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Biomedical subjects

R Pokan

Publications and source records attributed to R Pokan.

At least 37 records · Page 2Linked to original sources
PubMed1997

Left ventricular function in response to the transition from aerobic to anaerobic metabolism.

The purpose of this investigation was to study myocardial function at rest, during three phases of energy supply, and during recovery. Radionuclide angiography was performed during the aerobic phase (phase I, rest-first lactate increase), the aerobic-anaerobic transition phase (phase II, first lactate increase-second lactate increase), the anaerobic phase (phase III, second lactate increase-maximal work performance (Pmax)), and during recovery. Thirty-eight male patients (59 +/- 7 d after myocardial infarction) were compared with 19 healthy control subjects and 21 sport students of comparable age. Left ventricular ejection fraction (LVEF) increased from rest to phase I and from phase I to phase II in sports students and control subjects. During phase III, LVEF did not change significantly in sports students, but it decreased significantly in control subjects. This is in contrast to the patients, who showed an increase of LVEF from resting values (47 +/- 3%) to phase I (50 +/- 1%), no change during phase II (51 +/- 2%), and a decrease to resting values (45 +/- 2) during phase III. All subjects showed an increase in stroke volume (SV) during phase I and II, reaching a maximum at phase II. This was evidenced by an improvement of the systolic function with a constant left ventricular end-diastolic volume (EDV) in control subjects and sports students. In contrast, an improved SV in patients was achieved through an increase in EDV and a less distinct increase in the left ventricular end-systolic volume (ESV). Maximal LVEF values were measured during the first 90 s of recovery in all subjects. Values during recovery are not representative of load dependent myocardial function. This increase in LVEF does not cause an increase in cardiac output but is a consequence of changes in the EDV and ESV, which decrease again immediately after the end of exercise performance.

Adult↗
PubMed1996

[Serum digoxin level in patients with dilated cardiomyopathy].

To investigate whether measuring levels of digoxin in patients with idiopathic dilated cardiomyopathy (IDC) is helpful in dose adjustment of digoxin we did the following study. In 77 patients (63 male, 14 female) with invasively verified IDC serum-digoxin levels were measured after a treatment period with beta-acetyldigoxin of at least 6 months. All patients received digoxin, 76 had ACE-inhibitors and 69 used diuretics. Mean serum-levels of digoxin were 0.96 ng/ml while using a mean daily dose of digoxin of 0.24 mg. Those who showed a serum level of digoxin within the recommended range took a slightly higher daily dose of digoxin when compared to those with low levels of digoxin (0.26 vs. 0.23 mg/day, p < 0.05). Therefore, we conclude that low serum-levels of digoxin are mainly caused by low intake of digoxin and it is justified to measure digoxin-levels in IDC-patients even if it increases costs.

Adult↗
PubMed1996

[Smoking behavior and views on the smoking topic in the Styrian population--results of a survey at the Graz autumn convention].

Cigarette smoking has been identified as a major risk factor for cardiovascular diseases apart from hypercholesterolemia and arterial hypertension. Diseases of the respiratory system and several neoplasms as well as complications of pregnancy are considered to be "smoking-related", too. In order to survey the smoking habits and views on smoking in the Styrian population, a questionnaire was issued to 1034 visitors of the Graz Autumn Fair 1992. Pleasure proved to be the main motivation for smoking both in men and in women, habit, addiction, stress and boredom being further motivations. Not only non-smokers, but also smokers were assessed to be aware of smoking being a health hazard. Prohibition of tobacco advertising was accepted most widely as a mean of anti-smoking campaign. About half the non-smokers are exposed to environmental tobacco smoke, at place of work more frequently than at home. Percentage of smokers differs with age and job classes, however, no geographical variations were found. Further anti-smoking measures should be considered. Smoking restrictions at place of work and in public could prevent passive smoking. Ban on advertising seems to be the most effective anti-smoking campaign.

