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At least 325 records · Page 18Linked to original sources
PubMed1976

A clinicopathological study on the electrical axis of the heart in 1,000 autopsy cases.

The electrical axis of the heart in 1,000 aged people more than 56 years of age was classified as normal axis in 58%, left axis deviation in 17.4%, mild left axis devaition in 21.9%, and right axis deviation in 2.7%. Pathological examination disclosed that left axis deviation was associated with myocardial infarction in 20%, right bundle branch block in 16%, but showed no significant relationships with coronary sclerosis, myocardial fibrosis and cardiac hypertrophy. Right axis deviation was associated with right bundle branch block in 66.7% and right ventricular hypertrophy in 22.2%

Aged↗
PubMed1995

Femoral rotational alignment, based on the anteroposterior axis, in total knee arthroplasty in a valgus knee. A technical note.

The landmarks used to achieve correct rotational alignment of the femoral component in total knee arthroplasty may be indistinguishable or unreliable in the distal architecture of a valgus knee. Five observers identified the anteroposterior axis, the posterior condylar axis, and the transepicondylar axis in thirty cadaveric femora to determine the reliability of the use of each axis in the operative setting. In addition, radiographs were made of the distal aspect of each femur, the axes were constructed, and the angles were measured and compared with the visual measurements made by the observers. A line drawn perpendicular to the anteroposterior axis consistently approximated 4 degrees of external rotation relative to the posterior condylar surfaces. The transepicondylar axis was more difficult to define and was not as accurate. The radiographic results were similar to the visual results, but the standard deviations for the former were less than those for the latter. The anteroposterior axis appears to be a reliable landmark for rotational alignment of the femoral component in a valgus knee.

Humans↗
PubMed2006

MDCT determination of volume and function of the left ventricle: are short-axis image reformations necessary?

OBJECTIVE: Determination of left ventricular (LV) volumes and global function parameters from MDCT data sets is usually based on short-axis reformations from primarily reconstructed axial images, which prolong postprocessing time. The aim of this study was to evaluate the feasibility of LV volumetry and global LV function assessment from axial images in comparison with short-axis image reformations. SUBJECTS AND METHODS: This study consisted of 20 patients with either coronary artery disease or dilated cardiomyopathy. We evaluated MDCT results using cine MRI as the reference technique. RESULTS: LV end-diastolic volume (LVEDV) and end-systolic volume (LVESV) were significantly overestimated by the axial MDCT approach in comparison with volume measurements from short-axis CT image reformations. The mean LV ejection fraction (LVEF) was not significantly different (41.2% vs 42.7%). Short-axis and axial MDCT determination of LVEF revealed a systematic underestimation by a mean +/- SD of -2.1% +/- 3.6% versus -3.6% +/- 8.2%, respectively, when compared with LVEF values based on cine MRI. The interobserver variability for volume and function measurements from axial images (LVEDV = 8.5%, LVESV = 10.8%, LVEF = 9.6%) was slightly higher than those measurements from short-axis reformations (LVEDV = 7.2%, LVESV = 9.5%, LVEF = 8.7%). The mean total evaluation time was significantly shorter using axial images (14.1 +/- 3.9 min) compared with short-axis reformations (16.9 +/- 5.2 min) (p < 0.05). CONCLUSION: Determination of LV volumes and assessment of global LV function from axial MDCT image reformations is feasible and time efficient. This approach might be a clinically useful alternative to established short-axis-based measurements in patients with normal or near-normal LV function. A progressive underestimation of LVEF with increasing LV volumes may limit the clinical applicability of the axial approach in patients with dilated cardiomyopathy.

Cardiomyopathy, Dilated↗
PubMedDate not supplied

Celiac axis stenosis: incidence and etiologies in asymptomatic individuals.

OBJECTIVE: To determine the incidence and etiologies of celiac axis stenosis in asymptomatic individuals. MATERIALS AND METHODS: This prospective study involved 400 consecutive patients (male: 319, female: 81) referred to us for celiac arteriography between April and July 1999. When celiac axis branches were opacified by collateral circulation during superior mesenteric arteriography, the presence of celiac axis stenosis was suspected; lateral projection celiac arteriography was performed and the pressure gradient was measured. The indicators used to determine whether or not celiac axis stenosis was significant were luminal narrowing of more than 50% and a resultant pressure gradient of at least 10 mmHg. Its etiology was determined on the basis of angiographic appearances and CT findings. RESULTS: Twenty-nine patients (7.3%) had celiac axis stenosis. The etiology of the condition was extrinsic compression due to the median arcuate ligament in 16 patients (55%) and atherosclerosis in three (10%), while in ten (35%) it was not determined. The incidence of celiac axis stenosis did not vary significantly according to sex, age and the presence of calcified aortic plaque representing atherosclerosis. CONCLUSION: The incidence of hemodynamically significant celiac axis stenosis in this asymptomatic Korean population was 7.3% and the most important etiology was extrinsic compression by the median arcuate ligament of the diaphragm. Atherosclerosis was only a minor cause of the condition.

