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At least 1,171 records · Page 65Linked to original sources
PubMed2003

Improved cardiovascular risk stratification by a simple ECG index in hypertension.

BACKGROUND: We determined the prognostic value of the Cornell/strain [C/S] index, a simple electrocardiographic (ECG) index for left ventricular hypertrophy (LVH) defined by the presence of either a classic strain pattern or a Cornell voltage (sum of R in aVL + S in V(3)) >2.0 mV in women or 2.4 mV in men, or both. METHODS: In a prospective, cohort study, 2190 initially untreated subjects (age 51 [+/- 12], 47% women) with essential hypertension without prior events were followed for up to 14 years (median, 5 years). RESULTS: Prevalence of LVH at entry was 16.3% by using the C/S index, which yielded 33.6% sensitivity and 91.0% specificity. Other ECG criteria for LVH including Sokolow-Lyon, Romhilt-Estes, Framingham, Cornell, and strain alone, achieved a lower sensitivity and prevalence. Over the subsequent follow-up, 244 patients experienced a first major cardiovascular event. Event rate (x 100 person-years) was 2.01 in those without and 4.44 in those with LVH by the C/S index (P <.001). After adjustment for age, sex, smoking, and other counfounders, the C/S index identified subjects at increased risk of events (relative risk 1.76; 95% confidence interval 1.32-2.33). The C/S index achieved the highest population-attributable risk (16.1%) for cardiovascular events. CONCLUSIONS: A simple ECG index that can be quickly measured from nondigital machines and without algorithms identifies LVH in a consistent proportion (16.3%) of hypertensive subjects. The LVH defined by such technique allows identification of individuals at high risk for cardiovascular events.

Aged↗
PubMed1999

Pharmacologic evaluation of isometric contraction-relaxation coupling indexes in rabbit ventricular muscle.

Investigations of the coupling between contraction and relaxation (contraction-relaxation [CRC] process) in isometric conditions are essential in determining whether pharmacologic interventions or cardiac diseases specifically modify isometric relaxation (intrinsic lusitropic effect) or change it in proportion with the accompanying changes in contractility (or inotropy). For this purpose, the CRC process is quantified by various indexes, derived from differentiation and/or curve fitting the whole or relaxation phase of the isometric twitch, one of the most used being tau, the time constant of the final iso(volu)metric phase of relaxation. Nevertheless, the possible redundancy and validity of such indexes have not been thoroughly investigated. Accordingly, we performed a pharmacologic evaluation of such indexes in isolated rabbit ventricular muscles isometrically contracting in vitro, using modifiers of either intracellular Ca(2)+ handling (nifedipine, ryanodine, 2,5-di-tert-butyl-benzohydroquinone, all negative inotropic compounds, and BAY K 8644, a positive inotropic drug), or myofibrillar Ca(2)+ sensitivity (CGP 48506, a Ca(2)+ sensitizer, and butanedione monoxime, a Ca(2)+ desensitizer, respectively positive and negative inotropic compounds). The isometric twitch in control conditions and in the presence of increasing concentration of each compound was analyzed to determine the classically used CRC and/or lusitropic indexes, derived either from single parameters such as the maximal rate or contraction and relaxation (+dT(max) and -dT(max), respectively), or from curve fitting of the whole, or part, of the twitch. As the rate of isometric relaxation is dependent on myofilament properties, we expected that compounds modifying myofibrillar Ca(2)+ sensitivity in an opposite direction (CGP 48506 vs butanedione monoxime) would be the only drugs exerting an intrinsic lusitropic and opposite effect on a validated CRC index. Results showed that (1) none of the tested compounds affected the slope of the linear relationship between peak twitch tension and dT(max), a previously assumed CRC index, sensitive only to myofibrillar Ca(2)+ sensitivity modifiers; (2) the lusitropic parameter B, derived from mathematical curve fitting of the whole isometric twitch, and the ratio +dT(max)/dT(max), exhibited similar drug- and dose-dependency, but no opposite sensitivity to CGP 48506 and BDM for either index; and (3) negative inotropic compounds dose-dependently slowed relaxation (and conversely for positive inotropes), whether the latter was quantified by the rate constant beta, derived from double exponential curve fitting of the whole relaxation phase, or by the time constants tau(L) and tau(E), derived from the curve fitting (logistic and monoexponential, respectively) of the final phase of relaxation. Nevertheless, the pharmacologicly induced changes in beta were statistically significant at lower concentrations and exhibited less individual variability, compared with the time constants. We demonstrate that intrinsic lusitropic changes can be quantified by the value of the slope of the relationship relating beta to peak isometric tension: the slope value was unchanged by Ca(2)+ handling modifiers, decreased by CGP 48506, and reversed by BDM (indicating number, negative, and positive intrinsic lusitropic effects respectively). Based on these data, we propose that the linear relationship between beta and peak isometric tension could be used a new method to assess whether pharmacologic interventions or cardiac diseases exert intrinsic effects on isometric relaxation.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMedDate not supplied

