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Biomedical subjects

A Benassi

Publications and source records attributed to A Benassi.

At least 37 records · Page 2Linked to original sources
PubMed1987

[Ambulatory electrocardiography in patients with angina pectoris].

In the diagnosis of ischemic heart disease, long-term ECG recording has several distinct advantages. It allows one to relate patient symptoms to cardiac disturbances and to detect asymptomatic events, reveals the possible ischemic genesis of arrhythmias, and it is the most suitable method to assess the acute and chronic effectiveness of treatment and the evolution of the disease. In spite of these advantages, Holter monitoring has several limitations: the analysis of a single lead, is responsible in most systems for the low sensitivity in detecting ischemia occurring in unexplored regions; the period of 24-48 hours may not be sufficient for screening patients due to the unpredictable spontaneous variability of the disease; a common standard of analysis is still lacking even if the European Communities concerted action in Ambulatory Monitoring could represent the solution to this problem. Nevertheless the role of Holter monitoring appears essential in the ambulatory screening of patients with suspected ischemia for a better characterization of patients with ascertained myocardial ischemia, and for the evaluation of treatment and of the evolution of the disease.

Angina Pectoris↗
PubMed1986

Autosomal-dominant dystrophy with humeroperoneal weakness and cardiopathy: a genetic variant of Emery-Dreifuss disease?

Two females mother and daughter, were affected by a neuromuscular disorder, characterized by slow progression, humeroperoneal weakness and wasting, limited neck flexion, elbow and ankle joint contractures, cardiopathy and myopathic pattern on EMG. Muscle histology and histochemistry showed type I fiber atrophy and predominance in both. Cardiac abnormalities, in the first case, were suggestive of a hypertrophic cardiomyopathy while in the second hypotension and chronic bradycardia were present. Neurological signs, EMG and morphology seemed to point to a genetic variant of the form of dystrophy named Emery-Dreifuss disease. The mode of transmission and cardiac abnormalities, however, raise the problem of variability even in this well-defined, usually X-linked, disorder.

Adolescent↗
PubMed1986

The use of frequency histograms of ultrasonic backscatter amplitudes for detection of atherosclerosis in vitro.

This study was designed to determine whether a quantitative analysis of integrated backscatter amplitude distribution is potentially useful in characterizing the atherosclerotic lesion. One hundred measurements (10 X 10 array) were made in fresh aortic regions (2 cm X 2 cm) of nine normal and 19 atherosclerotic arterial walls. A 10 MHz transducer was used. The integrated backscatter distinguished normal from atherosclerotic specimens (-56.7 +/- 4.3 vs -42.5 +/- 8.9 dB, p less than .01). The shape of the integrated backscatter amplitude distribution was analyzed by calculation of skewness and kurtosis of each arterial region. Both skewness values (0.134 +/- 0.325 vs -0.193 +/- 0.491 in normal and atherosclerotic segments, respectively, p = NS) and kurtosis values (0.055 +/- 0.765 vs -0.610 +/- 0.379, p less than .01) discriminated between the two groups. When only the six atherosclerotic specimens with mostly fatty and fibrofatty sites were considered, skewness and kurtosis still distinguished normal from atherosclerotic regions (0.134 +/- 0.325 vs -0.404 +/- 0.232, p less than .05 and 0.055 +/- 0.765 vs -0.558 +/- 0.337, p less than .05, respectively), while integrated backscatter values did not (-56.7 +/- 4.5 vs -52.3 +/- 6.1 dB, p = NS). In conclusion, atherosclerosis may be detected in vitro by the quantitative analysis of integrated backscatter distribution. This variable could also be of help in the identification of less obvious forms of atherosclerotic disease that are not distinguishable on the basis of integrated backscatter amplitude.

Aorta↗
PubMed1986

The efficacy of ibopamine in long-term treatment of dilated cardiomyopathy. A clinical and instrumental evaluation.

