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PubMed2005

[Structural changes of the myocardium and 24-hour blood pressure profile in subjects with hypertension studied during expedition work in the Far North].

Echocardiography and 24-hour BP monitoring were carried out in 177 men with stage 1 and 2 essential hypertension aged 25-59 years when they worked the Far North shift (group l) and in 75 patients with essential hypertension living in moderate climatic zone (group 2). Normal left ventricular geometry was found in 10 and 39% of subjects in groups l and 2, respectively. Left ventricular hypertrophy (LVH) was 2 times more frequent in group 1 where it was predominantly concentric. Contrary to group 2 significant correlations between parameters of 24-hour BP monitoring and echocardiography were found in group 1. All variants of left ventricular geometry in group 1 were characterized by lower systolic BP, high variability of systolic and diastolic BP, impaired 24-hour BP rhythm because of decreased night-day difference. Group 1 subjects with concentric left ventricular hypertrophy had significantly increased left ventricular mass index. Diastolic nocturnal hypertension was the factor most closely related to the structural state of the myocardium in group 1.

Adult↗

PubMed1993

Long-term physical training and left ventricular remodeling after anterior myocardial infarction: results of the Exercise in Anterior Myocardial Infarction (EAMI) trial. EAMI Study Group.

OBJECTIVES: The aim of this multicenter randomized study was to investigate whether long-term physical training would influence left ventricular remodeling after anterior myocardial infarction. BACKGROUND: Exercise is currently recommended for patients after myocardial infarction; however, the effects of long-term physical training on ventricular size and remodeling still have to be defined. METHODS: Patients with no contraindications to exercise were studied 4 to 8 weeks after anterior Q wave myocardial infarction and 6 months later by echocardiography at rest and bicycle ergometric testing. After the initial study, patients were randomly allocated to a 6-month exercise training program (n = 49) or a control group (n = 46). A computerized system was used to derive echocardiographic variables of ventricular size, function and topography. RESULTS: After 6 months, a significant (p < 0.01) increase in work capacity (from 4,596 +/- 1,246 to 5,508 +/- 1,335 kp-m) was observed only in the training group, whereas global ventricular size, regional dilation and shape distortion did not change in either the control or the training group. However, compared with patients with an ejection fraction > 40%, patients with an ejection fraction < or = 40% had more significant (p < 0.001) ventricular enlargement at entry and demonstrated further (p < 0.01) global and regional dilation after 6 months, in both the control and the training group (end-diastolic volume from 77 +/- 14 to 85 +/- 17 ml/m2 in the control group and from 74 +/- 11 to 77 +/- 15 ml/m2 in the training group; regional dilation from 46 +/- 18% to 57 +/- 21% in the control group and from 42 +/- 18% to 44 +/- 26% in the training group). Ventricular size and topography did not change in patients with an ejection fraction > 40%. CONCLUSIONS: Patients with poor left ventricular function 1 to 2 months after anterior myocardial infarction are prone to further global and regional dilation. Exercise training does not appear to influence this spontaneous deterioration. Thus, postinfarction patients without clinical complications, even those with a large anterior infarction, may benefit from long-term physical training without any additional negative effect on ventricular size and topography.

Electrocardiography↗

PubMed1983

Systemic and regional hemodynamic characteristics of bilateral cellophane perinephritis hypertension in conscious rabbits.

Using the radioactive microsphere technique, systemic and regional hemodynamic variables were measured in normotensive rabbits and in rabbits with bilateral cellophane perinephritis hypertension. An average decrease in cardiac output of 18 percent was measured in the hypertensive rabbits as a result of a reduction in stroke volume; heart rate remained unchanged. Thus, in the established phase, hypertension was maintained by the elevated total peripheral resistance. A redistribution of cardiac output was observed in the hypertensive rabbits; a significantly higher fraction was received by the brain, small intestine and heart. The weight normalized blood flow to the kidneys, spleen, skeletal muscles, bones and fat was significantly decreased while an increase in vascular resistance was observed in the hypertensive rabbits in all the organs investigated. A negative correlation existed between the weight of the left ventricle and the blood flow to the left ventricle in hypertensive rabbits, suggesting inadequate coronary perfusion as myocardial hypertrophy becomes more pronounced.

