Biomedical subjects

A Distante

Publications and source records attributed to A Distante.

At least 73 records · Page 4Linked to original sources

PubMed1991

Monitoring of cardiac output during exercise in coronary patients: a Doppler study.

The monitoring of aortic blood flow velocities by transcutaneous continuous-wave Doppler was performed in 45 patients to determine, non-invasively, the haemodynamic response to exercise in subsets of coronary patients during a multistage supine exercise tests. Group I consisted of 14 patients with ischaemia on effort (IE); group II, 12 patients with both IE and prior myocardial infarction (MI); group III, 19 patients with MI and no IE; there were also 12 normals. Peak flow velocity (PV) indices of cardiac output (CO), of peripheral resistance (PR) and of stroke work (SW) were measured every min. Resting CO was lower and PR higher in coronary patients than in normals. With exercise, for the same muscular work, CO increased less in IE patients (group I: y = 26.9 + 1.8 x cm sec-1; Group II: y = 21.9 + 1.8 x cm sec-1) than in MI (group III: y = 26.6 + 2.1 x cm s-1) and in normals (y = 35 + 2.7 x cm s-1) and PR decreased less. This suggested a more efficient distribution of CO towards working muscles. A shallower increase in SW was observed in all coronary patients in comparison with normals even if resting SW was significantly lower only in patients with MI (groups II and III). PV increased up to peak exercise only in group III, while it tended to plateau in ischaemic patients even earlier than IE occurred on the ECG.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

[The diagnostic and prognostic value of echo-dipyridamole in patients with suspected coronary disease: a comparison with the stress test].

The aim of the study was to assess the relative diagnostic and prognostic accuracy of high-dose dipyridamole echocardiography test (DET: 2D-echo monitoring during dipyridamole infusion up to 0.84 mg/kg over 10') vs maximal symptom limited bicycle exercise electrocardiography test (EET) in patients with chest pain addressed to coronary angiography. We initially considered 477 consecutive patients, meeting the following inclusion criteria: 1) history of chest pain; 2) off antianginal therapy; 3) no previous myocardial infarction and/or obvious regional left ventricular dyssynergy of contraction. All patients were submitted to a DET and EET--on different days and in random order--within 1 week of coronary angiography (which was performed independently of test results). DET could not be performed in 32 patients for a poor acoustic window in resting conditions (n = 31) or for asthmatic disease requiring xanthine therapy (n = 1); EET could not be performed in 54 patients for inability to exercise, or resting electrocardiographic abnormalities making the EET interpretable. The overall feasibility was of 445/477 for DET and 423/477 for EET (93 vs 89%, p = ns). Criteria for positivity were: transient regional dyssynergy absent in the baseline examination for DET; ST segment shift greater than .15 m V from baseline for EET. Angiographically assessed coronary artery disease (CAD) was considered present when a luminal reduction greater than or equal to 50% occurred in at least 1 major coronary vessel. There were 135 pts with no significant CAD and 256 with CAD; 137 had single, 70 double, 49 triple and/or left main (15) vessel disease. The specificity was higher in DET vs EET (96 vs 59%, p less than .01). The overall sensitivity of DET was similar to EET (67 vs 69%, p = ns), with no significant differences in the subset with single (56 vs 63%, p = ns), double (74 vs 69%, p = ns) or triple (88 vs 86%, p = ns) vessel disease. Patients were followed-up for 26 +/- 22 (range 1 to 73) months considering only death and myocardial infarction as end-points. A Cox stepwise survival analysis identified the Wall Motion Score Index (an integrated semiquantitative measure of extent and severity of the dyssynergy) at peak dipyridamole as the most powerful prognostic predictor (X2 = 18.5, p less than 0001) of all invasive (number of stenotic coronary vessels, X2 = 5.8, p less than .05) and noninvasive (exercise electrocardiography positivity, p = ns) parameters.(ABSTRACT TRUNCATED AT 400 WORDS)

Coronary Angiography↗

PubMed1991

Dipyridamole-echocardiography in coronary artery disease.

