented by -adrenoceptor blockade. It is concluded that the sympathomimeticinduced coronary vasodilatation is mediated via the release of a vasoactive metabolite, the trigger for which is not the concomitant mechanical hyperactivity.This work was supported by a Science Research Council CASE award in collaboration with Fisons Pharmaceuticals Ltd., Loughborough, Great Britain     

Effects of atenolol,labetalol and propranolol on the peripheral circulation in hypertensive patients without obstructive vascular disease

Summary In an observer-blind, randomised cross-over trial, in 12 patients, the effects on the peripheral circulation of antihypertensive doses of atenolol, labetalol and propranolol and placebo were compared. After a placebo period of at least 4 weeks, patients were allocated at random to one of the three active drug treatments. After active treatment for at least 6 weeks and a fall in diastolic pressure (DP) to less than 90 mmHg subjects were switched to the next medication. At the end of each period, photoelectric plethysmography (PHELP) was done on all fingers of one hand cooled over 4 min in water in steps of 3°C from 33° to 12°C, and subsequently warmed in room air (20°C) for a period of 10 min. Blood flow changes during cooling were expressed as a percentage of the initial PHELP value (% PHELP). Areas under the curves, representing the % PHELP/cooling period and % PHELP/warming-up period, showed that within the temperature range normally encountered in daily life, labetalol preserved finger blood flow significantly better than propranolol and marginally better than placebo. With atenolol, finger blood flow was not significantly different from that during the three other regimens, but there were significantly fewer other side-effects. It is concluded that labetalol may be the drug of choice for hypertensive patients treated with beta-blocking agents whose peripheral arterial circulation seems inadequate at low temperatures.     

The portal vein as collateral in inferior vena cava obstruction

In five patients with obstruction of the inferior vena cava, collateral flow to the portal vein was demonstrated. Although there are many reports on caval occlusion, only 21 cases with this collateral circulation pattern have been reported. The reasons for this are most likely technical: To demonstrate this circulation, a large volume of contrast medium must be used and, because of the low flow velocity in the numerous wide collaterals, delayed films are also necessary.     

Low-dose cholinesterase inhibitors do not induce delayed effects on cerebral blood flow and metabolism

The acetylcholinesterase (AChE) inhibitors sarin and pyridostigmine bromide (PB) have been proposed as causes of neurobehavioral dysfunction in Persian Gulf War veterans. To test possible delayed effects of these agents, we exposed rats to low (subsymptomatic) levels of sarin (0.5 LD₅₀ s.c. 3 times weekly) and/or PB (80 mg/L in drinking water) for 3 weeks. Controls received saline s.c. and tap water. At 2, 4 and 16 weeks after exposure, regional cerebral blood flow (rCBF) and glucose utilization (rCGU) were measured in conscious animals with the Iodo-¹⁴C-antipyrine and ¹⁴C-2 deoxyglucose methods, respectively.

Two weeks after exposure, PB+sarin caused significant rCBF elevations, but no changes in rCGU, in neocortex, with lesser effects on allocortex. Four weeks after exposure, the same general pattern was found with sarin. Only a few changes were found at 16 weeks post-treatment. The predominant effects of sarin or PB+sarin on rCBF at earlier times after treatment are consistent with the well known direct cerebral vascular effect of cholinergic agonists. The lack of changes in rCBF and rCGU observed at 16 weeks after treatment does not support the hypothesis that repeat exposure to low-dose cholinesterase inhibitors can generate permanent alterations in cerebral activity.