Biomedical subjects

E Picano

Publications and source records attributed to E Picano.

At least 181 records · Page 10Linked to original sources

PubMed1989

Transmitral flow changes during dipyridamole-induced ischemia. A Doppler-echocardiographic study.

Myocardial ischemia results in altered left ventricular (LV) diastolic compliance, reflected by an abnormal mitral inflow pattern on Doppler echocardiography. To investigate the relationship of Doppler echocardiography and regional myocardial systolic function during dipyridamole infusion, we evaluated transmitral flow changes detected by pulsed Doppler technique during a high-dose dipyridamole echocardiography test (DET, two-dimensional echo monitoring with dipyridamole infusion, up to 0.84 mg/kg over 10 min). The DET response produced two groups: group 1 (34 patients) with negative DET, and group 2 (35 patients) with positive DET, defined as the development of a newly onset LV regional asynergy. The E/A values overlapped at baseline (1.07 +/- .32 vs .92 +/- .22; p = NS) but differed at peak changes (.92 +/- .26 vs. 75 +/- .25; p less than .01). Heart rate changes could not account for the observed Doppler changes, since the values of R-R interval were similar in the groups, both basally (.927 +/- .226 vs .867 +/- .143 s; p = NS) and at peak dipyridamole (.754 +/- .100 vs. 681 +/- .112; p = NS). Transient myocardial ischemia induced by dipyridamole administration is accompanied by changes in transmitral flow, which consist of an increase in the relative atrial contribution to LV filling, possibly owing to an acute impairment in LV relaxation.

Adult↗

PubMed1988

Aminophylline termination of dipyridamole stress as a trigger of coronary vasospasm in variant angina.

Dipyridamole testing represents an alternative to exercise stress testing for documentation of ischemia related to coronary artery disease (CAD). In such a case, ischemia is attributed to maldistribution of coronary flow during dipyridamole-induced vasodilation. The present study evaluated the potential role of dipyridamole testing in producing ischemia through a vasospastic mechanism, following rapid withdrawal of vasodilation induced by aminophylline. The possibility was tested in 36 in-hospital patients with variant angina pectoris who underwent dipyridamole infusion (up to 0.84 mg/kg over 10 minutes) with continuous 12-lead electrocardiographic and 2-dimensional echo monitoring. Medications were withdrawn from all patients. The test was pharmacologically stopped with the dipyridamole antidote (aminophylline, 80 to 240 mg intravenously over 1 to 3 minutes) in all patients. Two to 6 minutes after starting aminophylline infusion, 10 patients (28%) developed (greater than 0.10 mV) ST-segment elevation (2.9 +/- 0.8 mm from baseline), always accompanied by obvious asynergy detected by echocardiography, in the same electrocardiographic leads showing spontaneous or ergonovine-induced ST-segment elevation. Nitrates promptly resolved ischemia in all patients. At coronary angiography, 5 of these 10 patients showed significant CAD (greater than 70% lumen diameter reduction of at least 1 major coronary artery), whereas 5 had nonsignificant CAD. The rate pressure product at the onset of ST-segment elevation (after dipyridamole plus aminophylline) was considerably less than that recorded at peak exercise stress test in these patients (9,600 +/- 2,200 vs 18,400 +/- 4,900, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

Usefulness of the dipyridamole-exercise echocardiography test for diagnosis of coronary artery disease.