Regional wall motion impairment incurred by means of dipyridamole-induced ischemia, is regarded with higher sensitivity and specificity than the conventional findings in the ECG. Based on the latter considerations, a new test, the dipyridamole echocardiogram has been introduced in which the development of regional wall motion impairment is designated as the positive diagnostic criterion. Dipyridamole is a vasodilator of coronary arterioles. During the course of the examination, three consecutively occurring mechanisms are considered responsible for the appearance of dipyridamole-induced ischemia in the presence of coronary stenosis. The ischemia is initially attributed to a steal-effect, then to reflex-induced rise in rate-pressure product and, lastly, to a vasospastic component. In 680 patients with thoracic pain, on use of 0.84 mg/kg over ten minutes, there was a sensitivity of 74% in detection of angiographically-documented coronary artery disease, defined as greater than 70% stenosis in at least one major coronary artery, and a specificity of 95%. The onset of regional wall motion impairment after dipyridamole infusion was correlated with the severity of the disease, the localization of the wall motion impairment enabled delineation of the localization of the stenosis in the coronary vascular system. By means of the dipyridamole echocardiogram, the effectiveness of therapeutic measures such as PTCA, ACVB, medical antianginal treatment and thrombolysis can be assessed. Lastly, the dipyridamole echocardiogram provides important information with regard to prognosis.

Coronary Disease↗

PubMed1991

Myocardial perfusion by contrast echocardiography. From off-line processing to radio frequency analysis.

In the last decade, many efforts have been made to study myocardial perfusion by contrast echocardiography. The possibility of differentiating normal from nonperfused myocardium and measuring the extent of the area at risk and myocardial infarction size has already been demonstrated. The aim of this paper is to review the approaches to quantitation of coronary blood flow by contrast echocardiography. In a series of studies, echocardiographic contrast agents have been treated like "deposit tracers." After an upstream contrast injection, myocardial contrast intensity (according to the partition principle) hypothetically reflects the fraction of contrast, and consequently of flow, distributed to the myocardium. A good correlation was found between changes in peak myocardial contrast intensity and corresponding changes in coronary blood flow (r = 0.83). However, this approach is limited by electronic signal distortion and attenuation artifacts. In other studies contrast agents have been treated as intravascular "free-passing" tracers, and (according to the dilution principle) their myocardial transit times hypothetically reflect coronary blood flow. A prolonged myocardial washout halftime with coronary underperfusion has been documented in animal experiments and patients with severe coronary stenosis. However, the majority of contrast agents have intermediate characteristics and do not belong to either category of tracers; furthermore, signal distortion and attenuation phenomena affect the washout phase. The time of myocardial contrast appearance, which is independent of tracer characteristics, permitted the differentiation of baseline conditions from coronary underperfusion but seemed inaccurate in the quantitation of coronary blood flow (r = 0.60).(ABSTRACT TRUNCATED AT 250 WORDS)

Contrast Media↗

PubMed1990

In vivo identification of mitral valve fibrosis and calcium by real-time quantitative ultrasonic analysis.

Conventional echocardiography provides fundamental information about mitral valve morphology and function but has a relatively low specificity in evaluating valve calcific deposits, which is critical information for the preoperative decision to perform commisurotomy or replacement. In vitro radiofrequency ultrasonic quantitative analysis of the mitral valve has been demonstrated to be a reliable tool in identifying normal, fibrotic and calcific valves. This study evaluates quantitative ultrasound characterization of the mitral valve in vivo. Thirty-three patients, scheduled to undergo mitral valve replacement, and 20 normal subjects (10 young and 10 older control subjects) were studied with a 2.25-MHz transducer. Radiofrequency signal was analyzed by a microprocessor system (used with an M-mode commercially available echocardiograph) for on-line evaluation of ultrasonic backscatter with 8 bits of amplitude resolution, 40-MHz sampling rate and a 1-microsecond acquisition gate. The integrated value of the rectified radiofrequency signal amplitude was deemed the integrated backscatter index. The highest value recorded with the ultrasonic analysis from each valve was taken as representative and expressed as the percent value with respect to the pericardial integrated backscatter index value of that subject. The 33 excised mitral valves underwent histologic examination. Four groups were identified: young controls (group I, n = 10); older controls age-matched with patients (group II, n = 10); patients with fibrotic mitral valves (group III, n = 13); and patients with calcific mitral valves (group IV, n = 20).(ABSTRACT TRUNCATED AT 250 WORDS)

