Biomedical subjects

M Jensen-Urstad

Publications and source records attributed to M Jensen-Urstad.

At least 37 records · Page 2Linked to original sources

PubMed1999

Myocardial sestamibi uptake in healthy subjects is related to age, gender and habitus.

The object of this study was to evaluate the effect of gender, age and anthropometric data on regional isotope uptake in myocardial perfusion scintigraphy using 99mTc-MIBI-SPECT (myocardial sestamibi single-photon emission technique). Seventy-one healthy, non-smoking subjects, 42 men and 29 women between 40 and 80 years of age, with less than 5% likelihood of having coronary artery disease were studied. All subjects underwent a maximal exercise and rest MIBI-SPECT using a 2-day protocol and a 180 degrees anterior circular rotation. No correction for scatter or attenuation was made. Normalized regional activity was different in men and women in the anterior and inferior regions, with higher values anteriorly in men and inferiorly in women. Regional activity also differed with age in both women and men with higher relative activity in the anterior regions in the oldest age groups. Higher activities were seen in the basal parts of the left ventricle at rest compared with stress in both men and women. Regional isotope uptake was significantly affected by habitus expressed as body mass index (BMI) and thoracic circumference. Different protocols for stress and rest seem to be needed for men and women in different age groups, and for stress and rest when performing semiquantitative MIBI-SPECT and comparing data with a normal file of healthy subjects. Furthermore, such anthropometric data as BMI and/or thoracic circumference should be considered in order to minimize the risk for false-positive or false-negative scintigraphic results.

Adult↗

PubMed1999

Decreased heart rate variability in patients with type 1 diabetes mellitus is related to arterial wall stiffness.

OBJECTIVE: Low heart rate variability (HRV) is, in several patient groups, related to poor prognosis. The underlying mechanisms are still unclear. The aim was to study if there is a relationship between HRV, which is a measure of baroreceptor function, and atherosclerosis. DESIGN: The relationship between heart rate variability and carotid arterial wall stiffness was studied in subjects with type 1 diabetes mellitus in which autonomic dysfunction and early atherosclerosis are common. HRV was assessed from power spectral analysis of 24-h Holter recordings and arterial wall stiffness was assessed from an ultrasound study of the right common carotid artery. SETTING: A university hospital. SUBJECTS: Fifty-nine patients (41 +/- 8 years) from the Stockholm Diabetes Intervention Study (SDIS) were investigated. These patients were randomized to intensified conventional treatment or standard treatment approximately 12 years before this study. RESULTS: Patients with stiffer arteries had lower HRV in all spectral bands (r = -0.32 to -0.40, P = 0.06-0.001). This relation remained on correcting for age. All spectral parameters of HRV correlated with the mean HbA1c from 10 years of study (r = -0.37 to -0.40, P = 0.004-0.001). CONCLUSIONS: In patients with type 1 diabetes mellitus, heart rate variability and arterial wall stiffness are related to each other. The results suggests that the autonomic nervous system could be a link between diabetes and vascular disease.

Adult↗

PubMed1999

Antiplasmin correlates to arterial reactivity in a healthy population of 35-year-old men and women.

OBJECTIVE: To study whether haemostasis function variables correlate with endothelial function and other vasomotion characteristics of the brachial artery in a randomly selected healthy population of 35-year-old men and women. DESIGN: Endothelial function was measured as flow mediated dilatation (FMD) of the brachial artery during reactive hyperaemia and the nonendothelial dependent dilatation after sublingual nitroglycerin (NTG) was administered. Haemostasis and fibrinolysis function were estimated by analysis of von Willebrand factor, plasminogen activator inhibitor-1, antiplasmin and fibrinogen. SETTING: A general medicine research centre and a university hospital. SUBJECTS: Randomly chosen men (n = 53) and women (n = 56). RESULTS: Univariate correlation analysis showed significant correlations between haemostasis factors, conventional risk factors for cardiovascular disease and indices of vasomotion of the brachial artery. In multivariate analysis, with haemostasis variables and conventional risk factors included, antiplasmin was the strongest explanatory variable for FMD. When antiplasmin was removed from the analysis, the r-value dropped from 0.46 to 0.35. Antiplasmin also correlated with NTG-induced dilatation (positively) and brachial diameter at rest (negatively), albeit less consistently. CONCLUSIONS: Antiplasmin correlates significantly and independently to FMD, reflecting endothelial function, and also to brachial artery diameter at rest and nitroglycerin-induced dilatation. In multivariate analysis these correlations of antiplasmin to arterial characteristics were stronger than for 'conventional' risk factors, such as smoking, blood pressure and serum cholesterol.