The value of perioperative clinical indexes and dipyridamole thallium scintigraphy for the prediction of myocardial infarction and cardiac death in patients undergoing vascular surgery.

BACKGROUND: Dipyridamole thallium scintigraphy has previously been shown to have predictive value for both perioperative and late cardiac events in patients undergoing vascular surgery. However, despite the prognostic utility of this technique, the relative importance of clinical factors and scintigraphic information is not well known. The purpose of this study was to evaluate the value of commonly used clinical risk indexes, composed of historic variables, and dipyridamole thallium scintigraphy for predicting perioperative cardiac event-free survival rates. METHODS AND RESULTS: Clinical and scintigraphic variables in 360 patients undergoing vascular surgery were analyzed for their predictive utility for perioperative and late (up to 5 years) cardiac events (nonfatal myocardial infarction or cardiac death) by means of chart review and telephone contact. Patients were correctly categorized as being at low, moderate, or high risk for perioperative cardiac events based on two clinical indexes. Thallium redistribution, however, was a more powerful predictor of cardiac events than these indexes. Even in a clinically low-risk patient cohort, the odds ratio for an event increased by 6- to 8-fold (p < 0.05) if thallium redistribution was noted. These indexes also demonstrated prognostic utility for late cardiac event-free survival rates by life-table analysis (p < 0.001). The presence of a fixed thallium defect was associated with an increased risk of late cardiac events (p < 0.01). When stratified by risk index, in those patients at moderate to high risk who had a fixed defect the odds ratio increased by 3.9- to 5.4-fold (p < 0.001). Likewise, the low-risk subgroup had a 3.9- to 8.2-fold increase in the risk of a late cardiac event when a fixed perfusion defect was present. CONCLUSIONS: Preoperative clinical indexes are predictive of both perioperative and late cardiac events in patients undergoing vascular surgery. However, dipyridamole thallium scintigraphy is more powerful prognostically than these clinical indexes and provides supplemental value to clinical risk stratification.

Adult↗
PubMed2002

The utility of transition zone index in predicting acute urinary morbidity after 125I prostate brachytherapy.

PURPOSE: Acute urinary morbidity after prostate brachytherapy is common and, although usually self-limited, can be distressing to the patient, especially if acute urinary retention (AUR) develops. We undertook to determine whether prospective measurement of the transition zone index would be predictive of either urinary retention or the severity of urinary symptoms after brachytherapy. METHODS AND MATERIALS: One hundred men undergoing transperineal interstitial permanent prostate brachytherapy (TIPPB) with 125I underwent transrectal ultrasound before the procedure to measure prostate and transition zone (TZ) volumes. TZ index was calculated as TZ volume divided by total prostate volume. TIPPB was performed between July 2000 and January 2002. Patients were observed for 1, 3, or 6 months with an International Prostate Symptom Score (IPSS) at each visit. alpha-Blockers were prescribed prophylactically in all patients. Postimplant dosimetry was performed at 1 month by using CT/MRI fusion for all patients. RESULTS: The mean patient age was 65.1 years (range, 46-77 years). There were 59 T1c tumors and 41 T2a tumors. The Gleason score was 6 in 86% of patients, with 3% being Gleason 4 or 5 and 11% Gleason 7. The mean baseline IPSS was 7.4, with the mean at 1 month being 17.3; at 3 months, 14.4; and at 6 months, 11.3. Baseline IPSS was the only factor predictive of IPSS at 1 and 3 months after TIPPB. Neoadjuvant androgen deprivation was used for 26% of men for 2-6 months to reduce prostate size before the procedure. AUR developed in 17%. In univariate analysis, prior hormone therapy (p = 0.002), duration of hormone therapy (p = 0.005), TZ index (p = 0.014), number of seeds implanted (p = 0.016), T stage (p = 0.035), percentage of the prostate volume receiving at least the full prescribed dose (V100, p = 0.036), percentage of the prostate volume receiving > 200% of the prescribed dose (V200, p = 0.037), and prostate volume (p = 0.038) were all predictive of AUR. When the TZ index was divided into quartiles, the risk of AUR was 4%, 16%, 20%, and 28% (p = 0.032). However, in multivariate analysis, TZ index was no longer predictive of AUR. CONCLUSIONS: Baseline urinary function is the only factor predictive of symptom scores at 1 and 3 months after brachytherapy. TZ index, initial prostate volume, and use of neoadjuvant hormones are interrelated and are all predictive of AUR in univariate analysis, but in multivariate analysis, TZ index is not an independent prognostic factor.

