Stress echocardiography. From pathophysiological toy to diagnostic tool.
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Coronary Circulation↗
Biomedical subjects
E Picano
Publications and source records attributed to E Picano.
Normal ultrasonic myocardial reflectivity in athletes with increased left ventricular mass. A tissue characterization study.
BACKGROUND: Ultrasonic integrated backscatter of myocardial walls is directly related to the morphometrically evaluated collagen content. The integrated backscatter is also increased in hypertrophic cardiomyopathy, probably because of fiber disarray. The purpose of this study was to investigate myocardial tissue reflectivity in subjects with physiological hypertrophy caused by intense physical training and to assess the relation between the acoustic properties of myocardial tissue and left ventricular wall thickness assessed by conventional two-dimensional echocardiography. METHODS AND RESULTS: Twenty-four young male athletes (14 professional cyclists and 10 weight lifters, all in full agonistic activity) were studied together with 10 normal age-matched controls with sedentary life. By means of a commercially available two-dimensional echocardiograph, standard measurements were obtained according to the recommendations of the American Society of Echocardiography. With a prototype implemented in our Institute, an on-line radiofrequency analysis of ultrasound signals was also performed to obtain quantitative operator-independent measurements of the integrated backscatter of the myocardial walls. The integrated values of the radiofrequency signal were normalized for the pericardial interface and expressed in percent integrated backscatter (%IB). Compared with control subjects, athletes showed greater thickness values of septum (controls, 9 +/- 1; cyclists, 14 +/- 2; weight lifters, 15 +/- 1 mm, mean +/- SD; p less than 0.01) and posterior wall (9 +/- 1, 12 +/- 2, and 12 +/- 1 mm, respectively; p less than 0.01) but similar values of %IB for both septum (23 +/- 4%, 21 +/- 7%, and 23 +/- 8%, p = NS) and posterior wall (10 +/- 2%, 9 +/- 2%, and 11 +/- 2%, p = NS). In athletes, no correlation was found between septal and posterior wall thickness and the corresponding regional myocardial reflectivity (r = 0.23, p = NS and r = 0.01, p = NS, respectively). Furthermore, we compared the quantitative ultrasonic data between two subsets of 10 athletes and 10 patients with hypertrophic cardiomyopathy and similar degrees of septal thickness (16 +/- 1 versus 17 +/- 1 mm, respectively, p = NS). Septal and posterior wall %IB results were significantly higher in patients with hypertrophic cardiomyopathy (53 +/- 13% and 36 +/- 9%, respectively) than in athletes (21 +/- 7% and 10 +/- 3%, respectively; p less than 0.01 for both). CONCLUSIONS: We conclude that 1) endurance athletes show a normal pattern of quantitatively assessed ultrasonic backscatter despite of a marked left ventricular hypertrophy and 2) athletes and patients with hypertrophic cardiomyopathy and similar degrees of myocardial wall thickness can be differentiated on the basis of quantitative analysis of backscattered signal.
Adult↗
Activation of sympathetic tone during dipyridamole test.
Cardiac imaging with dipyridamole infusion has been proposed as an exercise-independent tool for the diagnosis of coronary artery disease. Dipyridamole acts through the accumulation of adenosine, which reduces sympathetic tone in vasomotor nuclei of the brainstem and inhibits norepinephrine release in noradrenergic neurons but also activates arterial chemoreceptors. The aim of this study was to assess whether dipyridamole administration (up to 0.84 mg/kg over 10 minutes, a dosage commonly employed for diagnostic testing) may modulate sympathetic activity either directly or indirectly through blood pressure reduction or myocardial ischemia, which may be evoked by dipyridamole infusion and represent two recognized sympathetic stimuli. Twenty patients were studied with infusion combined with two-dimensional echocardiography and 12-lead ECG monitoring. Blood pressure was recorded each minute by a cuff sphygmomanometer. In all patients, we obtained venous blood samples for epinephrine (an index of adrenomedullary catecholamine release) and norepinephrine (an index of neuronal activity) both in resting conditions and at peak dipyridamole, ie, at the first minute after termination of dipyridamole infusion in negative cases or in the presence of obvious ischemia in positive cases (ie, as soon as a regional ventricular dyssynergy or an ST segment depression greater than 0.1 mV appeared). Epinephrine and norepinephrine determinations were made by a high performance liquid chromatography (HPLC) method. After dipyridamole, there was a significant rise in norepinephrine, while epinephrine did not change significantly. Dipyridamole-induced percentage variations of norepinephrine from baseline were not significantly correlated with mean blood pressure changes (r = .1, p = ns) and were of a similar extent in patients with (n = 10) and without (n = 10) dipyridamole-induced ischemia (+68 vs +73 percent, p = ns). Dipyridamole administration provokes an activation of sympathetic tone which can be detected even in the absence of myocardial ischemia and is not related to blood pressure changes. The increased catecholamine release appears to be of neuronal rather than adrenomedullary origin.