Angiography↗
PubMedDate not supplied

Position of the subtalar joint axis and resistance of the rearfoot to supination.

Determination of the position of the subtalar joint axis is being more widely used clinically to facilitate the prescription of foot orthoses and the understanding of foot function, but clinical determination of the axis has not been widely investigated. The aim of this study was to determine the relationship between clinical determination of the subtalar joint axis and the amount of force needed to supinate the foot. The transverse plane position of the subtalar joint axis was determined in 47 subjects. The sagittal plane orientation of the subtalar joint axis was determined using the relative amounts of forefoot adduction and abduction obtained when the rearfoot was supinated and pronated. The amount of force needed to supinate the foot was measured using a device designed to measure resistance to supination. The only two parameters that were correlated to supination resistance of the rearfoot were body weight (r = 0.52) and the perpendicular distance from the fifth metatarsal head to the subtalar joint axis (r = 0.59). The model on which determination of the subtalar joint axis is based may not be valid, but it might help determine how much force is needed to supinate a foot using foot orthoses.

Adult↗
PubMedDate not supplied

Comparison of scalar with vectorial electrocardiogram in axis determination.

Axis deviation is one of the variables most commonly sought for in Electrocardiography (ECG). Although no one doubts the superiority of vector cardiography (VCG) as the most accurate in axis determination, most clinicians adopt the Hexaxial Reference System (HRS) of the 12-Lead ECG (12LS) as the most accessible for routine use. The question therefore arises: How accurate is the HRS? The 12LS and Orthogonal (Frank Lead) ECG (OLS) were recorded in 664 adult Nigerians without heart or metabolic diseases. Their VCG were constructed manually for the QRS complexes. On each subject, QRS axis was determined by three methods: the HRS for the 12LS, the trigonometric method for the OLS and the direction of the maximum deflection vector for the VCG. Axes by the three modalities were analysed and compared statistically as applicable to paired samples. The frontal plane (FP) QRS axis ranged between O degree and +90 degrees in 98.2% of cases by VCG, 96% by the OLS and 93.6% by the 12LS. There was excellent correlation between axes obtained by VCG and OLS (r = 0.85; P < 0.0001). It was lower but highly significant between VCG and the 12LS (r = 0.70; P < 0.0001). In the horizontal plane (HP), the 97 per centile distribution ranged from 240 degrees through 0 degree to 30 degrees; that is, posteriorly and to the left. In the left sagittal plane (LSP), the 95 per centile distribution ranged from 60 degrees counter-clockwise to 210 degrees; that is inferiorly and posteriorly. In a sample of healthy adult Nigerians, the QRS axis by VCG was located posteriorly, inferiorly and to the left. Axis determination by the 12LS is limited to the FP only, and it bears a good correlation with VCG. This commends the H RS as a condonable tool for estimating wave axis routinely and for epidemiologic studies.

Adult↗
PubMed2003

Ventricular long axis function is predictive of outcome in patients with chronic heart failure secondary to non-ischemic dilated cardiomyopathy.

BACKGROUND: Ventricular long axis function has recently been proved to be of prognostic value in patients with heart failure. However, it remains unclear whether it can provide additional independent information over that provided by conventionally used LVEF or functional status. We conducted this study to address this issue, and to determine the prognostic importance of sequential change in long axis function over time in patients with idiopathic DCM. MATERIAL/METHODS: We prospectively followed up 299 DCM patients with mean age of 55.5 years and LVEF of 41%. All patients underwent a complete clinical and echocardiographic evaluation including ventricular long axis function at baseline, 1- and 2-year follow-up. RESULTS: At the end of study, 50 patients died and 6 underwent cardiac transplantation. The majority of deaths occurred before the second examination. In univariate analysis, the absolute values of RV and LV long axis functions at the second examination were significantly related to mortality. In multivariate regression model, they did not maintain their prognostic values. However, a sequential increase in the LV long axis function significantly predicted prognosis, independently of age, NYHA class, and exercise tolerance. The subsequent survival of patients with increased LV long axis function was significantly better than those with either a decrease or no change in it. CONCLUSIONS: This study clearly indicates that the sequential increase of long axis function was related to significantly better survival in idiopathic DCM patients, which provides a novel method to estimate prognosis of these patients with moderate impairment of LVEF at initial presentation.