Adolescent↗
PubMed1995

[Thrombosis of a prosthetic mitral valve in the anticardiolipin syndrome].

A 40-year-old woman in whom the mitral valve had to be replaced with a prosthetic one (St. Jude's) had to be reoperated 8 months later because of endocarditis on the second prosthetic valve (Carbo-Medics). Four months later her general condition deteriorated progressively with cough and dyspnoea, requiring hospitalization. Auscultation revealed moist rales over both lung bases; heart sounds were distant but otherwise normal. The "international normalized ratio" was 2.5, while erythrocyte sedimentation rate, white cell count and C-reactive protein were normal. Transthoracic echocardiography demonstrated a hardly moving mitral valve prosthesis with an opening area of 0.8 cm. Subsequently this decreased further and measurement of the anticardiolipin antibody titre revealed an IgG fraction of 37.9 U/ml (normal up to 12 U/ml). Within 48 hours thrombolysis with streptokinase had increased the valve's opening area to 1.8 cm. The patient made an uneventful recovery under strict anticoagulation. This case illustrates that the anticardiolipin syndrome can be a cause of an otherwise unclear genesis.

Adult↗
PubMed1995

Heart rate deflection related to lactate performance curve and plasma catecholamine response during incremental cycle ergometer exercise.

The correlation between the behaviour of the heart rate/work performance (fc/W) curve and blood lactate ([la]b) and plasma adrenaline/noradrenaline concentrations ([A]/[NA]) during incremental cycle ergometer exercise was investigated. A group of 21 male sports students was divided into two groups: group I, with a clear deflection of the fc/W curve; group II, without or with an inverse deflection of the fc/W curve. The aerobic threshold (Thaer) and the lactate turn point (LTP) were defined. Between Thaer and maximal work performance (Wmax) the behaviour of the fc/W curve as well as the behaviour of [la-]b and [A]. [NA] were described mathematically. The fc, systolic blood pressure (BPs), W, [la-]b, [A] and [NA] at rest, Thaer, LTP, Wmax, after 3 and 6 min of recovery (Re3/Re6) were calculated. A significant difference between the two groups could only be detected for fc at LTP, Re3 and Re6 (P < 0.05). No significant correlation could be found between individual fc/W-behaviour and individual time course of [la-]b, [A] and [NA]. However, a significant correlation was visible between [la-]b/W-behaviour and individual catecholamine response. These results and the fact that the different flattening at the top of the fc/W curve was related to diminished stress-dependent myocardial function led us to the conclusion that it is possible that sympathetic drive is not directly involved in mechanisms of regulation between load dependent fc and myocardial function. In addition, individual fc/W behaviour was independent of BPs and Wmax, or individual conditions of energy supply.

Adult↗
PubMed1995

Effects of treadmill exercise protocol with constant and ascending grade on levelling-off O2 uptake and VO2 max.

In order to investigate the effect of an exercise protocol on the levelling-off O2 uptake and VO2 max values, ten male subjects aged 28 +/- 5 yrs, height 1.8 +/- 0.05 m, body mass 76 +/- 6 kg performed two treadmill exercise protocols: 1) constant grade (CG) of 5%, with increasing running speed starting at 6 km.h-1 and increments of 2 km.h-1 every 3 minutes. 2) ascending grade (AG) starting at 0% and increments of 5% every 3 minutes, with constant running speed of 5 km.h-1. During each protocol oxygen uptake (VO2), pulmonary ventilation (VE), tidal volume (Vt), and breathing rate (BR) as well as blood lactate concentration (La) and heart rate (HR) were measured. In CG a levelling-off phenomenon of VO2 in all cases was observed. Aerobic capacity expressed as VO2 max in CG was 46.2 +/- 6.0 ml.min-1.kg-1. In contrast, VO2 max was 35% higher in AG (62.6 +/- 7.2 ml.min-1.kg-1). The behaviour of VO2 indicates a lower efficiency with increasing work load in AG as compared to CG. Regarding maximum performance it can be concluded that VO2 in CG seems to be limited by a mechanical or neuromuscular constraint on the depth of breathing, which is confirmed by a distinct flattening of Vt. The levelling-off of the VO2 in CG, something which is not observed in AG, can be explained plausibly this way.