Adult↗
Oral vs intravenous dipyridamole echocardiography for detecting coronary artery disease.
The usefulness of the intravenous dipyridamole-echocardiography test (12-lead and two-dimensional [2-D] echo monitoring during dipyridamole infusion) in the diagnosis of coronary artery disease recently has been suggested. However, the intravenous form of dipyridamole is not available for clinical use in some countries and therefore the administration of oral dipyridamole has been employed in combination with echocardiography. In order to evaluate the relative usefulness of the oral (300 mg of pulverized tablets) vs the intravenous (up to 0.84 mg/kg in 10 min) dipyridamole-echocardiography test, we performed the two tests, on different days and in random order, in 28 inhospital patients: 21 had coronary artery disease (seven had one-vessel disease, eight had two-vessel disease, and six had three-vessel disease); seven patients had no significant coronary artery disease. For both tests, the diagnostic end-point was the development of a transient dyssynergy of contraction. Sensitivity was 95 percent for the intravenous and 52 percent for the oral dipyridamole-echocardiography test (p < 0.01); in positive cases, the dyssynergy after the dipyridamole administration appeared at 6.5 +/- 2.5 min for the intravenous and at 27.8 +/- 12.4 min for the oral test (p < 0.01). Specificity was 100 percent for both the intravenous and oral dipyridamole-echocardiography test. One or more extracardiac side effects (headache, gastrointestinal upset, flushing, etc) occurred in 61 percent of the intravenous and 68 percent of the oral tests (p = ns). Nine patients with a positive intravenous and oral dipyridamole-echocardiography test also had a positive exercise-electrocardiography test. A significant correlation between exercise time (ie, the time from onset of exercise and 0.1 m V of ST segment shift) and dipyridamole time (ie, the time from onset of dipyridamole administration and the development of frank dyssynergy) was present for the intravenous (r = 0.6, p < 0.05) but not for the oral test. We conclude that the oral dipyridamole-echocardiography test, in comparison with the intravenous dipyridamole-echocardiography test, has a lower sensitivity and requires a substantially longer imaging time. The dipyridamole time is related to exercise time for intravenous but not for the oral dipyridamole-echocardiography test.
Administration, Oral↗
Coronary microvascular disease in hypertensives.
Arterial hypertension can badly affect coronary circulation through several mechanisms that are not mutually exclusive, namely, coronary artery disease, left ventricular hypertrophy, and microvascular disease. Theoretical and experimental data suggest that coronary microvascular disease may exist in hypertensives, in whom it can cause both a reduction of coronary flow reserve and a shift to the right of the coronary flow autoregulation curve. To address this issue, we used dipyridamole- echocardiography test, which causes ischemic-like ST segment depression with no detectable changes in left ventricular function in different subsets of patients with microvascular disease (Syndrome X; Hypertrophic cardiomyopathy; acute heart rejection). We found that dipyridamole infusion can cause a similar pattern of response (i.e., echocardiographically silent ST segment depression) in mild-moderate essential hypertensives with normal epicardial coronary arteries, without left ventricular hypertrophy, with increased forearm minimal vascular resistances and with a reduced coronary reserve. This pattern of response identifies hypertensives with higher risk of ventricular arrhythmias, is amplified by acute reduction of diastolic blood pressure and can be reversed, together with the reduction of forearm vascular resistances by chronic antihypertensive treatment. Taken together these findings suggest that microvascular coronary disease can exist in hypertensives with two adverse consequences, consistent with the experimental background: the reduction of coronary flow reserve as well as a shift to the right of the coronary flow autoregulation curve.
Coronary Circulation↗
[Prognostic value of the dipyridamole-echocardiography test immediately after a non-complicated myocardial infarct: a large scale multicenter study. Echo Persantine Italian Cooperative Study].
