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Biomedical subjects

A Kardos

Publications and source records attributed to A Kardos.

At least 19 recordsLinked to original sources
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

Coronary artery-descending aorta fistula as an unusual collateral in a patient with postductal coarctation.

We report on the case of a 45-year-old man with recurrent syncope and angina with shortness of breath on exertion. Invasive and noninvasive diagnostic methods revealed severely stenosed bicuspid aortic valve, postductal coarctation of the aorta, and a coronary artery-descending aorta fistula. After surgical correction of the coarctation, ligation of the fistula, and aortic valve replacement, the patient's symptoms resolved.

Aorta, Thoracic↗
PubMed1998

Lipophilic versus hydrophilic beta(1) blockers and the cardiac sympatho-vagal balance during stress and daily activity in patients after acute myocardial infarction.

OBJECTIVE: To compare the effects of a lipophilic and a hydrophilic beta(1) blocker on cardiac sympatho-vagal balance during daytime activity and stress in patients four to six weeks after myocardial infarction. DESIGN: Randomised, double blind, crossover study comparing the effect of atenolol (50 mg once daily) with metoprolol CR (100 mg once daily) with treatment periods of four weeks. SETTING: Large teaching hospital. PATIENTS: 50 patients (45 male, 5 female, age range 40 to 75 years), four to six weeks after an acute myocardial infarction. METHODS: At the end of each treatment period the 24 hour heart rate variability, heart rate variability power spectra during head up tilt and mental stress, baroreflex sensitivity, and exercise performance were evaluated. RESULTS: During daytime activity and during orthostatic and mental stress, both heart rate and the ratio between the low and high frequency spectral components of the heart rate variability were significantly lower with atenolol. Conversely, there was no difference between treatments in baroreflex sensitivity and resting plasma catecholamines. Exercise duration and peak oxygen consumption did not differ between treatments, but the heart rate during submaximal and peak exercise was significantly lower with atenolol. CONCLUSIONS: At the doses used in this study, atenolol achieved greater beta(1) adrenergic blockade than metoprolol CR and this was associated with significant inhibition of vagal withdrawal during stress. This suggests that peripheral blockade of beta(1) adrenergic receptors may be more important than central blockade in preventing stress induced vagal withdrawal in patients after myocardial infarction.

Adrenergic beta-Antagonists↗
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↗
PubMed1997

QT interval dynamics and heart rate variability preceding a case of cardiac arrest.

A 71 year old man with hypertensive heart disease and chronic renal failure was wearing a Holter monitor when he had a cardiac arrest. He had ventricular fibrillation (VF) and died despite prompt resuscitation. In the 15 minutes preceding the VF there was a sudden increase in heart rate, followed by a brief period of atrial fibrillation leading to ventricular tachycardia, which in turn rapidly degenerated into VF. The QT interval and heart rate variability were studied half hourly over the seven hours preceding the cardiac arrest, using a computerised Holter system. A further detailed analysis was performed over the final hour before the cardiac arrest. An abrupt increase in the steepness of the QT/RR slope, a prolonged QTc, and a reduction in the heart rate variability were observed in the interval that immediately preceded the onset of the terminal rhythm disturbance.

Aged↗
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↗
PubMed1996

[Management of severe orthostatic hypotension by head-up-tilt posture and administration of fludrocortisone].

A case of a 66-year-old man with recurrent episodes of syncope is reported. The syncopal attacks started five years ago in sitting and standing positions. At the time of admission the fainting attacks occurred 2-3 times per day. The diagnostic tests revealed severe orthostatic hypotension. The medical treatment was started with salt enriched diet and fludrocortisone. The efficacy of the therapy was tested by using the tilt table test with a self developed computer system consisting of a non-invasive finger blood pressure monitor and ECG. The orthostatic tolerance improved with the medical therapy, however remained unsatisfactory for the patient's daily activity. Though the patient had less frequent symptoms, he had still sustained episodes of recurrent syncopes. The medical therapy was than combined with sleeping in the 15 degrees head-up-tilt position. The repeat tilt table test was performed two weeks after initiation of the 15 degrees head-up-tilt sleeping. The orthostatic tolerance was markedly improved. The patient became free of symptoms and during a four-week follow-up his condition remained stable. At the control the patient reported about deterioration of his symptoms as a result of the discontinuation of sleeping in "head-up-tilt" position for two weeks. The objective signs leading to aggravate his symptoms was documented by the tilt table test. We reinstituted the "head-up-tilt" sleeping in his therapeutic management.

