Dipyridamole-atropine-induced myocardial infarction in a patient with patent epicardial coronary arteries

BACKGROUND

The diagnostic accuracy of the physical and pharmacological stress echocardiography tests is higher than routine exercise electrocardiography. They have an acceptable safety profile and have been rarely associated with severe adverse effects.

CASE REPORT

We present a case of acute anterior myocardial reinfarction immediately after exercise and pharmacological (dipyridamole-atropine) stress echocardiography testing 1 month after successful stent implantation in LAD. Our patient was a 43-year-old man with a history of heavy smoking and hypertension. Remarkably, the stress echocardiogram was non-diagnostic few hours before the infarction occurred. Angiography performed 4 months after the reinfarction revealed neither a culprit lesion nor stent thrombosis.

CONCLUSION

Aggressive "last generation" pharmacological stress testing may provide optimal diagnostic accuracy, but as in our case, complications may occur, even after negative stress testing. To our knowledge, this is the first reported case of an acute myocardial infarction as a severe complication of stress testing, which developed in a patient after stent implantation.

The prognostic value of myocardial viability recognized by low dose dipyridamole echocardiography in patients with chronic ischaemic left ventricular dysfunction

AIMS

The aim of this study was to assess the prognostic value of myocardial viability recognized as a contractile response to vasodilator stimulation in patients with left ventricular dysfunction in a large scale, prospective, multicentre, observational study.

METHODS AND RESULTS

Three hundred and seven patients (mean age 60 +/- 10 years) with angiographically proven coronary artery disease, previous (>3 months) myocardial infarction and severe left ventricular dysfunction (ejection fraction <35%; mean ejection fraction: 28 +/- 7%) were enrolled in the study. Each patient underwent low dose dipyridamole echo (0.28 mg x kg(-1) in 4 min). Myocardial viability was identified as an improvement of >0.20 in the wall motion score index. By selection, all patients were followed up for a median of 36 months. One-hundred and twenty-four were revascularized either by coronary artery bypass grafting (n=83) or coronary angioplasty (n=41). The only end-point analysed was cardiac death. In the revascularized group, cardiac death occurred in one of the 41 patients with and in 16 of the 83 patients without a viable myocardium (2.4% vs 19.3%, P<0.01). Outcome, as estimated by Kaplan-Meier survival, was better for patients with, compared to patients without, a viable myocardium, who underwent coronary revascularization (97.6 vs 77.4%, P=0.01). Using a Cox proportional hazards model, the presence of myocardial viability was shown to exert a protective effect on survival (chi-square 4.6, hazard ratio 0.1, 95% CI 0.01-0.8, P<0.03). The survival rate in medically treated patients was lower than in revascularized patients irrespective of the presence of a viable myocardium (79.7% vs 86.2, P=ns).

CONCLUSION

In severe left ventricular ischaemic dysfunction, myocardial viability, as assessed by low dose dipyridamole echo, is associated with improved survival in revascularized patients.

