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J Engvall

Publications and source records attributed to J Engvall.

At least 19 recordsLinked to original sources
PubMed2004

Increasing incidence of childhood thyrotoxicosis in a population-based area of central Sweden.

AIM: To study the incidence, prevalence and clinical characteristics of childhood thyrotoxicosis in a population-based area comprising five counties in central Sweden. METHODS: Retrospective analysis of the medical records of all children below 16 y of age with thyrotoxicosis during a 10-y study period. RESULTS: Forty-six children were identified with thyrotoxicosis. The median age at onset was 11.7 y and 85% were females. At the end of the study period on 31 December 1999, the prevalence was 0.08 per 1000. The mean annual incidence was four times higher in the second 5-y period than in the first (2.7 and 0.7 per 100000, respectively; p < 0.001). A first-degree relative with thyrotoxicosis was found in 21% of the children and 11/46 children (24%) showed autoimmune-related co-morbidity. Increased heart rate was observed in 95%, goitre in 67% and exophthalmos in 33% of the children. TSH was completely suppressed and free T4 was clearly above the upper reference limit in all children. TSH receptor-stimulating antibodies and peroxidase antibodies were observed in 80% and 71% of the children, respectively. CONCLUSION: This study indicates an increase in the incidence of childhood thyrotoxicosis in a population-based area of central Sweden. A prospective study aimed at identifying specific aetiological risk factors for development of thyrotoxicosis has been initiated.

Adolescent↗
PubMed2003

Non-invasive diagnosis of coronary artery disease by quantitative stress echocardiography: optimal diagnostic models using off-line tissue Doppler in the MYDISE study.

AIMS: To develop optimal methods for the objective non-invasive diagnosis of coronary artery disease, using myocardial Doppler velocities during dobutamine stress echocardiography. METHODS AND RESULTS: We acquired tissue Doppler digital data during dobutamine stress in 289 subjects, and measured myocardial responses by off-line analysis of 11 left ventricular segments. Diagnostic criteria developed by comparing 92 normal subjects with 48 patients with coronary disease were refined in a prospective series of 149 patients referred with chest pain. Optimal diagnostic accuracy was achieved by logistic regression models, using systolic velocities at maximal stress in 7 myocardial segments, adjusting for independent correlations directly with heart rate and inversely with age and female gender (all p<0.001). Best cut-points from receiver-operator curves diagnosed left anterior descending, circumflex and right coronary disease with sensitivities and specificities of 80% and 80%, 91% and 80%, and 93% and 82%, respectively. All models performed better than velocity cut-offs alone (p<0.001). CONCLUSION: Non-invasive diagnosis of coronary artery disease by quantitative stress echocardiography is best performed using diagnostic models based on segmental velocities at peak stress and adjusting for heart rate, and gender or age.

Adult↗
PubMed2001

Estimation of relative cardiovascular pressures using time-resolved three-dimensional phase contrast MRI.

Accurate, easy-to-use, noninvasive cardiovascular pressure registration would be an important addition to the diagnostic armamentarium for assessment of cardiac function. A novel noninvasive and three-dimensional (3D) technique for estimation of relative cardiovascular pressures is presented. The relative pressure is calculated using the Navier-Stokes equations along user-defined lines placed within a time-resolved 3D phase contrast MRI dataset. The lines may be either straight or curved to follow an actual streamline. The technique is validated in an in vitro model and tested on in vivo cases of normal and abnormal transmitral pressure differences and intraaortic flow. The method supplements an intuitive visualization technique for cardiovascular flow, 3D particle trace visualization, with a quantifiable diagnostic parameter estimated from the same dataset.

Adult↗
PubMed2001

Daytime ambulatory blood pressure correlates strongly with the echocardiographic diameter of aortic coarctation.