To test the hypothesis that a dipyridamole infusion might sensitize the myocardium to exercise-induced ischemia, 33 patients with effort chest pain syndrome--including 24 with and 9 without angiographically documented coronary artery disease (CAD)--and 10 control subjects were studied. As inclusion criterion, all enrolled subjects had a negative resting high-dose dipyridamole-echocardiography test result for both mechanical (development of a transient asynergy) and electrocardiographic (greater than 0.1 mV ST-segment shift) changes. All performed 2 supine exercises during 2-dimensional echocardiography and 12-lead electrocardiography monitoring, immediately after high-dose (0.84 mg/kg over 10 minutes) dipyridamole (dipyridamole-exercise stress test) or placebo (exercise stress test) infusion. The overall sensitivity (by electrocardiographic, echocardiographic or combined criteria) for CAD detection was 10 of 24 for exercise stress test and 21 of 24 for dipyridamole-exercise stress test (42 vs 88%, p less than 0.01). The specificity was 19 of 19 for exercise stress test and 18 of 19 for dipyridamole-exercise stress test (100 vs 95%, difference not significant). Both exercise stress test and dipyridamole-exercise stress test yielded negative results in the 10 control subjects, with a similar peak rate-pressure product (X 1/100) reached in the 2 tests (287 +/- 55 vs 274 +/- 42, difference not significant). Eight patients (all with significant CAD) had positive results of their exercise stress test and all 8 had also positive dipyridamole-exercise stress test results, at a significantly lower rate-pressure product with respect to the exercise stress test (253 +/- 49 vs 204 +/- 35, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

High dose dipyridamole-echocardiography test in women: correlation with exercise-electrocardiography test and coronary arteriography.

The value of the exercise-electrocardiography test in detecting coronary artery disease in women is limited. Recently, the high dose dipyridamole-echocardiography test (two-dimensional echocardiographic monitoring during intravenous dipyridamole infusion, up to 0.84 mg/kg body weight over 10 min) was proposed as an alternative to exercise testing for the diagnosis of coronary artery disease. To establish the diagnostic usefulness of the exercise-electrocardiography and dipyridamole-echocardiography tests in this disease, the two tests were performed--on different days and in random order--in 83 consecutive women evaluated for a chest pain syndrome. All 83 women had taken no medications for greater than 48 h, and 15 had had a previous myocardial infarction. Positivity of the dipyridamole-echocardiography test was based on detection of a transient asynergy of contraction that was absent or of lesser degree at rest; the exercise-electrocardiography test (by upright cycloergometer) was considered positive when the ST segment was shifted greater than 0.1 mV 0.08 s after the J point. Coronary angiography showed significant coronary artery disease (greater than 70% luminal reduction of at least one major coronary vessel) in 39 women. No significant complications occurred in any patient during either test. Sensitivity and predictive value of a negative test were similar for the dipyridamole-echocardiography and the exercise-electrocardiography test (79 versus 72% and 84 versus 68%, respectively, whereas the dipyridamole-echocardiography test had greater specificity (93 versus 52%, p less than 0.001), accuracy (87 versus 62%, p less than 0.001) and a higher predictive value of a positive test (91 versus 57%, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

Short term reproducibility of exercise testing in patients with ST segment elevation and different responses to the dipyridamole test.

The short term reproducibility of exercise testing in 25 patients who had exercise induced ST segment elevation without baseline regional asynergy or a previous myocardial infarction, who had different responses to the dipyridamole test, was assessed. The patients performed a dipyridamole echocardiography test and a second exercise stress test. All underwent coronary arteriography. Seventeen patients had transient regional asynergy after dipyridamole (group 1) and either ST segment elevation (14 patients) or depression (three patients); a second group of eight had no asynergy and no electrocardiographic changes (group 2). The repeated exercise stress test was positive in 16 of the 17 patients of group 1 (11 with ST elevation and five with ST depression) and in two patients of group 2 (both had ST depression and one had coronary artery disease). The dipyridamole echocardiography test was positive in 17 of the 19 patients with coronary artery disease and was negative in all six patients without coronary artery disease. The repeated exercise stress test was positive in 17 of the 19 patients with coronary artery disease and in one patient without. The dipyridamole echocardiography test and a repeated exercise stress test, but not a single exercise stress test, identified coronary artery disease causing exercise induced ST segment elevation.

Adult↗

PubMed1988

Time domain echo pattern evaluations from normal and atherosclerotic arterial walls: a study in vitro.

