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At least 19 recordsLinked to original sources
PubMed1997

Ambulatory monitoring.

Ambulatory monitoring has been hailed as the 'way forward' in urodynamic investigation. Its introduction has caused much excitement and there is no doubt that it detects more abnormalities than does conventional cystometry. It is, however, labour intensive and time consuming for both operator and patient, and requires commitment from both to be successful. No standards have been set as to how long a test ought to last, how many voids are required and how to interpret traces. To date the standard cystometric criteria of normality have been applied, but this would appear to be inappropriate. Several commercial companies have developed systems and are marketing them widely as an adjunct, or alternative, to conventional cystometry. It is recommended that before this technique is introduced into routine clinical practice it is fully evaluated, with standardization of terminology relating to its use.

Female↗
PubMed1994

Improved detection of a blood pressure response to dietary intervention with 24-hour ambulatory monitoring.

Ambulatory blood pressure (ABP) monitoring was undertaken in 25 hypertensives on beta-blocker monotherapy who completed a double-blind crossover trial to compare the effects of fish oil and corn oil supplements on BP. Clinic BP was measured with a Dinamap monitor on two consecutive days at the end of each treatment phase. ABP was recorded during the intervening 24-h period with a Spacelabs 90207 monitor. Averages of 24-h, daytime, and nighttime ABP readings correlated closely with Dinamap readings. Within-subject BP differences between fish oil and corn oil treatment were similar for Dinamap (3.2 +/- 1.8/2.5 +/- 1.0 mm Hg) and for 24-h ABP (2.5 +/- 1.0/2.3 +/- 0.8 mm Hg), but were more significant with the latter. Thus detection of the antihypertensive effects of dietary intervention can be improved by the use of ABP.

Adult↗
PubMed1996

Evaluation of nocturnal blood pressure by the Multi-P Analysis of 24-hour ambulatory monitoring.

Ambulatory blood pressure monitoring (ABPM) is utilized to identify "dippers" and "non dippers" among hypertensives. Such a classification has either prognostic or therapeutical implications. Rigid definitions of nocturnal time period (e.g., from 10 p.m. to 7 a.m.) may not correspond to actual sleep patterns, and thus may lead to faulty interpretations. In our study, we analyzed 32 ABPM; diurnal and nocturnal blood pressure (BP) were assessed by three different ways: the patients' diary method; fixed intervals utilized by Spacelabs software; Multi-P Analysis (MPA) of the data. MPA method proved to be effective to evaluate nocturnal BP values. In comparison with Spacelabs program, it seems to define more precisely nocturnal BP, which differs less from the real sleep-time values. This modifies the percentage of dippers, which is greater than that obtained by Spacelabs program and equal to that calculated by the patients reported nocturnal sleep intervals. These results suggest that MPA method may be a contribution to a better definition of nocturnal BP.

Adolescent↗
PubMed2006

Using the net benefit regression framework to construct cost-effectiveness acceptability curves: an example using data from a trial of external loop recorders versus Holter monitoring for ambulatory monitoring of "community acquired" syncope.

BACKGROUND: Cost-effectiveness acceptability curves (CEACs) describe the probability that a new treatment or intervention is cost-effective. The net benefit regression framework (NBRF) allows cost-effectiveness analysis to be done in a simple regression framework. The objective of the paper is to illustrate how net benefit regression can be used to construct a CEAC. METHODS: One hundred patients referred for ambulatory monitoring with syncope or presyncope were randomized to a one-month external loop recorder (n = 49) or 48-hour Holter monitor (n = 51). The primary endpoint was symptom-rhythm correlation during monitoring. Direct costs were calculated based on the 2003 Ontario Health Insurance Plan (OHIP) fee schedule combined with hospital case costing of labour, materials, service and overhead costs for diagnostic testing and related equipment. RESULTS: In the loop recorder group, 63.27% of patients (31/49) had symptom recurrence and successful activation, compared to 23.53% in the Holter group (12/51). The cost in US dollars for loop recording was 648.50 dollars and 212.92 dollars for Holter monitoring. The incremental cost-effectiveness ratio (ICER) of the loop recorder was 1,096 dollars per extra successful diagnosis. The probability that the loop recorder was cost-effective compared to the Holter monitor was estimated using net benefit regression and plotted on a CEAC. In a sensitivity analysis, bootstrapping was used to examine the effect of distributional assumptions. CONCLUSION: The NBRF is straightforward to use and interpret. The resulting uncertainty surrounding the regression coefficient relates to the CEAC. When the link from the regression's p-value to the probability of cost-effectiveness is tentative, bootstrapping may be used.

Bayes Theorem↗
PubMed1998

[Evaluation of Spacelabs 90207, the noninvasive automatic monitor for ambulatory monitoring of blood pressure].

