Prospective multicenter Polish Stress Echocardiography Registry (PolStress-Echopro) - the role in clinical practice

BACKGROUND

Stress echocardiography (SE) is becoming an increasingly frequently performed diagnostic examination in Poland. After the published retrospective PolSTRESS Registry, this prospective study is the first one available so far.

OBJECTIVES

The aim of the study was to analyze SE tests, taking into account the clinical characteristics of the patients, indications, applied protocols, and diagnostic and therapeutic decisions.

MATERIAL AND METHODS

Reference cardiological centers in Poland were asked for a 1-month prospective analysis of the data obtained. The study included 189 SE examinations. To evaluate coronary artery disease (CAD) (178 tests), all 17 centers performed dobutamine SE (DSE) (100%), 3 centers (17%) performed pacing, while cycle ergometer and treadmill SE were performed by 1 (5%) and 2 (11%) centers, respectively. In patients with valvular heart disease (VHD) (11 tests), 3 centers (16%) performed SE to evaluate low-flow/low-gradient aortic stenosis (AS), 4 (22%) in asymptomatic AS and 1 (5%) to evaluate mitral regurgitation.

RESULTS

For CAD assessment, a positive result was found in 37 (20%) patients, negative in 109 (61%) and nondiagnostic in 32 (19%). In the CAD group, coronarography was performed in 41 (23%) people. The analysis of the significance of the SE results for decision-making on interventional measures revealed that 30 patients (from the total study population of 189) were referred for the intervention.

CONCLUSIONS

The most commonly used SE is the DSE. Negative test results allowed in almost half of the patients to resign from invasive coronarography. Stress echocardiography should be more frequently used in patients with VHD in the qualification for invasive treatment.

The new clinical standard of integrated quadruple stress echocardiography with ABCD protocol

BACKGROUND

The detection of regional wall motion abnormalities is the cornerstone of stress echocardiography. Today, stress echo shows increasing trends of utilization due to growing concerns for radiation risk, higher cost and stronger environmental impact of competing techniques. However, it has also limitations: underused ability to identify factors of clinical vulnerability outside coronary artery stenosis; operator-dependence; low positivity rate in contemporary populations; intermediate risk associated with a negative test; limited value of wall motion beyond coronary artery disease. Nevertheless, stress echo has potential to adapt to a changing environment and overcome its current limitations.

INTEGRATED-QUADRUPLE STRESS-ECHO

Four parameters now converge conceptually, logistically, and methodologically in the Integrated Quadruple (IQ)-stress echo. They are: 1- regional wall motion abnormalities; 2-B-lines measured by lung ultrasound; 3-left ventricular contractile reserve assessed as the stress/rest ratio of force (systolic arterial pressure by cuff sphygmomanometer/end-systolic volume from 2D); 4- coronary flow velocity reserve on left anterior descending coronary artery (with color-Doppler guided pulsed wave Doppler). IQ-Stress echo allows a synoptic functional assessment of epicardial coronary artery stenosis (wall motion), lung water (B-lines), myocardial function (left ventricular contractile reserve) and coronary small vessels (coronary flow velocity reserve in mid or distal left anterior descending artery). In "ABCD" protocol, A stands for Asynergy (ischemic vs non-ischemic heart); B for B-lines (wet vs dry lung); C for Contractile reserve (weak vs strong heart); D for Doppler flowmetry (warm vs cold heart, since the hyperemic blood flow increases the local temperature of the myocardium). From the technical (acquisition/analysis) viewpoint and required training, B-lines are the kindergarten, left ventricular contractile reserve the primary (for acquisition) and secondary (for analysis) school, wall motion the university, and coronary flow velocity reserve the PhD program of stress echo.

CONCLUSION

Stress echo is changing. As an old landline telephone with only one function, yesterday stress echo used one sign (regional wall motion abnormalities) for one patient with coronary artery disease. As a versatile smart-phone with multiple applications, stress echo today uses many signs for different pathophysiological and clinical targets. Large scale effectiveness studies are now in progress in the Stress Echo2020 project with the omnivorous "ABCD" protocol.

Quality control of B-lines analysis in stress Echo 2020

BACKGROUND

The effectiveness trial "Stress echo (SE) 2020" evaluates novel applications of SE in and beyond coronary artery disease. The core protocol also includes 4-site simplified scan of B-lines by lung ultrasound, useful to assess pulmonary congestion.

PURPOSE

To provide web-based upstream quality control and harmonization of B-lines reading criteria.

METHODS

60 readers (all previously accredited for regional wall motion, 53 B-lines naive) from 52 centers of 16 countries of SE 2020 network read a set of 20 lung ultrasound video-clips selected by the Pisa lab serving as reference standard, after taking an obligatory web-based learning 2-h module ( http://se2020.altervista.org ). Each test clip was scored for B-lines from 0 (black lung, A-lines, no B-lines) to 10 (white lung, coalescing B-lines). The diagnostic gold standard was the concordant assessment of two experienced readers of the Pisa lab. The answer of the reader was considered correct if concordant with reference standard reading ±1 (for instance, reference standard reading of 5 B-lines; correct answer 4, 5, or 6). The a priori determined pass threshold was 18/20 (≥ 90%) with R value (intra-class correlation coefficient) between reference standard and recruiting center) > 0.90. Inter-observer agreement was assessed with intra-class correlation coefficient statistics.

RESULTS

All 60 readers were successfully accredited: 26 (43%) on first, 24 (40%) on second, and 10 (17%) on third attempt. The average diagnostic accuracy of the 60 accredited readers was 95%, with R value of 0.95 compared to reference standard reading. The 53 B-lines naive scored similarly to the 7 B-lines expert on first attempt (90 versus 95%, p = NS). Compared to the step-1 of quality control for regional wall motion abnormalities, the mean reading time per attempt was shorter (17 ± 3 vs 29 ± 12 min, p < .01), the first attempt success rate was higher (43 vs 28%, p < 0.01), and the drop-out of readers smaller (0 vs 28%, p < .01).

CONCLUSIONS

Web-based learning is highly effective for teaching and harmonizing B-lines reading. Echocardiographers without previous experience with B-lines learn quickly.

Prognostic Value of Noninvasive Cardiovascular Testing in Patients With Stable Chest Pain: Insights From the PROMISE Trial (Prospective Multicenter Imaging Study for Evaluation of Chest Pain)

BACKGROUND

Optimal management of patients with stable chest pain relies on the prognostic information provided by noninvasive cardiovascular testing, but there are limited data from randomized trials comparing anatomic with functional testing.

METHODS

In the PROMISE trial (Prospective Multicenter Imaging Study for Evaluation of Chest Pain), patients with stable chest pain and intermediate pretest probability for obstructive coronary artery disease (CAD) were randomly assigned to functional testing (exercise electrocardiography, nuclear stress, or stress echocardiography) or coronary computed tomography angiography (CTA). Site-based diagnostic test reports were classified as normal or mildly, moderately, or severely abnormal. The primary end point was death, myocardial infarction, or unstable angina hospitalizations over a median follow-up of 26.1 months.