Cardiomyopathy, Dilated↗
PubMed2006

[Determination of femoral anatomic axis in robot-assisted surgery of total knee replacement].

Determination of femoral anatomic axis plays an important role in robot-assisted surgery of total knee replacement. In traditional total knee replacement surgery, the axis is obtained by inserting a rod into femoral lumen. However, in the robot-assisted total knee replacement based on CT model. the femoral anatomic axis must be determined preoperatively. Because the lengths in femurs are quite different in different patients, besides noises, the upper segment and lower segment of the femur influence the design of the axis greatly. Traditionally, the femoral anatomic axis is obtained by using the least-squares method directly. However, this method is easily disturbed by noise. To avoid the noise disturbance of CT data, the least median of squares method is used to fit the femoral anatomic axis for its characteristic of robust regression. The least median squares method eliminates the disadvantage brought by the method of least squares. In finding the best-fit line, genetic algorithms are used in the paper. In our experiment, we use the proposed method to fit the femoral anatomic axis and obtain an excellent result.

Algorithms↗
PubMed1991

Polar axis fixation in Fucus zygotes: components of the cytoskeleton and extracellular matrix.

Polar axis formation and polar axis stabilization (or fixation) can be separated and analyzed in synchronously developing zygotes of the brown alga Fucus. Extensive experimental evidence points to a role for both the cytoskeleton and the extracellular matrix (ECM) in the process of axis fixation in Fucus. A structural complex composed of the cytoskeleton and the ECM has been postulated to stabilize membrane asymmetries generated as a result of axis-forming vectors. This axis stabilizing complex (ASC) may take the form of transmembrane connections between the cytoskeleton on the cytoplasmic face and the ECM on the external side of the plasma membrane, similar to focal contacts in animal cells. At present we know of two components in the proposed ASC of Fucus: an adhesive sulfated glycoprotein which is localized in the ECM, and an actin network which is localized on the adjoining cytoplasmic face. This preliminary report describes evidence for the presence of molecules in two-celled Fucus embryos that are similar to those found in focal contacts in animal cells, i.e. vinculin, integrin and vitronectin. However, their localization and interaction with each other relative to the polar axis has yet to be determined. These initial observations will provide the basis to pursue further an analysis of these components in the process of polar axis fixation.

Cell Polarity↗
PubMed1991

The effect of the three columns of the spine on the instantaneous axis of rotation in flexion and extension.

Instrumentation designed for stabilization and correction of spinal deformities must limit the amount of motion in flexion and extension. In flexion or extension, the vertebral bodies move about a specific point called the instantaneous axis of rotation. The ability of the implant to limit this motion is a function of its relation to the axis of rotation of the spine. The goal of this study was threefold: 1) to define the instantaneous axis of rotation of the spine in flexion and extension; 2) to study the effect of the loss of the three columns of the spine on the location of the instantaneous axis of rotation; and 3) to determine how the above parameters relate to the choice of anterior or posterior instrumentation. Ten human cadaver spines were subjected to compressive loads in flexion and extension. The columns of the spine were then destroyed in sequence at L3. The instantaneous axis of rotation for each vertebral body was found by the method of Reuleaux, and the effect of the compromise of the columns on the location of the instantaneous axis of rotation was noted. Understanding the exact location of the instantaneous axis of rotation after a specific injury would allow the clinician to objectively choose the best surgical approach and the appropriate instrumentation.

Humans↗
PubMed1990

[Considerations of precision and consistance of mandibular transverse hinge axis].

This paper deals with the nature of mandibular hinge axis and the consequences for its application in diagnostics and treatment. The transversal hinge axis of the mandible can be characterized as an exact and true axis of pure mandibular rotation or a more or less exactly located axis as a result of a combined rotation and translation of the condyles. During opening movements of about 8 mm already an insignificant gliding of the condyles of 0.5 mm displaces the individual located hinge axis of more than 6 mm in its relation to the lower jaw. The true hinge axis as it is needed for achsiographic or pantographic registration techniques has inevitably not to be identical with the transferred axis for mounting casts in an adjustable articulator.