Flexible percutaneous pericardioscopy: inherent drawbacks and recent advances

Pericardioscopy enables endoscopic inspection and aimed biopsy of the parietal and visceral pericardium. To elucidate possible technical modifications contributing to the feasibility, diagnostic value and safety of the procedure, pericardioscopy with an Olympus HYF-1T flexible endoscope was performed in 32 patients (53.1% males, mean age 46.2 +/- 13.1 years) with pericardial effusions. In all patients, the initial step of the procedure was subxiphoid fluoroscopically controlled pericardiocentesis and drainage of the pericardial effusion. An Olympus FB-41ST biopsy forceps was applied for endoscopically guided pericardial biopsies. Standard sampling was used in 22/32 patients (3 to 6 samples/patient) and extensive sampling in 10/32 patients (18 to 20 samples/patient). In additional 12 patients pericardial biopsy was performed without pericardioscopy, under fluoroscopic control. Endoscopic visualization was clearly superior when pericardial effusion was partially replaced with 100 to 300 ml of air (29/32 procedures) in comparison to 3/32 procedures in which the pericardial effusion was replaced with warm normal saline (37 degrees C). In patients with hemorrhagic effusion (12/32), we either repeatedly injected and removed 100 to 150 ml volumes of normal saline (37 degrees C), or postponed pericardioscopy for 2 to 3 days of active drainage. The specificity of endoscopic findings is low and not decisive for the diagnosis. However, pericardioscopy is significantly contributing to the diagnostic value of pericardial biopsy, especially regarding establishing the new diagnosis and etiology of the pericardial disease. Sampling efficiency was also significantly higher for procedures using aimed pericardial biopsy with standard and extensive sampling compared to procedures performed under fluoroscopy: 86.2%, 87.3%, and 43.7%, respectively. No major complications directly related to the procedure were encountered. Minor complications included: short-run ventricular tachycardia (6.3%), pain at the sheath entry site (75%) and transient fever (37.5%). In conclusion, pericardioscopy with Olympus HYF-1T, after air instillation, is a technically complex, but safe procedure that enables excellent visualization and extensive pericardial sampling with improved diagnostic value of pericardial biopsies.

Arrhythmias in acute pericarditis. An endomyocardial biopsy study

It is still controversial whether the arrhythmias in acute pericarditis are of myocardial or pericardial origin. The aim of the present study was to investigate the occurrence of arrhythmias and conduction disorders in patients with acute pericarditis with no endomyocardial biopsy evidence of myocarditis (group 1: 40 patients, 65% males, mean age 45.6 +/- 15.7 years, mean heart rate [HR] 98.7 +/- 22.2 beats per minute) in comparison to endomyocardial biopsy proven acute myocarditis/perimyocarditis (group 2: 10 patients, 3/10 with perimyocarditis, 70% males, mean age 46.1 +/- 15.8 years, mean heart rate 76.7 +/- 33.1 beats per minute). At the initial assessment all patients underwent comprehensive clinical work-up including echocardiography, cardiac catheterization, and endomyocardial biopsy. In all patients biventricular endomyocardial biopsy was performed using standard femoral approach and Schikumed 7 F or 8 F bioptomes. Tissue samples were stained by H & E, v. Gieson and independently reviewed by two cardiac pathologists. In addition immunohistochemistry and immunocytochemistry were performed, and only patients fulfilling Dallas and World Heart Federation criteria were selected for group 2. Comparative analysis of electrocardiograms and 24-hour Holter recordings at initial presentation revealed in group 1 vs group 2 significantly less frequent paroxysmal supraventricular tachyarrhythmias (5% vs 40%), and ventricular fibrillation (0 vs 20%), in contrast to atrial fibrillation that occurred more often (20% vs 0) (all p < 0.05). Furthermore, in the group 2 one patient died due to VF and two patients underwent ICD implantation. Low voltage (40% vs 30%) and ST/T wave changes (47.5% vs 30%), as well as the incidence of the II degree AV block (5% vs 0) and complete AV block (2.5% vs 10%) were not significantly different between the groups. In conclusion, patients with pericarditis and no endomyocardial biopsy indications of myocarditis had significantly less often life threatening rhythm disorders in contrast to patients with endomyocardial biopsy proven acute myocarditis/perimyocarditis. On the contrary, incidence of transitory atrial fibrillation was higher in acute pericarditis, than in myocarditis.

Prediction of restenosis after coronary angioplasty by use of a new index: TIMI frame count/minimal luminal diameter ratio

BACKGROUND

It has been shown recently that postangioplasty coronary flow reserve and the degree of residual stenosis have a modest predictive value for short- and long-term clinical outcomes after coronary angioplasty. Corrected TIMI frame count (CTFC) is a simple quantitative index of coronary blood flow. Its relationship with Doppler coronary flow velocity and clinical outcome after coronary angioplasty has not been fully clarified. The aim of this study was to identify clinical, angiographic, and functional predictors of clinical and angiographic restenosis after conventional coronary angioplasty.