RESULTS

Both the prevalence of normal test results and incidence rate of events in these patients were significantly lower among 4500 patients randomly assigned to CTA in comparison with 4602 patients randomly assigned to functional testing (33.4% versus 78.0%, and 0.9% versus 2.1%, respectively; both P<0.001). In CTA, 54.0% of events (n=74/137) occurred in patients with nonobstructive CAD (1%-69% stenosis). Prevalence of obstructive CAD and myocardial ischemia was low (11.9% versus 12.7%, respectively), with both findings having similar prognostic value (hazard ratio, 3.74; 95% confidence interval [CI], 2.60-5.39; and 3.47; 95% CI, 2.42-4.99). When test findings were stratified as mildly, moderately, or severely abnormal, hazard ratios for events in comparison with normal tests increased proportionally for CTA (2.94, 7.67, 10.13; all P<0.001) but not for corresponding functional testing categories (0.94 [P=0.87], 2.65 [P=0.001], 3.88 [P<0.001]). The discriminatory ability of CTA in predicting events was significantly better than functional testing (c-index, 0.72; 95% CI, 0.68-0.76 versus 0.64; 95% CI, 0.59-0.69; P=0.04). If 2714 patients with at least an intermediate Framingham Risk Score (>10%) who had a normal functional test were reclassified as being mildly abnormal, the discriminatory capacity improved to 0.69 (95% CI, 0.64-0.74).

CONCLUSIONS

Coronary CTA, by identifying patients at risk because of nonobstructive CAD, provides better prognostic information than functional testing in contemporary patients who have stable chest pain with a low burden of obstructive CAD, myocardial ischemia, and events.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01174550.

Applying the diamond criteria could improve utilization of stress echocardiography for patients who present to the emergency department with low-risk chest pain

We identified all patients with age 21 years and older, without a history of obstructive coronary artery disease, who presented to the emergency department with chest pain, and were admitted for cardiac observation followed by stress echocardiography during a 1-year period. The positive predictive value of stress echocardiography and cardiovascular outcomes were compared based on patients' Diamond chest pain classification. In patients with typical chest pain, who accounted for 8.7% (44/503) of the total cohort, the positive predictive value of stress echocardiography was 75% compared with 0% for all other subgroups (P = 0.007). Six patients (14%) with typical chest pain went on to have coronary revascularization compared with 0% for all other subgroups (P < 0.001). No patient in any subgroup died or was readmitted with a myocardial infarction in 30 days. Applying the Diamond criteria could improve utilization of stress echocardiography for patients with low-risk chest pain in the emergency department.

Feasibility, safety and accuracy of regadenoson-atropine (REGAT) stress echocardiography for the diagnosis of coronary artery disease: an angiographic correlative study

Regadenoson (REG), a selective A2A receptor vasodilator, has not been widely evaluated in stress echocardiography (SE). We report results of 45 patients participating in REG + atropine (REGAT) SE protocol conducted in a single-center prospective trial. The REGAT study enrolled subjects before a clinically indicated cardiac catheterization for suspected coronary artery disease (CAD). After rest imaging, a 2 mg Atropine (AT) bolus followed by 400 mcg of REG was given. Standard stress imaging views were obtained and interpreted in blinded fashion. Sensitivity, specificity, positive and negative predictive values (PPV, NPV) were calculated using cardiac catheterization >70 % stenosis as gold standard. Additional endpoints included major adverse cardiac events (MACE) and patient questionnaire responses. The mean duration of REGAT was 18 ± 7.2 min. There were no MACE, with only transient side-effects of dry mouth, shortness of breath, and headache. The incidence of significant CAD was 51.1 %. The sensitivity and specificity for significant stenosis was 60.9 and 86.4 %, with a PPV and NPV of 82.4 and 67.9 %. By coronary territories, the sensitivity, specificity, PPV, and NPV were: left anterior descending artery 58.8, 92.9, 83.3, and 78.8 %; left circumflex artery 6.7, 93.3, 33.3, and 67.7 %; and right coronary artery 16.7, 93.9, 50, and 75.6 %. Over 90 % of subjects reported feeling comfortable, with 83 % preferring REGAT as a future stress modality. The REGAT protocol is fast, safe, and well-tolerated with good specificity for CAD detection, but its low sensitivity and NPV precludes it from being an imaging modality for routine use.

[Noninvasive radiodiagnosis of late coronary stent stenoses]

OBJECTIVE

To study the diagnostic value of stress echocardiography (stress echoCG) in the early diagnosis of coronary stent stenoses in the late postoperative period.

SUBJECTS AND METHODS

The study enrolled 39 men aged 37 to 58 years with symptoms of cardialgia, who had previously (3 to 8 years earlier) undergone balloon angioplasty and coronary artery stenting to treat coronary heart disease. To exclude coronary stent stenoses, all the patients had dobutamine stress echoCG, transesophageal atrial electrostimulation, and further coronary angiographies (CAG).

RESULTS

Stress echoCG showed a lesion of the stented coronary artery in 34 patients and that of previously angiographically intact coronary arteries in 5 patients. According to CAG data, there was stenosis of > 70% in the coronary stent lumen in 16 patients and that of 40 to 70% in 12 patients. Six patients were found to have de novo stenoses in the previously stented coronary artery. Stress echoCG showed that the diagnostic accuracy and sensitivity of both stenoses of intracoronary stents and de novo ones in the stented artery and previously intact coronary arteries was 100%.

CONCLUSION

Stress echoCG is a highly informative method for the early topical diagnosis of both stenoses of coronary stents and a stenotic lesion of previously intact portions of coronary arteries. The early diagnosis of coronary stent stenoses permits mini-invasive endovascular treatment to be performed.

[The role of coronary reserve in diagnosis of hemodynamically significant stenoses in anterior descending and right coronary arteries: transthoracic ultrasound study]

Analysis of possibilities of transthoracic echocardiography (TTEchoCG) diagnosis of hemodynamically significant stenoses of anterior descending and right coronary arteries (ADCA and RCA) based on Doppler assessment of coronary reserve (CR) was carried out in 73 patients with cardiac pain syndrome (mean age 48+/-7 years, 60 men, 13 women). As a referent method we used coronary angiography. Coronary blood flow at baseline and during administration of a vasodilator (dipyridamole up to 0.84 mg/kg) was assessed by broadband ultrasound transducer in the mode of noncontrast tissue second harmonic imaging in distal segments of ADCA and posterior interventricular artery (PIVA). CR was calculated as ratio of peak hyperemic to baseline diastolic coronary blood flow velocity. CR &lt;2.0 was diagnosed as lowered. We found that TTEchoCG was simple noninvasive method of assessment of CR in distal thirds of ADCA and PIVA, which can be fulfilled in 90 and 86%of patients, respectively. We also revealed that hemodynamically significant stenoses of ADCA and PIVA caused CR lowering distally to zone of stenosis and that degree of CR lowering depended on severity of vascular narrowing. We found that CR&lt;2.0 in distal third of ADCA was a predictor of its &gt;50% narrowing with sensitivity 78%, specificity 85%, positive predictive value (PPV) 67%, and negative predictive value (NPV) 90%. In the presence of &gt;70% ADCA stenosis sensitivity and NPV of the parameter reached 100%. We revealed that CR&lt;2.0 in PIVA served as a marker of &gt;50% RCA stenosis with sensitivity 88%, specificity 86%, PPV 68%, and NPV 95%. In the presence of &gt;70% RCA stenosis sensitivity and NPV of the parameter rose up to 92 and 97%, respectively.