Animals↗

PubMed1986

Metabolism and blood flow as new markers of myocardial viability in the evolution of myocardial infarction.

Animal studies have shown that increased regional 18F-deoxyglucose (FDG) uptake as demonstrated by positron emission tomography (PET) in ischemic and reperfused myocardium reflects reversible tissue injury. Therefore, we studied patients with acute myocardial infarction to define the extent and severity of injury. Left ventricular segments with reduced blood flow and metabolism, as demonstrated by matching defects of flow and FDG uptake, revealed irreversible injury as evidenced by lack of functional recovery. In contrast, segments with reduced flow but maintained FDG uptake showed variable functional outcome with improvement of the average wall motion score. Thus, PET may be useful in identifying myocardium at risk which may benefit from therapeutic interventions.

Ammonia↗

PubMed1992

Hypofrontality on topographic EEG in schizophrenia. Correlations with neuropsychological and psychopathological parameters.

Topographic EEG was performed in 17 DSM-III-R schizophrenic patients and in 15 sex- and age-matched healthy controls. Eleven patients were first-onset (neuroleptic naive) schizophrenics. EEG band power was compared with psychopathology, neuropsychology and neurological soft signs. The EEG was recorded at 14 topographic locations monopolarly and movements of the eye and of the lid were monitored by two bipolar electro-oculogram (EOG) derivations, one vertical and one horizontal. A multivariate correction of EOG artefacts was performed based on regression analysis with respect to EOG channels. Schizophrenic patients showed higher mean and median power in most bands. These differences were marked in the delta band, in the fast alpha and beta bands, in particular at left frontal sites. Delta power at F7 was by far the best separating variable between schizophrenics and controls in a discriminant analysis. Significant positive correlations were found between the Brief Psychiatric Rating Scale scores "Anxiety-depression" and "Activation" and power in the fast bands and negative ones between "Anergia" and the beta bands. Positive significant correlations emerged between the total score in the Negative Symptoms Rating Scale and the amount of delta power, predominantly over the temporal region. Impairment in the Luria-Nebraska neuropsychological scores "Rhythm" and "Memory" correlated highly significantly with EEG band power. No correlations were found between neurological soft signs and EEG band power. Our results are in line with the hypothesis of a hypofrontality in schizophrenia. It is unlikely that these findings are an artefact of prior psychiatric treatment, as they were also observed in first-onset, neuroleptic naive schizophrenics.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1998

FDG-PET predictors of response to behavioral therapy and pharmacotherapy in obsessive compulsive disorder.

In subjects with obsessive-compulsive disorder (OCD), lower pre-treatment metabolism in the right orbitofrontal cortex (OFC) and anterior cingulate gyrus (AC) has been associated with a better response to clomipramine. We sought to determine pre-treatment metabolic predictors of response to behavioral therapy (BT) vs. pharmacotherapy in subjects with OCD. To do this, [18F]fluorodeoxyglucose positron emission tomography scans of the brain were obtained in subjects with OCD before treatment with either BT or fluoxetine. A Step-Wise Variable Selection was applied to normalized pre-treatment glucose metabolic rates in the OFC, AC, and caudate by treatment response (change in Yale-Brown Obsessive-Compulsive Scale) in the larger BT group. Left OFC metabolism (normalized to the ipsilateral hemisphere) alone was selected as predicting treatment response in the BT-treated group (F = 6.07, d.f. = 1,17, P = 0.025). Correlations between normalized left OFC metabolism and treatment response revealed that higher normalized metabolism in this region was associated with greater improvement in the BT-treated group (tau = 0.35, P = 0.04), but worse outcome (tau = -0.57, P = 0.03) in the fluoxetine-treated group. These results suggest that subjects with differing patterns of metabolism preferentially respond to BT vs. medication.

Adult↗

PubMed2006

Task-dependent changes in brain activation following therapy for nonfluent aphasia: discussion of two individual cases.