OBJECTIVE: To validate a non-invasive apparatus for non-hospital monitoring of blood pressure, the Spacelabs 90207 model. DESIGN: A comparative cross-sectional study. SETTING: Primary Care. "La Orden" Health Centre in Huelva. PATIENTS: 90 people, 34 men, of all ages, hypertensive or not and without any treatment for Hypertension, and selected at random from the on-demand consulting room. MEASUREMENTS AND MAIN RESULTS: Four blood pressure (BP) readings measured with the standard manual apparatus (mercury sphygmomanometer) were compared with three obtained in sequence with the Spacelabs 90207, validated in line with the recommendations of the British Hypertension Society (BHS) and the Association for the Advancement of Medical Instrumentation (AAMI). Average age was 51.31 +/- 16.5, with SP between 102 and 200 mmHg and DP between 60 and 100 mmHg. Means and standard deviations of manual and automatic BP readings were worked out: 129.13 +/- 19 mmHg and 130.50 +/- 19 for SP, and 77.97 +/- 11 and 76.64 +/- 11 for DP. CONCLUSIONS: Spacelabs 90207 fulfills the validation criteria of the BHS and AAMI.

Adult↗
PubMed1987

A finger volume-oscillometric device for monitoring ambulatory blood pressure: laboratory and clinical evaluations.

A new portable device for the indirect measurement of ambulatory blood pressure in the finger was successfully applied to normotensive and hypertensive subjects in and outside a ward setting. The device uses the volume-oscillometric technique and, equipped with a microprocessor, permits long-term ambulatory monitoring of indirect systolic and mean blood pressure at desired intervals (once every 1-10 min). Systolic and mean blood pressures obtained by this method were well correlated with those measured by the direct (Oxford) and arm-cuff methods. Systolic and diastolic blood pressure obtained by the volume-oscillometric device were almost identical with those recorded by an arm-cuff. Systolic blood pressure obtained by the volume oscillometric method was, however, significantly lower than that measured by the direct method. The new device has also been used to measure blood pressure during treadmill exercise and ice-water immersion. Mean values of blood pressure and the SD of these averaged for 24 hours, or for every hour, were reproducible when the measurements were repeated under the same condition. The present device is portable, causes minimal noise, can detect rapid change in blood pressure and causes less discomfort when compared to the conventional arm-cuff method. Regular measurements can be made with minimal sleep disturbance. This fully automatic volume-oscillometric device allows reliable 24-hour monitoring of ambulatory blood pressure not only in but also outside a ward setting, and as such is useful for studies of hypertension.

Ambulatory Care↗
PubMed1998

Improved remote event marker for use in ambulatory monitoring.

During ambulatory monitoring, physiological signals and other parameters are measured and stored in a portable recorder. To optimise subsequent interpretation, additional information is provided by the subject pressing a button at the onset of any relevant symptoms or events, simultaneously noting these in a personal diary. To distinguish between different events, the subject is instructed to press the event button a specific number of times. Confusion arises when the subject fails to press the button correctly or to record the event accurately on paper. The device described overcomes these problems by providing the subject with separate switches on a single remote unit. Depending on the button pressed, the unit automatically sends a coded signal to the recorder, allowing unequivocal identification of events during data playback and analysis. Although primarily used in urodynamics, this simple device can be used in many other similar recording systems with little or no modification.

Electronics↗
PubMed1986

A representative value for 24-hour monitored ambulatory blood pressure.

Several shorter-term alternatives for whole-day ambulatory monitoring of blood pressure using Pressurometer III or conventional sphygmomanometer were evaluated in 12 male patients with mild hypertension. Averages of BP reading at 8 AM once, 3 consecutive-readings either with Pressurometer or manually, serial readings for 2-hour intervals from 8-10 AM and 2-4 PM were compared with that of 24-hour ambulatory, non-invasive BP readings by Pressurometer. Both systolic and diastolic 2-hour BP averages in the morning (8 to 10 o'clock) correlated more strongly with 24-hour averages (r = 0.91 and 0.91) than the 3 consecutive (r = 0.88 and 0.66) or single (r = 0.49 and -0.35) reading alternatives did. In conclusion, the average of serial readings obtained during 2-hour monitoring period from 8 to 10 AM is a reliable predictor of 24-hour ambulatory BP and represents it more closely than the conventional single or multiple BP readings.

Blood Pressure↗
PubMed1996

Antihypertensive efficacy of the angiotensin II AT1-receptor antagonist losartan: results of a randomized, double-blind, placebo-controlled, parallel-group trial using 24-hour blood pressure monitoring. Ambulatory Blood Pressure Monitoring Study Group.