Methodological Analysis of Diagnostic Dobutamine Stress Echocardiography Studies

BACKGROUND

Dobutamine stress echocardiography (DSE) is an accepted test for the diagnosis of coronary artery disease (CAD), despite its wide diagnostic accuracy.

AIM

Which factors cause test variability of DSE for the diagnosis of CAD.

METHODS

In a retrospective analysis of 46 studies in 5,353 patients, the potential causes of diagnostic variability were systematically analyzed, including patient selection, definition of CAD, chest pain characteristics, confounding factors for DSE (left ventricular hypertrophy, left bundle branch block, female gender), work-up bias (present when patient's chance to undergo coronary angiography is influenced by the result of DSE), review bias (present when DSE is interpreted in relation to CAG), DSE protocol and definition of a positive DSE.

RESULTS

Diagnostic variability was related to definition of a positive test, but not related to the definition of CAD or DSE protocol. However, only three of eight methodological standards for research design found general compliance. Differences in the selection of the study population (quality of echocardiographic window, angina pectoris), handling of confounding factors and analysis of disease in individual coronary arteries were observed. Lack of data on analysis of relevant chest pain syndromes and handling of nondiagnostic test results hampered further evaluation of these standards.

CONCLUSION

Methodological problems may explain the wide range in diagnostic variability of DSE. An improvement of clinical relevance of DSE testing is possible by stronger adherence to common and new methodological standards.

Isometric handgrip exercise during dobutamine-atropine stress echocardiography increases heart rate acceleration and decreases study duration and dobutamine and atropine dosage

BACKGROUND

Dobutamine-atropine stress echocardiography (DASE) is an established test for the diagnosis and risk stratification of patients with coronary artery disease. Atropine use to attain target heart rate prolongs test time.

HYPOTHESIS

The aim of this study was to assess the utility of isometric handgrip exercise (33% maximal voluntary contraction x 4 min) with DASE.

METHODS

We prospectively evaluated 131 patients undergoing DASE randomized to handgrip exercise or no handgrip. Effect of handgrip exercise on endpoints: time to target heart rate (85% maximum predicted), recovery time, total test time, mean dobutamine and atropine dosage, and the number of ischemic responses were assessed. Effect of current beta-blocker medication use was also evaluated.

RESULTS

Heart rate rose more quickly in the handgrip group. At 6-10 min (peak handgrip), mean heart rate rose 51 +/- 14 beats/min in the handgrip group compared with 38 +/- 18 beats/min in the no handgrip group (p < 0.0001). With handgrip, overall dobutamine study time was reduced by a mean of 4.3 min (16.4 +/- 6.9 vs. 20.7 +/- 8.4, p = 0.004) in all patients, and by a mean of 5.9 min in patients not on beta-blocker medication (p = 0.001). The handgrip group also had a lower mean dose of dobutamine (25.8 +/- 13.5 vs. 32.4 +/- 16.4 mg, p = 0.025). The mean atropine dose was also lower (0.2 +/- 0.4 vs. 0.4 +/- 0.5 mg, p = 0.04). Handgrip exercise, however, did not decrease endpoints in patients on beta-blocker medication.

CONCLUSIONS

Use of isometric handgrip exercise with DASE decreases time to target heart rate, recovery time, overall study time, and mean dosage of dobutamine and atropine. In patients not on beta-blocker medication, handgrip exercise should be routinely incorporated into all DASE protocols.

Safety of stress echocardiography (from the International Stress Echo Complication Registry)

The safety of any diagnostic test is a major issue in deciding its practicability and cost-effectiveness. The aim of this study was to evaluate the safety of various stress echocardiographic modalities in the "real world." From February 1998 to January 2004, a simple written questionnaire was distributed to echocardiography laboratories across the world known to perform stress echocardiography. The following categories of major complications (known to occur during stress testing) were indicated: sustained ventricular tachycardia (> 30 beats/min), ventricular fibrillation, myocardial infarction, third-degree atrioventricular block, severe hypotension requiring therapy, cardiac asystole, cardiac rupture, stroke, and death. Three hundred centers were polled, from which 71 co-investigators responded and reported on 85,997 patient examinations. Exercise was used in 26,295 cases, dobutamine in 35,103, and dipyridamole in 24,599 cases. Life-threatening events occurred in 86 cases: during exercise in 4 patients (event rate 1 in 6,574), during dobutamine infusion (small dose for viability and/or large dose for ischemia) in 63 patients (event rate 1 in 557), and during dipyridamole stress testing in 19 patients (event rate 1 in 1,294). Of the 86 patients with complications, 5 died during dobutamine stress testing (ventricular fibrillation, n = 2; cardiac rupture, n = 3) and 1 after dipyridamole testing (cardiogenic shock). In conclusion, stress echocardiography is a safe method in the real world, but serious complications may occur. Exercise seems safer than pharmacologic stress and dipyridamole safer than dobutamine, possibly because of preselection criteria.

Low-gradient aortic valve stenosis: value and limitations of dobutamine stress testing

Aortic valve stenosis has already reached endemic proportions in Western countries. As the prognosis of low-flow aortic valve stenosis under medical treatment is dismal, surgery is recommended in most patients. Preoperative dobutamine stress testing may help to assess surgical risk, but there is no strong scientific evidence to deny surgery based exclusively on the results of this test. The problems associated with clinical decision making in this condition are reviewed.

Evaluation of restenosis and extent of coronary artery disease in patients with previous percutaneous coronary interventions by dobutamine stress real-time myocardial contrast perfusion imaging

OBJECTIVES

To assess the accuracy of real-time myocardial contrast perfusion imaging (MCPI) for the diagnosis of restenosis and extent of coronary artery disease (CAD) in patients with previous percutaneous coronary intervention (PCI).

METHODS

56 patients were studied 1.9 (SD 1.4) years after PCI. They underwent MCPI with commercially available ultrasound contrast agents (Optison or Definity) at rest and at peak dobutamine-atropine stress. Coronary angiography was performed within one month. Significant CAD was defined as >or= 50% stenosis in >or= 1 major epicardial coronary artery. Significant restenosis was defined as >or= 50% stenosis in a coronary segment with previous intervention.