The aim of this study was to investigate whether long-term treatment with ibopamine (SB-7505), the 3,4-diisobutyryl ester of N-methyldopamine, in patients with severe symptomatic congestive cardiomyopathy is associated with an improvement in cardiovascular conditions. The investigation was carried out in 18 outpatients with idiopathic or post-ischemic dilated cardiomyopathy and chronic severe heart failure (NYHA (New York Heart Association) Class III-IV). Patients were randomly assigned to a protocol in which either digitalis and diuretics (8 patients, Group 2) or the same treatment plus ibopamine (10 patients, Group 1) were given. There were no significant differences between the two groups in age, weight, height, functional class and duration of symptoms. The results obtained showed that cardiovascular conditions worsened dramatically in the group of controls during the 10-week period, irrespective of the treatment with digitalis and diuretics. Some of the parameters deteriorated significantly (p less than 0.05 or less than 0.01) such as systolic and diastolic left ventricular diameters, fractional shortening, end-systolic stress and pressure/diameter ratio, and other parameters showed a tendency to become worse (exercise time, cardiothoracic ratio). On the contrary, in patients of group 1, ibopamine in association with digitalis and diuretics appeared to preserve left ventricle function from a progressive worsening. None of the parameters deteriorated with ibopamine by contrast with a sharp decrease in the control group. Some of the parameters (fractional shortening, pressure/diameter ratio, exercise time) showed a tendency to improve although not significantly. The data suggest than 10 weeks treatment with ibopamine may prevent any deterioration or even produce a mild improvement in patients with very severe congestive heart failure.

Adult↗
PubMed1986

Left partial absence of the pericardium.

A case of left partial absence of the pericardium in a young patient is presented. Plain roentgenographic findings were suggestive, and 2-D echocardiography was useful only to rule out associated cardiac abnormalities. Computerized tomography led to the diagnosis permitting to define some typical features.

Adolescent↗
PubMed1986

Electrocardiographic monitoring: temporal versus spatial information and data processing.

In the diagnosis of ischemic heart disease, long-term electrocardiographic recording has several distinct advantages. It allows one to relate patient symptoms to cardiac disturbances and to detect asymptomatic events, furnishes the whole spectrum of electrocardiographic alterations accompanying ischemic attacks, reveals the possible ischemic genesis of dysrhythmias, and is the most suitable method to assess the acute and chronic effectiveness of treatment and the evolution of the disease. In addition to its valuable application in the screening and follow-up of ambulatory patients, its use in the Coronary Care Unit is of great interest, being in this context much more sensitive than visual electrocardiographic monitoring. In spite of these advantages, Holter monitoring has several limitations: the recording and replay systems are below recommended standards; the analysis of a single lead is responsible in most systems for the low sensitivity in detecting ischemia occurring in unexplored regions; the period of 24-48 hours, usually adopted for Holter monitoring, may not be sufficient for screening patients with suspected myocardial ischemia due to the unpredictable spontaneous variability of the disease; a common standard of analysis is still lacking and a reliable computerized analysis is needed to manage data overflow. In conclusion, although further research and technical developments are desired to improve reliability and data processing, the role of Holter monitoring appears essential in the ambulatory screening of patients with suspected ischemia for a better characterization of patients with ascertained myocardial ischemia, and for the evaluation of treatment and of the evolution of the disease.

Angina Pectoris, Variant↗
PubMed1985

Echocardiographic versus hemodynamic monitoring during attacks of variant angina pectoris.