BACKGROUND: Any new diagnostic test should follow a pathway similar to that of a new drug, from initial studies in highly selected populations under strictly controlled conditions, up to large scale multicenter trials more likely to represent the true performance of the test in the clinical arena. AIM OF THE STUDY: To evaluate the capability of prognostic stratification of high dose (up to 0.84 mg/kg over 10') dipyridamole-echocardiography test (DET) early after an acute myocardial infarction in a "phase IV" study, based upon 11 different echocardiographic laboratories, all with established experience in stress echo and fulfilling quality control requirements for stress echo readings. STUDY POPULATION: Nine-hundred twenty five patients were evaluated after a mean of 10 days from an acute myocardial infarction and followed up for a mean of 14 months. RESULTS: During DET, one major adverse reaction occurred, consisting of a prolonged ischemia resistant to aminophylline and nitrates, and progressing to small uncomplicated reinfarction. In 11 patients the lower dipyridamole dose (0.56 mg/kg over 4') gave limiting side effects. Patients were followed up for 14 +/- 9.9 months (range = 1.53). During the follow-up, there were 34 deaths and 37 non-fatal myocardial infarctions; 104 patients developed class III or IV angina, and 149 had coronary revascularization procedures (bypass or angioplasty). Considering all spontaneous events (angina, reinfarction and death), the most important univariate predictor was the result of DET (chi-square = 45.8). With a Cox analysis, echocardiographic positivity, age and sex were found to have an independent and additive value. Considering survival (and therefore death as the only event) age was the most meaningful parameter, followed by the Wall Motion Score Index during dipyridamole (chi-square = 12.1); among other parameters, the resting Wall Motion Score Index was a significant predictor of death. By Cox analysis, age (relative risk estimate = 1.02) and Wall Motion Score Index during dipyridamole (relative risk estimate = 14) showed an independent and additional prognostic value. In particular, considering death only, the event rate was of 2% in patients with negative DET, 4% in patients with high dose positive DET and 7% in patients with low dose positive DET. CONCLUSIONS: Dipyridamole echocardiography is feasible and safe early after uncomplicated myocardial infarction and allows an effective risk stratification on the basis of the presence, severity, extent and timing of the induced dyssynergy. In particular, the risk of death doubles in patients with high dose positivity and almost quadruples in patients with low dose positivity.
Adult↗
Comparison of usefulness of high-dose dipyridamole echocardiography and exercise electrocardiography for detection of asymptomatic restenosis after coronary angioplasty.
The present study compares the relative usefulness of the maximal treadmill exercise electrocardiography test with the high-dose dipyridamole echocardiography test (echocardiographic monitoring during dipyridamole infusion up to 0.84 mg/kg in 10 minutes) in detecting severe restenosis or coronary artery disease progression (greater than 70% stenosis) in asymptomatic patients 12 months after a primary successful coronary angioplasty. Criteria of positivity were: for the exercise electrocardiography test, an ST-segment shift greater than or equal to 0.1 mV from baseline, 0.08 second from the J point; for the dipyridamole echocardiography test, a transient dyssynergy of contraction, absent or of a lesser degree than that in the baseline examination. The exercise electrocardiography and dipyridamole echocardiography tests revealed a similar feasibility (91 vs 87%, difference not significant). Both tests could be performed in 75 patients. For detection of restenosis or disease progression, or both, the exercise electrocardiography test revealed a sensitivity similar to the dipyridamole echocardiography test (71 vs 71%, difference not significant), but a lower specificity (61 vs 90%). It is concluded that the high-dose dipyridamole echocardiography test is equally feasible but more accurate than the exercise electrocardiography test for noninvasive detection of severe asymptomatic restenosis or disease progression at 1 year after successful coronary angioplasty.
Angioplasty, Balloon, Coronary↗
Stress echocardiography and the human factor: the importance of being expert.
The aim of this study was to evaluate how the diagnostic accuracy of a stress echocardiographic procedure, such as a dipyridamole echocardiography test, depends on the specific experience of the physician interpreting the test. Recordings of 50 consecutive dipyridamole echocardiographic tests were selected for the first part of the study. They were analyzed by 20 experienced echocardiographers with different backgrounds in stress echocardiography: 10 beginners (less than 20 stress studies interpreted with trained staff) and 10 experienced observers (greater than or equal to 100 stress studies performed). Diagnostic accuracy (true positive + true negative/total number of tests) versus the angiographic reference standard (greater than 70% coronary stenosis of at least one major coronary artery) was 62 +/- 6% for beginners and 85 +/- 3% for experienced observers (p less than 0.0001). In the second part of the study, 10 observers (5 beginners and 5 experienced observers) evaluated 2 different sets of 50 dipyridamole echocardiographic test studies before and after the training of the beginners. Before training, the accuracy of beginners was lower than that of experienced observers (61 +/- 7% versus 85 +/- 3%; p less than 0.001). After training, the accuracy gap was closed (83 +/- 3% versus 86 +/- 2%; p = NS). Therefore, interpretation of stress echocardiographic tests by an echocardiographer without specific training severely underestimates the diagnostic potential of this technique. One hundred stress echocardiographic studies are more than adequate to build the individual learning curve and reach the plateau of diagnostic accuracy that the test can yield.
