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Biomedical subjects

L Rudas

Publications and source records attributed to L Rudas.

At least 19 recordsLinked to original sources
PubMed2003

Oesophageal acid stimulation in humans: does it alter baroreflex function?

The aim of this study was to investigate if oesophagel acid stimulation (Bernstein test) had an influence on heart rate and blood prsure variability and baroreflex gain. We compared the cardiovascular responses in 10 patients with established gastro-esophageal reflux disease (Group 1) and 10 control subjects (Group 2) during esophageal saline and 0.1 mol/l hydrochloric acid instillation. Indices of heart rate and blood pressure variability and baroreflex gain (derived from linear spontaneous sequences and cross spectral analysis) were calculated. In Group 1 the standard deviation of RR intervals (SDRR: 46 ms vs 51 ms, p=0.030) and the root mean square of successive differences (RMSSD: 24 ms vs. 26 ms p=0.027) were significantly lower during acid infusions, than during saline. We found no significant difference in minimum, maximum and mean RR intervals and systolic blood pressures and in the percentage of RR intervals, which differed from adjacent cycles by more than 50 ms (PNN50). The power spectra of RR intervals in the high frequency band tended to be lower during acid infusion (p=0.055). There was no significant difference in blood pressure spectra, neither in low nor in high frequency band. In Group 2 there was no significant difference between any parameters measured during acid and saline. The baroreflex gain was not changed during the studied conditions in any group. Neither increased vagal tone, nor increased vagal variability occurred and the baroreflex gain was not altered during oesophageal acid simulation.

Adult↗
PubMed2002

Effect of axillary brachial plexus blockade on baroreflex-induced skin vasomotor responses: assessing the effectiveness of sympathetic blockade.

BACKGROUND: The combination of laser Doppler flowmetry and non-invasive blood pressure monitoring allows the continuous observation of cutaneous vascular resistance (CVR). Continuous recording of unmodulated skin blood flow (SBF) is very sensitive to artefacts, rendering the method unreliable. In contrast, intermittent short lasting challenges of the CVR by cardiovascular autonomic reflexes may provide information about the responsiveness of the sympathetic nervous system in the skin. METHODS: Eleven patients with below-wrist hand surgery (six males and five females; aged 35.2+/-7.1 years) performed Valsalva maneuver following axillary blockade. Skin blood flow was continuously monitored on the forearm of the side axillary blockade, as well as on the contra-lateral forearm, which was used as the control. The responses were expressed as changes compared with the baseline level derived from a resting period of 30 s. The maximal change in CVR was determined during the late strain phase of the Valsalva maneuver on both sides. For numerical comparison the change in CVR on the axillary blockade and control sides were simultaneously calculated. RESULTS: During the Valsalva maneuver a significant increase in CVR was observed on the control side with a maximum value during the late strain phase (baseline 0.18+/-0.1 and late strain phase 0.42+/-0.2 relative units; P<0.01). In contrast, only minimal changes were detected on the side of axillary blockade in CVR (baseline 0.17+/-0.8 and late strain 0.16+/-0.2 relative units; P=NS). CONCLUSIONS: Our findings support the disputed hypothesis that the human skin microvasculature is involved in baroreflex regulation under thermoneutral conditions. The determination of baroreflex stimulus-induced microvascular responses may serve as a feasible method for monitoring the effectiveness of sympathetic blockade.

Adult↗
PubMed2001

[The role of autopsy in verifying diagnostic accuracy at the intensive care unit].

The accuracy of the clinical diagnoses compared to the findings of an autopsy is a more relevant characteristic of the quality of care than the length of stay in the hospital or the daily costs of the stay. The aim of this retrospective study was: a) to compare the clinical and pathological diagnoses, b) to determine the amount of new information supplied by the autopsy and c) to determine wether the knowledge of correct clinical diagnosis would have resulted in a change of therapy. At the medical ICU 163 patients died during 1998, autopsy was performed in 110 cases. Agreement of clinical and pathological diagnoses and causes of death were retrospectively assessed by a board. Acute myocardial infarction accounted for 26% of deaths, pneumonia and respiratory insufficiency for 15%, cardiac failure for 14%, sepsis for 14%, stroke for 13%, pulmonary embolism for 5% and others for 13%. The accuracy of the clinical cause of death was proved in 81% of the cases. The main disease was diagnosed correctly in 86% of the cases. As a tool in quality control, the agreement of clinical and pathological diagnoses and causes of death proved to be good during the examined period of time.