Adult↗

PubMed1999

Beneficial effects of exercise training in heart failure patients with low cardiac output response to exercise - a comparison of two training models.

BACKGROUND: Exercise capacity of patients with chronic heart failure (CHF) correlates poorly with estimates of cardiac function. Yet, it has been suggested that only patients without severely impaired cardiac output (CO) benefit from exercise training. Comparisons of different training models have not been made in the same study. AIMS: To evaluate whether the response to different training models diverges according to the cardiac output response to exercise in patients with chronic heart failure. METHODS: Sixteen CHF patients (63 +/- 11 years) with an ejection fraction of 30 +/- 11% underwent a baseline cardiopulmonary exercise test, right heart catheterization and leg muscle biopsy. Cardiac output (CO) response to exercise was defined as the ratio between CO increase and the increase in oxygen uptake (CO response index) during exercise. Patients were randomized into two training regimens, differing with regard to active muscle mass, i.e. whole body and one-legged exercise. RESULTS: Baseline exercise capacity expressed as W kg-1 correlated with the CO response index (r = 0.51, P < 0.05). Exercise capacity on the cycle ergometer increased in both groups but more in the one-legged than in the two-legged training group (P < 0.05). The improvement in exercise capacity did not correlate with base-line exercise capacity. It correlated with CO response index in the one-legged (r = 0.75, P < 0.01) but not in the two-legged training group. CO response index correlated negatively with the pulmonary capillary wedge pressure at peak exercise (r = - 0.60, P < 0.05). The increase in leg muscle citrate synthase activity after training correlated negatively with the baseline CO response index (r = - 0. 50, P < 0.05). CONCLUSIONS: The improvement of exercise capacity after one-legged training correlates with the CO increase in relation to the O2 uptake before training. In patients with low CO response, individualization of the exercise regimen is needed and the benefits of training a limited muscle mass at a time deserve further study.

Adult↗

PubMed1999

Preserved vascular reactivity in elderly male athletes.

The objective was to characterise function and morphology of the arterial wall in 9 elderly men (mean age 75 +/- 3.4 years) with a history of lifelong regular strenuous exercise. A control group of 11 healthy sedentary or moderately physically active men (74.5 +/- 2.7 years) was also studied. With increasing age atherosclerosis becomes more common and endothelium-dependent vasodilation reduced. The effects of training on endothelial function and atherosclerosis have not been studied previously in elderly subjects. High-frequency ultrasound was used to estimate vasodilatory function in the brachial artery. The endothelium-dependent (flow-mediated) and non-endothelium-dependent (nitroglycerine-induced) dilation of the brachial artery were measured. Stasis was used to induce reactive hyperaemia. The carotid arteries were scanned for plaques, intima-media thickness was measured in the common carotid arteries and arterial wall stiffness was calculated from pulsatile diameter changes in the right carotid artery in relation to blood pressure. The athletes' maximal oxygen uptake during treadmill exercise was 2.90 +/- 0.50 l or 41 +/- 7 ml.kg-1. The athletes' and the controls' maximal exercise capacity on a bicycle was 254 +/- 38 W and 148 +/- 19 W respectively (P < 0.001). The athletes' body mass index was 22.6 +/- 2.6 kg.m-2 and the controls' body mass index was 25.8 +/- 3.5 kg.m-2 (P = 0.037). Three of 9 athletes had plaques in either or both carotid bifurcations compared with 6 of 11 controls. The athletes had less stiff arteries and better vasodilatory capacity in the brachial artery during increased flow, and borderline significantly greater vasodilation after nitroglycerine. So, elderly athletes with a lifelong training history appear to have better vasodilatory capacity and less stiff arteries than healthy controls. Plaques in the carotid bifurcation were common in both athletes and controls.