The aim of this study in vitro of human fresh specimens was to quantitatively evaluate the contribution of the aqueous phase-intima interface (the first 400 msec of the reflected signal) in normal and atherosclerotic arterial walls. Seventy-five samples were studied, 15 normal, 15 fatty, 15 fibrofatty, 15 fibrous, and 15 calcific. A broadband transducer (4 to 14 MHz) was used. The aqueous phase-intima reflection (expressed in dB, mean +/- SD) was lowest in the fatty plaques (-35.3 +/- 2.5), differing in a highly significant way from that in all other groups: normal (-13.2 +/- 8.8), fibrofatty (-20.4 +/- 8.3), fibrous (-13.0 +/- 9.7), calcific (-5.9 +/- 3.4). The echo coming from the intima-media transition was of relatively low amplitude in normal and in fatty samples; typically, strong reflections from the intima-media transitions were present in the other pathologic subsets. In conclusion, the time domain echo pattern of the arterial wall may provide a useful clue to the structure of the plaque.

Aorta↗

PubMed1988

Dipyridamole echocardiography in essential hypertensive patients with chest pain.

The exercise-electrocardiography test shows limited feasibility and diagnostic accuracy for the noninvasive detection of coronary artery disease in hypertensive patients. Recently, the dipyridamole-echocardiography test (two-dimensional echocardiographic monitoring with dipyridamole infusion, up to 0.84 mg/kg over 10 minutes) has been proposed as an exercise-independent method for the diagnosis of coronary artery disease. The diagnostic usefulness of the exercise-electrocardiography test and the dipyridamole-echocardiography test was evaluated in 63 consecutive inpatients with history of chest pain, essential hypertension, and no previous myocardial infarction. The criterion of positivity for the exercise-electrocardiography test was a horizontal or downsloping ST segment shift exceeding 0.1 mV and for the dipyridamole-echocardiography test, a transient dyssynergy of contraction. Fifteen patients could not perform a diagnostic exercise-electrocardiography test because of an inability to exercise adequately (two patients), severe hypertension in spite of full antihypertensive therapy (six patients), or excessive blood pressure rise at the first step of the exercise-electrocardiography test (seven patients). Five patients could not perform the dipyridamole-echocardiography test because of a poor acoustic window. The overall feasibility was 76% for the exercise-electrocardiography test and 92% for the dipyridamole-echocardiography test (p less than 0.05). All 43 patients who performed both tests underwent coronary angiography; 30 had significant coronary artery disease (greater than 70% lumen reduction of at least 1 major coronary vessel). Sensitivity was 67% for both the exercise-electrocardiography test and the dipyridamole-echocardiography test (p = NS); specificity was 46% for the exercise-electrocardiography test and 92% for the dipyridamole-echocardiography test (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗

PubMed1987

Usefulness of a high-dose dipyridamole-echocardiography test for diagnosis of syndrome X.

This study assesses whether the high-dose dipyridamole-echocardiography test (DET, 2-D echocardiographic and 12-lead electrocardiographic monitoring during dipyridamole infusion, up to 0.84 mg/kg over 10 minutes) can help to identify patients with syndrome X. DET was performed in 10 control subjects (group A) and in 19 patients with syndrome X (group B). Patients in group B had chest pain on effort, a positive exercise stress response (more than 0.1 mV of ST-segment depression), negative ergonovine test response and normal left ventricular function and coronary angiographic findings. During DET no subject in group A showed transient asynergy or ST-segment depression and none had chest pain; in group B, no patient had transient asynergy, 13 (68%) had chest pain and 16 (84%) had more than 0.1 mV of ST-segment depression. Percent fractional shortening was not significantly different in the 2 study groups, either basally (group A, 35 +/- 7; group B, 37 +/- 8) or at peak hyperkinesia during DET (group A, 48 +/- 8; group B, 54 +/- 10). Thus, dipyridamole-induced chest pain and ST-segment depression in patients with syndrome X are not associated with impaired regional or global left ventricular function. This entity of echocardiographically silent myocardial ischemia during DET may be a clue to noninvasive detection of syndrome X.

Adult↗

PubMed1987

Comparison of the high-dose dipyridamole-echocardiography test and exercise two-dimensional echocardiography for diagnosis of coronary artery disease.