The complex process of cortical reorganization of language-related brain regions during recovery from aphasia and the effects of therapeutic interventions on brain systems are poorly understood. We studied two patients with chronic aphasia and compared their functional neuroanatomical responses to a younger control group on two tasks, an oral-reading task involving overt speech and a "passive" audiovisual story-comprehension task. Following identical therapy, we re-examined behavioral (language) and functional neuroanatomical changes using the same functional magnetic resonance imaging (fMRI) tasks. We hypothesized that better recovery would be associated with brain activation patterns more closely resembling healthy controls, whereas positive responses to language treatment would be associated with increased activity in undamaged left perisylvian areas and/or right-hemisphere areas homologous to the damaged regions. For the participant with a frontal lesion who was most responsive to therapy, brain activation increased in the right hemisphere during oral-reading, but decreased bilaterally in most regions on story-comprehension. The other participant with a temporal-parietal lesion showed decreased activation, particularly in the right hemisphere, during oral-reading but increased activation bilaterally on story-comprehension. Results highlight individual variability following language therapy, with brain activation changes depending on lesion site and size, language skill, type of intervention, and the nature of the fMRI task.

Adult↗

PubMed1999

Modeling of surface myoelectric signals--Part I: Model implementation.

The relationships between the parameters of active motor units (MU's) and the features of surface electromyography (EMG) signals have been investigated using a mathematical model that represents the surface EMG as a summation of contributions from the single muscle fibers. Each MU has parallel fibers uniformly scattered within a cylindrical volume of specified radius embedded in an anisotropic medium. Two action potentials, each modeled as a current tripole, are generated at the neuromuscular junction, propagate in opposite directions and extinguish at the fiber-tendon endings. The neuromuscular junctions and fiber-tendon endings are uniformly scattered within regions of specified width. Muscle fiber conduction velocity and average fiber length to the right and left of the center of the innervation zone are also specified. The signal produced by MU's with different geometries and conduction velocities are superimposed. Monopolar, single differential and double differential signals are computed from electrodes placed in equally spaced locations on the surface of the muscle and are displayed as functions of any of the model's parameters. Spectral and amplitude variables and conduction velocity are estimated from the surface signals and displayed as functions of any of the model's parameters. The influence of fiber-end effects, electrode misalignment, tissue anisotropy, MU's location and geometry are discussed. Part II of this paper will focus on the simulation and interpretation of experimental signals.

Action Potentials↗

PubMed2006

Usefulness of two-dimensional speckle strain for evaluation of left ventricular diastolic deformation in patients with coronary artery disease.

We investigated the influence of > or =70% luminal coronary artery stenosis on regional diastolic deformation at rest using 2-dimensional strain echocardiography. We prospectively imaged patients during/within 24 hours of coronary angiography. Longitudinal systolic (SRs), early (SRe), and late diastolic strain rates, systolic, early, and late diastolic strain and times to isovolumic relaxation and peak SRe were measured in the 3 major vascular territories. Regions subtended by > or =70% coronary stenosis were labeled ischemic. Ischemic regions were compared with the same region in patients without significant coronary stenosis. Of 61 enrolled patients (38 men), 39 had > or =70% coronary stenosis (1 vessel in 14, 2 vessels in 15, 3 vessels in 10), and 15 had normal coronary arteries. There were no significant differences between the normal and ischemic groups with regard to age (59 +/- 13 vs 64 +/- 10 years, p = 0.20), clinical variables (dyslipidemia, smoking, diabetes), systolic (130 +/- 26 vs 139 +/- 31 mm Hg, p = 0.38) or diastolic (72 +/- 13 vs 72 +/- 11 mm Hg, p = 0.81) blood pressure and ejection fraction (58 +/- 12% vs 56 +/- 11%, p = 0.66). SRs and SRe were significantly decreased in ischemic compared with normal regions in all vascular distributions. SRs and SRe together (values below cutoff) or SRe alone were the most specific (93%) and SRe or SRs below cutoff the most sensitive (93%) parameters for detecting ischemic regions. In conclusion, analysis of regional deformation by 2-dimensional strain echocardiography enables detection of significantly diseased coronary arteries at rest. Altered diastolic deformation at rest identifies regions subtended by > or =70% coronary stenosis with high specificity.