RESULTS

Reversible perfusion abnormalities were detected in 40 of 43 patients with significant CAD and in 4 of 13 patients without (overall sensitivity 93%, 95% CI 85% to 99%; specificity 69%, 95% CI 44% to 94%; and accuracy 88%, 95% CI 79% to 96%). Significant restenosis in >or= 1 coronary artery with previous PCI was detected in 38 (68%) patients. Reversible perfusion abnormalities were present in 35 of them (sensitivity 92%, 95% CI 84% to 99%). Reversible perfusion abnormalities were detected in >or= 2 vascular distributions in 20 of 28 patients with multivessel CAD and in 3 of 28 patients without (sensitivity 71%, 95% CI 55% to 88%; specificity 89%, 95% CI 78% to 99%; and accuracy 80%, 95% CI 70% to 91%). Restenosis was detected in 41 coronary arteries. Sensitivity of MCPI for regional diagnosis of restenosis was 73% (95% CI 60% to 87%), specificity was 75% (95% CI 60% to 90%), and accuracy was 74% (95% CI 64% to 84%).

CONCLUSION

Dobutamine stress MCPI is a useful technique for the evaluation of restenosis and extent of CAD after PCI.

Outcomes after normal dobutamine stress echocardiography and predictors of adverse events: long-term follow-up of 3014 patients

AIMS

Normal exercise echocardiography predicts a good prognosis. Dobutamine stress echocardiography (DSE) is generally reserved for patients with comorbidities which preclude exercise testing. We evaluated predictors of adverse events after normal DSE.

METHODS AND RESULTS

We studied 3014 patients (1200 males, 68+/-12 years) with normal DSE, defined as the absence of wall motion abnormality at rest or with stress. During median follow-up of 6.3 years, all-cause mortality and cardiac events, defined as myocardial infarction and coronary revascularization, occurred in 920 (31%) and 231 (7.7%) patients, respectively. Survival and cardiac event-free probabilities were 95 and 98% at 1 year, 78 and 93% at 5 years, and 56 and 89% at 10 years, respectively. Age, diabetes mellitus, and failure to achieve 85% age-predicted maximal heart rate were independent predictors of mortality and cardiac events. Patients with all three of these characteristics had a 13% probability of cardiac events within the first year and higher risk throughout follow-up.

CONCLUSION

Prognosis after normal DSE is not necessarily benign, but depends on patient and stress test characteristics. Careful evaluation, using clinical and stress data, is required to identify patients with normal DSE who are at increased risk of adverse outcomes during long-term follow-up.

Comparison of real-time tri-plane and conventional 2D dobutamine stress echocardiography for the assessment of coronary artery disease

AIMS

Although dobutamine stress echocardiography (DSE) is an accepted tool for the diagnosis of coronary artery disease (CAD), it requires subsequent image acquisitions of the left ventricle (LV) in order to visualize all segments. This makes the procedure relatively time-consuming and might limit its accuracy. With the introduction of matrix array transducers, the real-time simultaneous acquisition of all LV segments has become possible using multi-plane imaging. The purpose of this study was: (i) to test the feasibility and efficiency of real-time tri-plane (RT3P) imaging during DSE, (ii) to compare the accuracy of RT3P DSE in detecting CAD using coronary angiography as the reference method.

METHODS AND RESULTS

Thirty-six patients suspected of CAD were prospectively enrolled. Both conventional two-dimensional (2D) and RT3P imaging were performed during a DSE protocol. Coronary angiography was performed within 24 h. Ultrasound data were acquired at each stage of the DSE. The total effective acquisition time for RT3P imaging was significantly shorter (55+/-29 vs. 137+/-63 s, P<0.001). Data yield was similar for both methods (2D: 98% vs. 3D: 97%). Overall sensitivity (93%), specificity (75%), and accuracy (89%) were identical between both methods. On a segmental level, the sensitivity, specificity, and accuracy of the RT3P and the 2D DSE were similar.

CONCLUSION

RT3P imaging fastens the DSE protocol without compromising the accuracy for the diagnosis of CAD. This could facilitate a more wide-spread use of DSE and therefore contributes positively to its routine clinical acceptance.

[Myocardial viability in a single-vessel disease: the role of a dobutamine stress echocardiography]

OBJECTIVE

To investigate a group of patients that have a significant lesion in a single-vessel and to demonstrate whether or not the sensitivity and specificity of a dobutamine stress echocardiography (DSE) was valuable in the evaluation of myocardial viability for these patients.

METHODS

Twenty patients who had undergone percutaneous transluminal coronary angioplasty (PTCA) were studied. This group was evaluated 2 to 7 days (3.65 +/- 1.69) before the procedure and 2 to 5 days (4 +/- 0.80) after the procedure with a DSE. Myocardial viability was assessed three months after the procedure using a two dimensional echocardiogram. Twelve patients underwent PTCA on the left anterior descending artery (LAD), 7 on the right coronary artery (RC) and 1 on the circumflex artery (CX). Only one right coronary artery procedure was not 100% successful.

RESULTS

From the 340 segments that were studied, 99 (29.18%) demonstrated contractile alterations of which 63 were hypokinetic (63.4%), 28 akinetic (28.28%) and 8 dyskinetic (8.08%). In reference to the segments involved, we obtained a sensitivity of 92.59%, specificity of 84.45%, and accuracy of 88.88% for the DSE. The solitary case of PTCA for the circumflex artery demonstrated 100% sensitivity. The LAD demonstrated a sensitivity of 88.58%, specificity of 95% and accuracy of 90.91%. For the RC segments, sensitivity was 91.30%, specificity 83.33% and accuracy 88.71%. All dyskinetic segments were unviable. The DSE predicted a 91.48% recovery rate for the 63 hypokinetic segments.

CONCLUSION

The DSE is an effective test for evaluating myocardial viability in patients with a significant single-vessel disease.

Incremental Value of Strain Rate Analysis as an Adjunct to Wall-Motion Scoring for Assessment of Myocardial Viability by Dobutamine Echocardiography

Background— Assessment of myocardial viability based on wall-motion scoring (WMS) during dobutamine echocardiography (DbE) is difficult and subjective. Strain-rate imaging (SRI) is quantitative, but its incremental value over WMS for prediction of functional recovery after revascularization is unclear.