Fifty-five patients with effort angina pectoris and technically satisfactory baseline echocardiograms performed a supine exercise-echocardiography test (EET) and a high-dose dipyridamole-echocardiography test (DET, up to 0.84 mg/kg of intravenous dipyridamole in 10 minutes). All underwent coronary arteriography, which showed that at least 1 major artery had more than 70% stenosis in 34 patients. For each patient, the same physician performed both tests, with the same echocardiographic equipment. Detection of new onset or worsening regional asynergy was the only criterion of positivity for both tests. DET yielded interpretable studies in all 55 patients (100%); EET yielded only 40 such studies (73%) (p less than 0.01). In the 40 patients in whom both tests were interpretable, DET showed, compared with EET, a similar sensitivity (72% vs 76%) and specificity (100% vs 87%) (difference not significant for both) for detecting angiographically assessed coronary artery disease. In the 16 patients in whom both DET and EET yielded positive responses for ischemia, the same myocardial region showed reversible asynergy. Thus, independent of all factors that can affect the performance of each test (operator, patient and instrumentation), DET was significantly more feasible than EET, with comparable sensitivity and specificity. Dipyridamole provokes asynergy in the same regions that show ischemia during exercise.

Adult↗

PubMed1987

Different degrees of ischemic threshold stratified by the dipyridamole-echocardiography test.

Dipyridamole-echocardiography (echo) testing, exercise stress testing and coronary arteriography were performed in 141 patients with effort chest pain. Patients were separated into 5 groups according to the dose of dipyridamole needed to induce ischemia (0.56 mg/kg over 4 minutes vs 0.84 mg/kg over 10 minutes) and to the time of onset of the asynergy with the small dose (within vs beyond 3 minutes after the end of dipyridamole administration): group 1--early positive response to a small dose (33 patients); group 2--late positive response to a small dose (29 patients); group 3--negative response to a small dose, positive response to a large dose (17 patients); group 4a--negative response to both large and small doses, with significant coronary artery disease (CAD) (32 patients); and group 4b--negative response to small and large doses, without CAD (30 patients). All patients in groups 1, 2 and 3 had significant CAD. The rate-pressure product on exercise stress testing was measured at 0.10 mV of ST-segment shift in patients with a positive response and at peak exercise in patients with a negative response. Rate-pressure product significantly separated group 1 and group 2 from each other (157 +/- 46 and 229 +/- 33 mm Hg X beats/min X 1/100, respectively, mean +/- standard deviation) and from group 3, group 4a and group 4b (284 +/- 40, 290 +/- 51, and 298 +/- 45 mm Hg X beats/min X 1/100); values in the 3 latter groups overlapped.2+ Thus, the dipyridamole-echo test can stratify groups of patients with different levels of ischemia threshold on effort.

Adult↗

PubMed1987

Does the combination with handgrip increase the sensitivity of dipyridamole-echocardiography test?

The aim of this study was to assess the possibility of increasing the sensitivity of dipyridamole-echocardiography testing (DET:2-D echo monitoring during dipyridamole infusion) by combining this procedure with handgrip testing. Dipyridamole-handgrip test (DHT) was therefore performed in 24 patients with rest/effort angina, negative DET, and negative handgrip-echo (without dipyridamole pretreatment). DHT consisted of 4.5 min of sustained 25% maximum grip strength, started 4 min after the end of dipyridamole infusion (0.56 mg/kg for 4 min). Interpretable studies were obtained in all patients. Of the 24 patients tested (10 without and 14 with significant coronary artery disease, CAD), only one CAD patient had a positive DHT, which indicates an increased sensitivity of 7% versus DET alone. In conclusion, DHT is feasible in all patients and--if compared to DET--has the same specificity. However, in spite of the theoretical premises, it provides only a modest step up in sensitivity.

Angina Pectoris↗

PubMed1987

Short-term reproducibility of dipyridamole-echocardiography test.