Aged↗

PubMed1999

Prognostic value of symptom limited versus low level exercise stress test before discharge in patients with myocardial infarction treated with thrombolytics.

OBJECTIVE: To evaluate the benefits and risks of symptom limited exercise testing versus low level exercise testing soon after a thrombolytic treated acute myocardial infarction. DESIGN AND PATIENTS: 98 patients (71 men, 27 women), mean (SD) age 64 (9) years (range 45-75 years), were investigated 5-8 days after admittance to hospital. An ergometer cycle test was used, starting at 30 W with 10 W increments per minute. Each exercise test was interpreted at the symptom limited end point and a low level end point, which was defined as the point at which the patient rated exhaustion as 13 on the 6-20 point Borg scale for rating perceived exertion. SETTING: A university hospital. RESULTS: 75 of the 98 patients were able to perform a predischarge exercise test. Of the remaining 23 patients who could not perform an early exercise test (because of unstable angina, heart failure, or thrombus detected at echocardiography), five died or had a myocardial infarction and six underwent bypass surgery or percutaneous transluminal coronary angioplasty (PTCA) during a follow up period of one year. There were no complications related to the symptom limited exercise tests. The test results were positive in 15 patients at the low level end point and in 39 patients (p < 0.001) at the symptom limited end point. During a follow up period of one year, six of the 75 patients died or had a myocardial infarction. Two of these six patients had a positive low level exercise test and four had a positive symptom limited exercise test. Twenty three of the 75 patients who performed an exercise test had a cardiac event within one year (death, myocardial infarction, bypass surgery or PTCA); of these, 19 had a positive symptom limited exercise test and nine had a positive low level exercise test (p = 0.025). Four of the 36 patients with a negative symptom limited test suffered cardiac events within a year (two patients had a myocardial infarction and two had bypass surgery). CONCLUSION: Symptom limited exercise testing soon after thrombolytically treated myocardial infarction will identify more patients with exercise induced ST depression or chest pain than a low level test, and seems safe. A negative symptom limited test has a better negative predictive value (11% risk of an event within a year) than a negative low level (25% risk of an event within a year).

Adult↗

PubMed1999

Carotid artery diameter correlates with risk factors for cardiovascular disease in a population of 55-year-old subjects.

BACKGROUND AND PURPOSE: We investigated whether, in a randomly selected population of 55-year-old men and women, there is a relationship between common carotid artery (CCA) diameter and intima-media (IM) thickness and conventional risk factors for cardiovascular disease such as gender, smoking, elevated blood lipids, and high blood pressure. METHODS: CCA diameter and IM thickness of the distal right and left CCAs were measured by high-frequency ultrasound methods. Fifty-seven men (73% of the invited men) and 47 women (62% of the invited women) participated. RESULTS: In the whole group the CCA diameter was correlated with gender (P<0.001), cholesterol (P=0.007), triglycerides (P<0.001), apoB (P<0.001), apoB/A-1 (P<0.001), systolic blood pressure (P=0. 001), and glucose (P=0.006). HDL was inversely correlated with mean CCA diameter (P=0.003). In men the CCA diameter was correlated with a combined risk factor score (P=0.005), systolic blood pressure (P=0. 011), platelet count (P=0.033), apoB (P=0.025), and occurrence of plaque (P=0.003). In women the CCA diameter was correlated with a combined risk factor score (P=0.010), systolic blood pressure (P=0. 033), body mass index (P<0.001), cholesterol (P=0.009), triglycerides (P=0.14), apoB (P=0.002), and apoB/A1 (P=0.003). IM thickness was correlated with systolic blood pressure (P<0.001). CONCLUSIONS: There are correlations between risk factors for cardiovascular disease and carotid artery diameter and IM thickness in both women and men in a population of 55-year-old subjects. The increased vessel diameter in subjects with cardiovascular risk factors may be a sign of attenuated vasoregulation, which could be an important factor during the development of atherosclerosis.

Age Factors↗

PubMed1998

Comparison of different echocardiographic methods with radionuclide imaging for measuring left ventricular ejection fraction during acute myocardial infarction treated by thrombolytic therapy.