Methods and Results— DbE and SRI were performed in 55 stable patients (mean age, 64±10 years; mean ejection fraction, 36±8%) with previous myocardial infarction. Viability was predicted by WMS if function augmented during low-dose DbE. SR, end-systolic strain (ESS), postsystolic strain (PSS), and timing parameters were analyzed at rest and with low-dose DbE in abnormal segments. Regional and global functional recovery was defined by side-by-side comparison of echocardiographic images before and 9 months after revascularization. Of 369 segments with abnormal resting function, 146 showed regional recovery. Compared with segments showing functional recovery, those that failed to recover had lower low-dose DbE SR, SR increment (ΔSR), ESS, and ESS increment (ΔESS) (each P <0.005). After optimal cutoffs for the strain parameters were defined, the sensitivity of low-dose DbE SR (78%, P =0.3), ΔSR (80%, P =0.1), ESS (75%, P =0.6), and ΔESS (74%, P =0.8) was better though not significantly different from WMS (73%). The specificity of WMS (77%) was similar to the SRI parameters. Combination of WMS and SRI parameters augmented the sensitivity for prediction of functional recovery above WMS alone (82% versus 73%, P =0.015; area under the curve=0.88 versus 0.73, P <0.001), although specificities were comparable (80% versus 77%, P =0.2).

Conclusions— The measurement of low-dose DbE SR and ΔSR is feasible, and their combination with WMS assessment improves the sensitivity of viability assessment with DbE.

Myocardial Strain Analysis in Acute Coronary Occlusion

Background— This study proposes 2 new echocardiographic indices with potential application in acute coronary artery occlusion to differentiate between viable and necrotic myocardium and to identify reperfusion. We investigated whether the ratio between systolic lengthening and combined late and postsystolic shortening (L-S ratio) could identify viable myocardium and whether systolic myocardial compliance, calculated as systolic lengthening divided by systolic pressure rise, could identify necrotic myocardium.

Methods and Results— In anesthetized dogs, we measured left ventricular (LV) pressure and long-axis strain by Doppler echocardiography (SDE) and sonomicrometry. The left anterior descending coronary artery was occluded for 15 minutes with 3-hour reperfusion (n=6), for 4 hours with 3-hour reperfusion (n=6), or for 4 hours with no reperfusion (n=6). Myocardial work was quantified by pressure–segment length analysis, necrosis by triphenyltetrazolium chloride staining, and edema by water content. L-S ratio and systolic compliance were calculated by SDE. The L-S ratio ranged between 0.00 and 1.00 and was well correlated with regional myocardial work ( r =0.77, P <0.0001). In entirely passive myocardium, the L-S ratio approached 1 and was similar in viable (0.88±0.02) and necrotic (0.81±0.03) myocardium. Compliance, however, was reduced in necrotic myocardium owing to edema (0.07±0.01%/mm Hg) but was preserved in viable myocardium (0.15±0.01%/mm Hg, P <0.05). Reperfusion of viable myocardium caused a reduction of the L-S ratio after 15 minutes (0.57±0.06, P <0.05), reflecting recovery of function. Reperfusion of necrotic myocardium caused no change in the L-S ratio, but compliance was further reduced within 15 minutes (0.03±0.01%/mm Hg, P <0.05).

Conclusion— Myocardial L-S ratio and compliance by SDE identified active contraction and necrosis, respectively. These indices should be tested clinically for assessment of myocardial viability and reperfusion.

Right vs. left ventricular contractile reserve in one-year prognosis of patients with idiopathic dilated cardiomyopathy: Assessment by dobutamine stress echocardiography

AIM

To determine prognostic implications of the assessment of right (RV) vs. left ventricular (LV) contractile reserve with dobutamine echocardiography in patients with idiopathic dilated cardiomyopathy.

METHODS AND RESULTS

Forty-eight consecutive patients (41 male, NYHA class III/IV 13 patients, LV ejection fraction 19+/-8%) were subjected to dobutamine stress echocardiography in incremental stages lasting 5 min each. Contractile reserve was defined as the difference between the values of LV ejection fraction and RV fractional area change obtained at peak dobutamine dose and the baseline values. Patients were followed for one year after enrollment for combined end-point of cardiac death, partial left ventriculectomy and hospitalization for congestive heart failure. During the follow-up 15/48 patients reached combined end-point. Patients who reached end-point had lower RV and LV contractile reserves (14+/-5 vs. 8+/-6%, p=0.0014, and 9+/-5 vs. 3+/-2%, p<0.001, respectively). Kaplan-Meier curves demonstrated that both LV and RV contractile reserves can identify patients with dismal prognosis (log rank=17.02 and log rank=14.66, respectively, p<0.001 for both). Multivariate analysis identified dobutamine induced change in LV functional reserve as the only independent predictor of combined end-point (beta=-0.63, p=0.0035).

CONCLUSION

Both RV and LV contractile reserves can be used for prognostic stratification in patients with idiopathic dilated cardiomyopathy. It appears that dobutamine induced change in LV functional reserve may better identify patients with dismal prognosis.

Segurança e exeqüibilidade do ecocardiograma sob estresse com dobutamina e atropina em pacientes octogenários

OBJECTIVE

To assess the feasibility and safety of dobutamine-atropine stress echocardiography (DASE) in octogenarians.

METHODS

We evaluated 5,467 DASE which were distributed in two groups: group I (GI) with 203 DASE performed in octogenarians, and group II (GII), the control group, with 5,264 DASE. The mean age of GI and GII was 83 +/- 3 (80-95) and 59 +/- 11 (17-79) years, respectively. DASE parameters that were prospectively collected, were compared and analyzed.

RESULTS

The percentage of patients that achieved maximum heart rate was 63.5% in GI and 41% in GII (p < 0.001), and GI patients required less atropine compared to GII (GI = 47%, GII = 78%, p < 0.001). The presence of chest pain (GI = 13%, GII = 15.6%, p = 0.429) and DASE positive for myocardial ischemia (GI = 20.7%, GII = 16.9%, p = 0.296) were not statistically different between the two groups. However, concomitant positive DASE and absence of chest pain (GI = 17%, GII = 11%, p = 0.029) was higher in GI. The incidence of premature beats in GI was higher than in GII (GI = 47.8%, GII = 27.6%, p < 0.001), and there were more supraventricular tachyarrhythmias (ST) in GI than in GII (GI = 5.9%, GII = 1.9%, p = 0.001). Out of 11 ST that happened in GI, 9 reverted spontaneously. There weren't either deaths or acute myocardial infarction. Ventricular fibrillation only happened in GII (2 cases, 0.03%).

CONCLUSION

In the present study, octogenarians achieved maximum heart rate more frequently despite the lesser amount of atropine that they required for DASE completion. Moreover, in this elderly population, there was a higher correlation between positive DASE and absence of chest pain. Although octogenarians did present more heart rhythm disturbs, they usually resolved spontaneously. In our study, DASE proved to be feasible and safe in octogenarians.

End-systolic pressure/volume relationship during dobutamine stress echo: a prognostically useful non-invasive index of left ventricular contractility

AIMS

Left ventricular end-systolic pressure-volume relationship (PVR) provides a robust, relatively load-insensitive evaluation of contractility and can be assessed non-invasively during exercise echo. Dobutamine might provide an exercise-independent alternative approach to assess inotropic reserve. The feasibility of a non-invasive estimation of PVR during dobutamine stress in the echo lab and its relationship with subsequent clinical events was assessed.