Acute Disease↗
PubMed2003

[Ponderal index to describe a term neonatal population].

INTRODUCTION: The terms small, appropriate, and large for gestational age cannot identify some alterations in body composition that might be identified by the ponderal index. The aim of the present study was to correlate birth weight with ponderal index to identify other patterns of intrauterine growth. POPULATION AND METHODS: We performed a cross-sectional, descriptive study in which only one curve of the ponderal index was created for each week of gestational age (weeks 33 to 42) and including the 10th, 50th and 90th centiles because sex does not influence this index. This curve was based on 26,770 healthy infants born in Uruguay and registered in the Perinatal Information System of the Latin American Center for Perinatology. The database consisted of 194,908 infants born between 1995 and 1999. Exclusion criteria were mothers aged less than 15 years or more than 35 years, primiparas, those with > 4 pregnancies, smokers, a diagnosis of intrauterine growth retardation, chronic and pregnancy-related hypertension, cardiac problems, anemic and diabetic mothers, twins with congenital malformations, and intervals between pregnancies of less than 2 years or more than 5 years. Finally, the ponderal index of 43,189 neonates with a gestational age of 40 weeks was compared with the centiles of weight for gestational age to establish alterations in intrauterine growth. RESULTS: Relating the ponderal index with birth weight revealed altered patterns of intrauterine growth in 13 %, 10.3 % and 7.9 % of neonates with appropriate, small and large birth weights, respectively. Moreover, six unusual patters were identified. CONCLUSIONS: Use of the ponderal index curve for gestational age together with other growth curves improves the nutritional assessment of newborns. Further studies should be designed to develop strategies for the immediate, medium- and long-term management of identified risk groups.

Anthropometry↗
PubMed2002

Sedation assessment in critically ill patients with bispectral index.

BACKGROUND AND OBJECTIVE: Clinical sedation assessment becomes insufficient in deeply sedated patients. Bispectral index as a processed electroencephalogram parameter provides a continuous and observer-independent value reported to change with sedation. The aim of this prospective observational study was to determine the reliability and possible confounding factors of the bispectral index to assess sedation in surgical intensive care patients. METHODS: Following major surgery, bispectral index, body temperature and electromyographic activity of 44 ventilated patients were recorded. Sedation levels were assessed with Ramsay sedation score. RESULTS: Although bispectral index correlated with Ramsay sedation score (-0.64; P < 0.01) we found that in deeply sedated patients temperature instability and electromyographic activity increased bispectral index. Bispectral index correlated significantly with electromyographic activity (0.80; P < 0.01) and with an increase of body temperature (0.55; P < 0.01) not only in all patients but also in clinically deeply sedated patients (0.57; P < 0.01 and 0.46; P < 0.05). CONCLUSIONS: Only under certain conditions, such as low muscular activity and body temperature stability, may the bispectral index be a useful addition to clinical scoring in the sedation assessment of critically ill patients.

Body Temperature↗
PubMed2006

Monitoring sedation in critically ill patients: bispectral index, Ramsay and observer scales.