Six attacks of variant angina (2 spontaneous, 4 induced by ergonovine) were studied in 6 patients by combined echocardiographic and hemodynamic monitoring. A decrease of percent systolic thickening of the ischemic wall, which occurred as early as the decrease in peak dP/dt of contraction, was detected before the onset of ST-segment elevation ("pre-electrocardiographic phase"). At this stage, no significant change in left ventricular (LV) end-diastolic pressure or end-diastolic diameter was observed. Subsequently, in the presence of clear-cut ST-segment elevation ("electrocardiographic phase"), percent systolic thickening (an index of regional function) reached its nadir, while dP/dt of contraction (an index of global function) was almost back to preischemic values. In this phase, a significant increase in LV end-diastolic diameter and end-diastolic pressure could be also detected. In the recovery phase, when the ST segment had returned to the isoelectric line ("post-electrocardiographic phase"), percent systolic thickening and dP/dt of contraction showed supernormal values, while LV end-diastolic pressure and end-diastolic diameter decreased below basal values. Thus, echocardiographic signs of impairment in LV mechanics are as early and sensitive as hemodynamic indexes during attacks of variant angina. Furthermore, information on morphologic characteristics and regional LV function, not available with hemodynamic monitoring, can be obtained by echocardiography.

Adult↗
PubMed1985

On-line evaluation of ultrasonic integrated backscatter.

Although it is already known that reflected ultrasonic signals (backscatter) are changed by the structure of the tissue through which they pass, clinicians are still awaiting a practical instrument in which information from backscatter reflections will serve as a diagnostic aid additional to that provided by conventional ultrasonic scans. The equipment described here is both small and fast, and is integrated into a normal ultrasound installation. No new operating procedures have to be learned. The integrated backscatter is calculated on-line and presented on an LED as tissue characterization parameters. In order to minimize noise due to physical movement of the heart during an investigation of the myocardium, the analysis is synchronized with the ECG; and as an aid to the user, the normal system VDU displays both the ECG and the activating trigger pulse derived from the R-wave peak. An A-scan display has been used but this could readily be adapted for B-scan operation and single line analysis. Tests with backscattering models and standard instrumentation have shown no significant difference between results using time domain or frequency domain analysis.

Biomedical Engineering↗
PubMed1985

Fibrosis, lipids, and calcium in human atherosclerotic plaque. In vitro differentiation from normal aortic walls by ultrasonic attenuation.

This study was designed to determine whether attenuation of ultrasound by the aortic wall is potentially useful in characterizing the atherosclerotic lesion. Measurements were made on fresh specimens taken from a human aorta at autopsy. Four hundred different sites, 4 mm in diameter each, corresponding to the dimension of the ultrasonic beam at the focal zone, were ultrasonically analyzed and histologically studied. Attenuation of ultrasound in each site was assessed by Fourier analysis of the echo produced by a specular reflector placed behind the specimen. Two parameters were measured over the range 7-11 MHz: the integrated attenuation index (per cm), and slope (per cm per MHz) of the best fit straight line relating attenuation and frequency. Histological examination--performed for each of the 400 sites where attenuation had been measured--identified four subsets (100 samples each): normal aortic walls, fibrous plaques, fibrofatty plaques, and calcified plaques. Results obtained from ultrasonic and histological analyses showed that the integrated attenuation index was lowest in normal walls (24 +/- 2.1, mean +/- SE) and progressively increased in fibrous (32 +/- 3.1), fibrofatty (82 +/- 6.5), and calcific (185 +/- 8.7) subsets (all intergroup differences were significant, except for the normal vs. fibrous comparison). The slope value was significantly lower in the fibrous than in the normal subsets: (10(-3)) 31.9 +/- 4.5 vs. (10(-3)) 99.5 +/- 9.1, respectively. Values of fibrofatty and calcific plaques overlapped: (10(-3)) 383 +/- 21 vs. (10(-3)) 320 +/- 23, respectively. Both were significantly different from normal and fibrous groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗
PubMed1984

Echocardiographic evaluation of cardiovascular effects of amrinone.