METHODS AND RESULTS

We enrolled 137 consecutive patients referred for dobutamine stress echo. To build the PVR, the force was determined at different heart rate increments during stepwise dobutamine infusion as the ratio of the systolic pressure/end-systolic volume index. The PVR at increasing heart rate was flat-biphasic in 65 and up-sloping in 72 patients: 42 patients underwent surgery and 95 patients were treated medically (median follow-up, 18 months; interquartile range, 12-24). Events occurred in 18 patients (death in eight, acute heart failure in 10); a flat-biphasic PVR was independent predictor of events (RR=10.16, P<0.01).

CONCLUSION

PVR is feasible during dobutamine stress. This index of global contractility is reasonably simple, does not affect the imaging time, and only minimally prolongs the off-line analysis time. It allows unmasking quite different, and heterogeneous, contractility reserve patterns underlying a given ejection fraction at rest. The best survival is observed in patients with up-sloping PVR, whereas flat-biphasic pattern is a strong predictor of cardiac events.

Detection of myocardial viability by dobutamine stress echocardiography: incremental value of diastolic wall thickness measurement

OBJECTIVE

To assess the diagnostic accuracy of baseline diastolic wall thickness (DWT) alone and as an adjunct to dobutamine stress echocardiography (DSE) for prediction of myocardial viability in patients with ischaemic left ventricular (LV) dysfunction, with the recovery of resting function after revascularisation as the yardstick.

PATIENTS

24 patients with ischaemic LV dysfunction (ejection fraction < 40%) scheduled for surgical revascularisation.

SETTING

Regional cardiothoracic centre.

METHODS

All patients underwent DSE before and resting echocardiography six months after revascularisation. DWT was measured in each of the 16 LV segments. A receiver operating characteristic (ROC) and a multi-ROC curve were generated to assess the ability of DWT alone and in combination with DSE to predict myocardial viability.

RESULTS

DWT > 0.6 cm provided a sensitivity of 80%, a specificity of 51%, and a negative predictive value of 80% for the prediction of viability in akinetic segments. DSE had an excellent specificity (92%) but a modest sensitivity (60%) in akinetic segments. A combination of improvement at DSE or DWT > 0.8 cm improved sensitivity (90% v 60%, p < 0.001) and negative predictive value (92% v 78%, p = 0.03) in akinetic segments compared with DSE alone. This was achieved with some loss in specificity (75% v 92%, p = 0.01) and positive predictive value (71% v 82%, p = 0.79).

CONCLUSIONS

DWT measurement may improve the sensitivity of DSE for the detection of myocardial viability. Akinetic segments with DWT > 0.8 cm have a good chance of recovery despite the absence of contractile reserve during DSE. Further testing may be required before excluding myocardial viability in these cases.

Intravenous myocardial contrast echocardiography predicts regional and global left ventricular remodelling after acute myocardial infarction: comparison with low dose dobutamine stress echocardiography

OBJECTIVE

To assess the role of intravenous myocardial contrast echocardiography (MCE) in predicting functional recovery and regional or global left ventricular (LV) remodelling after acute myocardial infarction (AMI) compared with low dose dobutamine stress echocardiography (LDSE).

METHODS

21 patients with anterior AMI and successful primary angioplasty underwent MCE and LDSE during the subacute stage (2-4 weeks after AMI). Myocardial perfusion and contractile reserve were assessed in each segment (12 segment model) with MCE and LDSE. The 118 dyssynergic segments in the subacute stage were classified as recovered, unchanged, or remodelled according to wall motion at six months' follow up. Percentage increase in LV end diastolic volume (%DeltaEDV) was also calculated.

RESULTS

The presence of perfusion was less accurate than the presence of contractile reserve in predicting regional recovery (55% v 81%, p < 0.0001). However, the absence of perfusion was more accurate than the absence of contractile reserve in predicting regional remodelling (83% v 48%, p < 0.0001). The number of segments without perfusion was an independent predictor of %DeltaEDV, whereas the number of segments without contractile reserve was not. The area under the receiver operating characteristic curve showed that the number of segments without perfusion predicted substantial LV dilatation (%DeltaEDV > 20%) more accurately than did the number of segments without contractile reserve (0.88 v 0.72).

CONCLUSION

In successfully revascularised patients with AMI, myocardial perfusion assessed by MCE is predictive of regional and global LV remodelling rather than of functional recovery, whereas contractile reserve assessed by LDSE is predictive of functional recovery rather than of LV remodelling.

Comparison of deformation imaging and velocity imaging for detecting regional inducible ischaemia during dobutamine stress echocardiography

AIMS

To determine whether Doppler based myocardial tissue velocity imaging (TVI) or strain rate imaging (SRI) is more accurate in detecting stress-induced ischaemia during dobutamine stress echocardiography (DSE).

METHODS AND RESULTS

Regional myocardial velocity, displacement, strain rate and strain patterns during DSE were investigated in 44 routine patients with known or suspected coronary artery disease. Simultaneous perfusion scintigraphy defined regional ischaemia. Curves and curved-M-mode patterns were analysed and receiver-operating-characteristics of TVI and SRI parameters were compared by their area under the curve (AUC) in the receiver-operating-characteristics. In non-ischaemic segments, peak systolic velocity and strain rate increased significantly. Unlike SRI, TVI parameters had higher values in basal than in apical segments. In 47 segments of 19 segments DSE-induced ischaemia, which was proven by scintigraphy. In ischaemia, velocity and strain rate increased less. Post-systolic shortening (PSS) was always seen in SRI but not regularly in TVI. Peak systolic velocity and systolic displacement were the best TVI-parameters of stress-induced ischaemia (AUC 0.68 and 0.77, respectively.), in SRI it was the ratio of PSS and maximal segmental deformation (AUC=0.95, p < 0.0001).

CONCLUSION

Compared to TVI, SRI parameters showed no major apico-basal gradient and had significantly higher diagnostic accuracy, comparable to conventional reading. SRI thus appears superior to TVI for regional ischaemia detection during DSE and may be preferred to support conventional DSE reading.

Anginal Threshold between Stress Tests: Exercise versus Dobutamine Stress Echocardiography

PURPOSE

Dobutamine echocardiography (DOB) can be substituted to exercise testing when necessary for clinical reasons. Current literature suggests DOB is maximal when 85% of maximal predicted heart rate (%PHR) is achieved (similar to EX), but there is little evidence to determine whether this target has the same clinical significance as during EX. We therefore performed this study to compare the ischemic threshold between EX and DOB.

METHODS

Twenty men with stable angina underwent in a random order DOB and EX echocardiograms after being weaned off their cardiac medications. Electrocardiography, heart rate (HR), and systolic blood pressure were recorded every minute. Ischemic threshold was defined as the precise time at which clinical angina occurred.