The aim of this study was to: (1) compare the usefulness, in clinical practice, of different echocardiographic methods of left ventricular (LV) function determination in patients with a recent thrombolytic-treated acute myocardial infarction (AMI); (2) compare these measurements with the reference method radionuclide imaging; and (3) evaluate the reproducibility of visual estimation of the LV ejection fraction (EF) and the use of the biplane method of discs (Simpson's rule) in clinical practice. Echocardiography and radionuclide imaging were performed within 2 hours of each another, 5 to 8 days after hospital admission. Ninety-six patients (70 men and 26 women) age 64 +/- 9 years (range 45 to 75) were studied. The echocardiographic study was performed by 2 experienced physicians, independently of each another. LV wall motion score index and visual estimation of the EF correlated best with the radionuclide EF (r = 0.72 and r = 0.71), thereafter simply counting the number of affected LV segments (r = 0.67) or atrioventricular plane measurements (r = 0.64). Simpson's rule had low correlation to the radionuclide EF (r = 0.45 to 0.51) and could not be used in approximately half of the patients due to poor identification of endocardial borders. The interobserver coefficient of variation for independent visual echocardiographic estimation of the EF was 10%, for Simpson's rule 18%, and for the radionuclide EF 5%. We conclude that the EF estimated from quantitative echocardiographic volume calculations (Simpson's rule) may differ substantially from radionuclide methods of measuring the EF. However, with experienced sonographers, the LV wall motion score index or visual estimation of the EF had reasonable agreement with the radionuclide EF in most of the patients. Atrioventricular plane measurement is an acceptable alternative.

Aged↗

PubMed1998

Left ventricular function in endurance runners during exercise.

Left ventricular function in elite runners and controls was compared by means of nuclear angiocardiography. Fifteen middle- or long-distance runners and a control group of 10 sedentary to moderately physically active subjects were studied at rest and during semi-sitting incremental exercise. Ejection fraction was higher in the runners than the controls both at rest and during exercise. At the transition from rest to exercise left ventricular end-diastolic volume initially increased similarly in runners and controls by an average of 14 and 12%, respectively, with an increase in stroke volume by approximately 25 and 23%. The parallel increase in stroke volume and left ventricular end-diastolic volume could at least partly be because of the Frank-Starling mechanism. With increasing workloads, left ventricular end-diastolic volume and ejection fraction remained fairly constant, resulting in an unchanged stroke volume from the lowest to the highest exercise intensity. This was in the runners accomplished by a 41% increase in peak filling rate and a 38% increase in peak emptying rate with similar changes observed in the controls. This has to be due to increased myocardial contractility paralleling the systolic shortening with increasing heart rate. We conclude that endurance-trained athletes have a better systolic function expressed as higher ejection fraction both at rest and during exercise than untrained subjects reflecting an enhanced myocardial contractility contributing to the maintenance of a large stroke volume during exercise. The regulatory mechanisms however, appear to be similar for athletes and healthy controls.

Adult↗

PubMed1998

Myocardial perfusion scintigraphy (SPECT) during adenosine stress can be performed safely early on after thrombolytic therapy in acute myocardial infarction.

The objective of this study was to evaluate the safety of myocardial perfusion scintigraphy with Tc-99 m sestamibi during adenosine stress in patients with recent thrombolytically treated myocardial infarction. Eighty-four patients with thrombolytically treated myocardial infarction, 59 males and 25 females, aged 62.9 +/- 8.4, were eligible for myocardial perfusion scintigraphy during adenosine provocation. Exclusion criteria for adenosine stress were hypotension, unstable angina pectoris, cardiac failure, pericarditis and atrioventricular block (AV block) II-III. Adenosine-stress and resting myocardial perfusion scintigraphy was performed 2-5 days after thrombolysis. Scintigraphy at rest was done 24 h after the stress study. Sixty patients (71%) experienced some kind of side-effects during adenosine infusion. The most frequent side-effects were dyspnoea in 43/84 patients (51%) and unspecific chest discomfort in 26/84 patients (31%). During infusion, ST depressions or elevations on ECG were seen in 9 patients (11%), 5 of whom experienced atypical chest discomfort. Five patients (6%) described typical angina but none of them showed electrographic signs of myocardial ischaemia during infusion. Six patients (7%) developed transient AV block I-II. Reversible scintigraphic perfusion defects were seen in 67 patients (79%). No serious complications, such as death, reinfarction or severe arrhythmias, occurred during adenosine infusion or during a 3-day clinical follow-up period. In conclusion, MIBI-SPECT during adenosine stress is a safe diagnostic method that can be performed in most patients early on after thrombolytically treated acute myocardial infarction. Side-effects are common but benign, and not different from those seen in patients with chronic coronary artery disease.