Autopsy↗
PubMed2001

Determinants of spontaneous baroreflex sensitivity in a healthy working population.

Baroreflex sensitivity (BRS) by the spontaneous sequence technique has been widely used as a cardiac autonomic index for a variety of pathological conditions. However, little information is available on determinants of the variability of spontaneous BRS and on age-related reference values of this measurement in a healthy population. We evaluated BRS as the slope of spontaneous changes in systolic blood pressure (BP) and pulse interval from 10 minutes BP (Finapres) and ECG recordings in 1134 healthy volunteers 18 to 60 years of age. Measurement of BRS could be obtained in 90% of subjects. Those with unmeasurable spontaneous BRS had a slightly lower heart rate but were otherwise not different from the rest of the population. BRS was inversely related to age (lnBRS, 3.24-0.03xage; r(2)=0.23; P:<0.0001) in both genders. In addition, univariate analysis revealed a significant inverse correlation between BRS and heart rate, body mass index, and BP. Sedentary lifestyle and regular alcohol consumption were also associated with lower BRS. However, only age, heart rate, systolic and diastolic BP, body mass index, smoking, and gender were independent predictors of BRS in a multivariate model, accounting for 47% of the variance of BRS. The present study provides reference values for spontaneous BRS in a healthy white population. Only approximately half of the variability of BRS could be explained by anthropometric variables and common risk factors, which suggests that a significant proportion of interindividual differences may reflect genetic heterogeneity.

Adolescent↗
PubMed2000

Severe cardiovascular autonomic dysfunction in a patient with Guillain-Barre syndrome: a case report.

Autonomic dysfunction is a frequent and severe complication of Guillain-Barre syndrome. It is often responsible for cardiovascular abnormalities, even cardiac arrest. We report a 49-year-old patient, who suffered from Guillain-Barre syndrome necessitating mechanical ventilation. He showed wide fluctuations of blood pressure and heart rate spontaneously or in relation with medical procedures. Though heart rate variability (HRV) and baroreflex sensitivity (BRS) values derived from different methods were extremely low, vigorous stimuli, like eyeball pressure test and carotid sinus massage, produced exaggerated responses, like severe bradycardias, hypotension and cardiac arrest. Despite the plasma exchange and supportive therapies, the patient finally developed adult respiratory distress syndrome (ARDS), sepsis and died due to septic shock.

Arrhythmias, Cardiac↗
PubMed2000

[Electrocardiographic Osborn wave in hypothermia].

The authors report the first Hungarian case of electrocardiographic Osborn wave with accidental hypothermia (core temperature 32 degrees C). The cellular and ionic mechanisms of the development of J-wave-elevation and the cardiac electrophysiological and ECG changes caused by hypothermia are briefly reviewed. An account is presented of those conditions in which, in a few or in all ECG leads, an Osborn wave or distinct J-point-elevation may be observed.

Aged↗
PubMed1999

Human sympathetic and vagal baroreflex responses to sequential nitroprusside and phenylephrine.