The antihypertensive efficacy of once- and twice-daily losartan was evaluated in a randomized, double-blind, placebo-controlled, parallel-group trial using ambulatory 24-h blood pressure monitoring in 122 patients with mild to moderate essential hypertension. Data are reported for 112 patients who completed the active treatment phase. Losartan exerted a sustained 24-h antihypertensive effect at all doses studied (50 or 100 mg once daily, or 50 mg twice daily). Losartan demonstrated a smooth, gradual onset of action, did not affect normal circadian variations on blood pressure, and had no significant effect on heart rate. An additive antihypertensive effect was obtained by adding low-dose hydrochlorothiazide to losartan monotherapy at all doses of losartan studied. Losartan was well tolerated during the study with a frequency of adverse events comparable with placebo. No major adverse events were recorded. The results of this study indicate that losartan is an effective and well-tolerated antihypertensive agent that provides 24-h blood pressure-lowering efficacy from a single daily dose of 50 mg.

Administration, Oral↗
PubMed2002

Common electrocardiographic artifacts mimicking arrhythmias in ambulatory monitoring.

BACKGROUND: Ambulatory electrocardiographic monitoring is used in clinical practice as a means of detecting cardiac arrhythmias during daily activities. Current equipment provides analysis for the detection of arrhythmias, ST-segment deviation, and more sophisticated analyses (late potentials, Q-T behavior, and heart-rate variability). However, despite the system used, a number of artifacts could mislead diagnosis. METHODS AND RESULTS: We prospectively searched for artifacts during ambulatory electrocardiography in patients referred for monitoring to our institution, a tertiary referral center. Patients were ambulatory at home, work, school, or within the hospital. We divided artifacts according to Krasnow and Bloomfield's classification (pseudoarrhythmia, nonarrhythmia), and we added a new category, artifacts in patients with pacemakers. Artifacts encountered mimicked sinus arrest, supraventricular arrhythmias, ventricular arrhythmias, and aberrancy. Examples of each one and diagnostic clues are provided to recognize these artifacts properly. CONCLUSIONS: A substantial amount of invalid data (false-positive findings because of electrocardiographic artifacts) were identified during ambulatory electrocardiographic monitoring that can lead to inappropriate interpretation and may result in severe diagnostic errors.

Arrhythmias, Cardiac↗
PubMed2002

Advances in modern electrocardiographic equipment for long-term ambulatory monitoring.

Electrocardiographic ambulatory "Holter" monitoring (AECG) is an essential tool in the diagnostic evaluation of patients with cardiac arrhythmias. Recent advances in digital Holter technology have improved the quality of the ECG signals and new dedicated algorithms have expanded the clinical application of software-based AECG analysis systems. Due to the availability of inexpensive large storage capacities, very long-term (weeks to months) continuous high-quality AECG monitoring will soon be available, together with devices for long-term long-distance telemetric surveillance for high-risk cardiac patients, utilizing trans-telephonic transmission of ECG data. New digital recorders will also have the capability for multichannel simultaneous recordings (currently from 3 to 8 simultaneous leads). Multichannel digital recordings will allow the recording of different biological signals by appropriate sensors, such as respiratory frequency, peripheral oxygen tension, arterial pulse pressure, EEG, and others. This will transform conventional AECG in ambulatory policardiography, allowing the comprehensive evaluation of patients with complex disorders, such as heart failure or sleep apnea syndromes. By this global approach, Holter analysis becomes a real "noninvasive electrophysiological test," to identify potential risk factors for life-threatening cardiac arrhythmias.

Arrhythmias, Cardiac↗
PubMed1997

Detrusor activity index: quantification of detrusor overactivity by ambulatory monitoring.

PURPOSE: Ambulatory urodynamic monitoring has been developed and evaluated during the last decade, and its appreciation is growing rapidly. We investigated the usefulness of this technique to quantify detrusor activity, and developed a parameter to quantify the grade of detrusor overactivity. MATERIALS AND METHODS: We investigated 167 female patients with lower urinary tract symptoms and 61 asymptomatic volunteers. Detrusor behavior was classified according to the medical history findings and independently based on urodynamic investigation. The possible categories were termed overactive or not overactive. Subjects who were classified consistently formed the 2 reference groups, which were used in the statistical analysis of logistic regression. RESULTS: By logistic regression a scoring rule was developed. The individual score (detrusor activity index 0 to 1) is a measure of detrusor activity during the filling phase. At a cutoff point of 0.41 the sensitivity equaled specificity of 85% in our patient and volunteer groups. CONCLUSIONS: The scoring rule can be applied clinically as a test to detect and quantify detrusor overactivity in patients with urinary incontinence.

Adolescent↗
PubMed1983

Ambulatory monitoring of pulmonary artery pressure. A preliminary clinical evaluation.

