Study of ejection fraction of professional divers during simulated diving in hyperbarism and various respiratory mixture.

This study was done to elucidate the influence of high pressure (5.5 and respectively 20.0 ATA) and various respiratory mixtures (nitrox and heliox) on cardiac output investigated (by the Ejection fraction) as in the medical literature there have not been found studies on the left ventricular performance of the divers under these conditions.

Study of heart rate of professional divers in hyperbarism during simulated diving in saturation with different respiratory mixture.

Study of heart rate of professional divers in hyperbarism during simulated diving in saturation with different respiratory mixture. Study of heart rate of professional divers in hyperbarism (5.5 ATA and 20 ATA) during simulated divings and in saturation with different respiratory mixture (nitrox and heliox respectively) show a nonsignificant difference in bradycardia response. Results have confirmed that bradycardia is not influenced by respiratory gases and the depth and is only due to high pressure.

A dynamic study of vanilmandelic acid elimination in the urine of divers in a dive at 21 ATA in saturation with a helium-oxygen respiratory mixture.

The purpose of this paper is a first assessment of the effect of stress agents specific for hyperbarism in professional divers. We selected the elimination of vanilmandelic acid (VMA) in the urine as an indicator. We studied four professional divers in a dive at 21 ATA. In order to assess the strain-induced by every distinct moment of the saturation profile we took samples of urine and determined VMA at four-hour intervals, before and after the distinct moment of saturation. The values found in the same four divers at the surface were used as "controls". VMA dosing in the urine proves to be a sensitive indicator for the assessment of stress and adaptive reactions during saturation.

Dynamic study of postural tremor in high pressure conditions.

Tremor holds a central place in the high pressure nervous syndrome generated by hyperbarism, a fact that prompted us to carry out this study. We found that tremor appears after diving to a depth of 150 m (16ATA) and progressively intensifies with the increase of pressure. We discuss the pathogenic mechanism in which, besides the involvement of several central mechanisms, one can also incriminate some peripheral ones (probably the change of interstitial pressure at the nerve and/or muscle level).

Electroclinical correlations in temporal lobe epilepsy.

2,698 epileptic patients were studied, 2,019 cases (64.3%) presenting temporal lobe epileptic attacks. Besides the routine EEG recordings and the corroboration of the clinical data with the meticulous observations by video monitoring on a closed circuit TV-screen (the patients being observe in a specially arranged room, provided with infra-red cameras), the diagnostic procedure was supported in all cases by several computerized EEG mappings, according to a model achieved by us, transcribing the primary data obtained by Hjorth's NSD parameters from the Siemens-Elema Mingograph to a Romanian M-118 microprocessor. In many cases we utilized an interface--built by us--for analog-digital conversion which allowed the direct introduction and conversion of amplitudes and frequencies from the Mingograph to the micro-computer. These were isolated to analyse the following electroclinical forms: 1. temporal absences: 360 cases (17.8%); 2. psychomotor attacks: 439 cases (21.7%) 3. psychosensory attacks: 77 cases (3.8%); 4. attacks with cognitive symptomatology: 260 cases (12.8%); 5. crises with ideative-affective symptomatology: 76 cases (3.8%); 6. vegetative attacks: 51 cases (2.5%); 7. akinetic attacks: 89 cases (4.4%); 8. focal temporal attacks secondarily generalized: 667 cases (33.0%). In 112 patients with nocturnal attacks, polysomnographic recordings were performed with sequential computerized EEG mappings during the various stages of sleep (concomitantly with the infrared video-TV monitoring).

Experimental validation of sino-atrial conduction time using sinus node potential recording, right and left atrial continuous pacing method.

In an experimental study indirect sino-atrial conduction time (SACT) was measured, using continuous pacing method from right and left atrial sites, and compared with direct SACT obtained from sinus node potential recording, all the determination being done before and after autonomic blockade. The distance between the two sites of stimulation may be taken into account as a correction factor for SACT determination. The SACT obtained with sinus node potential technique is the same as the indirect SACT after autonomic blockade. These findings are valuable for SACT determination with transesophageal pacing method. Left atrial pacing, thus transesophageal pacing, is a valuable method in estimating the SACT, but a time correction and autonomic blockade is required in order to obtain a real value, eliminating the extrinsic influences.

The effect of acute anoxia on ventricular monophasic action potential. Experimental study.

Acute hypoxia induced in dogs by breath stopping produces a significant increase of ventricular epicardial monophasic action potential duration, thus an increase in myocardial refractoriness. This may be an explanation of the effect of breath holding test in terminating reentrant cardiac arrhythmias.

Experimental ventricular preexcitation--type WPW syndrome.

Experimental ventricular preexcitation type WPW was performed in five dogs, through an artificial bypass, an electric conductor, made of copper, with a diameter of 8 mm and 12 cm in length. Whenever the conductor was put in contact with both the atrial and the ventricular wall, a WPW electrocardiogram pattern was obtained. This work has been done to better localize with epicardial mapping the site of preexcitation for surgical purposes.

New mathematical statistical methods for detecting correct echocardiographic (ECG) and vectorcardiographic (VCG) diagnosis criteria by computerization. I. The determination of the upper (Lu) and low (Ll) limits for VCG amplitudes. The multivariate analysis.

The mathematical statistical methods for the determination of the upper (Lu) and low (Ll) limits of the 95 percentile range of symmetrical and asymmetrical frequency distribution curves for electrocardiographic (ECG) or vectorcardiographic (VCG) amplitudes, ECG and VCG diagnostic criteria, and the multivariate analysis as well as the bases of their computerization-program have been presented, in order to find out the ECG and VCG diagnostic criteria. The formulae for the determination of sensitivity, specificity and performance score of the ECG and VCG diagnostic criteria, in both the above mentioned methods are presented.

Studies concerning the significance of orthogonal ECG changes with age in normal men and in arterial hypertension without congestive cardiac failure in men past forty.

Great ECG changes (Frank system) with age were found in normal men. ECG diagnostic criteria valid in Romania were studied by multivariate analyses in men aged 40--60 suffering from hypertension (Hyp) without cardiac congestive failure (CCF), out of which one group with left ventricular hypertrophy (LVH) and another one without it. Echocardiographic studies in normal and hypertensive men past forty, as well as studies in experimental Hyp with LVH and without CCF were carried out. Heart X-ray evaluation is not a functional one. Some non-invasive methods in men do not determine an accurate evaluation of LV performance. The increase of LV muscular mass alone cannot explain the ECG changes in LVH in Hyp without CCF. Two conditional adaptive mechanisms: the liberation of catecholamines from the myocardium storage, induced by the pressure overload stress, and the increase of intracellular Ca++ influx could contribute to the respective ECG changes.