Coronary Angiography↗
Quantitative texture analysis in echocardiography: application to the diagnosis of myocarditis.
Altered myocardial texture associated with inflammatory infiltration or fibrosis of the myocardium has already been described using qualitative and subjective analysis of two-dimensional echocardiograms. The aim of this work is to test whether quantitative analysis of regional image texture in two-dimensional echocardiograms would be an accurate method to identify myocarditis and myocardial fibrosis. A set of 20 two-dimensional studies with endomyocardial biopsy evaluation was examined in 13 patients. Biopsy-proven myocarditis was present in 8 studies; myocarditis and fibrosis in 4; fibrosis in 3; healing/healed myocarditis in 5. A control group of 8 normal subjects was also studied by echocardiography. After quantitative texture analysis of the first order, entropy appeared to consistently differentiate myocarditis from controls. Among second-order parameters, patients affected by myocarditis or fibrosis showed a decreased entropy and higher angular second moment versus controls. We conclude that myocarditis and fibrosis induce similar image texture alterations in ultrasonic images, with increased spatial heterogeneity of the gray level distribution, which can be differentiated from normal structures with digital image analysis techniques.
Adult↗
Quantitative assessment of ultrasonic myocardial reflectivity in hypertrophic cardiomyopathy.
The purpose of this study was to investigate the relation between acoustic properties of the myocardium and magnitude of left ventricular hypertrophy in patients with hypertrophic cardiomyopathy. An on-line radio frequency analysis system was used to obtain quantitative operator-independent measurements of the integrated backscatter signal of the ventricular septum and posterior free wall in 25 patients with hypertrophic cardiomyopathy and 25 normal age-matched control subjects. The integrated values of the radio frequency signal were normalized for the pericardial interface and expressed in percent. Tissue reflectivity was significantly increased in the hypertrophied ventricular septum, as well as in the nonhypertrophied posterior free wall, in patients with hypertrophic cardiomyopathy (58 +/- 15% and 37 +/- 12%, respectively) compared with values in normal subjects (33 +/- 10% and 18 +/- 5%, respectively; p less than 0.001). Furthermore, measurements of reflectivity of the septum or posterior free wall, or both, were beyond 2 SD of normal values in greater than 90% of the patients and were also abnormal in each of the five study patients who had only mild and localized left ventricular hypertrophy. No correlation was identified between myocardial tissue reflectivity and left ventricular wall thickness in the patients with hypertrophic cardiomyopathy (correlation coefficient r = 0.4; p = NS). These findings demonstrate that myocardial reflectivity is abnormal in most patients with hypertrophic cardiomyopathy and is largely independent of the magnitude of left ventricular hypertrophy. Moreover, quantitative analysis of ultrasonic reflectivity can differentiate patients with hypertrophic cardiomyopathy from normal subjects independently of clinical features and conventional echocardiographic measurements.
Adolescent↗
Increased prevalence of ventricular arrhythmias in essential hypertensives with dipyridamole-induced ischemic-like S-T segment changes.