METHODS AND RESULTS

We studied 70 consecutive patients in whom intracoronary Doppler flow-velocity measurements were performed before and after angioplasty. Patients were evaluated for restenosis by clinical follow-up, exercise stress test/(201)Tl scintigraphy, and follow-up angiography, which was performed at 10. 5+/-10.3 months in 63 patients. According to the results of univariate analysis, a new index, postangioplasty CTFC/minimal luminal diameter (MLD) ratio, was created. Multivariate analysis revealed that CTFC/MLD ratio was the only independent predictor of angiographic (OR 2.02; 95% CI 1.37 to 2.97; P<0.0004) and clinical (OR 1.60; 95% CI 1.15 to 2.21; P<0.005) restenosis. The receiver operating characteristic curve area of this index was 79% for angiographic and 73% for clinical restenosis. The optimal CTFC/MLD ratio cutoff values were 7.88 for angiographic and 7.94 for clinical restenosis, respectively.

CONCLUSIONS

Our data indicate that postangioplasty CTFC/MLD ratio, which incorporates both the angiographic and functional features of coronary lesions, is a reliable, objective, and inexpensive index for prediction of angiographic and clinical restenosis after conventional coronary angioplasty.

Pharmacological radionuclide ventriculography for detection of myocardial contractile reserve in patients after myocardial infarction: head-to-head comparison of low dose dobutamine and low dose dipyridamole

BACKGROUND

Low dose pharmacological stress echocardiography with either dobutamine or dipyridamole infusion has been proposed for recognition of myocardial viability. However, dependence on adequate acoustic window, observer experience, and the mild degree of wall motion changes make the viability assessment by stress echocardiography especially bothersome. The objective of the study was to evaluate the ability of low dose dobutamine and low dose dipyridamole radionuclide ventriculography to detect contractile reserve in patients after myocardial infarction and functional recovery after coronary angioplasty.

METHODS

The study group consisted of 20 consecutive patients (52 +/- 10 years, 17 male, 3 female) with previous myocardial infarction and resting regional dyssynergy, in whom diagnostic cardiac catheterization revealed significant one-vessel coronary artery stenosis suitable for angioplasty. Each patient underwent equilibrium 99m-Tc radionuclide ventriculography which was performed at rest and during low dose dipyridamole (0.28 mg/kg over 2 minutes) and low dose dobutamine infusion (up to 10 mcg/kg/min). Left ventricular global and regional ejection fractions were determined. Increase of regional ejection fraction for > 5% (inferoapical and posterolateral regions) or > 10% (anteroseptal regions) during low dose dobutamine and dipyridamole in infarcted regions, as well as in the followup period, was considered as index of contractile reserve. After 8 weeks of successful angioplasty, resting radionuclide ventriculography was repeated in all patients in order to identify functional recovery of the infarct zone.

RESULTS

Out of the 180 analyzed segments (20 x 9), 90 regional ejection fractions have shown depressed contractility. The mean of the regional ejection fractions showing depressed contractility increased from the resting value of 34 +/- 12% to 42 +/- 14% in the follow-up period (p = 0.06). Of the 90 with baseline dyssynergy, 46 were responders during low-dose dobutamine (51%), whereas 32 segments were responders (36%, p = 0.05 vs. dobutamine) during low dose dipyridamole. Positive predictive value of dobutamine and dipyridamole for predicting functional recovery was 72% and 75% (p = ns), respectively. Negative predictive value of dobutamine and dipyridamole was 48% and 69% (p = 0.05), respectively. In the group of patients with most severe dyskinesia (regional ejection fraction < 35%, 42 segments) positive predictive value was 73% and 82%, while negative predictive value was 42% and 64% for low dose dobutamine and low dose dipyridamole respectively (p = ns).