The aim of this study was to assess the short-term reproducibility of dipyridamole-echocardiography test (DET) consisting of two-dimensional echo monitoring during dipyridamole infusion (up to 0.84 mg/kg in 10 min). The diagnostic end-point of the test is the detection of new onset or worsening regional asynergy. A group of 87 patients with rest and/or effort angina performed two DETS on two consecutive days. All 60 patients with a positive DET had a positive repeat test, and the 27 negative DETs were also negative on the following day. The timing of the asynergy was also very similar between the two tests, both in patients with angina on effort (r = .93, p less than 0.01) and at rest (r = .92, p less than 0.01). In conclusion, DET has a very high short-term reproducibility regarding the presence and timing of asynergy.

Angina Pectoris↗

PubMed1987

In vitro identification of different degrees of mitral valve disease by online evaluation of radiofrequency ultrasound signal.

Sixty five mitral valves were studied in vitro with a 2.25 MHz transducer. Radiofrequency signals were analysed by a microprocessor system (implemented on an M-mode commercially available echocardiography) for online evaluation of ultrasonic backscatter (8 bits of amplitude resolution, 40 MHz sampling rate, 1 microsecond acquisition gate). The integrated value of the rectified signal amplitude was expressed as the integrated backscatter index (in db). The highest value recorded with ultrasonic scanning of each sample was taken as representative of that specimen. Calcification of mitral valves was assessed by radiography (24 mitral valves). Non-calcified mitral calves underwent pathological examination, and fibrotic valves (22 mitral valves) were differentiated from normal valves (19 mitral valves). A statistically significant (p less than 0.005) difference was recorded among the three groups for the index maximal value: calcific -7.4(3.1) db (mean(SD)), fibrotic -18.9(4.9) db, and normal -37.9(7.6) db. In conclusion, a microprocessor based system for online evaluation of radiofrequency ultrasonic signals, which may also be feasible for in vivo studies, provided a clear differentiation in vitro of calcific, fibrotic, and normal mitral valves.

Calcinosis↗

PubMed1987

Dipyridamole-echocardiography test as a clue for assessing the organic 'ceiling' of individual coronary reserve.

Twenty-four patients with a history of effort angina, a positive exercise stress test (EST) and coronary artery disease were enrolled in the study; 12 patients had a positive dipyridamole-echocardiography test (DET) and 12 had a negative DET. Each patient performed a total of 4 ESTs in the absence of therapy on two successive days; for each test the rate-pressure product (RPP), an established index of myocardial oxygen demand, was measured at the onset of ischaemia (ST depression greater than 0.15 mV) or at the peak of maximal exercise (if a repeated EST was negative). Taking into account the lowest of the 4 RPP values (X 1/100) in each patient, there was no significant difference between DET-negatives and DET-positives (185.2 +/- 49.3 vs 157.4 +/- 32.4). Conversely, when considering the highest of the 4 RPP values in each patient, there was a significant difference between DET-negatives and DET-positives (280.3 +/- 63.9 vs 183.3 +/- 37.0; p less than 0.01). Thus, DET may provide a clinically useful tool for assessing in the individual the organic 'ceiling' of coronary reserve, by eliminating the variability in coronary tone, which may affect EST reproducibility and the correct evaluation of the impairment of organic coronary reserve.

Adult↗

PubMed1986

Role of dipyridamole-echocardiography test in electrocardiographically silent effort myocardial ischemia.

A frequent clinical problem is documentation of the elusive entity of "electrocardiographically silent" effort myocardial ischemia. In this study, 83 patients with angina on effort and either negative or nondiagnostic exercise stress test results underwent a dipyridamole-echocardiography (echo) test, a feasible and useful tool for detection of coronary artery disease (CAD). The dipyridamole-echo test (2-dimensional echocardiographic monitoring combined with intravenous dipyridamole infusion at a maximal dosage of 0.84 mg/kg over 10 minutes) and coronary arteriography were performed in all patients. Positivity of dipyridamole-echo test was based on the detection of regional transient asynergy of contraction. At coronary arteriography, 50 of the 83 patients had significant (more than 70% diameter reduction) CAD: 27 had 1-vessel, 17 had 2-vessel and 6 had 3-vessel CAD. Interpretable echocardiograms were recorded in all the patients studied. The dipyridamole-echo test results were positive in 27 of the 50 patients (54%) with CAD. No patient without CAD had a positive test result. In conclusion, the dipyridamole-echo test frequently unmasks electrocardiographically silent effort myocardial ischemia by providing objective mechanical evidence of the ischemic event.