Coronary Artery Disease↗

PubMed1984

Multivariate analysis of a personal series of 247 consecutive patients with liver metastases from colorectal cancer. I. Treatment by hepatic resection.

In the United States, there are an estimated 5000 to 6000 new patients annually who might be candidates for major hepatic resection to treat their recurrent colon cancer. Since 1971, the program reported here has evaluated various factors that might influence the curative potential of such an approach. Sixty-five patients had a major hepatic resection from March 1971 through May 1982. Using a stepwise proportional hazard analysis, all data that had been stored in CLINFO (a data analysis system by Bolt, Beranek and Newman; Boston, MA) were evaluated for the effect of multiple variables on the survival of patients with resected hepatic metastases. Twenty-seven had a right hepatic lobectomy; 14 had extended right hepatectomy with one having the caudate lobe also removed; ten had left lobectomy, nine had left lateral segmentectomy; and five had a major hepatic resection with three-dimensional wedge excision of a metastatic deposit in the contralateral lobe. The 30-day operative mortality rate was 7% (4/58) for patients undergoing the standard major hepatic resection. It was 14% for seven patients in whom the isolation-hypothermic perfusion technique was used early in the series. In ten patients, wedge excision only was required to remove the tumor. Stage I disease is defined as tumor confined to the resected portion of the liver without invasion of major intrahepatic vessels or bile ducts. Stage II disease is regional spread and Stage III disease is metastasis to lymph nodes or extraregional sites. The 3-year survival estimate was 66% for the 37 patients with Stage I disease. The 3-year survival estimate for 13 patients with Stage II disease was 58%. Five of the nine patients with Stage III disease are presently alive from 3 to 23 months; one of the other four died at 35 months of disease. The stage of liver disease was the most significant variable in this survival analysis (p = 0.02); Dukes' classification of colorectal primary was significant at p less than 0.05. Those factors found not to be significant determinants of survival were: number of metastatic hepatic deposits, site of colon primary, age, sex, preoperative liver function tests, and CEA.

Adult↗

PubMed2000

Hyperlipidemia with hypoglycemia reduces myocardial oxygen utilization efficiency but not contractile function during coronary hypoperfusion.

This study was designed to determine changes in myocardial contractile function and fuel selection during moderate coronary hypoperfusion in the presence of elevated plasma free fatty acid (FFA) at normal and reduced blood glucose concentrations. Coronary perfusion pressure (CPP) was sequentially lowered from 100 to 60, 50, and 40 mmHg in the left anterior descending coronary artery (LAD) of anesthetized, open-chest dogs. Regional glucose uptake (GU), fatty acid uptake (FAU), percentage segment shortening (%SS), and oxygen consumption (MV O(2)) were determined with normal arterial plasma FFA concentrations (Group 1) or with elevated FFA concentrations (Groups 2 and 3). In Group 3, glucose in the coronary perfusate blood was reduced from 3.53+/-0.36 to 0.15+/-0.03 m M by hemodialysis. In Group 1, FAU fell by 85% as CPP was lowered to 60 mmHg and remained depressed as CPP was reduced further; GU did not fall significantly. Hyperlipidemia in Group 2 did not alter GU at any CPP, but maintained FAU at baseline levels until CPP was lowered to 40 mmHg. At 40 mmHg CPP, myocardial function and metabolic variables were similar in Groups 1 and 2. In Group 3 at 40 mmHg, FAU increased four-fold and MV O(2)doubled v Groups 1 and 2, and GU fell to zero. Despite these metabolic changes, %SS in Group 3 was unchanged relative to Group 2. Addition of glucose to the dialysate prevented the effects of dialysis on FAU, GU, and MV O(2). Thus, preferential glucose oxidation sustains myocardial oxygen utilization efficiency [(heart rate x %SS x maximum left ventricular pressure)/MV O(2)] during hypoperfusion. Blocking preferential glucose oxidation by combined hyperlipidemia and hypoglycemia lowers oxygen utilization efficiency, but does not compromise myocardial contractile function.