BACKGROUND AND OBJECTIVE: Sedation is commonly required by critically ill patients and inadequate sedation may be hazardous. Traditionally, subjective scales have been used for monitoring sedation. Bispectral index has been proposed, although its utility in the intensive care unit is debated. Our aim was to evaluate the depth of sedation in intubated surgical critically ill patients by means of two sedation scales (Ramsay and Observer's Assessment of Alertness and Sedation) and bispectral index. METHODS: Sedation was assessed prospectively in 50 postoperative intubated patients requiring at least 24 h of sedation (35 propofol, 15 midazolam/fentanyl), every 8 h for a 24 -h period. The bispectral index value recorded was the mean value obtained during a 10-min observation period, whenever the quality signal index was above 75% and the electromyographic signal was below 25%. RESULTS: Most of the patients (78%) were oversedated (bispectral index < 60). The three sedation scores (global data) correlated significantly (P < 0.001). This correlation was lost in the midazolam group in which the patients were also significantly more sedated than the propofol group (P = 0.001). The correlation between the bispectral index and the scales in the midazolam group reappeared when the measurements with a Ramsay = 6 or an Observer's Assessment of Alertness and Sedation = 1 were excluded. CONCLUSIONS: Sedation should be monitored routinely in intensive care units. The Ramsay and the Observer's Assessment of Alertness and Sedation scales showed equal efficacy. Bispectral index might prove useful for discriminating between deeper levels of sedation.

Aged↗
PubMedDate not supplied

Variable neighborhood search for extremal graphs. 6. Analyzing bounds for the connectivity index.

Recently, Araujo and De la Peña gave bounds for the connectivity index of chemical trees as a function of this index for general trees and the ramification index of trees. They also gave bounds for the connectivity index of chemical graphs as a function of this index for maximal subgraphs which are trees and the cyclomatic number of the graphs. The ramification index of a tree is first shown to be equal to the number of pending vertices minus 2. Then, in view of extremal graphs obtained with the system AutoGraphiX, all bounds of Araujo and De la Peña are improved, yielding tight bounds, and in one case corrected. Moreover, chemical trees of a given order and a number of pending vertices with minimum and with maximum connectivity index are characterized.

Journal Article↗
PubMed2002

Auditory evoked potential monitoring with the AAITM-index during spinal surgery: decreased desflurane consumption.

BACKGROUND: The auditory evoked potential (AEP) is sensitive to the depth of anesthesia. The A-line monitor is a novel device that processes the amplitude and latency of the AEP during the mid-latency time window to provide a simple numerical index, the AAItrade mark-index. The hypothesis of the present study was that titration of anesthetic depth (desflurane) by means of the AAItrade mark-index could decrease the consumption of the main anesthetic and shorten emergence times. METHODS: Thirty ASA I-II patients scheduled for elective open spine surgery under general anesthesia were randomly allocated to two groups. Group I (n=15), the main anesthetic, desflurane, was titrated with a target AAItrade mark-index of 20+/-5. Group II (n=15), desflurane was titrated according to routine clinical signs, including heart rate, blood pressure, sweating and tears. No fixed MAC-multiple was sought. The primary study variable was desflurane consumption; and secondary study variables were time to extubation and orientation. RESULTS: All patients had an uncomplicated course and no patients showed signs of awareness or had any recall postoperatively. AAItrade mark-index guidance reduced desflurane consumption by 29% and improved emergence. Time until extubation and orientation and ability to state name and date of birth was significantly shortened among AAItrade mark-index titrated patients. CONCLUSION: Titrating depth of desflurane anesthesia using AAItrade mark-index guidance decreased main anesthetic consumption and improved emergence during spine surgery.

Aged↗
PubMed1977

Somatic and autonomic indexes of recovery from electroconvulsive shock-induced amnesia in rats.

Autonomic response indexes of experimental amnesia have recently been found to have higher electroconvulsive shock (ECS) intensity thresholds and steeper retrograde gradients than have traditional somatic indexes. The present studies examined the hypothesis that recovery from somatically indexed experimental amnesia depends upon the existence of autonomically available residual memory. In a between-subjects design, a 200-mA ECS was used to produce amnesia for a tone-footshock pairing as indicated by lick suppression, defection, and bradycardia. The next day, these amnesic animals received a reminder footshock outside of the training apparatus, which was found to restore memory on a test trial 24 hr later. The behavior of control groups indicated that this reminder effect was due to the restoration of specific memory rather than systemic consequences of treatment. With a within-subjects design, a second experiment obtained a reminder effect in animals individually shown to be "fully" amnesic by all three response indexes monitored. A third experiment varied the intensity of the reminder footshock and revealed that the different memory indexes examined do not have reminder-footshock thresholds inversely related to their initial resistance to amnesia. The results support a retrieval-failure view of experimental amnesia and suggest that the same fundamental physiological processes underlie both autonomically indexed memory and somatically indexed memory.