CONCLUSION

Although low dose dobutamine induced higher rate of positive responses during radionuclide ventriculography imaging, dipyridamole radionuclide ventriculography has shown superior, particularly negative, prognostic value for predicting functional recovery of infarcted regions.

Integrated evaluation of relation between coronary lesion features and stress echocardiography results: the importance of coronary lesion morphology

OBJECTIVES

The aim of this study was to analyze, in the same group of patients, the relationship between multiple variables of coronary lesion and results of exercise, dobutamine and dipyridamole stress echocardiography tests.

BACKGROUND

Integrated evaluation of the relation between stress echocardiography results and angiographic variables should include not only the assessment of stenosis severity but also evaluation of other quantitative and qualitative features of coronary stenosis.

METHODS

Study population consisted of 168 (138 male, 30 female, mean age 51+/-9 years) patients, on whom exercise (Bruce treadmill protocol), dobutamine (up to 40 mcg/kg/min) and dipyridamole (0.84 mg/kg over 10 min) stress echocardiography tests were performed. Stress echocardiography test was considered positive for myocardial ischemia when a new wall motion abnormality was observed. One-vessel coronary stenosis ranging from mild stenosis to complete obstruction of the vessel was present in 153 patients, and 15 patients had normal coronary arteries. The observed angiographic variables included particular coronary vessel, stenosis location, the presence of collaterals, plaque morphology according to Ambrose classification, percent diameter stenosis and obstruction diameter as assessed by quantitative coronary arteriography.

RESULTS

Covariates significantly associated with the results of physical and pharmacological stress tests included for all three stress modalities presence of collateral circulation, percent diameter stenosis and obstruction diameter, as well as lesion morphology (p < 0.05 for all, except collaterals for dobutamine stress test, p = 0.06). By stepwise multiple logistic regression analysis, the strongest predictor of the outcome of exercise echocardiography test was only percent diameter stenosis (p = 0.0002). However, both dobutamine and particularly dipyridamole stress echocardiography results were associated not only with stenosis severity - percent diameter stenosis (dobutamine, p = 0.04; dipyridamole, p = 0.003) - but also, and even more strongly, with lesion morphology (dobutamine, p = 0.006; dipyridamole, p = 0.0009). As all of stress echocardiography results were significantly associated with percent diameter stenosis, the best angiographic cutoff in relation to the results of stress echocardiography test was: exercise, 54%; dobutamine, 58% and dipyridamole, 60% (p < 0.05 vs. exercise).

CONCLUSIONS

Integrated evaluation of angiographic variables have shown that the results of dobutamine and dipyridamole stress echocardiography are not only influenced by stenosis severity but also, and even more importantly, by plaque morphology. The results of exercise stress echocardiography, although separately influenced by plaque morphology, are predominantly influenced by stenosis severity, due to a stronger exercise capacity in provoking myocardial ischemia in milder forms of coronary stenosis.

Coronary vasodilation without myocardial erection. Simultaneous haemodynamic, echocardiographic and arteriographic findings during adenosine and dipyridamole infusion

AIM

The aim of this study was to evaluate simultaneously echocardiographic, haemodynamic and angiographic changes that occur during adenosine and dipyridamole infusion, in patients with one-vessel coronary artery stenosis. This would assess whether deterioration in left ventricular haemodynamics during vasodilator agent infusion is influenced by vasodilation per se, or the development of myocardial ischaemia.