Dental Articulators↗
PubMed1987

Normal fetal heart axis and position.

Cardiac position and axis were evaluated by ultrasound in 183 normal fetuses; both position and axis were found to be constant throughout gestational life. In the four-chamber view of the fetal heart, the normal axis lies at a 45 degree angle (range 22-75 degrees) to the left of an anteroposterior line drawn from the spine to the anterior chest wall. The normal position of the posterior portion of the heart can also be defined. The axis or position of the heart deviated from the established normal range in 15 cases, the outcome of which is discussed. Abnormal axis was associated with 50% mortality; abnormal position with 81% mortality. Deviation from the normal position of the fetal heart should initiate a search for an intrathoracic mass, whereas an abnormal axis is an indication for fetal echocardiography. Axis and position of the fetal heart are easily evaluated during a standard obstetric scan.

Female↗
PubMedDate not supplied

Electrical axis of the heart in healthy adult Nigerians.

The twelve-lead electrocardiogram (ECG) was analysed to describe the frontal plane P wave, T wave and QRS axes in 1220 healthy adult Nigerians. Axis determination was based on the principle of resolution of forces along the three Einthoven and three Goldberger leads referred to as the 'hexaxial reference system'. The P-wave axis ranged from 37.8 to 72.6 degrees without sex variation but with slight rightward shift with age. The T-wave axis ranged from 24.1 to 68.5 degrees without exhibiting age or sex variation. The proposed ranges of QRS axis deviation in the Nigerian were 0 to +90 degrees for normal, 0 to -90 degrees for LAD, and +90 to +/- 180 degrees for RAD. There was no sex variation in QRS axis until after the sixth decade of life. The axis in Nigerians was more leftward than that of Caucasians of the same age; but in both races the QRS axis exhibited a leftward shift with age.

Adolescent↗
PubMed1994

Hypothalamic-pituitary-adrenal axis and immune system.

Complex and bidirectional relationships operate between the hypothalamic-pituitary-adrenal (HPA) axis and the immune system (IS) and either in vivo or in vitro evidence supports a physiological role of the HPA axis-IS network. A part of the well-known pharmacological effects of glucocorticoid hormones (GC) as immunodepressive agents, the direct effects of many HPA axis hormones on IS functions are actually documented also in physiologic conditions. Conversely, numerous IS soluble mediators are reported to affect the HPA axis functions at various steps of HPA axis regulation, in both physiologic and pathologic conditions. Stress and aging may represent two paradigmatic conditions to show the relevance of the bidirectional network between HPA axis and IS, as in both HPA activation and IS impairment are frequently coexistent. Finally, in the context of the wide spectrum of HIV-related HPA axis abnormalities, a case of a Cushing's syndrome associated to an acquired immunodeficiency syndrome (AIDS-related complex) in a 24-year-old homosexual drug abuser is reported.

AIDS-Related Complex↗
PubMed1995

[Relationship between the fetal axis and dystocia in cephalic presenting deliveries].

OBJECTIVE: To study the relationship between the fetal axis and dystocia in cephalic presenting deliveries. METHODS: The fetal axis of the observed cases in their late pregnancy were measured by the method which was designed by anatomical projection. During labor the cases with abnormal fetal axis were divided randomly into control group and study group. The abnormal fetal axis in the study group was corrected by hand. RESULTS: The abnormal fetal axis existed in 108 of 512 (21.1%) cases in late pregnancy and were divided into different degrees. The rate of severe degree was 51.8%. During labor 88 of 483 (18.2%) cases were severe degree. They were sub-divided into control group (30 cases) and study group (58 cases). The results showed: in the study group the descent of fetal-presentation was accelerated, the stage of labor became shorter, the incidence of persistent occipito-posterior or occipito-transverse position and operative delivery were decreased, and the postpartum hemorrhage out down also. CONCLUSIONS: The abnormality of fetal axis exists and it can affect the progress of labor. The abnormal fetal axis should be diagnosed and corrected in time. To some extent, it can reduce the mother's physical consumption in labor and decrease the incidence of dystocia.

Delivery, Obstetric↗
PubMed1998

The effect of atlas anterior translation and rotation on axis canal size. A computer-assisted anatomic study.