Adenosine↗

PubMed1998

Ultrasound-Doppler technique for monitoring blood flow in the brachial artery compared with occlusion plethysmography of the forearm.

Blood flow changes in the brachial artery of seven subjects during and after submaximal static handgrip contractions were measured by duplex Doppler ultrasound technique. These measurements were compared with the results of occlusion plethysmography, measured immediately (2-3 heartbeats) after. For the combined data from all measurements, a common calibration line could be drawn (linear regression, r=0.92). The flow measurements from the two methods were tested by a four-way analysis of variance and there was no significant difference between the methods during (static) exercise, indicating acceptable coherence. Occlusion plethysmography may well be used for monitoring forearm blood flow during conditions of static exercise. In addition, the cuff occlusion pressure of the plethysmograph (50 mmHg) decreased the blood flow of the brachial artery by approximately 28% as measured by duplex Doppler ultrasound.

Adult↗

PubMed1998

Delayed recovery of myocardial perfusion in acute myocardial infarction: a scintigraphic study after early thrombolytic treatment.

BACKGROUND: Assessments of compromised myocardium and infarct size early after thrombolytic treatment in acute myocardial infarction (AMI) are important for risk stratification and for treatment management. We have therefore evaluated the clinical usefulness of myocardial perfusion scintigraphy (MIBI-SPECT) for the assessment of myocardial viability early after AMI. METHODS: Seventy-one patients [53 men and 18 women, aged 64 +/- 9 years (range 45-75 years)] with AMI treated by thrombolysis took part in this prospective study at University Hospital, Stockholm, Sweden. Sixty of them underwent adenosine-stress and resting MIBI-SPECT 2-4 days after AMI, and 11 were examined only at rest. Six months after the AMI, a repeat MIBI-SPECT at rest was obtained for comparison. RESULTS: All patients had significant perfusion defects compared with an age- and sex-matched healthy reference population. Seventy-six percent of the patients able to undergo a complete adenosine-stress and rest SPECT showed signs of reversible perfusion defects. Defect size (extent) and severity at rest decreased between the tests at 2-5 days and 6 months after AMI (P < 0.001). Reversible perfusion defects early after AMI were not related to spontaneous improvement of myocardial perfusion 6 months later. Early, semiquantitative MIBI-SPECT was not able to predict final infarct size as measured by resting perfusion data 6 months after AMI, regardless of whether the threshold value was set at 30, 40, 50 or 60% of the maximal isotope uptake in the early resting scan. CONCLUSIONS: Myocardial perfusion scintigraphy with adenosine-stress and resting MIBI-SPECT early after AMI underestimates myocardial viability in the majority of patients treated with thrombolytic agents. Neither reversible perfusion defects nor regional semi-quantitative perfusion data appear to predict spontaneous improvement of perfusion 6 months after AMI.

Adenosine↗

PubMed1998

High prevalence of arrhythmias in elderly male athletes with a lifelong history of regular strenuous exercise.

OBJECTIVE: To characterise cardiac arrhythmias and cardiac autonomic function in 11 elderly men (mean (SD) age 73.2 (2.8) years) with a lifelong history of regular very strenuous, exercise. A control group of 12 healthy sedentary or moderately physically active men (74.5 (2.7) years) was also studied. DESIGN: 48 hour ambulatory electrocardiograms were recorded. Cardiac autonomic function was estimated from power spectral analysis of heart rate variability. Maximal oxygen uptake during treadmill exercise testing was 2.91 (0.52) l (41 (7) ml/kg). RESULTS: Nine of 11 athletes had complex ventricular arrhythmias compared with five of 12 controls. Seven athletes but none of the controls had episodes of heart rate below 40 beats/min and two athletes had RR intervals longer than two seconds. Heart rate variability in the athletes was higher than in the controls. CONCLUSIONS: Elderly athletes with a lifelong training history seem to have more complex arrhythmias and profound bradyarrhythmias than do healthy elderly controls, which may increase the risk of sudden cardiac death. In contrast, the age related decrease in heart rate variability seems to be retarded, which has a positive prognostic value and may decrease the risk of life threatening ventricular arrhythmias.