METHODS AND RESULTS

We performed adenosine (140 micrograms.kg-1.min-1 over 4 min) and dipyridamole (up to 0.84 mg.kg-1 over 10 min) stress echocardiography tests, together with angiographic and haemodynamic assessment, in 26 patients undergoing elective coronary angioplasty. In 12 of 26 patients, adenosine and dipyridamole tests were repeated 24 h after angioplasty. The criterion for echocardiography test positivity was the appearance of a new transient regional wall motion abnormality. Coronary angiograms were analysed with quantitative coronary arteriography. Adenosine and dipyridamole induced regional dysfunction in 18/26 (69%) and 14/26 (54%) patients before angioplasty, respectively (P = ns). In the echocardiography-positive patients, the percent diameter stenosis was significantly (P < 0.05) tighter stenosis than in the echocardiography-negative patients (adenosine, 66.6 +/- 8.3% vs 58.0 +/- 8.9%; dipyridamole, 69.2 +/- 7.1% vs 57.7 +/- 7.6%). During both tests, left ventricular end-diastolic pressure significantly increased (P < 0.05) in echocardiography-positive patients (adenosine, 9.8 +/- 2.7 mmHg to 13.5 +/- 4.1 mmHg; dipyridamole, 10.1 +/- 2.8 mmHg to 14.1 +/- 4.3 mmHg), but not in echocardiography-negative patients. In the patients who had undergone successful angioplasty (reduction to < 50% diameter stenosis), both adenosine and dipyridamole confirmed the arteriographic success of the procedure (echocardiography negative in all patients). In this group of patients, no significant change was observed in left ventricular end-diastolic pressure during adenosine or dipyridamole infusion.

CONCLUSIONS

Intravenous infusion of either adenosine or dipyridamole was accompanied by an obvious increase in left ventricular end-diastolic pressure only in patients with induced wall motion abnormalities. Coronary vasodilation per se has no significant effect on left ventricular end-diastolic pressure when no ischaemia is induced, disproving any clinically significant 'erectile' and adverse effects of coronary vasodilation per se.

Dipyridamole stress echocardiography: state of the art 1996. EPIC (Echo Persantin International Cooperative) Study Group

Dipyridamole stress is the forerunner and prototype of pharmacological stress echo tests in the diagnosis of coronary artery disease. Among the various stress echo tests, it is probably the least technically demanding to perform and the easiest to interpret. Its accuracy is similar to dobutamine stress echocardiography but its feasibility is higher. The prognostic impact of dipyridamole stress echo has also been proven for presentation of hard end-points such as cardiac death. The safety and prognostic value of this test has been conclusively demonstrated as a result of extensive experience in large scale multicentre projects. Dipyridamole stress is many different tests in one: dipyridamole atropine is best for diagnosis; dipyridamole dobutamine or dipyridamole-exercise is highly sensitive for the detection of minor forms of coronary artery disease; low and high dose dipyridamole is best suited for prognostic stratification; infra-low dipyridamole with low dose dobutamine administration is probably best suited for selective myocardial viability identification. Each patient should have their own test, tailored on the basis of the clinical picture and the diagnostic issue.

Combined low dose dipyridamole-dobutamine stress echocardiography to identify myocardial viability

OBJECTIVES

We sought to evaluate the effects of combined administration of infra-low dose dipyridamole and low dose dobutamine on assessment of myocardial viability.

BACKGROUND

Low dose pharmacologic stress echocardiography with either dobutamine or dipyridamole infusion has been proposed for the recognition of myocardial viability.

METHODS

Thirty-four patients with rest wall motion dyssynergy by two-dimensional echocardiography and with angiographically proved coronary artery disease underwent in combination with two-dimensional echocardiographic monitoring: 1) low dose (5 to 10 microgram/kg per min over 3 min) dobutamine infusion; 2) infra-low dose (0.28 mg/kg over 4 min) dipyridamole infusion; 3) combination of infra-low dose dipyridamole infusion immediately followed by low dose dobutamine infusion (combined dipyridamole-dobutamine).