We evaluated a method of baroreflex testing involving sequential intravenous bolus injections of nitroprusside followed by phenylephrine and phenylephrine followed by nitroprusside in 18 healthy men and women, and we drew inferences regarding human sympathetic and vagal baroreflex mechanisms. We recorded the electrocardiogram, photoplethysmographic finger arterial pressure, and peroneal nerve muscle sympathetic activity. We then contrasted least squares linear regression slopes derived from the depressor (nitroprusside) and pressor (phenylephrine) phases with 1) slopes derived from spontaneous fluctuations of systolic arterial pressures and R-R intervals, and 2) baroreflex gain derived from cross-spectral analyses of systolic pressures and R-R intervals. We calculated sympathetic baroreflex gain from integrated muscle sympathetic nerve activity and diastolic pressures. We found that vagal baroreflex slopes are less when arterial pressures are falling than when they are rising and that this hysteresis exists over pressure ranges both below and above baseline levels. Although pharmacological and spontaneous vagal baroreflex responses correlate closely, pharmacological baroreflex slopes tend to be lower than those derived from spontaneous fluctuations. Sympathetic baroreflex slopes are similar when arterial pressure is falling and rising; however, small pressure elevations above baseline silence sympathetic motoneurons. Vagal, but not sympathetic baroreflex gains vary inversely with subjects' ages and their baseline arterial pressures. There is no correlation between sympathetic and vagal baroreflex gains. We recommend repeated sequential nitroprusside followed by phenylephrine doses as a simple, efficientmeans to provoke and characterize human vagal and sympathetic baroreflex responses.

Adolescent↗
PubMed1998

[Cardiovascular autonomic regulation following orthoptic heart transplantation].

Numerous recent observations have indicated autonomic reinnervation of transplanted human hearts. In order to assess autonomic regulation 5 patients were studied 1 to 5 years following cardiac transplantation. A series of tests were performed, including blood pressure and ECG recordings on rest, during 15/min patterned breathing, isometric handgrip exercise, and Valsalva manoeuvre. The time domain indices (SDRR, pNN50, rMSSD) and the frequency domain indices of heart rate variability were also studied. Among the five patients under study only one exhibited features compatible with both sympathetic and parasympathetic reinnervation. Traditional autonomic reflex tests and the analysis of time and frequency domain indices of HRV serve as simple tool in primary assessment of cardiac reinnervation.

Adult↗
PubMed1998

[Pacemaker syndrome without a pacemaker].

Circulatory consequences of cardiac arrhythmias are not always evident. Proper interpretation of the clinical symptoms in certain cases requires assessment of the patients' other hemodynamic characteristics. The authors present the case of a patient with left ventricular hypertrophy, who developed severe circulatory failure at the time of artrioventricular dyssynchrony in association with junctional rhythm. Analogy between the circulatory consequences of the junctional rhythm and ventricular pacing was documented by hemodynamic measurements. The patient was subsequently treated by implanting an atrioventricular pacemaker.

Aged↗
PubMed1998

[Carotid sinus syncope: the vasodepressor component].

Carotis sinus syncope is one of the leading indications for pacemaker implantation in Hungary. Although the role of the vasodepressor component is emphasized in our current guidelines, documentation of the vasodepression in technically difficult and therefore often abandoned. A case of a patient is presented who received a VVI pacemaker in spite of documented mixed carotid sinus syncope. Subsequent to the pacemaker implantation, patient's condition deteriorated, characterized by frequent syncopal episods. Replacing the VVI pacemaker by a DDD device resulted in prompt relief of symptoms. The importance of invasive or noninvasive hemodynamic monitoring in the diagnostic workup of these patients is emphasized.

Aged↗
PubMed1998

[Angina pectoris induced by pacemaker syndrome].

Pacemaker syndrome is caused primarily by the lack of atrial kick and by neurocardiogenic reflex mechanisms due to simultaneous atrial and ventricular contractions. The most common clinical symptoms are dyspnoe, hypotension, dizziness and syncopal attacks. A case report of a patient with pacemaker syndrome is presented, in which the main clinical manifestation was a recurrent chest pain. A VVI demand pacemaker was implanted because of sick sinus syndrome ten years ago and shortly afterwards anginal attacks of rest developed. Coronary angiography revealed a non-significant (25%) narrowing of the right coronary artery (RCA). Casual and long-term ambulatory blood pressure (ABPM) measurements elucidated that the patient occasionally has extremely low diastolic blood pressure. This later phenomenon was confirmed and refined by a "beat-to-beat" blood pressure measuring technique. The elimination of the pronounced "beat-to-beat" variability of arterial blood pressure and transient coronary hypoperfusion due to implantation of an AV sequential bifocal pacemaker resulted in a full disappearance of angina pectoris.