Essential hypertensives are at greater risk for ventricular arrhythmias than normotensive controls. A reduction in coronary flow reserve may be one of the mechanisms underlying this increased prevalence of ventricular dysrhythmias in hypertensives. It has previously been shown that dipyridamole infusion may provoke ischemic-like S-T segment depression in essential hypertensives with angiographically normal coronary arteries and reduced flow reserve. The aim of the present study was to assess whether electrocardiographic positivity (S-T segment depression greater than 0.1 mV from baseline) during dipyridamole testing (12-lead electrocardiogram and two-dimensional echomonitoring, with the infusion of 0.84 mg/kg dipyridamole over 10 min) might identify hypertensives at greater risk for ventricular dysrhythmias. We therefore studied 51 mild-to-moderate essential hypertensives by dipyridamole testing and 48-h Holter monitoring. All patients were off therapy for at least 2 weeks before testing and Holter evaluation. Left ventricular mass (by Penn convention) and ejection fraction (by Teichholtz rule) were evaluated by two-dimensional echocardiography. Lown classes 0-1 were found in 31 patients (Group 1) and Lown classes II-IV in 20 (Group 2). The two groups overlapped for mean blood pressure (121 +/- 9 versus 124 +/- 8 mmHg), left ventricular mass index (120 +/- 27 versus 141 +/- 42 g/m2) and left ventricular ejection fraction (54 +/- 6 versus 52 +/- 6). An electrocardiographically-positive dipyridamole test was found in seven of Group I and 16 of Group II patients (23 versus 80%, P less than 0.01). No patient showed a transient, either regional or global, systolic dysfunction during dipyridamole testing.(ABSTRACT TRUNCATED AT 250 WORDS)
Arrhythmias, Cardiac↗
Two-dimensional echocardiography in myocardial amyloidosis.
Two-dimensional echocardiography is the best means of identifying early cardiac amyloid infiltration and gauging its subsequent progression. The early asymptomatic phase is characterized on echocardiography by a mild-to-moderate increase in left ventricular and/or right ventricular wall thicknesses. The distinctive combination of low electrocardiography voltage and increase in left ventricular mass on the echocardiogram, both compatible with substantial amyloid infiltration, is valuable in diagnosis and appears to indicate the severity of the disease. Other ancillary but common findings are left atrial dilatation, a small pericardial effusion, thickening of cardiac valves, papillary muscles, and interatrial septum. Finally, there is a peculiar texture of myocardial walls, with highly refractile areas that are typical, although not specific, of myocardial amyloidosis and can also be quantitatively described by digital image analysis techniques. The echocardiographic appearance of amyloidosis can closely mimic several other diseases. Asymmetric hypertrophy of the septum due to amyloid deposition may occur, simulating hypertrophic cardiomyopathy. The granular sparkling of myocardial walls is also found in myocarditis with severe fibrosis, and it is quite common in hypertrophic cardiomyopathy, as well as in other infiltrative diseases of the myocardium. It is not uncommon that the echocardiographic examination represents a turning point in the work-up of the patient, briskly orienting the clinician towards the correct diagnostic pathway. However, the likelihood of the cardiologist-echocardiographer to successfully and prospectively identify myocardial amyloidosis is substantially higher if all the clinical and electrocardiographic information is reviewed at the time of the echocardiographic examination.
Amyloidosis↗
Inhibition of dipyridamole-induced ischemia by antianginal therapy in humans. Correlation with exercise electrocardiography.
BACKGROUND: Dipyridamole echocardiography test (DET: two-dimensional echocardiographic monitoring with dipyridamole infusion up to 0.84 mg/kg in 10 minutes) is a useful tool for the noninvasive diagnosis of coronary artery disease. Aims of the present study were to assess the effects of antianginal drugs on dipyridamole-induced ischemia and to evaluate whether drug-induced changes in DET response may predict variations in exercise tolerance. METHODS AND RESULTS: Fifty-seven patients with angiographically assessed significant coronary artery disease (greater than 70% lumen reduction in at least one major coronary vessel) performed a DET and an exercise electrocardiography test (EET) in random order both off treatment and on antianginal drugs (beta-blockers, calcium antagonists and nitrates, alone or in various combinations). The criterion for DET positivity was a transient dyssynergy of contraction absent or of a lesser degree in the baseline examination. In DET, two parameters were evaluated: the dipyridamole time (i.e., the time from onset of dipyridamole infusion to obvious dyssynergy) and the wall motion score index. DET sensitivity was 91% off therapy and fell to 65% under therapy (p less than 0.01). In the 37 patients who had a positive DET both off and on therapy, the dipyridamole time increased from 6 +/- 3 (off therapy) to 8 +/- 3 minutes (on therapy) (p less than 0.01). The wall motion score index at peak dipyridamole went from 1.38 +/- 0.14 to 1.31 +/- 0.14 (p less than 0.01). EET and DET yielded concordant (positive versus negative) results in 41 of 57 (71%) patients off and in 35 of 57 (61%) on therapy (p = NS). In the subgroup of 38 patients with both positive DET and EET without treatment, the therapy-induced variations in exercise time were significantly correlated with the variations in dipyridamole time (r = 0.5; p less than 0.01), not with variations in wall motion score index (r = 0.3; p = NS). CONCLUSIONS: 1) Antianginal therapy can protect from dipyridamole-induced ischemia and 2) the therapy-induced changes in DET response parallel variations in exercise tolerance and might be useful for the objective, exercise-independent assessment of the therapy efficacy.