OBJECTIVE: To relate the echocardiographic aortic arch-diameter to ambulatory and clinic blood pressure (BP) in patients with aortic coarctation. DESIGN: Eighteen adult patients (50% men) were recruited from the coarctation registry of the Linkoping Heart Centre. Biplane-trans-oesophageal echocardiography (TEE) was performed with Acuson XP 128/10, ambulatory BP was recorded with Spacelab models 90202/90205. RESULTS: Systolic clinic and ambulatory BP levels were higher in patients than in the 36 controls (clinic BP: 146 +/- 25 mmHg vs 119 +/- 10 mmHg, p = 0.0009, ambulatory BP: 140 +/- 18 mmHg vs 124 +/- 11 mmHg, p = 0.009). The differences in diastolic BP levels were less obvious (clinic BP: 87 +/- 16 mmHg vs 76 +/- 8 mmHg, p = 0.02, ambulatory BP: 84 +/- 13 mmHg vs 77 +/- 9 mmHg, p = 0.052). Daytime ambulatory BP was more strongly related than clinic BP to the coarctation diameter (AD) (systolic BP r= -0.73, p = 0.0006 and r = -0.61, p = 0.007, respectively). In surgically corrected patients (n = 14) only the correlations between ambulatory systolic daytime (r = -0.61, p = 0.02) and night-time (r = -0.58, p = 0.03) BP to AD was statistically significant. CONCLUSION: Ambulatory BP correlates strongly with aortic coarctation measured by TEE and would thus be the preferred technique for evaluating BP in this patient category.

Adult↗
PubMed2001

Three dimensional flow in the human left atrium.

BACKGROUND: Abnormal flow patterns in the left atrium in atrial fibrillation or mitral stenosis are associated with an increased risk of thrombosis and systemic embolisation; the characteristics of normal atrial flow that avoid stasis have not been well defined. OBJECTIVES: To present a three dimensional particle trace visualisation of normal left atrial flow in vivo, constructed from flow velocities in three dimensional space. METHODS: Particle trace visualisation of time resolved three dimensional magnetic resonance imaging velocity measurements was used to provide a display of intracardiac flow without the limitations of angle sensitivity or restriction to imaging planes. Global flow patterns of the left atrium were studied in 11 healthy volunteers. RESULTS: In all subjects vortical flow was observed in the atrium during systole and diastolic diastasis (mean (SD) duration of systolic vortex, 280 (77) ms; and of diastolic vortex, 256 (118) ms). The volume incorporated and recirculated within the vortices originated predominantly from the left pulmonary veins. Inflow from the right veins passed along the vortex periphery, constrained between the vortex and the atrial wall. CONCLUSIONS: Global left atrial flow in the normal human heart comprises consistent patterns specific to the phase of the cardiac cycle. Separate paths of left and right pulmonary venous inflow and vortex formation may have beneficial effects in avoiding left atrial stasis in the normal subject in sinus rhythm.

Adult↗
PubMed2001

Major and minor axes of the normal mitral annulus.

BACKGROUND AND AIM OF THE STUDY: A dilated or abnormally shaped mitral annulus is a common cause of mitral valve regurgitation, and may be cured by annuloplastic surgery. Multiplane transesophageal echocardiography (TEE) is the diagnostic technique of choice. Our aim was to evaluate and suggest two-dimensional TEE reference values from a standardized procedure of measuring the mitral annular major and minor axes, and their cyclic changes. METHODS: The annulus was approximated elliptic in the horizontal plane. The intercommissural (IC, major axis) and anteroposterior (AP, minor axis) distances were measured at end-systole (ES), at maximal valve opening (MO), and at end-diastole (ED) from a mid-esophageal view, in 13 men and eight women with normal echocardiographic findings. Indexed values and reproducibility were calculated. RESULTS: The success rate was 100% at ES, 90% at MO, and 29% at ED. ES distances were largest (p <0.001) and most reproducible (5-5.9%). Body weight, but not height or age, had a significant impact. ES 95% prediction intervals for IC were 27 to 46 mm (16-23 mm/m2) and 22 to 36 mm (13-18 mm/m2) for AP (p <0.001). Corresponding body weight-corrected intervals were 0.39 to 0.59 (IC) and 0.32 to 0.48 (AP) mm/kg. No subject had IC:AP <1.1 together with an AP >0.45 mm/kg. CONCLUSION: Among measurements made at ES, MO and ED, those at ES provided the most reproducible results, and high-quality images were obtained in normal, non-obese subjects. The distances should be judged in relation to body weight or surface area and each other. The largest IC distance and the most elliptic shape were at ES, while the annulus was minimal at ED. The procedure and normal ranges presented may contribute to the evaluation of patients with mitral regurgitation.