Adult↗

PubMed1986

Dipyridamole-echocardiography test in patients with exercise-induced ST-segment elevation.

Fourteen consecutive patients with exercise-induced ST-segment elevation in the absence of previous infarction and basal left ventricular asynergy at rest performed a dipyridamole test (infusion of dipyridamole, 0.14 mg/kg/min intravenously for 4 minutes) during 12-lead electrocardiographic (ECG) and 2-dimensional echocardiographic monitoring. In 7 of the 14 patients, dipyridamole infusion consistently induced ST-segment elevation in the leads that showed ST elevation on effort; reversible asynergy (occurring in the region corresponding to the ECG leads with diagnostic changes) could always be documented by echocardiography. In 2 patients dipyridamole induced reversible asynergy in presence of ST-segment depression. In these 9 patients angiography invariably revealed a severe organic stenosis in the coronary artery feeding the region that became transiently asynergic after dipyridamole. In the other 5 patients (all of whom had either spontaneous or ergonovine-induced ST-segment elevation), the dipyridamole test yielded no significant echocardiographic or ECG change; coronary angiography showed absent (2 patients) or significant (3 patients) coronary artery disease. In conclusion, dipyridamole may induce transmural ischemia in humans, as detected by the electrical hallmark of ST elevation; this ECG pattern, in contrast to ST depression, reliably predicts the presence and site of transient regional asynergy. When dipyridamole induces ST-segment elevation, severe basal stenosis is invariably present in the coronary artery supplying the transiently asynergic myocardial region.

Adult↗

PubMed1986

Dipyridamole-echocardiography test in angina at rest: noninvasive assessment of coronary stenosis underlying spasm.

In a previous study performed in patients with effort angina pectoris, we showed that the dipyridamole-echocardiography test (DET) is feasible and useful for the detection of coronary artery disease. The positivity of the test (consisting of two-dimensional echocardiography [2 DE] combined with dipyridamole infusion [0.14 mg/kg/min for 4 minutes]) is linked to the appearance of regional asynergy. In the present study, DET and exercise stress test (EST) were performed in 62 patients with angina at rest in the active phase. The overall sensitivity of DET and EST for the detection of coronary artery disease was 62% and 83%, respectively (p less than 0.05); the specificity of DET and EST was 100% and 64%, respectively (p less than 0.05). In 10 DET-positive patients, a spontaneous attack was also monitored by 2DE; the myocardial wall involved by ischemia was invariably the same both in patients with spontaneous and in those with dipyridamole-induced ischemia. Thus, in our population of patients with angina at rest (in whom an important functional component is also likely to be present during exercise), DET was significantly less sensitive but significantly more specific than EST in detecting coronary artery disease.

Adult↗

PubMed1986

Evaluation of frequency dependence of backscatter coefficient in normal and atherosclerotic aortic walls.

For five groups of aortic specimens (normals and with different degrees of atherosclerosis) the ultrasonic backscatter coefficient was measured as a function of frequency in the range 4-15 MHz. The results of the study are related to two classes of structure, connective and fatty tissue (whose relative amount in the arterial wall is related to the different stages of atherosclerosis), as the main determinants of the scattering from aorta. The structure of connective tissue in the aorta produces a power law frequency dependence of the backscatter coefficient typical of small scale structures (Ka much less than 1). Fatty tissue introduces a frequency dependence of the backscatter coefficient typical of structures of intermediate scale (Ka approximately equal to 1). Biochemical composition and structure of normal and atherosclerotic aorta therefore, specifically affect the employed acoustical parameter.

Aorta↗