Animals↗

PubMed2005

Non-invasive detection of acute allograft rejection in children by tissue Doppler imaging: myocardial velocities and myocardial acceleration during isovolumic contraction.

BACKGROUND: In adults, an acute decrease of regional myocardial velocities is a sensitive marker of rejection. In children, velocities are more variable. A new marker, myocardial acceleration during isovolumic contraction (IVA), appears to be less age-dependent than myocardial velocities. This study therefore compared tissue Doppler (TDI)-derived velocities and IVA as potential rejection markers for children. METHODS: TDI was performed in 15 pediatric heart transplant recipients (age 8.0 +/- 3.6 years) during acute rejection and at baseline without rejection, 50 additional transplant children without rejection (7.8 +/- 5.9 years) and 30 age-matched healthy children (7.5 +/- 5.2 years). Color Doppler cine-loops of 3 cardiac cycles were stored as echocardiographic raw data. Using off-line post-processing, systolic (S) and diastolic (E) myocardial velocities and IVA were measured in 5 basal left ventricular segments. IVA is the peak isovolumic contraction wave velocity divided by acceleration time. RESULTS: Without rejection, transplant children had significantly lower diastolic velocities (basal lateral E 10.4 +/- 2.9 vs 11.9 +/- 2.6 cm/s; p < 0.001) and systolic velocities (S 5.6 +/- 1.4 vs 7.1 +/- 2.0 cm/s; p < 0.001) than normal age-matched controls, but IVA was similar (1.2 +/- 1.4 vs 1.3 +/- 0.5 m/s2). During rejection, all markers decreased significantly compared with age-matched normal control, the non-rejecting transplant group and individual baseline values. CONCLUSIONS: Regional myocardial velocities change significantly during acute allograft rejection in children. However, many children already have wall motion abnormalities at baseline, so results are often difficult to interpret. In contrast, isovolumic acceleration was normal without rejection and selectively decreased during the event. IVA is a promising non-invasive rejection marker for pediatric patients.

Blood Flow Velocity↗

PubMed2004

Huntington disease: volumetric, diffusion-weighted, and magnetization transfer MR imaging of brain.

PURPOSE: To investigate whether diffusion-weighted and magnetization transfer (MT) magnetic resonance (MR) imaging depict regional and/or global brain abnormalities in patients with Huntington disease (HD). MATERIALS AND METHODS: Twenty-one carriers of the HD mutation (mean age, 58 years +/- 11 [SD]) and 21 healthy control subjects (mean age, 54 years +/- 13) underwent conventional, diffusion-weighted, and MT MR imaging. Volumes, mean apparent diffusion coefficients (ADCs), and MT ratios (MTRs) for left and right caudate nucleus, putamen, and cerebral periventricular white matter-as well as an index of normalized brain volume and whole-brain ADC and MT histograms-were computed. Asymmetry in volume, ADC, and MTR measurements in caudate nucleus, putamen, and periventricular white matter in control subjects and HD carriers were evaluated with Wilcoxon testing for paired samples. Differences in MR imaging variables between HD carriers and control subjects were evaluated with Mann-Whitney U testing; correlations between stages of clinical severity and MR imaging data were investigated with Spearman rank correlation testing. RESULTS: No significant asymmetry was observed for any of the MR imaging variables. Caudate nucleus, putamen, and whole-brain volumes were smaller (P <.001 for all) in HD carriers than in control subjects. HD carriers also had increased ADC in the caudate nucleus (P =.002), putamen (P <. 001), cerebral periventricular white matter (P <.001), and whole brain (P <.001). MTR was not significantly different between HD carriers and control subjects. Correlation was observed between stages of increasing clinical disease severity and both decrease in volume of caudate nucleus (Spearman rho = -0.63), putamen (rho = -0.64), and whole brain (rho = -0.46) and increase in ADC in caudate nucleus (rho = 0.52), periventricular white matter (rho = 0.45), and whole brain (rho = 0.44). CONCLUSION: Regional and global volume loss in HD is accompanied by an increase in ADC; this correlates with disease severity.