Acoustic Stimulation↗
PubMed1985

DNA index of ovarian carcinomas from 56 patients: in vivo in vitro studies.

Out of 130 ovarian cancer patients the DNA index of cells from ovarian carcinoma was studied in 56 cases in which cytospin preparations showed the presence of atypical cells. In 24 patients the population had a diploid DNA index (1.0) and in the others the DNA index ranged from 1.2 to 2.0 (tetraploid). No hypodiploid or hypertetraploid populations were detected. Repeated samples from the same patients did not show any significant differences and primary culture did not alter the DNA index. In contrast, cell cycle phase distribution differed greatly from sample to sample, as also the ratio between DNA diploid and DNA aneuploid populations. Primary culture was successful in 57% of the tumours, with a higher percentage of success in DNA aneuploid tumours. After primary culture the ratio between DNA aneuploid cells and DNA diploid cells increased. In relation to the histological gradings of malignancy, DNA aneuploid cells clustered in the highest grade of malignancy. The mean S-phase for tumours with a DNA index of 1.0 was 3.5 and 14.1% for those with DNA index greater than 1. Ovarian carcinomas show a large difference in DNA index between patients even after primary culture.

DNA, Neoplasm↗
PubMed1999

Echocardiographic definition of left ventricular hypertrophy in the hypertensive: which method of indexation of left ventricular mass?

OBJECTIVES: It has been suggested that hypertensives at high risk of cardiovascular complications can be identified on the basis of their left ventricular mass as determined echographically. However, there is as yet a lack of consensus on the mode of indexation (body surface area, height, height 2.7) of left ventricular mass (LVM), and on the cut-off values for definition of left ventricular hypertrophy (LVH). The main objective of this study is to test the influence of the different modes of indexation for LVM on the prevalence of LVH in a population of never treated hypertensive patients on the basis of cut-offs for LVM based upon its relationship with ambulatory blood pressure (BP) measurement. METHODS: A population of 363 untreated hypertensives was investigated using a standardised procedure. The men and women were analysed separately. We studied the relationship between mean daytime ambulatory systolic BP and LVM and calculated the LVM cut-off for a BP of 135 mm Hg using three different methods of indexation. On the basis of these criteria, the population was divided into those with and those without LVH. RESULTS: The prevalence of LVH was found to be higher when LVM was indexed to height2.7 (50.4%) or height (50.1%). Prevalence was lowest when LVM was indexed to body surface area (48.2%), which tended to minimise the hypertrophy in obese individuals. Only indexation by height 2.7 fully compensates for relationships between height and ventricular mass in this population. CONCLUSIONS: Indexing LVM to height 2.7 thus appeared to give a more sensitive estimate of LVH by eliminating the influence of growth. Cut-offs of 47 g/m2.7 in women and 53 g/m2.7 in men corresponded to a cardiovascular risk indicated by a daytime systolic BP >/=135 mm Hg.

Adult↗
PubMed2003

Application and validation of a new biotic index using data from several water systems.

Protozoans of Lake Donghu were collected from five stations using the PFU method. The sampling was conducted for one year and two times a month. The aim of this research was to test the applicability of a new protozoa biotic index, species pollution value (SPV) and community pollution value (CPV), established by the authors using data from the River Hanjiang. Each station's CPV was calculated from the SPV and the correlation analysis between the CPV and the comprehensive chemical index of stations I, II, III showed a significant correlation between them. The pollution status of the five stations was correctly evaluated by the CPV. These results suggested that the biotic index could be applied in water systems other than the River Hanjiang. The SPV of some protozoa species in Lake Donghu, not observed in the River Hanjiang were established. In order to further test the applicability of the biotic index, protozoan and chemistry data from the Rivers Torrente Stirone and Parma of Italy were used. The results showed that the CPV for the two rivers had a close relationship with the chemical water quality, which indicated that the biotic index could be applied in other parts of the world for the monitoring and estimating of water quality. Since the results of testing and verifying the biotic index in some other water systems in China were also satisfactory, this indicated that the biotic index has an extensive suitability for freshwater ecosystems. As long as more than 50% of the species in a sample have a SPV, the CPV calculated from the SPV is reliable for monitoring and evaluating water quality.