Eighteen adult paired atlas and axis specimens were used in conjunction with computer analysis to determine the average transverse canal area of the axis after different degrees of anterior translation and three types of rotation of the atlas. After each displacement, the remaining transverse canal area of the axis was calculated. The data showed that the mean transverse canal area of the axis was 351.5 +/- 8.8 mm2 for males and 276.9 +/- 8.6 mm2 for females, respectively. After a 3-, 4-, and 5-mm anterior translation of the atlas, the mean transverse canal area of the axis decreased to 300.4 +/- 5.1 mm2 (85.5%) for males and 238.0 +/- 2.1 mm2 (85.9%) for females, 283.9 +/- 5.9 mm2 (80.8%) for males and 228.5 +/- 3.1 mm2 (82.5%) for females, and 260.4 +/- 4.2 mm2 (74.1%) for males and 216.4 +/- 2.8 mm2 (78.2%) for females, respectively. After a 40 degree rotation, 40 degree rotation with 4-mm anterior translation, and 40 degree rotation with 8-mm anterior translation of the atlas, the mean transverse canal area of the axis for both sexes decreased approximately to 58%, 42%, and 23%, respectively. This study confirmed that the size of the transverse canal area of the axis was consistently correlated with the degrees of the anterior translation and rotation of the atlas.

Adult↗
PubMed1998

[ECG anomalies and axis deviations in heart transplant recipients: MRI studies].

The electrocardiogram is often abnormal after orthotopic cardiac transplantation. This study was conducted in order to evaluate the frequency of these abnormalities in a population of 29 patients transplanted according to the conventional mode or the total mode. We also investigated the correlation between these abnormalities and the presence of left ventricular hypertrophy or deviation of the left ventricular long axis. The left ventricular mass was measured by TM echocardiography. The position of the left ventricular long axis was determined by MR on a ultrarapid sequence. The ECG was normal in 5 patients. The abnormalities revealed in the other 24 patients were: an rSr' or rsr' appearance in V1 with a QRS complex less than 0.12 sec in 11 patients, complete right block in 1 patients, repolarization abnormalities (apart from those associated with branch blocks) in 8 patients, left axis deviation of the QRS in 5 patients, a biphasic P wave in V1 with a Morris index greater than 4 mV.sec in 5 patients, and double atrial activity in 3 patients. These abnormalities were observed regardless of the type of transplantation, with the exception of double atrial activity which was only observed in the group of patients undergoing conventional transplantation. On average, the long axis of the left ventricle was more horizontal and deviated to the left compared to age- and sex-matched controls. All patients with left axis deviation of the QRS had left ventricular hypertrophy versus 13 of the 24 patients without QRS axis deviation and abnormalities of position of the anatomical left ventricular long axis. Our results therefore suggest that the frequent presence of right branch block in heart transplant recipients is due to factors other than the position of the heart in the thorax, for example right ventricular hypertrophy.

Adult↗
PubMed1995

Morphology of the second cervical vertebra and the posterior projection of the C2 pedicle axis.

STUDY DESIGN: This study assessed numerous structural features of the second cervical vertebra (C2), describing the projection point of the pedicle on its posterior aspect. OBJECTIVES: Evaluation of the specimens included quantitative description of 18 linear and four angular parameters, which then were correlated between male and female specimens. The point of projection of the C2 pedicle axis was described with an emphasis on a perspective relevant to a posterior approach. SUMMARY OF BACKGROUND DATA: The literature regarding the anatomy of the axis focuses mainly on the dens. Very little research regarding the quantitative study of the C2 pedicle has been reported. METHODS: Fifty dry C2 cervical vertebrae (30 male, 20 female) were obtained for anatomic measurements. Anatomic evaluation focused on the pedicle, vertebral body, dens, superior facet, and vertebral canal. All measurements were made using calipers and a standard rule linear measurements and a goniometer for angular measures. Based on the measurement of 50 specimens, including 18 linear and four angular parameters, the mean, range, and standard deviation were calculated for all of the specimens and for male and female separately. RESULTS: A significant difference was found to exist for 11 of 18 linear measurements and one of four angular parameters. The projection point of the pedicle axis on the posterior aspect of the lateral mass was described with an emphasis on a perspective relevant to a posterior surgical approach. The location of the projection point of the pedicle axis was found to be 5.4 +/- 1.2 mm inferior to the horizontal line, and 7.2 +/- 1.3 mm lateral to the vertical line. The pedicle axis was found to lie at 33 degrees in the medial direction and 20 degrees in the superior direction form the point of pedicle axis projection. CONCLUSIONS: When the techniques described here are used, the findings may be helpful in cases involving C2 when surgical intervention and instrumentation are desired.

Adult↗