RESULTS

Follow-up rest echocardiography was available in 30 patients. After revascularization, 82 segments showed a contractile improvement of > or = 1 grade, whereas 63 segments remained unchanged. The sensitivity of dobutamine, dipyridamole and combined dipyridamole-dobutamine for predicting recovery was 72% (95% confidence interval [CI] 60.9% to 81.3%), 67% (CI 55.8% to 77%) and 94% (CI 86.3% to 97.9%), respectively. The specificity of dipyridamole, dobutamine and combined dipyridamole-dobutamine was 95% (CI 86.7% to 99%), 92% (CI 82.4% to 97.3%) and 89% (CI 78.4% to 95.4%), respectively. The accuracy of the dobutamine, dipyridamole and combined dipyridamole-dobutamine test was 80%, 79% and 92%, respectively (combined dipyridamole-dobutamine vs. dobutamine, p < 0.05; combined dipyridamole-dobutamine vs. dipyridamole, p < 0.01).

CONCLUSIONS

Infra-low dose dipyridamole added to low dose dobutamine recruits an inotropic reserve in asynergic segments that were nonresponders after either dobutamine or dipyridamole alone and destined to recover after revascularization.

Infra-low dose dipyridamole test. A novel dose regimen for selective assessment of myocardial viability by vasodilator stress echocardiography

Low (0.56 mg.kg-1 over 4 min) and high (0.84 mg.kg-1 over 10 min) doses of dipyridamole can identify viable myocardium through the contractile recovery of basally dyssynergic regions; however, it also induces ischaemia in susceptible patients. The aim of this study was to assess the potential of an "infra-low' dose of dipyridamole to selectively identify myocardial viability, independently evaluated by low dose dobutamine. Forty patients with resting dyssynergy and angiographically assessed coronary artery disease (1-vessel in 18, 2-vessel in 12, and 3-vessel in 10 patients) separately underwent a low dose dobutamine (5-10 micrograms.kg-1.min-1 for 3 min) echo test and an infralow dose (0.28 mg.kg-1 over 4 min) dipyridamole echo test. Systolic blood pressure (rest: 131 +/- 19 mmHg) changed slightly after dobutamine (137 +/- 21, P < 0.05 vs rest) and remained stable after dipyridamole (130 +/- 17, P = ns vs rest). Heart rate (rest: 68 +/- 13 beats.min-1) was also unchanged after dipyridamole (69 +/- 12, P = ns vs rest) and increased slightly after dobutamine (71 +/- 15, P < 0.05 vs rest and vs dipyridamole). No patient developed echocardiographic or electrocardiographic signs of ischaemia after either dipyridamole or dobutamine. Of the 243 segments with baseline dyssynergy, 70 were responders (i.e. they showed an improvement of 1 grade or more, from 1 = normal/hyperkinetic to 4 = dyskinetic in a 16-segment model of the left ventricle) by both dipyridamole and dobutamine, 157 were non-responders (i.e. they showed no change) by both dipyridamole and dobutamine, and 16 showed discordant results (five responders by dipyridamole only; 11 by dobutamine only). The overall concordance of dipyridamole and dobutamine was 93%. An echocardiographic follow-up could be obtained > 6 weeks after successful revascularization (achieved with angioplasty in 17, with by pass surgery in 3) in 19 patients and showed an improvement of one grade or more in 50 segments (viable) and no improvement in 50 segments (necrotic). The sensitivity of dobutamine and dipyridamole for predicting recovery was 76 and 78% respectively (P = ns); the specificity of both tests was 94%. In conclusion, infra-low dose dipyridamole is a haemodynamically neutral stress test which does not affect either heart rate or systolic blood pressure; it allows myocardial viability to be explored selectively, without eliciting ischaemia; it shows excellent overall concordance with low dose dobutamine and has good sensitivity and excellent specificity for predicting functional recovery following successful revascularization.

Dipyridamole and dobutamine: competitors or allies in pharmacological stress echocardiography?