Angina Pectoris↗
PubMed1997

[Defecation syncope following pacemaker implantation].

A case of syncope is reported, where hemodynamic responses compatible with pacemaker syndrome occurred during defecation. A 73 year old female received a VVI pacemaker for complete heart block. Subsequently she sustained repeated episodes of defecation syncope. Hemodynamic investigations revealed an abnormal blood pressure drop occurring at the overshoot phase of the Valsalva maneuver in association with alternation of sinus and pacemaker rhythm. This modified Valsalva response in the presence of contributing factors, such as hypovolemia and nitroglycerin therapy manifested as defecation syncope. The abnormal condition was treated by eliminating the contributing factors, and by programming a low pacemaker frequency, thus precluding sinus-pacemaker alterations.

Aged↗
PubMed1997

Epidemiology of congenital coronary artery anomalies: a coronary arteriography study on a central European population.

The anatomical patterns and frequency of occurrence of congenital coronary anomalies (CCA) in a Central European cohort has not yet been studied. The angiographic data of 7,694 consecutive patients undergoing coronary arteriography at the Albert Szent-Györgyi Medical University, Szeged, Hungary, from 1984 to 1994 were analyzed. CCA were found in 103 patients (1.34% incidence). Ninety-eight of them (95.2%) had anomalies of origin and distribution, and five (4.8%) had coronary artery fistulae. The incidence was the highest for the separate origin of left descending artery and left circumflex from the left sinus of Valsalva (52.42%). Anomalous origin of the left circumflex coronary artery from the right coronary was 8.7% while from the right sinus of Valsalva 18.4%. CCA, which may be associated with potentially serious events, such as ectopic coronary origin from the opposite aortic sinus (1.9%) and single coronary arteries (3.88%), were not frequent. The incidence of CCA in the Central European cohort under study was similar to that of the largest North American study. The anatomic classification presented can be useful from both clinical and surgical standpoints.

Adult↗
PubMed1997

Effect of postural changes on arterial baroreflex sensitivity assessed by the spontaneous sequence method and Valsalva manoeuvre in healthy subjects.

The objective of this study was to compare the baroreflex sensitivity (BRS) assessed by the new, non-invasive, spontaneous sequence method (BRS-sequence) with the Valsalva manoeuvrebased BRS. Fourteen healthy volunteers were studied in the supine position, during 60 degrees head-up tilt (HUT) and during -30 degrees head-down tilt (HDT). Blood pressure and R-R intervals were continuously and non-invasively recorded using a Finapres device. The BRS-sequence was assessed by analysing the slopes of spontaneously occurring sequences of three or more consecutive beats in which systolic blood pressure and R-R interval of the following beat increased or decreased in the same direction in a linear fashion; it was compared with data obtained during the Valsalva manoeuvre in each position. The time and frequency domain indices of R-R interval variability were also evaluated. The mean difference of BRS between the two non-invasive methods was 3.86 ms/mmHg with a standard deviation of 9.14 ms/mmHg. BRS was decreased during HUT and increased during HDT as assessed by both techniques. The changes in BRS were associated with vagal withdrawal and sympathetic activation during HUT and enhancement in the cardiac vagal tone and reduction in the sympathetic activity during HDT. We conclude that the BRS-sequence technique provides a reliable method to study the neural control of the circulation, although the body position in consecutive measurements needs to be standardized.

Adolescent↗
PubMed1996

[Micturition syncope].

The micturition syncope is a special manifestation of the so called "situational syncopes". These reflex syncopes share efferent mechanisms with the neurocardiogenic, or vasovagal syncope. A case of a patient is reported, who presented with micturition syncope. The patient's tendency for vasovagal syncope was documented by a positive tilt table test. The uniform premonitory symptoms preceding the two fainting attacks indicated the relation between the episodes. The authors review the literature of the micturition syncope, and discuss the potential pathomechanisms.

Humans↗