A. Kardos | University of Oxford (original) (raw)
Papers by A. Kardos
Orvosi hetilap, Jan 12, 1997
A case of syncope is reported, where hemodynamic responses compatible with pacemaker syndrome occ... more 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.
Heart (British Cardiac Society), 1997
A 71 year old man with hypertensive heart disease and chronic renal failure was wearing a Holter ... more 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.
Heart, 1998
Myocardial infarction occurring in young people with angiographically normal coronary arteries is... more Myocardial infarction occurring in young people with angiographically normal coronary arteries is well described but the pathophysiology of this condition remains unknown. Coronary artery spasm in association with thrombus formation and minimal atheromatous disease or spontaneous coronary artery dissection are possible causes. Two young men presented with severe chest pain after acute alcohol intoxication and each sustained an extensive anterior myocardial infarction. Investigations including intravascular ultrasound showed no evidence of atherosclerotic coronary artery disease. Coronary artery spasm associated with acute alcohol intoxication as well as a prothrombotic state and endothelial damage related to cigarette smoking may be mechanisms leading to acute myocardial infarction in these cases. Acute myocardial infarction occurs in young persons with normal coronary arteries and the diagnosis should be considered in young patients presenting with severe chest pain, particularly those abusing cocaine or alcohol, so that reperfusion therapy can be initiated promptly.
The Journal of Physiology, 2001
1. Positron emission tomography (PET) was used to identify the neuroanatomical correlates underly... more 1. Positron emission tomography (PET) was used to identify the neuroanatomical correlates underlying 'central command' during imagination of exercise under hypnosis, in order to uncouple central command from peripheral feedback.
Intensive Care Medicine, 1996
Hypertension, 2001
Baroreflex sensitivity (BRS) by the spontaneous sequence technique has been widely used as a card... more 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, 3.24Ϫ0.03ϫage; r 2 ϭ0.23; PϽ0.0001) 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. (Hypertension. 2001;37:911-916.)
Clinical Autonomic Research, 1997
The objective of this study was to compare the baroreflex sensitivity (BRS) assessed by the new, ... more 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.
European Heart Journal, 2002
Aims Aims: To assess the heritability (i.e. relative contribution of genetic factors to the varia... more Aims Aims: To assess the heritability (i.e. relative contribution of genetic factors to the variability) of continuous measures of left ventricular hypertrophy determined by electrocardiography and echocardiography.
Orvosi hetilap, Jan 12, 1997
A case of syncope is reported, where hemodynamic responses compatible with pacemaker syndrome occ... more 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.
Heart (British Cardiac Society), 1997
A 71 year old man with hypertensive heart disease and chronic renal failure was wearing a Holter ... more 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.
Heart, 1998
Myocardial infarction occurring in young people with angiographically normal coronary arteries is... more Myocardial infarction occurring in young people with angiographically normal coronary arteries is well described but the pathophysiology of this condition remains unknown. Coronary artery spasm in association with thrombus formation and minimal atheromatous disease or spontaneous coronary artery dissection are possible causes. Two young men presented with severe chest pain after acute alcohol intoxication and each sustained an extensive anterior myocardial infarction. Investigations including intravascular ultrasound showed no evidence of atherosclerotic coronary artery disease. Coronary artery spasm associated with acute alcohol intoxication as well as a prothrombotic state and endothelial damage related to cigarette smoking may be mechanisms leading to acute myocardial infarction in these cases. Acute myocardial infarction occurs in young persons with normal coronary arteries and the diagnosis should be considered in young patients presenting with severe chest pain, particularly those abusing cocaine or alcohol, so that reperfusion therapy can be initiated promptly.
The Journal of Physiology, 2001
1. Positron emission tomography (PET) was used to identify the neuroanatomical correlates underly... more 1. Positron emission tomography (PET) was used to identify the neuroanatomical correlates underlying 'central command' during imagination of exercise under hypnosis, in order to uncouple central command from peripheral feedback.
Intensive Care Medicine, 1996
Hypertension, 2001
Baroreflex sensitivity (BRS) by the spontaneous sequence technique has been widely used as a card... more 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, 3.24Ϫ0.03ϫage; r 2 ϭ0.23; PϽ0.0001) 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. (Hypertension. 2001;37:911-916.)
Clinical Autonomic Research, 1997
The objective of this study was to compare the baroreflex sensitivity (BRS) assessed by the new, ... more 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.
European Heart Journal, 2002
Aims Aims: To assess the heritability (i.e. relative contribution of genetic factors to the varia... more Aims Aims: To assess the heritability (i.e. relative contribution of genetic factors to the variability) of continuous measures of left ventricular hypertrophy determined by electrocardiography and echocardiography.