RESULTS

Anginal threshold appeared consistently at a higher level for DOB than EX as evidenced by the higher rate-pressure product (RPP) values (22,492 +/- 4,300 vs 20,371 +/- 5,367 bpm x mm Hg, DOB vs EX, respectively, P = 0.02), HR (126 +/- 23 vs 119 +/- 15 bpm, P = 0.01), and %PHR (79 +/- 15% vs 74 +/- 10%, P < 0.01). Thirty-two percent of the subjects presented an ischemic HR above 85% of PHR and 60% had a higher ischemic HR during DOB versus EX.

CONCLUSIONS

This study shows that estimation of anginal threshold during DOB is feasible and is slightly higher (approximately 10%) than during EX. Extrapolation of a cut off target heart rate from an exercise modality to a pharmaceutical one may not be valid.

Implementing contrast echocardiography in the laboratory

Contrast echocardiography is an important and a significant addition to a modern echocardiography laboratory. Its successful implementation is dependent on a team approach between sonographers, nurses, and physicians. A practical plan is one that includes a proper understanding of indications, logistical matters, technical and performance standards, and reimbursement issues.

Is post-systolic motion the optimal ultrasound parameter to detect induced ischaemia during dobutamine stress echocardiography?

AIMS

Doppler myocardial imaging (DMI) has been suggested as a method of quantifying induced ischaemia during dobutamine stress echocardiography (DSE). The aim of the present study was to investigate both standard systolic and diastolic parameters, but more specifically to address the phenomenon of post-systolic motion (PSM) as a marker of acquired ischaemia during DSE using pulsed-wave DMI.

METHODS AND RESULTS

We examined 60 patients without previous myocardial infarction who underwent DSE. Peak systolic, post-systolic, early and late diastolic velocities were measured at rest and during stress. Myocardial segments (n = 908) were divided into ISCHAEMIC and NON-ISCHAEMIC groups according to the presence of significant angiographic coronary stenosis. ISCHAEMIC segments (n = 357) compared with NON-ISCHAEMIC segments (n = 551) demonstrated a reduced increase of systolic velocity (8.0-12.7 vs 9.3-16.4 cm/s, P < 0.05), prominent PSM (5.8-8.3 vs 0.63-2.1 cm/s, P < 0.000001) and reduced early diastolic velocity (6.5-10.2 vs 7.9-13.2 cm/s, P < 0.04) during stress. The peak velocity of PSM was the most accurate index of induced ischaemia (sensitivity 73-100%, specificity 82-97%) compared to systolic and early diastolic velocities (sensitivity 52-77% and 63-68%, specificity 63-77% and 59-81%, respectively).

CONCLUSION

PSM derived by pulsed-wave DMI during DSE was the most sensitive index of acquired ischaemia compared to other functional DMI indices.

A meta-analysis comparing the prognostic accuracy of six diagnostic tests for predicting perioperative cardiac risk in patients undergoing major vascular surgery

OBJECTIVE

To evaluate the discriminatory value and compare the predictive performance of six non-invasive tests used for perioperative cardiac risk stratification in patients undergoing major vascular surgery.

DESIGN

Meta-analysis of published reports.

METHODS

Eight studies on ambulatory electrocardiography, seven on exercise electrocardiography, eight on radionuclide ventriculography, 23 on myocardial perfusion scintigraphy, eight on dobutamine stress echocardiography, and four on dipyridamole stress echocardiography were selected, using a systematic review of published reports on preoperative non-invasive tests from the Medline database (January 1975 and April 2001). Random effects models were used to calculate weighted sensitivity and specificity from the published results. Summary receiver operating characteristic (SROC) curve analysis was used to evaluate and compare the prognostic accuracy of each test. The relative diagnostic odds ratio was used to study the differences in diagnostic performance of the tests.

RESULTS

In all, 8119 patients participated in the studies selected. Dobutamine stress echocardiography had the highest weighted sensitivity of 85% (95% confidence interval (CI) 74% to 97%) and a reasonable specificity of 70% (95% CI 62% to 79%) for predicting perioperative cardiac death and non-fatal myocardial infarction. On SROC analysis, there was a trend for dobutamine stress echocardiography to perform better than the other tests, but this only reached significance against myocardial perfusion scintigraphy (relative diagnostic odds ratio 5.5, 95% CI 2.0 to 14.9).

CONCLUSIONS

On meta-analysis of six non-invasive tests, dobutamine stress echocardiography showed a positive trend towards better diagnostic performance than the other tests, but this was only significant in the comparison with myocardial perfusion scintigraphy. However, dobutamine stress echocardiography may be the favoured test in situations where there is valvar or left ventricular dysfunction.

[Use of stress echocardiography in detecting silent myocardial ischemia in hemodialysis patients]

The chronic renal failure treated by hemodialysis is associated with a high incidence of prematured cardiovascular diseases, which represents the major causes of morbidity and mortality in hemodialysis patients.

OBJECTIVE OF THE STUDY

To evaluate the interest of stress echocardiography for the detection of silent myocardial ischaemia in the chronic renal failure treated by hemodialysis.

METHODS

24 dobutamine stress echocardiography have been achieved in to patients having an average old of 61 +/- 11 years, 15 men and 3 women, with an average dialysis duration of 55 +/- 27 months. Only asymptomatic patients and those presenting an anomaly during the systematic annual echocardiography supervision have been included in this retrospective work. All echocardiography enregistrements have been achieved in the same center and by the same and experimented cardiologist.

RESULTS

75% of patients had an arterial hypertension antecedents, 65% were smokers, 50% had a dyslipidemia, 38% presented an arteriopathy of the inferior members, 30% had diabetes and 22% were obese; 8 (33.5%) stress echocardiographies were negatives. 6 patients have had 2 stress echocardiographies. A coronarography was realized in 16 patients and one of those was strictly normal (6.25% were false positive). 8 patients have had an angioplasty with stent making (1 simple stent, 7 double stent); 2 coronaries by-pass have been done in 2 patients. One patients refused surgery. Insignificant atheroumatous coronary lesions have been detected in 4 patients. In this study, the stress echocardiography enabled to detect a silent myocardial ischaemia in 15/16 patients (93.7%) and to treat 10/15 patients (66.5% including 20% by surgery).

CONCLUSION

The sensibility of this test must be compared to the thallium scintigraphy coupled with dipyridamole as part of a larger prospective study.

Prediction of mortality in patients without angina: use of an exercise score and exercise echocardiography

BACKGROUND

Exercise testing has limited efficacy for identifying coronary artery disease (CAD) in the absence of anginal symptoms. Exercise echocardiography is more accurate than standard exercise testing, but its efficacy in this situation has not been defined. We sought to identify whether the Duke treadmill score or exercise echocardiography (ExE) could be used to identify risk in patients without anginal symptoms.

METHODS

We studied 1859 patients without typical or atypical angina, heart failure, or a history or ECG evidence of infarction or CAD, who were referred for ExE, of whom 1832 (age 51+/-15 years, 944 men) were followed for up to 10 years. The presence and extent of ischaemia and scar were interpreted by expert reviewers at the time of the original study.