Animals↗
PubMed1999

Effect of epidural bupivacaine on the relationship between the bispectral index and end-expiratory concentrations of desflurane.

We compared the relationship between the bispectral index and end-tidal desflurane concentrations in 20 patients undergoing elective surgery. Patients received epidurally either 10 ml saline (group S) or 10 ml bupivacaine 0.125% with epinephrine 1/800 000 (group B) before induction of anaesthesia with sufentanil (0.15 microgram.kg(-1)) and propofol (2 mg.kg(-1)); muscle relaxation was obtained with cisatracurium (0.2 mg.kg(-1)). Patients lungs were ventilated to maintain end-tidal desflurane at 3% in O2/N2O (50/50) until 5 min after skin incision, followed by two consecutive 10 min periods at end-tidal desflurane 6% and 9%. bispectral index values were recorded before induction, at 3% desflurane before and 5 min after skin incision, and at 6% and 9% end-tidal desflurane. Bispectral index decreased with increasing end-tidal desflurane concentration (ANOVA: p < 0.05). The decrease in bispectral index was significant between pre-induction, 3% and 6% desflurane. No significant difference was observed at 3% desflurane before and after skin incision, or between 6 and 9% desflurane. The relationship between bispectral index and end-tidal desflurane concentration was fitted by a linear regression in each group. No significant difference in bispectral index was observed between the groups at any time. We conclude that bispectral index decreases with increasing desflurane concentration and that this relationship is not affected by epidural 0.125% bupivacaine.

Adolescent↗
PubMed1999

The effects of nitrous oxide and ketamine on the bispectral index and 95% spectral edge frequency during propofol-fentanyl anaesthesia.

In this study, we have sought to establish whether N2O and ketamine alter the bispectral index during propofol-fentanyl anaesthesia. Fourteen surgical patients were randomly assigned to one of two groups: the N2O group (n = 7) and the ketamine group (n = 7). In both groups, anaesthesia was induced with propofol 1.5-2 mg kg-1 and fentanyl 2 micrograms kg-1 and maintained with propofol 5-7 mg kg-1 hr-1 to target the bispectral index between 40 and 50. After the bispectral index value had stabilized the propofol infusion rate was fixed. In the N2O group, the following concentrations of N2O were subsequently inhaled at 20-min intervals; 20, 40, 60 and 70%, and then N2O was terminated. In the ketamine group, ketamine (0.4 mg kg-1 + 1.0 mg kg-1h-1) was given. The bispectral index and 95% spectral edge frequency were recorded 20 min after each change in concentration of N2O or ketamine infusion. The bispectral index and 95% spectral edge frequency did not change significantly in the N2O group, but increased significantly from 44.1 +/- 0.7 and 16.0 +/- 0.5 to 58.6 +/- 1.4 and 19.5 +/- 0.3 (P < 0.01), respectively, in the ketamine group. Additional N2O or ketamine did not decrease the bispectral index and 95% spectral edge frequency values. The depth of sedation should be assessed carefully using a bispectral index monitor when these anaesthetic agents are used together.

Adult↗
PubMed2001

Doppler index and plasma level of atrial natriuretic hormone are improved by optimizing atrioventricular delay in atrioventricular block patients with implanted DDD pacemakers.