Adult↗
PubMed1995

Cases of Lyme borreliosis resistant to conventional treatment: improved symptoms with cephalosporin plus specific beta-lactamase inhibition.

We present four cases of verified late Lyme borreliosis with persistent symptoms and positive serology despite repeated courses of high-dose intravenous penicillin G and/or cephalosporins (including cefoperazone). The patients were now treated with cefoperazone 2 g plus sulbactam 1 g bid iv for 14 days. At the end of treatment, patients were symptom free and have remained so for the following 12 months. By then, IgG against Borrelia burgdorferi had decreased. It is concluded that the addition of beta-lactamase inhibitors to intravenous treatment could be beneficial in Lyme disease refractory to conventional treatment.

Cefoperazone↗
PubMed1995

Changes in thyroid hormone parameters after acute myocardial infarction.

Abnormalities in circulating thyroid hormone levels are very common in systemic nonthyroidal illnesses, such as acute myocardial infarction. In this study, thyroid parameters were determined in a series of 16 consecutive infarction patients treated by thrombolysis. Blood samples were taken before therapy as well as 2, 4, 6, 8, 12 and 72 h following admission. Total and free serum thyroxin and triiodothyronine decreased and reverse T3 increased significantly showing no major variations up to 72 h, whereas thyroid-stimulating hormone values remained almost unchanged during the observation period. Subjects with CK-MB levels of more than 150 ng/ml (n = 10) revealed similar changes in thyroid parameters in comparison to those with lower values (n = 6; NS). Thus, although hormone modifications very often occur following acute infarction, thyroid status may not serve as a marker for the extent of left ventricular dysfunction in the early phase of myocardial infarction.

Aged↗
PubMed1995

[What are the therapeutic consequences of evaluating hypertensive patients with 24-hour blood pressure monitors and blood pressure self-measurement?].

Arterial hypertension is an important risk factor for excessive cardiovascular morbidity and mortality due to its high prevalence of about 20% in the adult population. Causal readings, which have been obtained for diagnosis and control of treatment in hypertension are of limited value. They are not reproducable due to physiologic variability of blood pressure, which causes a rise of blood pressure, if a straining situation (e.g. in doctor's office) occurs (white-coat-hypertension). Furthermore, no correlation between causal readings and signs of endorgan-damage (EOD) such as left ventricular hypertrophy (LVH) can be observed. Especially the development of LVH comprises an independent risk factor and worsens prognosis. Results of ambulatory monitoring and self-measurement of blood pressure are reproducable and show an excellent correlation to EOD. Both methods are able to exclude white-coat-hypertension. Furthermore, ambulatory blood pressure monitoring allows to obtain blood pressure values during sleep, which may give further information concerning secondary hypertension, EOD and prognosis. Self measurement of blood pressure reinforces compliance of the patient and gives the possibility of self-titration and long-term control of antihypertensive drug treatment. The non-consensus concerning normal values is one limitation of both methods, but the cut-off level of office blood pressure recordings appears arbitrary, too. For optimal concomittance of hypertensives both methods have to reach more importance for diagnosis, evaluation of prognosis as well as treatment control.

Adult↗
PubMed1995

[Thrombolytic therapy of acute myocardial infarct in advanced age (based on 2 case reports)].