Adult↗
PubMed2000

Correction for acceleration-induced displacement artifacts in phase contrast imaging.

The acceleration-induced displacement artifact impairs the accuracy of MR velocity measurements. This study proposes a post processing method for correction of this artifact. Velocity measurements were performed in a flow phantom containing a constriction. Velocity curves were obtained from streamlines parallel to the frequency, phase, and slice directions, respectively. The acceleration-induced displacement artifact was most prominent when the frequency encoding direction was aligned with the flow direction. After correction, velocity assignment improved and a more accurate description of the flow was obtained. In vivo measurements were performed in the aorta in a patient with a repaired aortic coarctation. The correction method was applied to velocity data along a streamline parallel to the frequency encoding direction. The result after correction was a new location of the peak velocity and improved estimates of the velocity gradients.

Adult↗
PubMed1999

Particle trace visualization of intracardiac flow using time-resolved 3D phase contrast MRI.

The flow patterns in the human heart are complex and difficult to visualize using conventional two-dimensional (2D) modalities, whether they depict a single velocity component (Doppler echocardiography) or all three components in a few slices (2D phase contrast MRI). To avoid these shortcomings, a temporally resolved 3D phase contrast technique was used to derive data describing the intracardiac velocity fields in normal volunteers. The MRI data were corrected for phase shifts caused by eddy currents and concomitant gradient fields, with improvement in the accuracy of subsequent flow visualizations. Pathlines describing the blood pathways through the heart were generated from the temporally resolved velocity data, starting from user-specified locations and time frames. Flow trajectories were displayed as 3D particle traces, with simultaneous demonstration of morphologic 2D slices. This type of visualization is intuitive and interactive and may extend our understanding of dynamic and previously unrecognized patterns of intracardiac flow.

Heart↗
PubMed1999

Pitfalls in Doppler evaluation of diastolic function: insights from 3-dimensional magnetic resonance imaging.

Ultrasound-Doppler assessment of diastolic function is subject to velocity errors caused by angle sensitivity and a fixed location of the sample volume. We used 3-dimensional phase contrast magnetic resonance imaging (MRI) to evaluate these errors in 10 patients with hypertension and in 10 healthy volunteers. The single (Doppler) and triple (MRI) component velocity was measured at early (E) and late (A) inflow along Doppler-like sample lines or 3-dimensional particle traces generated from the MRI data. Doppler measurements underestimated MRI velocities by 9.4% +/- 8.6%; the effect on the E/A ratio was larger and more variable. Measuring early and late diastolic inflows from a single line demonstrated the error caused by their 3-dimensional spatial offset. Both errors were minimized by calculating the E/A ratio from maximal E and A values without constraint to a single line. Alignment and spatial offset are important sources of error in Doppler diastolic parameters. Improved accuracy may be achieved with the use of maximal E and A velocities from wherever they occur in the left ventricle.

Adult↗
PubMed1998

Regional mean systolic myocardial velocity estimation by real-time color Doppler myocardial imaging: a new technique for quantifying regional systolic function.