Aged↗
PubMed1996

[Association of AV reciprocating tachycardia, using a concealed bundle of Kent, and paroxysmal atrial fibrillation in neurocardiogenic syncope].

A case of neurocardiogenic syncope is reported in which both AV-reciprocating tachycardia due to a concealed retrogradely conducting posteroseptal bypass tract and paroxysmal atrial fibrillation were observed. In connection with this case, attention is paid to the difficulties of differential diagnosis and to the pathophysiological correlations concerning the occurrence of neurocardiogenic/vasovagal reflex syncope and cardiac arrhythmias. A prolonged period of freedom from syncope and tachycardia was achieved by means of drug treatment, through the combined administration of disopyramide, bisoprolol and theophylline.

Aged↗
PubMed1996

Changes in blood pressure and heart period variability in patients with recent acute myocardial infarction.

1. A decreased heart period variability and baroreflex sensitivity in patients with acute myocardial infarction have already been documented. Since one of the major determinants of heart period variability is blood pressure variability, it would be important to know the characteristics of blood pressure regulation in this setting. The changes in blood pressure variability during the acute phase of myocardial infarction have not yet been studied. 2. We investigated the blood pressure variability and the heart period variability in 11 patients with acute myocardial infarction 3 to 5 days after their admission. Thirteen age matched patients with no evidence signs of ischaemic heart disease or previous myocardial infarction served as controls. We used the frequency domain indexes of short term measurements of finger blood pressure variability and heart period variability. The spectral powers for both heart period variability and blood pressure variability were divided into three major components: total frequency (0.01-0.4 Hz), low frequency (0.04-0.15 Hz) and high frequency (0.15-0.4 Hz). 3. All of the frequency-domain components of the heart period variability were significantly decreased in patients with recent acute myocardial infarction compared to the controls: Ln(total power): 5.68 +/- 0.24 vs. 7.21 +/- 0.29, Ln(low-frequency power): 4.31 +/- 0.28 vs. 7.05 +/- 0.53, Ln(high-frequency power): 3.50 +/- 0.33 vs. 5.48 +/- 0.32. Acute myocardial infarction patients showed a significantly reduced blood pressure variability in all frequency components compared to the controls: Ln(total power): 4.21 +/- 0.18 vs. 6.79 +/- 0.48, Ln(low-frequency power): 2.40 +/- 0.24 vs. 4.36 +/- 0.21, Ln(high-frequency power): 3.31 +/- 0.25 vs. 5.66 +/- 0.38. 4. We hypothesize that the reduced blood pressure variability in the acute phase of myocardial infarction could be related to a relative invariance of stroke volume. The underlying mechanism is the reduced left ventricular compliance.

Blood Pressure↗
PubMed1996

Regulation of immediate blood pressure response to orthostasis in patients with fixed ventricular pacemaker rhythm.

1. The immediate heart rate and blood pressure changes upon standing have been well documented. It has been recognized, that blood pressure transients elicit baroreflex responses contributing to the complex mechanism of post standing heart rate fluctuations. On the other hand the influence of heart rate changes on orthostatic blood pressure control is not well understood. Therefore we have studied the blood pressure regulation of 28 pacemaker dependent subjects with fixed ventricular pacemaker rhythm during active orthostasis, and their responses were compared to that of 10 elderly (66 +/- 11 year), and 12 young (35 +/- 5 year) volunteers. 2. The young volunteers exhibited the characteristic biphasic heart rate response on standing, with a maximum acceleration of 29 +/- 12 beats. The heart rate response of the elderly volunteers was very limited, and no response was seen among pacemaker subjects. A significantly greater (-37 +/- 15 mmHg) systolic blood pressure drop was seen in the pacemaker group than in the group of young volunteers (-22 +/- 13 mmHg). The systolic blood pressure overshoot of the young volunteers (36 +/- 17 mmHg) was significantly greater than that of the pacemaker patients' (11 +/- 22 mmHg). The blood pressure transients of the elderly volunteers and pacemaker subjects were very similar. Significant correlation was detected between the extent of maximum heart rate acceleration and the magnitude of the subsequent blood pressure overshoot (R = 0.68, p < 0.0005) among healthy volunteers. 3. Our results indicate that certain post standing blood pressure transients are heart rate dependent. The chronotrop incompetency of healthy elderly volunteers and pacemaker subjects result in similar alteration of the orthostatic blood pressure regulation, however this modified response does not interfere with a satisfactory hemodynamic stabilization.