The introduction of thrombolysis has reduced the mortality of acute myocardial infarction (MI) by 25%. Large-scale studies have revealed that especially patients over 65 benefit from this therapy. Nevertheless, many centers apply an age limit for thrombolytic therapy due to the higher risk of stroke or bleeding in elderly patients. In 1993 181 patients suffering from acute MI were admitted to the intensive care unit of the University Clinic of Internal Medicine, Graz, and 54 (29.4%) of them were treated with fibrinolytic drugs. In this paper we report on the successful thrombolytic management of acute MI in two male patients (87 and 88 years old) who were treated with 100 mg recombinant tissue-type plasminogen activator complex. As a sign of successful reperfusion a rapid increase in plasma creatinine kinase levels and fast amelioration of the ischemia-related ECG changes were observed. In the follow-up examination after four months the first patients showed only minimal exertional dyspnea and was otherwise well. The second patient died one month after MI following a laparotomy for ileus. We draw the conclusion that patients of advanced age also benefit from thrombolytic treatment of acute myocardial infarction, but the indications and contraindications have to be carefully observed.

Aged↗
PubMed1995

Metabolic and cardiorespiratory reactions in tennis-players in laboratory testing and under sport-specific conditions.

Metabolic and cardiorespiratory reactions were investigated during a sport-specific incremental field test (FT) for tennis and compared with a treadmill step test (TT) in a group of 13 trained male tennis players. In both the FT and the TT lactate acid (La), heart rate and oxygen uptake (VO2) were measured. VO2 was determined using a portable telemetric system (K2, Cosmed, Italy). Aerobic- (AT) and anaerobic threshold (ANT) at a blood lactate concentration of 2 mmol/l and at 4 mmol/l respectively was indicated to characterize the endurance capacity of the athletes. In both FT and TT, minimum value of lactate equivalent (LE(min)), measured in every exercise test, was also registered. At AT and ANT values for HR (AT: p < 0.001; ANT: p < 0.001) and VO2 (AT: p < 0.001; ANT: p < 0.001) were significantly higher in FT than in TT at submaximal loads. At LE(min) only higher values for HR (p < 0.05) were registered in FT. In contrast to maximum range significantly higher values for VO2 (p < 0.001) could be seen in TT (there were no significant differences for HR). Comparing maximum lactate (La(max)) subjects reached a higher lactate (p < 0.05) in TT. A particular aim of our investigation was to characterize the individual cardiopulmonal and metabolic adaptation of tennis players, considering sport-specific criteria. As a result, differences in cardiorespiratory and metabolic adaptations could be determined between laboratory TT and FT. This finding seems to point to the fact that, using field testing in addition to laboratory exercise testing, makes a better judgement of aerobic and anaerobic endurance under sport-specific conditions possible. Furthermore, it was important for us to put data, determined in the field test into practice, using the given pattern of the field test as an element of training. This kind of training has the advantage of combining an individually intensity-controlled specific endurance training for tennis with a training of technical skills.

Adult↗
PubMed1994

Heart rate threshold related to lactate turn point and steady-state exercise on a cycle ergometer.

The aim of this study was to investigate heart rate threshold (HRT) related exercise intensities by means of two endurance cycle ergometer tests using blood lactate concentration [La], pulmonary ventilation (VE), oxygen uptake (VO2), heart rate (HR) and electromyogram (EMG) activity of working muscle. Firstly, 16 healthy female students [age, 21.4 (SD 2.8) years; height, 167.1 (SD 5.1) cm; body mass 62.7 (SD 7.1) kg] performed an incremental exercise test (10 W each minute) on an electrically braked cycle ergometer until they felt exhausted. The HRT and lactate turn point (LTP) were assessed by means of computer-aided linear regression break point analysis from the relationship of HR or [La] to power output. No significant difference was found between HRT and LTP for all the variables measured. Secondly, two endurance tests (ET) of 20 min duration were performed by 7 subjects. The first (ET I) was performed at an exercise intensity which was about 10% lower than the power output at HRT [61.2 (SD 3.1)% maximal oxygen uptake (VO2max)], the second (ET II) at an exercise intensity about 10% higher than the power output at HRT [79.2 (SD 3.4) % VO2max]. The parameters measured showed a clear steady state in ET I. All mean values were lower than values at HRT [power, 138.7 (SD 18.9) W; HR, 172.1 (SD 4.7) beats.min-1; VO2, 2.2 (SD 0.3) l.min-1; VE, 54.0 (SD 9.1) l.min-1; [La], 3.7 (SD 1.1) mmol.l-1; EMG, 81.1 (SD 24.0) microV] except HR which was the same.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Relationship between heart rate threshold, lactate turn point and myocardial function.