Calcinosis↗

PubMed1990

Electrocardiographic changes suggestive of myocardial ischemia elicited by dipyridamole infusion in acute rejection early after heart transplantation.

Acute cardiac rejection, syndrome X, and arterial hypertension can induce small vessel damage and, therefore, restriction of coronary reserve in the presence of normal epicardial coronary arteries. A characteristic response pattern to dipyridamole (DIP) infusion has been previously described in syndrome X and arterial hypertension: ST segment depression without any measurable systolic dysfunction. The aim of this study was to establish whether acute cardiac rejection might induce electrocardiographic alterations during DIP infusion. Changes in the 12-lead electrocardiogram and two-dimensional echocardiogram during high-dose DIP infusion (up to 0.84 mg/kg in 10 minutes) were evaluated within 24 hours of endomyocardial biopsy in 14 transplanted patients. A total of 47 biopsy-controlled DIP studies were performed within 5 weeks after cardiac transplantation. For each patient, at least 7 days elapsed between two consecutive studies. Electrocardiographic and echocardiographic tracings were analyzed without prior knowledge of endomyocardial biopsy findings. No remarkable side effects occurred in any case, so that the DIP study could be completed in all patients. A diagnostic (greater than 0.1 mV) ST segment depression was found in 11 studies. The sensitivity and specificity of DIP-induced ST segment depression for the detection of biopsy-proven acute rejection were 72% and 94%, respectively. These data show that DIP stress is feasible and safe in transplanted patients and that acute cardiac rejection can be accompanied by DIP-induced ST segment depression without detectable impairment in systolic function. These changes might provide noninvasive markers for surveillance of rejection.

Adult↗

PubMed1990

ST segment depression elicited by dipyridamole infusion in asymptomatic hypertensive patients.

In asymptomatic patients with essential hypertension, electrocardiographic changes suggestive of myocardial ischemia can be elicited by rapid pressure lowering or by pronounced coronary arteriolar dilation. The aim of this study was to assess whether dipyridamole infusion might induce ischemic-like electrocardiographic changes in asymptomatic essential hypertensive patients and to describe the clinical and echocardiographic correlates possibly associated with this response. We therefore studied a control group of 20 normotensive individuals and a group of 28 asymptomatic patients with mild-to-moderate essential hypertension. All underwent dipyridamole-echocardiography testing (12-lead electrocardiogram and two-dimensional echocardiographic monitoring with dipyridamole infusion, 0.84 mg/kg over 10'). No patient showed transient regional dyssynergy during dipyridamole infusion. None of the normotensive and 10 of 28 of the hypertensive participants had horizontal or downsloping ST segment depression more than 0.1 mV during dipyridamole (0% versus 36%, p less than 0.01). Hypertensive patients with ("responders") (n = 10) and without ("nonresponders") (n = 18) ST segment depression showed similar values of percent fractional shortening in baseline conditions (32 +/- 5 versus 33 +/- 6, p = NS) and at peak dipyridamole infusion (45 +/- 8 versus 43 +/- 5, p = NS). The peak early to peak late velocity ratio values (evaluated from transmitral flow tracings by Doppler technique) were also similar in baseline conditions (0.86 +/- 0.14 versus 0.94 +/- 0.30, p = NS) and at peak dipyridamole (0.72 +/- 0.15 versus 0.78 +/- 0.32, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

Multiparametric approach to diagnosis of non-Q-wave acute myocardial infarction.