Adrenergic beta-Antagonists↗
Lack of correlation between cardiac mass and arteriolar structural changes in mild-to-moderate hypertension.
A morphological restructuring of cardiac and arteriolar tissue is common in hypertension. The parallel evolution of these two processes as a compensatory response to pressure overload is a frequently assumed but unsubstantiated hypothesis. To evaluate this possibility, we have concomitantly measured left ventricular mass (LVM; two-dimensional echo) and minimal forearm vascular resistance (FVR; derived from the ratio of intra-arterial blood pressure: forearm blood flow by venous plethysmography) at maximal postischemic (13 min ischemia + 1 min hand exercise) reactive hyperemia. The study was performed on 29 essential hypertensive patients (15 males, 14 females, aged 50 +/- 10 years) who had not been undergoing treatment for hypertension for at least 15 days at the time of study. Minimum FVR was taken as a hemodynamic index of the integrated arteriolar lumen at the forearm level. LVM index and minimum FVR ranged from normal to clearly altered values. In spite of a wide spread of values, no correlation existed between the individual values of the two variables. Systemic mean blood pressure correlated with minimum FVR and tended to correlate with LVMI. Thus, morphological restructing of cardiac and arteriolar tissue does not seem to evolve in parallel in human hypertension. Pressure overload may contribute to cardiovascular hypertrophy, but other unrelated mechanisms may also underlie the development of cardiac and arteriolar abnormalities of human hypertension.
Arterioles↗
[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↗
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↗
Dipyridamole echocardiography stress testing in hypertensive patients. Targets and tools.
Arterial hypertension can provoke a reduction in coronary flow reserve through several mechanisms that are not mutually exclusive, namely, coronary artery disease, left ventricular hypertrophy, and microvascular disease. These different targets of arterial hypertension should be explored with different diagnostic markers. The transient dyssynergy detected by two-dimensional echocardiography and evoked during dipyridamole infusion is a marker of coronary disease that is equally reliable in normotensive and hypertensive individuals. On the contrary, dipyridamole-induced ST segment depression is frequently elicited in hypertensive patients when angiographically assessed coronary disease is absent. This ischemiclike electrocardiographic response can be found in echocardiographically assessed left ventricular hypertrophy. However, even when left ventricular mass is normal, dipyridamole-induced ST segment depression is associated with an impaired coronary flow response to pacing, which is consistent with microvascular disease. Whether echocardiographically silent electrocardiographic changes are simply diagnostic noises transmitting a misleading false positive response or a potentially important clinical marker of early myocardial damage remains a pivotal though still unanswered question.
Cardiomegaly↗
Dipyridamole-induced myocardial ischaemia increases ANF release in man.
Atrial natriuretic factor (ANF) release is modulated by several haemodynamic factors, including ventricular and atrial wall stretch. Dipyridamole infusion, which is commonly used as a pharmacological stressor in patients with coronary artery disease, can acutely increase ventricular and atrial pressure via myocardial ischaemia. The aim of this study was to assess whether dipyridamole infusion (up to 0.84 mg kg-1 over 10') can affect ANF release in man. Nineteen patients (13 men, 6 women) with a history of chest pain were studied. Their drug regimen was interrupted and instead they were administered a dipyridamole infusion, combined with two-dimensional echocardiography and 12-lead ECG monitoring. Plasma ANF was measured by RIA while the patients rested, and after dipyridamole infusion. Eight patients had no evidence of myocardial ischaemia, as measured by electrocardiographic and/or echocardiographic criteria, during dipyridamole infusion: among them, ANF values were similar while they were at rest and at peak dipyridamole administration (23.9 +/- 9.5 vs 23.4 +/- 6.9 pg ml-1, P = ns). Eleven patients had dipyridamole-induced transient ischaemia (regional ventricular dyssynergy and/or ST segment depression): among them, ANF values rose significantly at peak dipyridamole administration (31.8 +/- 13.8 vs 65.5 +/- 36.4, P less than 0.01). We conclude that dipyridamole infusion does not increase ANF release in man in the absence of ischaemia. The induction of myocardial ischaemia acutely increases ANF release, probably through a rise in ventricular and atrial wall stress.
Atrial Natriuretic Factor↗