Adult↗
PubMed1995

The mechanism of blood pressure variability. Study in patients with fixed ventricular pacemaker rhythm.

BACKGROUND: Several studies have shown that heart rate variability plays an anti-oscillatory role in the regulation of blood pressure variability in humans. We tested whether systolic blood pressure variability in patients with a fixed ventricular pacemaker rhythm differs from that in patients with sinus rhythm. METHODS AND RESULTS: In 18 patients with a fixed ventricular pacemaker rhythm and in ten age-matched patients with sinus rhythm the systolic blood pressure oscillation and the low and high-frequency spectral components of systolic blood pressure were studied in the resting supine position during spontaneous breathing and during forced deep ventilation of 6 cycles.min-1. Patients with a pacemaker had a higher amplitude of systolic blood pressure oscillation than control subjects during spontaneous breathing (13.5 +/- 2.0 mmHg vs 6.4 +/- 1.6 mmHg, P = 0.035), and a slight but not significant difference also persisted during forced deep ventilation 19.0 +/- 2.3 mmHg vs 15.0 +/- 2.3 mmHg, P = 0.18). The increment in systolic blood pressure fluctuation from spontaneous breathing to forced deep ventilation was less marked in the pacemaker group than in the control subjects (40% vs 130%, P = 0.43). Although all the systolic blood pressure spectral components of the pacemaker patients were higher during both spontaneous breathing and forced deep ventilation, the differences between the two groups did not reach statistical significance. CONCLUSIONS: Our observations in patients with a fixed ventricular pacemaker rhythm suggest that the mechanical effects on the intrathoracic vessels and the consecutive stroke volume changes are responsible for respiration-related systolic blood pressure oscillation and reflex systolic blood pressure changes.

Aged↗
PubMed1995

Comparison of two mechanical carotid baroreceptor stimulation techniques.

We compared two mechanical carotid baroreceptor stimulation techniques, the phase related external suction (PRES) method and the conventional neck suction techniques concerning their effects on blood pressure and heart rate responses in a group of 10 normotensive men. The cuff pressure using the PRES method was phase-locked in time to the R-wave of the ECG. During the conventional neck suction technique the cuff pressure changes were not related to the cardiac cycle, it was either negative or positive. Blood pressure was measured in four of the patients both invasively and noninvasively to compare the two baroreceptor stimulating methods. The results have indicated that (1) both mechanical carotid baroreceptor stimulation technique showed a significant heart rate deceleration to baroreceptor stimulation. (2) The heart rate changes were more pronounced during the continuous neck cuff technique, and the heart rate recovered sooner to the baseline. The variation of baroreceptor activity as induced by the PRES method seems to prevent habituation much more than the continuous neck suction method. (3) The systolic blood pressure decrease was significant both during PRES and continuous neck suction stimulation. A higher decrease in systolic blood pressure was shown during continuous neck suction stimulation compare to the PRES stimulation. (4) The diastolic blood pressure changes showed the same alteration for baroreceptor stimulation as compared to the control condition but there was no difference between the two stimulation methods. (5) The noninvasive Finapres blood pressure device measures blood pressure reliably.

Adult↗
PubMed1994

[Continuous non-invasive blood pressure monitoring in the diagnosis of pacemaker syndrome].

The drop in blood pressure coinciding with the atrioventricular dyssynchrony plays an important role in the genesis of pacemaker syndrome. The diagnosis is often based on continuous blood pressure recording. Formerly the continuous blood pressure monitoring could only be performed by invasive methods. The authors demonstrate the feasibility of a new non invasive continuous blood pressure recorder, the Finapres 2300, by presenting illustrative case reports. The authors recommend more widespread use of non invasive haemodynamic monitoring for the diagnosis of pacemaker syndrome.

Aged↗
PubMed1994

Baroreceptor stimulation: pain perception and sensory thresholds.

Baroreceptor activity has been implicated in the modulation of pain. Sensory detection thresholds and pain ratings were measured in a group of 28 men during carotid baroreceptor manipulation with the PRES (phase-related external suction) neck suction technique. Brief, cardiac phase-related electrical impulses were delivered intracutaneously to the finger. The results indicate that minimum baroreceptor activity was associated with more severe pain, but had no effect on sensory detection threshold. The results are discussed in terms of the learned model of hypertension.

Adult↗