The present study investigated whether the lack of enzyme increase is reason enough to exclude necrosis in patients with ischemic heart disease who develop electrocardiographic sustained ST-T changes in the absence of Q waves. In 15 consecutive patients with angina who developed sustained ST-T changes during hospitalization, the presence of myocardial necrosis was investigated by a prospective multiparametric approach. Serum enzymes and myoglobin, pyrophosphate uptake, 2-dimensional echocardiography, perfusion scintigraphy, left ventriculography and coronary angiography were evaluated. According to creatine kinase and creatine kinase-MB peak at twice the upper normal value, the diagnosis of acute myocardial infarction applied only to 40% of patients. However, myoglobin was positive in 80% and a perfusion defect could be documented by an electrocardiographic gated microsphere technique in 100% of patients. The positivity of myoglobin increased to 100% and of creatine kinase and creatine kinase-MB to 87 and 60%, respectively, when a peak value twice the individual lowest value was considered for positivity. The 100% presence of perfusion defects associated with the high prevalence of both positive pyrophosphate uptake (87%) and regional dyssynergies (87 and 73%, respectively, by left ventriculography and echocardiography) strongly suggest that sustained (greater than or equal to 7 days) ST-T changes in this population were indicative of myocardial necrosis. Thus, by conventional enzymatic approach, diagnosis of non-Q-wave infarction can be missed in a sizable number of patients and present important clinical implications.

Adult↗

PubMed1989

Exercise capacity after acute aminophylline administration in angina pectoris.

Exercise-induced ischemia is generally attributed to an increase in myocardial demand in the presence of coronary stenosis limiting flow supply. An additional mechanism--the occurrence of coronary steal due to excessive endogenous adenosine release--has also been hypothesized. The effect of adenosine receptor blocking by aminophylline in effort ischemia was tested in 8 patients with stable effort-induced angina pectoris, reproducible positive exercise stress tests and angiographically assessed coronary artery disease. Following double-blind, randomized intravenous infusion of aminophylline (3 mg/kg over 3 minutes) or placebo (20 ml of saline over 3 minutes), the patients underwent upright bicycle exercise stress tests on 2 consecutive days. After aminophylline, there was an increase in work tolerance (aminophylline 7.5 +/- 1.8 minutes of exercise vs placebo 5.4 +/- 1.5 minutes; p less than 0.05). There was a parallel increase in the ischemic threshold, evaluated with the rate-pressure product (mm Hg X beats/min X 100(-2)) at 0.1 mV of ST-segment depression (221 +/- 35 vs 184 +/- 20; p less than 0.01). Thus, at a dosage that should effectively inhibit adenosine receptors, aminophylline infusion exerts a beneficial effect on exercise-induced ischemia, possibly through the prevention of myocardial flow maldistribution elicited by excessive adenosine release during effort.

Aminophylline↗

PubMed1989

Role of myocardial oxygen consumption in dipyridamole-induced ischemia.

The aim of this study was to assess whether myocardial oxygen consumption can be responsible for aminophylline resistance in dipyridamole-induced ischemia. We analyzed 163 consecutive patients who had a positive low-dose (0.56 mg/kg over 4 minutes) dipyridamole-echocardiography test, requiring intravenous aminophylline as an antidote. All patients also performed an exercise stress test. In 141 of these patients, the signs of ischemia were reversed by administration of intravenous aminophylline (group I), while the remaining 22 patients were resistant to aminophylline (240 mg/kg over 3 minutes) and received additional treatment with nitrates to relieve ischemia (group II). The increase in rate-pressure product (RPP = mm Hg x beats/min x 100) measured during the exercise stress test in the patients in group I was significantly greater than that determined during dipyridamole-induced ischemia (204 +/- 41 versus 145 +/- 33, p less than 0.01). However, the increases in RPP under both conditions were similar for the patients in group II (147 +/- 24 versus 150 +/- 20, p = ns). In patients with dipyridamole-induced ischemia who were resistant to aminophylline, the rise in myocardial oxygen consumption--probably linked to reflex sympathetic activation--might maintain ischemia independently from flow maldistribution, which should be reversed by aminophylline.