Aged↗

PubMed1998

Heart rate variability is related to leucocyte count in men and to blood lipoproteins in women in a healthy population of 35-year-old subjects.

OBJECTIVES: To investigate if, in a healthy randomly-selected population of 35-year-old men and women, there already is a relation between decreased heart rate variability and conventional risk factors for cardiovascular disease. BACKGROUND: Analysis of heart rate variability (HRV) has been used for estimating tonic autonomic activity. HRV is reduced in patients with various cardiovascular diseases. If a decreased HRV is a late phenomenon in the progression of cardiovascular disease, or if it parallels or even precedes manifest disease is unknown. DESIGN: Spectral analysis of HRV was made from 24-hour ambulatory electrocardiograms in a randomised population of healthy 35-year-old men (n = 63) and women (n = 70). The different spectral indices of HRV were analysed against gender, leucocyte count (previously described as an independent risk factor for cardiovascular disease), blood lipoproteins, smoking, heredity, body mass index (BMI) and systolic blood pressure. SETTING: A research centre of general medicine and a university hospital. RESULTS: Mean heart rate was lower, total power (TP), very low frequency power (VLF) and low frequency power (LF) were higher in men than in women. In women TP, VLF and LF were negatively correlated to BMI, smoking, triglycerides and positively correlated to HDL cholesterol. TP and VLF were also negatively correlated to risk factor score. High frequency power (HF), a marker of parasympathetic activity, was positively related to HDL cholesterol. In men, at daytime, TP, VLF, LF and HF were negatively correlated to leucocyte count. TP, VLF and LF were also negatively correlated to triglycerides and VLF also to risk factor score. CONCLUSIONS: There are correlations between HRV and known risk factors for cardiovascular disease already in a healthy 35-year-old population. A novel observation is the relationship in men between leucocyte count and heart rate variability.

Adult↗

PubMed1997

Heart rate variability in healthy subjects is related to age and gender.

The effects of age and gender on heart rate variability as measured by spectral and time domain analysis of 24 h ECG recordings were evaluated in 101 healthy subjects, 49 men and 52 women (20-69 years of age). In the frequency domain, total power, very low-frequency power, low-frequency power and high-frequency power were negatively correlated to age (P < 0.001 for all variables). Total power decreased by 30% between 20-29 and 60-69 years of age. In the time domain, SDNN-index, the mean of the standard deviations of all normal R-R intervals for all 5 min segments of a 24 h ECG recording, was negatively correlated to age (P < 0.001). Total power, very low-frequency power, low-frequency power and the low-frequency/high-frequency ratio were lower in women (P < 0.05, P < 0.05, P < 0.01 and P < 0.01), although the absolute differences were much smaller than for age. There was a pronounced circadian variation; at night total power increased in all age groups (P < 0.01). The results show that age, and to a lesser degree gender, are important determinants of heart rate variability in healthy subjects. Heart rate variability is a valuable tool for risk stratification in cardiovascular disease, but the physiological effects of ageing, with diminishing heart rate variability in older age groups, must also be taken into account.

Adult↗

PubMed1997

Vascular function correlates with risk factors for cardiovascular disease in a healthy population of 35-year-old subjects.