A new color Doppler myocardial imaging (CDMI) system with high spatial and temporal resolution and novel postprocessing modalities has been developed that could allow quantifiable stress echocardiography. The purpose of this study was to determine whether regional myocardial systolic velocities could be accurately and reproducibly measured both at rest and during bicycle ergometry by using CDMI. Thirty normal subjects were examined with CDMI at rest, and peak mean systolic myocardial velocities (MSV) were measured for 34 predetermined left ventricular myocardial segments. Interobserver variability and intraobserver variability were established for all segments. Submaximal bicycle ergometry was performed in 20 normal subjects by using standardized weight-related increases in workload. MSV were measured at each step of exercise for 16 left ventricular stress echo segments. At rest, a base-apex gradient in regional MSV was recorded with highest longitudinal shortening velocities at the base. A similar pattern was noted for circumferential shortening MSV. Measurements were predictable and highly reproducible with low interobserver and intraobserver variability for 26 of 34 segments. Reproducibility was poor for basal anteroseptal segments in all views and mid anterior, anteroseptal, and septal segments in the short-axis views. During exercise, mid and basal segments of all walls showed a significant increase of MSV between each workload step and for apical segments between alternate steps. The resting base-apex velocity gradient observed at rest remained in all walls throughout ergometry. Thus a CDMI system with improved spatial and temporal resolution and postprocessing analysis modalities provided reproducible and accurate quantification of segmental left ventricular circumferential and longitudinal contraction both at rest and during exercise.

Adult↗
PubMed1997

Case management and patient reactions: a study of STD care in a province in Zambia.

Sexually transmitted disease (STD) case management was evaluated through observation and interviews at 2 urban and 4 rural health centres and 2 district hospital STD clinics in one urban and 2 rural districts in Central Province, Zambia. The analysis was limited to 59 patients (42 men and 17 women) who paid first visits for their disease and were managed by a clinical officer. The evaluation suffered from the lack of a standard for case management. Results showed that the patients engaged in risky sexual behaviour without being aware of the risks. At the health institutions, few patients were informed about condoms, the risk of HIV, and abstinence from sex during treatment and few were asked to notify their partners. Clinical officers with special STD training performed better than others but sill informed only one-fifth of the patients. Few clinical officers managed patients according to the syndromic approach recommended by the STD control programme.

Adolescent↗
PubMed1996

Cardiovascular effects of dobutamine stress testing in women with suspected coronary artery disease.

OBJECTIVE: To investigate the central and peripheral haemodynamic response to dobutamine stress testing in women with suspected ischaemic heart disease and to seek an explanation for the hypotension phenomenon. DESIGN: 18 women aged 54-73 years were investigated with Doppler echocardiography and venous occlusion plethysmography during intravenous infusion of dobutamine 5-10 d after an episode of unstable angina. RESULTS: An average peak dose of 33 (SD 9.7) micrograms/kg/min was given. Heart rate and cardiac output increased by 49% and 59%, respectively (P < 0.001). Total and leg peripheral vascular resistance decreased by 44% and 26%, respectively (P < 0.001). Four patients developed hypotension (decrease in systolic blood pressure > 10 mm Hg), one of whom had a paradoxical bradycardia and two a low increase in cardiac output. Patients with hypotension had a more pronounced decrease in total peripheral vascular resistance but a similar change in leg peripheral vascular resistance compared with patients without hypotension. CONCLUSIONS: Dobutamine infusion leads to marked peripheral vasodilatation and an increase in cardiac output. Some patients experience hypotension during the test for reasons which include paradoxical vasovagal reactions and diminished capacity for adequate increase in cardiac output. There is also a disparity between the pattern of total and leg peripheral vascular resistance in patients with hypotension which might reflect a baroreceptor mediated compensatory increase in vasoconstrictor tone of muscle vessels not matched in other vascular territories.

Aged↗
PubMed1995

Biplane transoesophageal echocardiography, transthoracic Doppler, and magnetic resonance imaging in the assessment of coarctation of the aorta.