Aminophylline↗

PubMed1989

Quantitative texture analysis in two-dimensional echocardiography: application to the diagnosis of myocardial amyloidosis.

Qualitative and subjective analysis of two-dimensional echocardiographic images of the myocardial wall allows one to identify amyloid heart disease; the quantitative analysis of regional image texture might be an accurate method to differentiate normal from amyloid myocardial structures. To test this hypothesis, two-dimensional echocardiograms of nine normal subjects and six patients with histologically documented amyloid heart disease were evaluated. Quantitative texture measurements of the first order (mean gray level, skewness, kurtosis, energy and entropy) overlapped between the two groups. Among the second order statistics variables, entropy was significantly and consistently higher in amyloid versus normal patient data (septum in parasternal long-axis view: 6.3 +/- 0.3 versus 5.9 +/- 0.4; septum in apical four chamber view: 6.2 +/- 0.2 versus 5.8 +/- 0.3). Therefore, amyloid-involved myocardial walls show ultrasound image texture alterations that may be quantified with digital image analysis techniques.

Adult↗

PubMed1989

Dipyridamole-echocardiography test in essential hypertensives with chest pain and angiographically normal coronary arteries.

Microvascular angina--chest pain syndrome in the presence of angiographically normal epicardial coronary arteries and reduced flow reserve--has been described in patients with essential hypertension (EH) and linked to the development of left ventricular hypertrophy (LVH). We performed a dipyridamole-echocardiography test (DET: 2D-echo and 12 lead ECG monitoring with dipyridamole infusion, up to 0.84 mg/kg over ten minutes) in 28 essential hypertensives meeting the following inclusion criteria: (1) history of chest pain; (2) angiographically normal coronary arteries; (3) normal resting regional and global left ventricular function. A group of 12 (age- and sex-matched) normotensives with the same inclusion criteria, as well as with negative exercise stress test, was also evaluated. During DET, none of the essential hypertensives or the control group developed a regional dyssynergy of contraction. Fifteen essential hypertensives and two in the control group had a diagnostic (greater than 0.1 mV from baseline) ST segment depression on ECG tracing (54 v 17%, P less than .01); 16 essential hypertensives and two in the control group had chest pain (57 v 17%, P less than .01). None of the control group and nine of the essential hypertensives had echocardiographically assessed LVH. In the essential hypertensive group ventricular hypertrophy was present in seven of 20 patients with and in two of eight patients without dipyridamole induced chest pain and/or ST segment depression (35% v 25%, P = NS). In conclusion, essential hypertensive patients with chest pain and angiographically normal coronary arteries frequently show echocardiographically silent angina and/or ST segment depression during DET.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗

PubMed1989

Nonuniformity of the transmural distribution of coronary blood flow during the cardiac cycle. In vivo documentation by contrast echocardiography.

This study was performed to examine the transmural (endocardial vs. epicardial) heterogeneity of myocardial blood flow during the cardiac cycle (systole vs. diastole). Twenty-four contrast echocardiographic injections were performed in seven open-chest anesthetized dogs either into left anterior descending or circumflex coronary artery or into the aortic root. Two-dimensional echocardiography in short-axis view was performed and was digitized off-line into a 256 x 256 pixel matrix with 256 gray levels/pixel. All end-diastolic and end-systolic frames before and to peak contrast were analyzed. A region of interest corresponding to the most intensely opacified myocardial segment was traced, the mean videodensity measured, and the frame of initial contrast appearance detected. The region of interest was divided into three equal parallel layers corresponding to the endocardial, midcardial, and epicardial myocardium. When the echocardiographic contrast effect initially appeared in diastole, the increment in videodensity was greater for the endocardium (131 +/- 48%) than for the epicardium (71 +/- 37% of the increment in videodensity of the entire wall) (p less than 0.05). This inhomogeneity subsequently disappeared in the following end-systolic frame. When the initial echocardiographic contrast effect appeared in systole, intensity was higher in epicardium (136 +/- 83%) than in endocardium (60 +/- 60%) (p less than 0.05). However, in the following diastole, intensity was not significantly different for the two layers. Thus, myocardial contrast echocardiography demonstrates that coronary blood flow is primarily subendocardial in distribution during diastole and subepicardial during systole.