Doppler index is the sum of isovolumetric contraction time and isovolumetric relaxation time divided by ejection time and has clinical value as an index of combined systolic and diastolic myocardial performance. This crossover study compared the Doppler index and atrial natriuretic hormone (atrial natriuretic peptide) [ANP] between optimal (AV) delay and prolonged AV delay in patients with DDD pacemakers. The study included 14 patients (6 men, 8 women, age 78.4+/-9.3 [SD] years) with AV block with an implanted DDD pacemaker. AV delay was prolonged in a 25-ms, stepwise fashion starting from 125 ms to 250 ms. Pacing rate was set at 70 beats/min. Cardiac output (CO) was assessed by pulsed Doppler echocardiography, and optimal AV delay was defined as the AV delay at which CO was maximum, and an AV delay setting of 250 ms as prolonged AV delay. Plasma level of ANP and Doppler index determined by echocardiography were measured 1 week after programming. AV delay was switched to another AV delay and measurements were repeated after 1 week. Optimal AV delay was 159+/-19 ms. Doppler index was significantly lower at optimal AV delay than at prolonged AV delay (0.68+/-0.26 vs 0.92+/-0.30, P < 0.05). The plasma ANP level was significantly lower at optimal AV delay than at prolonged AV delay (29.0+/-30.7 vs 52.6+/-44.9 pg/mL, P < 0.05). In conclusion, the Doppler index and the plasma ANP level were significantly lower at optimal AV delay than at prolonged AV delay. This study shows the importance of the optimal AV delay setting in patients with an implanted DDD pacemaker, the Doppler index and plasma ANP levels are good indicators for optimizing AV delay.

Aged↗
PubMed1993

Ductus venosus index: a method for evaluating right ventricular preload in the second-trimester fetus.

This study was designed to examine ventricular preload by measuring the ductus venosus index during the second trimester of pregnancy. A total of 137 women were entered into the study. Each fetus was examined with real-time, color and pulsed Doppler ultrasound. The color Doppler maximal velocity setting was adjusted so that the umbilical vein was homogeneous in color, did not demonstrate aliasing, and filled the venous lumen. The pulsed Doppler gate was placed within the ductus venosus in all subjects. Color Doppler identified a turbulent flow velocity within the ductus venosus which was not present in the umbilical vein, hepatic vein or inferior vena cava. The ductus venosus pulsed Doppler waveform demonstrated flow velocity from the umbilical vein to the heart during ventricular systole, the rapid filling phase of ventricular diastole, and atrial systole. However, flow velocity was decreased during atrial systole compared to ventricular systole and the rapid filling phase of diastole. The ductus venosus index was computed from the Doppler waveform of the ductus venosus at points consistent with ventricular and atrial systole ((ventricular systole - atrial systole)/ventricular systole). Regression analysis demonstrated a significant (p = 0.001) relationship between the ductus venosus index and gestational age (ductus venosus index = 75.5757 - 7.25484 x weeks gestation), standard error of the estimate = 7.21959; R = -0.451. One fetus with a hypoplastic left atrium and ventricle demonstrated a normal ductus venosus index. Two fetuses, one with pulmonary atresia and the second with severe cardiovascular dysfunction, demonstrated an abnormal ductus venosus index associated with absent flow velocity during atrial systole. This was associated with notching in the umbilical vein. The ductus venosus index is an angle-independent measurement from which right ventricular preload may be evaluated.

Journal Article↗
PubMed2003

The assessment of automated measures of hydrogel contact lens refractive index.

PURPOSE: To investigate within- and between-operator reliability and validity of refractive index measures of hydrogel lenses. METHODS: Twenty-three lenses of various nominal water contents were examined by two operators on two occasions separated by 1 h. An automated refractometer (CLR 12-70, Index Instruments, Cambridge, UK) was used for refractive index measures. Lenses were presented in a random order to each operator by a third party, and operators were masked to any potential lens identifiers. Intraclass correlation coefficients (ICC), 95% limits of agreement (LoA), and paired t-tests were used to characterize the within- and between-operator reliability and validity of lens refractive index measures. RESULTS: The mean (+/-S.D.) difference between sessions was 0.0001 +/- 0.0011, which did not significantly differ from zero (p = 0.64). Within-operator reliability was excellent (ICC = 0.9990, 95% LoA = -0.0021 to 0.0024). The mean (+/-S.D.) difference between-operators was 0.0002 +/- 0.0010, which was not significantly different from zero (p = 0.54). Between-operator reliability was also excellent (ICC = 0.9984, 95% LoA = -0.0026 to 0.0029). The mean difference between the nominally reported refractive index and our refractive index measures was -0.0009 +/- 0.082, which did not differ statistically from zero (p = 0.52); the 95% LoA for this difference was -0.0152 to 0.0169. CONCLUSION: There is good reliability within- and between-operators in measuring the refractive index of hydrogel lenses using the CLR 12-70 automated refractometer.

Contact Lenses, Hydrophilic↗