This study compared flow-sensitive magnetic resonance imaging with biplane transoesophageal echocardiography in combination with continuous wave Doppler from the suprasternal notch in patients with native coarctation or after surgical repair. Twenty patients (mean age 33 years, range 17-60) were investigated, of whom 15 had undergone surgery at mean age 13 years, range 5-43. Peak and mean flow in the ascending and descending aorta as well as coarctation peak velocity were determined with the magnetic resonance imaging phase contrast technique. Coarctation peak velocity was also measured by Doppler from the jugulum. Magnetic resonance imaging axial sections as well as biplane transoesophageal echocardiography were used to measure the smallest diameter of the constricted segment. Sixteen healthy volunteers, mean age 36 years, range 22-63, provided reference values for magnetic resonance imaging determined volume of flow in the aorta. Peak flow in the descending aorta was 9.2 +/- 3.7 l. min-1 (reference 13.0 +/- 2.5, P < 0.01) and mean flow 3.1 +/- 0.9 l. min-1 (reference 3.4 +/- 0.8, P > 0.05). The ratio of descending-to-ascending peak flow was 0.54 +/- 0.17 (reference 0.69 +/- 0.10, P < 0.01) and mean flow 0.68 +/- 0.15 (reference 0.69 +/- 0.08, P > 0.05). The coarctation velocity was slightly higher with Doppler than with magnetic resonance imaging (+0.24 +/- 0.44 m. s-1, 95% confidence interval +0.45 to +0.02 m. s-1, P = 0.05). The coarctation diameter was slightly larger with magnetic resonance imaging than with transoesophageal echocardiography (1.4 +/- 3.5 mm, 95% confidence interval +3.1 to -0.3 mm, P = 0.11). Both methods are suitable for the assessment and follow-up of coarctation of the aorta. Flow assessment with magnetic resonance imaging provides a hitherto unavailable measure with which to assess the severity of obstruction.

Adolescent↗
PubMed1995

Arm-ankle systolic blood pressure difference at rest and after exercise in the assessment of aortic coarctation.

OBJECTIVE: To evaluate the difference in systolic blood pressure at the arm and ankle at rest and after various exercise tests for the assessment of aortic coarctation. METHODS: 22 patients (mean age 33 years, range 17-66) were investigated on the suspicion of having haemodynamically significant aortic coarctation. Eight had undergone previous coarctation surgery, of whom five had received vascular grafts and three end to end anastomoses. The patients exercised submaximally while supine, seated on a bicycle, and walking on a treadmill, as well as exercising maximally on a treadmill. Arm and ankle blood pressure were measured with a cuff at rest and 1-10 minutes after exercise. Invasive pressures and cardiac output by thermodilution were recorded during catheterisation while patients were at rest and during and after supine bicycle exercise. The degree of constriction was assessed by angiography. Twelve healthy volunteers (mean age 32 years, range 17-56) provided reference values for cuff pressures after exercise. RESULTS: All patients with a difference in cuff pressure at rest of 35 mm Hg or more had a difference in invasive pressure of 35 mm Hg or more. Increasing severity of constriction on angiography correlated with larger pressure gradients at rest and during exercise (P < 0.0001). When cuff measurements after exercise were considered singly or combined to form a predictor they did not improve the prediction of the invasive pressure gradients at rest or after maximal exercise. A pressure gradient between arm and ankle also developed in normal subjects after maximal but not after submaximal exercise. CONCLUSION: In most patients with suspected haemodynamically significant coarctation the difference in cuff pressure between arm and ankle at rest is sufficient to select patients in need of further evaluation. If exercise is performed submaximal exercise is preferable.

Adolescent↗
PubMed1994

Importance of collateral vessels in aortic coarctation: computer simulation at rest and exercise using transmission line elements.

Coarctation of the aorta causes arterial hypertension in the upper body and a low blood pressure downstream. Collateral blood vessels compensate by reducing the downstream pressure drop. To study the effect of various coarctation and collateral properties, we designed a computer model of the arterial circulation. The model contains a flow source and a library of subroutines for the lines and connectors. Distributed friction and wall viscoelasticity effects are included. Computer simulation was performed, using published values for vessel dimensions, in an arterial model with a coarctation and one lumped collateral. Rest and two levels of exercise (by increased heart rate) were studied. Without a collateral, we found the downstream pressure of the model was extremely dependent on the size of the coarctation. A collateral vessel reduced the pressure difference between the up- and downstream circulations. For a severe coarctation, the length and the diameter of the collateral were the main factors determining the downstream pressure and flow, whereas wall stiffness of the collateral had little influence. The relationship between mean pressure drop and cardiac output in coarctation was also dependent on the peripheral resistance in different flow beds, especially during exercise.

Aortic Coarctation↗