Animals↗

PubMed1989

Prognostic importance of dipyridamole-echocardiography test in coronary artery disease.

We studied the value of dipyridamole-echocardiography test in comparison with clinical, resting electrocardiogram and echocardiogram variables in predicting cardiac events occurring in 539 consecutive patients referred for dipyridamole-echocardiography test from 1984 to 1987. There were 118 cardiac events: 11 cardiac deaths, 12 nonfatal myocardial infarctions, and 95 coronary revascularization (bypass or angioplasty) procedures. A Cox survival analysis identified echocardiographic positivity after dipyridamole administration as the best predictor of cardiac events (relative risk ratio, 2.7). The next most powerful predictor was angina after dipyridamole administration (relative risk ratio, 1.9). Cardiac events occurred in 14 (6%) of 253 patients with normal high-dose dipyridamole echocardiographic test results, in 21 (26%) of 82 patients with high-dose dipyridamole echocardiographic positivity (0.84 mg/kg during 10 minutes), and in 83 (41%) of 204 patients with low-dose dipyridamole echocardiographic positivity (0.56 mg/kg during 4 minutes) (p less than 0.0001). In a subset of 341 patients, exercise electrocardiography stress test and coronary angiography were also available. A Cox survival analysis again identified echocardiographic positivity after dipyridamole as the best predictor of cardiac events (relative risk ratio, 1.9) followed by a pathologic coronary arteriography (relative risk ratio, 1.2). We conclude that the presence and timing of a transient dyssynergy during dipyridamole stress are useful predictors of subsequent cardiac events.

Actuarial Analysis↗

PubMed1989

Usefulness of high-dose dipyridamole echocardiography test in coronary angioplasty.

Seventy-four consecutive patients with angina undergoing single-lesion percutaneous transluminal coronary angioplasty were evaluated with high-dose (up to 0.84 mg/kg during 10 minutes) dipyridamole echocardiography test (DET) before angioplasty and when possible, afterward. Angioplasty was clinically or angiographically successful in 63 patients and unsuccessful in 11. Before the procedure, 69 patients had a positive DET. Of these 69 patients, six with clinicall unsuccessful angioplasty had a dipyridamole time (i.e., the time from the onset of dipyridamole infusion to development of asynergy) lower than the 63 patients with clinically successfully angioplasty (4.2 +/- 2.9 vs. 7.0 +/- 2.9 minutes, mean +/- SD, p less than 0.01). In the five patients with angiographically unsuccessful angioplasty (residual stenosis diameter, greater than 50%), coronary stenosis decreased from 89 +/- 10 to 69 +/- 22 (p = NS); DET was positive in all five before and in four of the five after the procedure (100% vs. 80%, p = NS). In the 63 patients with angiographically successful angioplasty, coronary stenosis diameter was reduced from 85 +/- 9% to 30 +/- 10% (p less than 0.01). DET was positive in 58 patients before and in only 16 after the procedure (92% vs. 25%, p less than 0.01). In the 16 patients with positive DET, before and after angioplasty, dipyridamole time increased from 5.6 +/- 2.2 before to 7.3 +/- 2.4 minutes immediately after the procedure (p less than 0.05). After an average follow-up time of 10.8 +/- 5.9 months, angina recurred in eight of 47 patients with negative DET after angioplasty and in 11 of 16 patients with positive DET (17% vs. 69%, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗

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↗