Stress echocardiography has become an accepted and cost-effective method for diagnosing coronary artery disease. However, as exercise stress echocardiography is a demanding technique, difficult to reproduce, pharmacological stress echocardiography has become very popular in recent years. The two most popular tests from the pharmacological stress echocardiography arena are dipyridamole and dobutamine. They have enabled the technical limitations inherent in exercise echocardiography to be overcome, and have provided the opportunity to obtain, during stress, images of unchanged quality in comparison to baseline. However, the sensitivity of both pharmacological stresses applied separately is less than ideal in patients with milder forms of coronary artery disease and in patients under therapy. To overcome this, a new generation of pharmacological stress tests, the combined dipyridamole-dobutamine tests were introduced. A combined dipyridamole-dobutamine echocardiography stress test should suggest that the agents are natural allies rather than competitors but in some instances they are applicable only in selected patients, and each pharmacological agent may be clinically contraindicated for administration. This is the message from a large scale study of recent years.

Stress echocardiography in the detection of myocardial ischemia. Head-to-head comparison of exercise, dobutamine, and dipyridamole tests

BACKGROUND

Exercise and pharmacological stress echocardiography have emerged as convenient alternatives to myocardial scintigraphy. The objective of this study was to compare in the same patients the diagnostic values of exercise, dobutamine, and dipyridamole stress echocardiography tests for detection of myocardial ischemia.

METHODS AND RESULTS

We performed exercise (maximal treadmill Bruce protocol), dobutamine (up to 40 micrograms/kg per minute) and dipyridamole (up to 0.84 mg/kg over 10 minutes) stress echocardiography tests, in random sequence and on separate days, in 136 consecutive patients. All patients underwent coronary angiography. Significant coronary artery disease was defined by quantitative coronary angiography as a lesion with a diameter stenosis > or = 50%. A stress echocardiogram was considered positive when new or worsening of preexisting wall motion abnormality was observed. Most of the patients (94%) were receiving the same antianginal medication for each stress test; 59 patients were receiving concomitant beta-blocker therapy. The prevalence of coronary artery disease was 87.5%, with 108 patients having one-vessel coronary artery disease. Peak heart rate and systolic blood pressure were higher with exercise than with dobutamine or dipyridamole (P < .01). Sensitivity of exercise, dobutamine, and dipyridamole stress echocardiography was 88%, 82%, and 74% (dipyridamole versus exercise, P < .01), respectively. Specificity was 82%, 77%, and 94%, respectively. The overall accuracy was 87%, 82%, and 77% (dipyridamole versus exercise, P < .01), respectively. The accuracy of dipyridamole was higher (P = .02) in the group of patients not receiving beta-blockers (84%) than in the patients receiving beta-blocker therapy (66%), whereas the accuracy of exercise and dobutamine were only slightly higher in the patients not receiving beta-blockers. Significant side effects occurred in 3%, 11%, and 1% of patients during exercise, dobutamine, and dipyridamole tests, respectively.

CONCLUSIONS

Despite the different hemodynamic effects, exercise, dobutamine, and dipyridamole echocardiography have high overall diagnostic values. In this group of patients with a predominance of one-vessel coronary artery disease, the overall diagnostic accuracy of stress echocardiography tests was higher for exercise than for dobutamine or dipyridamole. Concomitant beta-blocker therapy significantly decreased the accuracy of the dipyridamole stress echocardiography test. Pharmacological stress testing (dipyridamole without beta-blockers) can therefore be used as an efficient option for detection of myocardial ischemia in patients who are unable or poorly motivated to exercise adequately.

Dipyridamole-dobutamine echocardiography: a novel test for the detection of milder forms of coronary artery disease

OBJECTIVES

This study was designed to assess the clinical, hemodynamic and diagnostic effects of the addition of dobutamine to dipyridamole echocardiography.

BACKGROUND

Pharmacologic stress echocardiography with either dipyridamole or dobutamine has gained acceptance because of its safety, feasibility, diagnostic accuracy and prognostic power. The main limitation of the two tests is a less than ideal sensitivity in some patient subsets, such as those with limited coronary artery disease. We hypothesized that two pharmacologic stresses might act synergistically in the induction of ischemia by combining the mechanisms of inappropriate coronary vasodilation (with dipyridamole) and an increase in myocardial oxygen consumption (with dobutamine).