RESULTS

Exercise provoked significant (>0.1mV) ST segment depression in 215 patients (12%), and wall motion abnormalities in 137 (8%). Seventy-eight patients (4%) died before revascularization, only 17 from known cardiac causes. The independent predictors of death were age (RR 1.1, p<0.0001), smoking, Duke treadmill score (RR 0.9, p<0.0001) and resting LV dysfunction (RR 1.9, p<0.04), but did not include ischaemia at ExE. Echocardiography was not predictive of outcome in subgroups with an intermediate or high risk Duke score, nor in patients with two or more risk factors.

CONCLUSIONS

Patients without anginal symptoms have a low mortality, especially from cardiac causes. If such individuals undergo exercise testing and a resting echocardiogram, exercise echocardiography does not offer additional prognostic information.

Exercise stress testing, myocardial perfusion imaging and stress echocardiography for detecting restenosis after successful percutaneous transluminal coronary angioplasty: a review of performance

When chest symptoms recur in a patient who underwent percutaneous transluminal coronary angioplasty (PTCA), it is necessary to rule out restenosis (R). Three main noninvasive tests suggest the presence of R: exercise stress test (XT), myocardial perfusion imaging (MPI) and stress echocardiography (s-echo). The objectives of this review were: (1) to estimate the pretest probability of R as a function of time after PTCA in symptomatic patients and (2) to obtain an approximation of the diagnostic parameters of the XT, MPI and s-echo for detecting R. A MEDLINE search (English-language, years: 1980-2001) was conducted to identify studies examining post-PTCA functional testing for diagnosing R. Data from the studies were pooled. Comparing studies was often difficult due to varying methodology in the studies. Pretest probability of R in symptomatic patients increases in a nonlinear fashion from 20% or less at 1 month, to nearly 90% at 1-year postangioplasty. The approximated accuracy of the XT, MPI, and s-echo for detecting R was 62, 82 and 84%, respectively. During the first month after PTCA, none of the noninvasive modalities is able to accurately detect R. Late (7-9 months) after PTCA, the pretest probability of R is high and therefore the noninvasive measure may be spared. Our analysis suggests that MPI and s-echo should be preferred over the XT for diagnosing R.

Incremental value of myocardial contrast echocardiography for the prediction of recovery of function in dobutamine nonresponsive myocardium early after acute myocardial infarction

We hypothesized that the presence of microvascular integrity, detected by myocardial contrast echocardiography (MCE) in dobutamine nonresponsive segments, may enhance identification of recovery of function, which is a surrogate marker of myocardial viability. Accordingly, 96 patients underwent dobutamine echocardiography (DE) and intravenous MCE on the same day, 4.6 +/- 1.5 days after acute myocardial infarction (AMI). Recovery of function of akinetic segments was assessed at 3 months after AMI. Of 387 akinetic segments, 102 (26%) recovered function during follow-up. Sensitivities and specificities of MCE, DE, and the combination of DE and MCE in dobutamine nonresponsive segments were 58%, 59%, and 79%, respectively (p <0.001, compared with MCE and DE) and 76%, 84%, and 69%, respectively (p <0.05 compared with DE) for predicting recovery of function. In anterior AMI, the positive and negative predictive values of MCE, DE, and the combination of DE and MCE were 47% and 88%, 57% and 89%, and 49% and 95%, respectively. Multivariate analysis using clinical characteristics, electrocardiography, biochemical factors, MCE, and DE showed that the combination of DE and MCE in dobutamine nonresponsive segments (p <0.00001) and Q-wave AMI (p = 0.002) were the only independent predictors of recovery of function. Thus, for optimum prediction of recovery of function after AMI, a combination of DE and MCE in dobutamine nonresponsive segments may be utilized.

Usefulness of quantitative echocardiographic techniques to predict recovery of regional and global left ventricular function after acute myocardial infarction

The left ventricular response to dobutamine may be quantified using tissue Doppler measurement of myocardial velocity or displacement or 3-dimensional echocardiography to measure ventricular volume and ejection fraction. This study sought to explore the accuracy of these methods for predicting segmental and global responses to therapy. Standard dobutamine and 3-dimensional echocardiography were performed in 92 consecutive patients with abnormal left ventricular function at rest. Recovery of function was defined by comparison with follow-up echocardiography at rest 5 months later. Segments that showed improved regional function at follow-up showed a higher increment in peak tissue Doppler velocity with dobutamine therapy than in nonviable segments (1.2 +/- 0.4 vs 0.3 +/- 0.2 cm/s, p = 0.001). Similarly, patients who showed a >5% improvement of ejection fraction at follow-up showed a greater displacement response to dobutamine (6.9 +/- 3.2 vs 2.1 +/- 2.3 mm, p = 0.001), as well as a higher rate of ejection fraction response to dobutamine (9 +/- 3% vs 2 +/- 2%, p = 0.001). The optimal cutoff values for predicting subsequent recovery of function at rest were an increment of peak velocity >1 cm/s, >5 mm of displacement, and a >5% improvement of ejection fraction with low-dose dobutamine.

Effects of acute myocardial ischemia on QT dispersion by dipyridamole stress echocardiography

Increased dispersion of the QT interval has been observed during pacing or exercise stress testing in patients with coronary artery disease (CAD). It has not been established whether this phenomenon is a consequence of ischemia. Therefore, we sought to evaluate whether dipyridamole-induced myocardial ischemia, as directly detected by echocardiographic monitoring of regional contractile function, would affect QT dispersion. Twenty-four patients with nonsignificant and 34 patients with significant CAD but no previous myocardial infarction underwent dipyridamole stress echocardiography while not taking medications. QT dispersion was measured on a 12-lead electrocardiogram at baseline and at various times after dipyridamole infusion. Dipyridamole infusion did not influence QT dispersion in patients without CAD. QT dispersion was similarly unaffected in patients with CAD in whom dipyridamole did not induce wall motion abnormalities. In contrast, in patients with positive dipyridamole stress test findings, QT dispersion increased from 60 +/- 17 ms at baseline to 94 +/- 25 ms during peak infusion (p <0.0001), with a time course mirroring that of development of contractile abnormalities. QT dispersion returned to 63 +/- 25 ms upon relief of ischemia by administration of aminophylline. The increase in QT dispersion was significantly related to the extent of contractile dysfunction induced by dipyridamole. Although ST-segment depression occurred in only 40% of patients with positive dipyridamole stress test findings, 88% of such patients had an increase in QT dispersion. Analysis of the receiver-operating characteristic curve showed that a QT dispersion increase of > or =20 ms identified positive findings for dipyridamole stress echocardiography with 68% sensitivity and 91% specificity. Thus, QT dispersion is acutely affected by myocardial ischemia induced by the administration of dipyridamole. Measurement of QT dispersion may improve detection of stress-induced ischemia on surface electrocardiograms.