Amrinone, a new inotropic drug, was infused at a dosage of 2.5 mg/kg body weight in 14 patients affected by dilatative cardiomyopathy in New York Heart Association (NYHA) functional class III and IV. Cardiac index, mean arterial pressure, and some echocardiographic parameters were evaluated. Cardiac index (CI) increased from 2.03 +/- 0.24 to 2.82 +/- 0.43 1/min/m2 (p less than 0.001). Fractional shortening (FS) increased from 16.4 +/- 5.2 to 21.5 +/- 5.3% (p less than 0.05). End-diastolic and end-systolic diameters showed a significant reduction. Mean arterial pressure decreased from 90.7 +/- 88 to 87.3 +/- 8.4 mmHg (p less than 0.001), the end-systolic stress (ESS) decreased from 5.8 +/- 1 to 5.2 +/- 1 g/cm (p less than 0.001). Analyzing the relationship between FS and ESS, it was possible in some cases to suppose the presence of an important vasodilator effect of the drug. The afterload in 7 patients was therefore modified before and after infusion of the drug to analyze FS at the same levels of afterload. This was done to evaluate the vasodilator effect of amrinone. Examining the regression line of FS/ESS ratio it was possible to observe a predominant vasodilator effect in some patients, but in most, a sinergic action was noted. This may be useful for chronic treatment of congestive heart failure, reducing amrinone doses, and using it in association with other vasodilator drugs.

Adult↗
PubMed1984

Unreliability of conventional visual electrocardiographic monitoring for detection of transient ST segment changes in a coronary care unit.

Visual monitoring at the central station of coronary care units (CCUs) may not adequately assess the presence and frequency of transient asymptomatic ST segment changes in patients with unstable angina. We have performed continuous 24-h electrocardiographic recordings over a total period of 50 days in 10 patients admitted to our CCU with frequent attacks of angina at rest. Over the corresponding period, at the central monitoring station (6 beds), the nursing-staff detected only 31 transient ischaemic episodes (27 with ST elevation, 4 with depression, 9 of which were asymptomatic). By contrast the retrospective analogue analysis of tapes identified 213 ischaemic episodes: 143 with ST elevation (greater than or equal to 0.2 mV) and 70 with ST depression (greater than or equal to 0.2 mV); usual CCU monitoring failed to report changes during 13 episodes (8 with ST elevation, 5 with depression) accompanied by anginal pain. When the tapes were played back in real time on a CCU monitoring scope, a cardiologist (who had the option of interrupting the play-back whenever tired) recognized 48% of the episodes when presented in groups of 4 and randomly positioned on the screen together with 2 other electrocardiographic tracings not related to the study; he recognized 92% of the episodes when only one ECG was presented on the screen. Thus conventional visual monitoring in a CCU considerably underestimates the incidence of transient ischaemic ST segment changes, some of which were accompanied by pain. This low rate of detection is the result of the presentation on the central monitoring station of several ECGs and of fatigue.

Adult↗
PubMed1984

An electronic "diaphragm" for the gamma camera, with adjustable zooming and offset.

We describe a new device for data acquisition from a gamma camera using an electronic spatial "diaphragm," with variable offset and zooming. The device, mainly applied to cardiac studies, permits selection of the desired part of the field of vision to be digitized and to zoom, before the computer acquisition. The spatial diaphragm spans 0.4-0.9 of the diameter of the FOV, and the amplification factor from 1.1 to 2.5.

Computers↗
PubMed1984

Regional myocardial performance before, during and after coronary occlusion.

The effects of transient coronary occlusion upon segment length and intramyocardial pressure were studied in seven open-chest dogs. The subendocardial and subepicardial layers in the territory of the left anterior descending coronary artery were instrumented with pairs of ultrasonic crystals and miniature pressure probes. During coronary occlusion, systolic subendocardial pressure decreased from 194 +/- 11 to 141 +/- 12 mmHg (p 0.001) and systolic subepicardial pressure from 82 +/- 7 to 62 +/- 12(p 0.05). Systolic shortening was abolished in both layers. During reperfusion, systolic subendocardial pressure reached 242 +/- 22 mmHg (p 0.05) and systolic subepicardial pressure 100 +/- 10 mmHg (p 0.05). Early during reperfusion a transient overshooting was also observed in subendocardial and subepicardial systolic shortening. The observations of this study are consistent with the hypothesis that unrestricted reperfusion is associated with an overshooting in regional myocardial contractile performance.

Animals↗