Adult↗

PubMed2005

Easily identifiable bony landmarks as an aid in targeted regional ankle blockade.

Regional anesthesia around the ankle joint is well suited to a large number of surgical procedures of the foot. Previous studies have alluded to the variable nerve distribution of the foot, which may result in incomplete blocks. The aim of the study was to determine the position of the nerves in relation to the ankle joint to easily identifiable bony and prominent soft tissue landmarks to aid more accurate targeting of these nerves. A number of 94 ankles (47 left; 47 right) were dissected to expose the tibial, sural, deep fibular (peroneal), superficial fibular (peroneal), and saphenous nerves. The distance of the nerves relative to easy to find bony landmarks was measured. A distance (alpha) was measured from the middle of the tibial nerve to the most medial aspect of the medial malleolus. Measurement beta was considered from the inferior tip of the lateral malleolus to the anterior border of the sural nerve on a horizontal plane. Measurement delta was taken from the medial border of the deep fibular (peroneal) nerve to the most anterior aspect of the medial malleolus. epsilon was measured from the middle of the superficial fibular (peroneal) nerve to the most anterior aspect of the medial malleolus on a horizontal plane. The saphenous nerve was measured (gamma) from its medial border to the most anterior aspect of the medial malleolus on a horizontal plane. Factors such as sex, length, and ankle side were also analyzed concerning their influence on the position of the nerves. This study suggests that a greater degree of certainty may possibly be attained when palpable and easy to find bony landmarks are used to determine the position of the nerves around the ankle and ensure a simple to perform, predictable, and selectively targeted block.

Anesthetics, Local↗

PubMedDate not supplied

The relationship between social alienation and disorganized thinking in normal subjects and localized cerebral glucose metabolic rates assessed by positron emission tomography.

This study investigated the relationships between the relatively mild manifestations in verbal behavior of social alienation and disorganized thinking in normal subjects and cerebral glucose metabolic rates measured by positron emission tomography (PET). Three groups of 10 young normal male subjects were injected with D-[18F]deoxyglucose (FDG) during either wakefulness, rapid eye movement (REM), or non-REM (NONREM) sleep, and 32 to 45 minutes later they were asked to report their thoughts, emotions, or dreams and free-associations to these mental events. Nonparametric correlations were obtained between measures of interpersonal social alienation, intrapsychic conflicts, and thought disorder derived from the typescripts of these reports by content analysis--using the Gottschalk-Gleser Social Alienation-Personal Disorganization Scale--and regional cerebral glucose metabolic rates obtained from PET scans. Total social alienation-personal disorganization scores obtained from the reports of wakeful, silent mentations showed significant positive correlations with glucose metabolic rates in the left temporal lobe. The patterns of significant correlations involving these verbal behavior measures derived from the content analysis of verbal reports of dreams or other mental events occurring during REM and non-REM sleep were in different cerebral locations from those found with these variables during silent, waking mentation. Previous observations suggesting that increased left temporal lobe glucose may typify chronic schizophrenia may instead be indicative of a wide range of thought disorder and/or social alienation manifestations occurring, at times transiently and minimally, in normal people.

Adult↗

PubMed1992

Protein synthesis in pulmonary, cardiac, and skeletal muscle in acute hypertension induced by aortic constriction in the rat.