We examined the relationship between heart rate threshold (HRT), lactate turn point (LTP) and myocardial function expressed as left ventricular ejection fraction (LVEF) determined by radionuclide ventriculography. Two groups of subjects (G I: N = 8; G II: N = 7) with and without a deflection of heart rate performance curve (HRPC) underwent sitting cycle ergometry. HRT (G I), aerobic threshold (AeT; G I, G II), and LTP (G I, G II) were determined by means of linear regression break point analysis. Also, a break point in LVEF performance curve (LVEFBP) was obtained. Power output at HRT and at LTP was not significantly different between G I and G II (272.5 +/- 38.7 W; 294.3 +/- 20.6 W). Power output at LVEFBP (G I: 182.6 +/- 31.7 W; G II: 211.8 +/- 21.5 W) was not significantly different to power output at LTP (G I: 194.2 +/- 32.7 W; G II: 215.2 +/- 24.4 W) and HRT (G I: 193.0 +/- 38.2 W). Significant differences (p < 0.05) could only be found between G I and G II for heart rate (HR) at LTP (G I: 163.5 +/- 5.8 b.min-1; G II: 154.4 +/- 6.7 b.min-1) and LVEF at the end of the load (LVEFend) (G I: 77.9 +/- 2.9%; G II: 71.3 +/- 7.0%). The drop of LVEF at LVEFBP was significantly related to LTP in all cases. The present data suggest that the noninvasive determination of anaerobic threshold by means of heart rate curve analysis is not always possible due to different response of myocardial function and heart rate to graded cycle ergometer exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[ECG of the athlete's heart].

The athlete's heart is characterized by eccentric hypertrophy of all cardiac cavities and there is a close connection to increased tone of the vagal system. As a consequence, not only arrhythmias are observed in the ECG of healthy athletes, but also changes in the QRS complex and in the ST-T-segment. Left ventricular hypertrophy is diagnosed in ECG by a positive Sokolow-Lyon index. The frequent finding of a right ventricular conduction delay is possibly due to hypertrophy of the myocardium in the apex of the right ventricle. The causes of various T wave changes are generally unclear and await further diagnostic clarification. In cases when normalization of the T-wave deviation is observed under stress, such changes are of functional nature. Echocardiography is indicated in any case to establish the heart's size and function; hypertrophic cardiomyopathy has to be excluded. Frequent cardiac dysrhythmias found in athletes are sinus bradycardia and sinus arrhythmia, less often escape rhythms are seen. A arrhythmia more often found in athletes is the respiration-dependent simple atrioventricular dissociation. Also, escape rhythms are observed in some cases with ventricular origin. Finally, a pronounced vagotonia can lead to a prolonged conduction time; AV-blocks of all degrees of severity are observed in athletes. The functional character of these arrhythmias can be easily demonstrated by their disappearance under stress.

Arrhythmias, Cardiac↗
PubMed1994

[First aid measures by lay persons in cardiovascular arrest].

The efficiency of first aid resuscitation is affirmed by many publications. In a questionnaire of the division of Cardiology of the Department of Internal Medicine, Graz and the Styrian Heart Patient Society distributed during the course of the Graz spring fair 1993 the population was approached as to first aid in cardiac arrest. 550 subjects responded to answer this circular for assessment dividing the population statistically in 4 different age groups showing differences among male and female and country and city dwellers. It has been shown that general first aid resuscitation has been known sufficiently, whereas special cardiorespiratory procedures (such as artificial respiration or cardiac massage) were unknown to most.

Adolescent↗