Traditional measurement and recording methods are inadequate for continuous monitoring of ambulatory pulmonary artery pressure. Therefore a new miniaturised solid state system has been developed and assessed. A manometer tipped catheter, inserted via a subclavian or cephalic vein, was used together with an isolated amplifier and peak detectors to determine systolic and diastolic pressures. Pressures were averaged over 30 seconds and stored in digital memory. After a 24 hour recording period data were rapidly transferred to a microcomputer for numerical or graphical display. Thirteen patients had continuous ambulatory monitoring performed for between 24 and 96 hours, in seven to evaluate symptoms of dyspnoea in subjects with valvular or coronary disease (group 1), and in six to achieve optimal oral treatment for left heart failure (group 2). The catheter was calibrated before insertion and was rechecked after removal. There was less than 1% zero level drift and similar gain stability. Systolic pressures ranged from 10 to 97 (mean 39.5) mmHg, and diastolic from 1 to 46 (mean 15.3) mmHg. Four patients in group 1 had symptoms of dyspnoea associated with normal pressures, while three had raised pressures. Four of the six patients monitored in group 2 had major alterations in their treatment based on data obtained during monitoring. There were no complications. This system, which allows safe, reliable, and prolonged recording of ambulatory pulmonary artery pressure, represents a considerable advance in the ability to assess the cause of dyspnoea and to manage left heart failure.

Adult↗
PubMed2003

The 'ABPM effect' gradually decreases but does not disappear in successive sessions of ambulatory monitoring.

OBJECTIVES: Previous results have indicated that ambulatory monitoring provides a pressor effect on patients using the device for the first time, but not on successive sessions of monitoring. Our objective was to validate and quantify the extent and duration of this pressor effect in hypertensive patients repeatedly evaluated every few months. METHODS: We studied 823 mild-to-moderate hypertensive subjects (347 men), 53.4 +/- 14.1 years of age. Blood pressure was measured at 20-min intervals during the day and at 30-min intervals at night for 48 consecutive hours, and physical activity was simultaneously evaluated every minute with a wrist actigraph. Forty per cent of the patients were evaluated twice or more. RESULTS: In patients evaluated for the first time, results indicated a highly statistically significant (P < 0.001) reduction during the second day of monitoring as compared to the first in the diurnal mean of systolic and diastolic blood pressure, but not in heart rate or physical activity. This pressor effect remained statistically significant for the first 10 h of monitoring, independent of gender, day of the week of monitoring, or number of antihypertensive drugs used by the patients. The nocturnal mean of blood pressure was, however, similar between both days of sampling. This 'ambulatory monitoring effect' was diminished, although not eliminated, in extent and duration for successive sessions of ambulatory monitoring. CONCLUSIONS: Ambulatory monitoring for 48 h revealed a statistically significant pressor response that could mostly reflect a novelty effect in the use of the monitoring device. This effect has marked implications in both research and clinical daily practice for a proper diagnosis of hypertension and evaluation of treatment efficacy by the use of ambulatory monitoring.

Adolescent↗
PubMed2005

Is ambulatory monitoring for "community-acquired" syncope economically attractive? A cost-effectiveness analysis of a randomized trial of external loop recorders versus Holter monitoring.

BACKGROUND: Out patient ambulatory monitoring is often performed in patients with syncope that present in the primary care setting to include or exclude an arrhythmia. The cost-effectiveness of 2 monitoring strategies was assessed in a prospective randomized trial. METHODS: One hundred patients referred for ambulatory monitoring with syncope or presyncope were randomized to a 1-month external loop recorder (n = 49) or 48-hour Holter monitor (n = 51). Patients were offered crossover if there was failed activation or no symptom recurrence. The primary end point was symptom-rhythm correlation during monitoring. Direct costs were calculated based on the 2003 Ontario Health Insurance Plan fee schedule, combined with calculation of labor, materials, service, and overhead for diagnostic testing and related equipment. RESULTS: Before enrollment, the cost of all previous health care resource use was USD 472 +/- USD 397 (range USD 21-USD 1965). In the loop recorder group, 63% of patients had symptom recurrence and successful activation, compared with 24% in the Holter group (P < .0001). The cost per Holter was USD 177.64, and per loop recorder, USD 533.56, with a similar cost per diagnosis with the 2 techniques. The incremental cost-effectiveness ratio of the loop recorder was USD 901.74 per extra successful diagnosis. A strategy of Holter followed by offered loop recorder trended toward lower cost than initial loop recorder followed by Holter (USD 481 +/- USD 267 vs USD 551 +/- USD 83, P = .08), but was associated with a lower overall diagnostic yield (49% vs 63%) and a resultant higher cost per diagnosis (USD 982 vs USD 871, P = .08). Bootstrapping suggested that 90% of incremental cost-effectiveness ratios were less than USD 1250. CONCLUSION: Despite the increased upfront cost of external loop recorders, the marked improvement in diagnostic yield offsets the cost. External loop recorders are an economically attractive alternative. First-line use of external loop recorders in patients with "community-acquired" syncope and presyncope should be considered to optimize diagnostic yield given its value.

Cost-Benefit Analysis↗