OBJECTIVE: To investigate whether, in a healthy, randomly selected population of 35-year-old men and women, there is a relation between vascular function and conventional risk factors for cardiovascular disease such as gender, smoking, elevated blood-lipids, high blood pressure and heredity for cardiovascular disease, and to blood glucose. DESIGN: Basal brachial artery diameter was measured. Endothelial function was measured as flow mediated dilation (FMD) in response to reactive hyperaemia. The nonendothelial dependent dilation was measured after sublingual nitro-glycerine (NTG). SETTING: A research centre of general medicine and a university hospital. SUBJECTS: One hundred men and 100 women all 35 years old, were invited by letter. Sixty-six of the 92 men (72%) living in the community and 74 of the 88 women (84%) participated. RESULTS: Gender had the largest influence on FMD and NTG induced arterial dilation, probably reflecting the larger vessel diameters in the men as FMD and NTG induced dilation is inversely related to basal vessel size (r = -0.55, P < 0.001 and r = -0.40, P < 0.001). In women basal vessel diameter was positively correlated to blood glucose (r = 0.35, P = 0.009) and BMI (r = 0.34, P = 0.012) and negatively correlated to HDL cholesterol (r = -0.43, P = 0.001). FMD and NTG induced arterial dilation correlated with a combined risk factor score (r = -0.32, P = 0.019 and r = -0.31, P = 0.024). The men with the highest risk factor scores had larger vessel size and higher blood flow at rest compared to men without risk factors (4.8 +/- 0.6 mm, 240 +/- 84 mL min-1 and 4.0 +/- 0.8 mm, 139 +/- 72 mL min-1, respectively, P = 0.014 and P = 0.016). FMD or NTG induced dilation did not correlate to any of the risk factors in men. CONCLUSIONS: There are correlations between vascular reactivity and risk factors for IHD in women and correlations between vessel diameter and risk factors for IHD in both men and women already in a healthy population 35-year-old subjects. Further studies are needed to determine if the vessel diameter in itself, in a healthy population, is a sign of attenuated endothelial function.

Adult↗

PubMed1997

Pronounced resting bradycardia in male elite runners is associated with high heart rate variability.

Forty-eight hour Holter monitoring was undertaken of 16 male elite middle- and long-distance runners, age 25 +/- 3 years, with peak oxygen uptake 4.83 +/- 0.43 1 O2/min or 73.0 +/- 3.9 ml O2/kg/min. The athletes had pronounced bradycardia during the night-time, with heart rate calculated from four RR intervals < 30 beats/min in five runners. Twelve of 16 runners had RR intervals > 2 s. Of those, 10 runners had sinus pauses exceeding 2 s, the longest being 3.06 s. Three runners had AV block II, two with Mobitz type 1, and one with both Mobitz type 1 and 2. Autonomic function was estimated by time domain and power spectral analysis of heart rate variability. The runners were compared with a control group of 13 sedentary or moderately active subjects. The runners had a mean of 14 b.p.m. lower heart rate at night than the controls. The runners had higher heart rate variability in all spectral bands. In the time domain pNN50 and rMSSD, which are considered to reflect strongly vagal tone, were markedly higher in the runners than the controls. The findings suggest that an increased parasympathetic tone might at least partly explain the pronounced resting sinus bradycardias found in endurance-trained runners.

Bradycardia↗

PubMed1997

High incidence of scintigraphic myocardial uptake defects at rest and during exercise in male elite runners.

OBJECTIVE: To evaluate the usefulness of myocardial perfusion scintigraphy (MIBI-SPECT) as a diagnostic tool in well trained men. DESIGN: The study was prospective, involving 2 d stress-rest myocardial scintigraphy (MIBI-SPECT), polar map reconstruction with and without uniform attenuation correction, and comparison with a healthy male group (local Swedish) and with a commonly used reference group (American, Emory University Hospital). SETTING: University Hospital, Stockholm, Sweden. SUBJECTS: 16 healthy, male elite runners (mean (SD) age 26.1 (3.1) years). Peak oxygen uptake 73 (4) ml O2/kg/min. RESULTS: Uptake defects on polar maps were found in the majority of the runners compared with both reference groups (local Swedish 13/16, American 10/16). Most defects (91%) were fixed. Defects were located in the anterior, lateral, and posterior regions of the left ventricle. Application of a uniform attenuation correction algorithm enhanced rather than reduced perfusion defect size, probably because this correction method is imperfect in SPECT studies of the thoracic cavity. CONCLUSIONS: If myocardial perfusion scintigraphy is used for evaluating well trained men, existing normal reference files for semiquantitative evaluation appear to be inadequate.

Adult↗