OBJECTIVE: The aim was to investigate nucleic acid composition and rates of protein synthesis in cardiopulmonary tissues and skeletal muscle in response to hypertension induced by aortic constriction. METHODS: After five days of abdominal aortic constriction, protein, RNA, and DNA contents were measured in the lung, the left and right atria, the left and right ventricles, and gastrocnemius muscle from young male Wistar rats weighing 120-140 g. Rates of protein synthesis were also measured in these tissues with L[4-3H]phenylalanine. RESULTS: Aortic constriction significantly increased the right atrial weight and in contrast reduced the lung weight, compared to pair fed and sham operated controls. The wet weights of all other tissues were unaffected. The concentrations of right atrial proteins, RNA, and DNA were also significantly reduced though total protein, RNA, and DNA contents were unaltered. The left ventricular RNA concentration increased and there were variable alterations in protein and DNA composition. The protein, RNA, and DNA compositions of the other tissues showed patterned responses, which included reductions in lung and skeletal muscle DNA concentrations, reductions in the skeletal muscle RNA/DNA ratio, and a decrease in the lung protein/DNA ratio. In response to aortic constriction there were increases in the left ventricular fractional rate of protein synthesis in mixed, high salt (myofibrillar), and low salt (sarcoplasmic) fractions. Rates of protein synthesis in all other regions of the heart, lung and skeletal muscle were not significantly changed. CONCLUSIONS: We conclude that in abdominal aortic constriction, the left ventricles display early adaptive responses without any concomitant change in mass. Those regions of the rat cardiopulmonary system which are not directly exposed to the acute pressure overloading, ie, right atrium, lungs, and skeletal muscle, also show disturbances.

Acute Disease↗

PubMed2003

Influence of patient variables and sensor location on regional cerebral oxygen saturation measured by INVOS 4100 near-infrared spectrophotometers.

Cerebral oximeter based on near-infrared spectroscopy has been used as a continuous, noninvasive monitoring of regional cerebral oxygen saturation (rSO2). Although the absolute rSO2 values have a wide range of variability, the factors affecting a variability of rSO2 values have not been extensively investigated. The authors investigated the influence of patient variables and sensor location on rSO2 measured by the cerebral oximeter INVOS 4100 in 111 patients anesthetized with sevoflurane, fentanyl, and nitrous oxide in oxygen. The sensors for rSO2 measurements were applied on the right forehead (R), 1 cm lateral to R (R1), on the left forehead (L), 1 cm lateral to L (L1), and on the center of the forehead (C). The relationship between the rSO2 values and patient variables were also analyzed. Values of rSO2 at R1 and L1 were significantly lower than those at R and L, respectively. Values of rSO2 at C were significantly higher compared with those at other sites. There were no significant correlations between the rSO2 values and values of weight, height, and head size. Values of rSO2 were similar between males and females. A significant negative correlation between the rSO2 values and age and a positive correlation between the rSO2 values and hemoglobin concentration were observed. These data indicate that patient age, hemoglobin concentration at the measurement, and sensor location can affect rSO2 values.

Adolescent↗

PubMed1986

Altered left ventricular diastolic properties during pacing-induced angina in patients with aortic stenosis.

An increase in left ventricular diastolic pressure has been repeatedly observed during angina in patients with coronary artery stenoses and regional demand ischemia, but the role of relaxation abnormalities versus left ventricular segmental dyssynchrony is controversial. In contrast, patients with angina due to aortic stenosis are likely to have diffuse rather than segmental ischemia and thus may provide an alternative model for examining the diastolic physiology of angina in man. Accordingly, we examined the hemodynamic manifestations of angina in eight patients with aortic stenosis without significant coronary artery disease. Angina was induced by pacing tachycardia, and hemodynamic and echocardiographic variables were measured in the control period and during angina in the beats immediately after cessation of pacing. Heart rate (control vs angina, 69 +/- 12 vs 70 +/- 11 beats/min, p = NS) and left ventricular peak systolic pressure (207 +/- 39 vs 222 +/- 22 mm Hg, p = NS) were similar in the control and postpacing angina periods. Left ventricular end-diastolic pressure, on the other hand, was significantly higher during postpacing angina (15 +/- 7 vs 28 +/- 8 mm Hg, p less than .01). The time constant of left ventricular pressure decline during isovolumetric relaxation (TL), calculated as the slope of a linear fit of the natural log of pressure vs time, increased from 44 +/- 5 to 51 +/- 7 msec (p less than .05); the time constant TD, derived from the slope of a linear fit of dP/dt vs pressure, also increased slightly, although the change was not statistically significant (69 +/- 5 vs 75 +/- 5 msec, p = .06).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