METHODS

One hundred fifty patients (mean [+/- SD] age 51 +/- 11 years) referred for stress echocardiography were initially studied by dipyridamole-dobutamine echocardiography. The test was stopped during the dipyridamole step in 95 patients for achievement of a predetermined end point (obvious dyssynergy induced by lower or higher dipyridamole dose), and dipyridamole-dobutamine tests were performed in 55 patients (negative dipyridamole echocardiographic test). In the same 150 patients the dobutamine echocardiographic test (up to 40 micrograms/kg body weight per min) was performed on a separate day.

RESULTS

Significant coronary artery disease (> 50% diameter stenosis of at least one major coronary vessel by quantitative coronary arteriography) was present in 131 patients (one vessel in 115; two vessels in 10, three vessels in 6), with normal coronary arteriography in 19. The feasibility of the dipyridamole-dobutamine test was 96%. Self-limiting side effects occurred in 5% of patients. The peak rate-pressure product was lowest during the dipyridamole test (132 +/- 30) and was comparable during the dobutamine (186 +/- 59) and dipyridamole-dobutamine tests (179 +/- 45, p = NS vs. dobutamine; p < 0.01 vs. dipyridamole). Sensitivity was 71% for dipyridamole, 75% for dobutamine and 92% for dipyridamole-dobutamine echocardiography (dipyridamole vs. dipyridamole-dobutamine, p < 0.01; dobutamine vs. dipyridamole-dobutamine, p < 0.01; dipyridamole vs. dobutamine, p = NS), whereas specificity was 89% for dipyridamole, 79% for dobutamine and 89% for dipyridamole-dobutamine echocardiography (p = NS for all).

CONCLUSIONS

Routine dobutamine addition to dipyridamole stress testing is clinically useful and well tolerated. It expands the spectrum of the disease detectable by pharmacologic stress echocardiography and allows documentation of milder forms of coronary artery disease that can be missed by conventional dipyridamole or dobutamine stress echocardiography.

Mitral valve replacement and septal myomectomy in hypertrophic cardiomyopathy. Ten-year follow-up in 80 patients

Between 1970 and 1980, 80 patients with hypertrophic cardiomyopathy were treated with mitral valve replacement (MVR) at our institution; 54 of these (Group 1) underwent MVR alone, and the remaining 26 (Group 2) underwent MVR plus septal myomectomy. The 1-month mortality was 7.4% for Group 1 and 7.6% for Group 2. After 10 years of follow-up, the annual mortality was 1.5% for Group 1 and 1.6% for Group 2 (this difference was not significant). Sixty-nine percent of the patients in both groups continued to experience marked symptomatic improvement. In Group 1, 96% of the patients had been assigned to New York Heart Association (NYHA) functional class III or IV before surgery; only 17% remained in these two classes postoperatively (p less than 0.01). In Group 2, 98% had been assigned to NYHA functional class III or IV before surgery, whereas only 20% remained in these two classes postoperatively (p less than 0.01). A comparison of preoperative and postoperative hemodynamic findings revealed that the left ventricular end-diastolic pressure was significantly reduced from 20 to 14 mm Hg in Group 1 and from 20 to 15 mm Hg in Group II (p less than 0.05). There was also a significant postoperative reduction in left ventricular outflow gradient at rest (from 79 to 6 mm Hg in Group 1 and from 75 to 7 mm Hg in Group 2) (p less than 0.01). These findings indicate that, in patients with hypertrophic cardiomyopathy who require surgical treatment, MVR alone or in conjunction with septal myomectomy offers significant improvement of symptoms and hemodynamic values.(ABSTRACT TRUNCATED AT 250 WORDS)