[Flow through the mitral and aortic ostium quantified with magnetic resonance velocity measurement].
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Aortic Valve↗
Biomedical subjects
E Gymoese
Publications and source records attributed to E Gymoese.
Comparison between retrospective gating and ECG triggering in magnetic resonance velocity mapping.
ECG-triggered cinematographic studies of the cardiovascular system are hampered by several technical restrictions such as the inability to image end-diastole, ghosting, varying signal intensity, and phase contributions from eddy currents. Retrospective gating may solve these problems, but involves signal manipulation such as interpolating raw data from a time window. In this study, the performance of the two gating strategies was compared in quantitative MR velocity mapping on the abdominal aorta in eight healthy volunteers and on a pulsatile flow phantom. The results were compared to a one-dimensional velocity mapping technique and Doppler ultrasound. Finally, the consequence of decreasing the time window in the raw data interpolation used for retrospective gating was also examined. With retrospective gating, a low-pass filtering was seen, causing significantly prolonged duration and decreased amplitude of flow pulses. However, by reducing the time window retrospectively gated flow measurements were in good agreement with those that are ECG triggered. When fulfilling the demand of a narrow time window for interpolation, retrospective gating offers several advantages in MR velocity mapping.
Algorithms↗
Comparison of different orthogonal systems in high resolution ECGs and the significance of the number of averaged beats in detecting late potentials.
For non-invasive detection of late potentials in the signal-averaged electrocardiogram (SAECG) most studies use modified orthogonal leads. In the present study the significance of three different lead systems for the detection of late potentials was examined. SAECGs were recorded at five different (32, 64, 128, 256, and 512) numbers of averaged beats in 24 patients with ventricular tachycardia after myocardial infarction and in 76 normal subjects. The original Frank leads and two different modified orthogonal vector lead systems were used. There was no clinical difference between the three orthogonal systems in sensitivity and the difference in specificity (P less than 0.01) seemed to be primarily related to differences in noise content. When the vector systems were compared at equally low noise levels of 0.47-0.50 microV, the apparent differences in specificity between the vector systems disappeared. At decreasing noise levels the sensitivity increased, at the cost of a loss in specificity which at very low noise levels was out of proportion with the gain in sensitivity. A modified approach with a fixed threshold noise level to determine the QRS endpoint is suggested.
Adult↗
Intermittent high-dose aclarubicin in patients with advanced cancer: a phase I study with special reference to cardiac toxicity.
Aclarubicin was given iv every 3 weeks to 21 patients with a variety of solid tumors. Four dose levels were tested: 80, 100, 120, and 140 mg/m2. The median cumulative dose was 270 mg/m2 (range, 80-900). No objective responses were observed. Hematologic toxicity was dose-limiting. All patients experienced moderate to severe gastrointestinal toxicity. Five of 13 patients evaluable for cardiac function showed clinical signs and ECG changes suggestive of cardiac dysfunction. The suggested maximum dose for phase II trials is 120-140 mg/m2 iv given in an intermittent 3-week schedule.
Aclarubicin↗
Kinetics and neuropsychologic effects of IV diazepam in the presence and absence of its active N-desmethyl metabolite in humans.
In 12 healthy volunteers the kinetics and neuropsychological actions of IV diazepam (DZ) (single dose) were studied with and without the presence of its main metabolite N-desmethyldiazepam (NDDZ). Both the maximal plasma concentration and the steepness of the alpha-slope were correlated with variations in the corresponding continuous reaction time (CRT). EEG profiles, CRT and clinical ratings for anxiety and sedation all showed significant changes between the situations with the metabolite present or absent, but no significant correlation could be found with the kinetic pattern of DZ in the two situations. Tolerance to NDDZ did not develop. The results indicate that the presence of the active metabolite changes the pharmacodynamic profile of the parent compound probably by an interaction at the receptor site between DZ and NDDZ. Changes in the spectrum of effects during long-term therapy with DZ may, therefore, partly be explained in this way.
Adolescent↗
Long-term ECG monitoring in suspected Adams-Stokes disease.
Long-term ECG recording techniques have facilitated the diagnosis in atypical cases of Adams-Stockes syndrome. In the use of ambulatory ECG monitoring, new and mainly technical problems have been arisen. In 200 ECG recordings on cassette tape, 78% was considered sufficient for an accurate diagnosis. More than 50% of the unsuccessful recordings were unreadable due to electrode problems. The use of ambulatory monitoring demands that electrode fixation and placement be handled carefully and that the mechanical and electronic equipment be serviced frequently. Patients with third-degree atrioventricular block and syncopes of fainting spells run a high risk of sudden death. It is therefore not recommended to use ambulatory monitoring techniques on these patients.
Adams-Stokes Syndrome↗
Neuropsychologic effects of diazepam related to single dose kinetics and liver function.
The neurophysiologic and neuropsychologic effects and their relation to the kinetics of diazepam (DZ) were studied in 10 patients with impaired liver function of various degrees and in three normal subjects after 10 mg DZ i.v. The plasma concentration data were treated according to a two-compartment open model. Neurophysiologic effect measurements were obtained from galvanic skin response, continuous reaction times (CRT), heart rate, and averaged evoked potentials; neuropsychologic measurements were obtained from trail making A + B, hidden pattern, word fluency, and subtraction tests; in addition, clinical effects were rated by Beechers Mood Scale and Spielbergers Anxiety Scale. Except for trail making A and word fluency all tests discriminated well between the experimental conditions with or without diazepam. No difference from normal in the response to acute diazepam administration could be detected in patients with reduced liver function. A linear correlation between prolongation in CRT and DZ log plasma concentration was demonstrated in the entire, heterogenous patient material. In the clinical ratings only items of a predominantly sedative and autonomic significance responded to the diazepam injection, while predominantly anxiolytic items did not.
Diazepam↗
Mitral and aortic valvular flow: quantification with MR phase mapping.
When magnetic resonance phase mapping is used to quantitate valvular blood flow, the presence of higher-order-motion terms may cause a loss of phase information. To overcome this problem, a sequence with reduced encoding for higher-order motion was used, achieved by decreasing the duration of the flow-encoding gradient to 2.2 msec. Tested on a flow phantom simulating a severe valvular stenosis, the sequence was found to be robust for higher-order motion within the clinical velocity range. In eight healthy volunteers, mitral and aortic volume flow rates and peak velocities were quantified by means of phase mapping and compared with results of the indicator-dilution technique and Doppler echocardiography, respectively. Statistically significant correlations were found between phase mapping and the other two techniques. Similar studies in patients with valvular disease indicate that phase mapping is also valid for pathologic conditions. Phase mapping may be used as a noninvasive clinical tool for flow quantification in heart valve disease.
Aortic Valve↗