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Biomedical subjects

T H Marwick

Publications and source records attributed to T H Marwick.

At least 91 records · Page 5Linked to original sources
PubMed1998

Myocardial viability during dobutamine echocardiography predicts survival in patients with coronary artery disease and severe left ventricular systolic dysfunction.

OBJECTIVES: The purpose of this study was to assess whether the presence or absence of myocardial viability during dobutamine echocardiography (DE) predicts survival in patients with coronary artery disease (CAD) and severe left ventricular (LV) dysfunction. BACKGROUND: In patients with CAD, the presence of myocardial viability during DE identifies viable myocardium and predicts recovery of LV systolic function after revascularization. However, there is little data on the relation between myocardial viability and clinical outcome in patients with CAD and severe LV dysfunction. METHODS: We studied 318 patients with CAD and a LV ejection fraction (EF) < or =35% who underwent DE and were followed for 18+/-10 months. Patients were classified into four groups. Group I (n=85) consisted of patients who had evidence of myocardial viability and subsequently underwent revascularization. Group II (n=119) consisted of patients with myocardial viability who did not undergo revascularization. Group III (n=30) consisted of patients who did not have myocardial viability and underwent revascularization. Finally, group IV (n=84) patients lacked myocardial viability and did not undergo revascularization. RESULTS: The four groups had similar baseline characteristics and rest LVEF. During follow-up there were 51 deaths (16%). The mortality rate was 6% in group I, 20% in group II, 17% in group III and 20% in group TV (p=0.01, group I vs. other groups). CONCLUSIONS: In patients with CAD and severe LV dysfunction who demonstrated myocardial viability during DE, revascularization improved survival compared with medical therapy.

Aged↗
PubMed1998

Accuracy and feasibility of contrast echocardiography for detection of perfusion defects in routine practice: comparison with wall motion and technetium-99m sestamibi single-photon emission computed tomography. The Nycomed NC100100 Investigators.

OBJECTIVES: We sought to assess the feasibility and accuracy of myocardial contrast echocardiography (MCE) using standard imaging approaches for the detection of perfusion defects in patients who had a myocardial infarction (MI). BACKGROUND: Myocardial contrast echocardiography may be more versatile than perfusion scintigraphy for identifying the presence and extent of perfusion defects after MI. However, its reliability in routine practice is unclear. METHODS: Fundamental or harmonic MCE was performed with continuous or triggered imaging in 203 patients with a previous MI using bolus doses of a perfluorocarbon-filled contrast agent (NC100100). All patients underwent single-photon emission computed tomography (SPECT) after the injection of technetium-99m (Tc-99m) sestamibi at rest. Quantitative and semiquantitative SPECT, wall motion and digitized echocardiographic data were interpreted independently. The accuracy of MCE was assessed for detection of segments and patients with moderate and severe sestamibi-SPECT defects, as well as for detection of patients with extensive perfusion defects (>12% of left ventricle). RESULTS: In segments with diagnostic MCE, the segmental sensitivity ranged from 14% to 65%, and the specificity varied from 78% to 95%, depending on the dose of contrast agent. Using both segment- and patient-based analysis, the greatest accuracy and proportion of interpretable images were obtained using harmonic imaging in the triggered mode. For the detection of extensive defects, the sensitivity varied from 13% to 48%, with specificity from 63% to 100%. Harmonic imaging remained the most accurate approach. Time since MI and SPECT defect location and intensity were all determinants of the MCE response. The extent of defects on MCE was less than the extent of either abnormal wall motion or SPECT abnormalities. The combination of wall motion and MCE assessment gave the best balance of sensitivity (46% to 55%) and specificity (82% to 83%). CONCLUSIONS: Although MCE is specific, it has limited sensitivity for detection of moderate or severe perfusion defects, and it underestimates the extent of SPECT defects. The best results are obtained by integration with wall motion. More sophisticated methods of acquisition and interpretation are needed to enhance the feasibility of this technique in routine practice.

Contrast Media↗
PubMed1998

Association of chronotropic incompetence with echocardiographic ischemia and prognosis.

OBJECTIVES: This study sought to examine the prognostic importance of chronotropic incompetence among patients referred for stress echocardiography. BACKGROUND: Although chronotropic incompetence has been shown to be predictive of an adverse prognosis, it is not clear if this association is independent of exercise-induced myocardial ischemia. METHODS: Consecutive patients (146 men and 85 women; mean age 57 years) who were not taking beta-adrenergic blocking agents and were referred for symptom-limited exercise echocardiography were followed for a mean of 41 months. Chronotropic incompetence was assessed in two ways: (1) failure to achieve 85% of the age-predicted maximum heart rate and (2) a low chronotropic index, a heart rate response measure that accounts for effects of age, resting heart rate and physical fitness. RESULTS: The primary end point, a composite of death, nonfatal myocardial infarction, unstable angina and late (>3 months after the exercise test) myocardial revascularization, occurred in 41 patients. Failure to achieve 85% of the age-predicted maximum heart rate was predictive of events (relative risk [RR] 2.47, 95% confidence interval [CI] 1.28 to 4.79, p=0.007); similarly, a low chronotropic index was predictive (RR 2.44, 95% CI 1.31 to 4.55, p=0.005). Even after adjusting for myocardial ischemia and other possible confounders, failure to achieve 85% of age-predicted maximum heart rate was predictive (adjusted RR 2.20, 95% CI 1.11 to 4.37, p=0.02). A low chronotropic index also remained predictive (adjusted RR 1.85, 95% CI 0.98 to 3.47, p=0.06). CONCLUSIONS: Chronotropic incompetence is predictive of an adverse cardiovascular prognosis even after adjusting for echocardiographic myocardial ischemia.

Echocardiography↗
PubMed1998

Use of dobutamine echocardiography for cardiac risk stratification of patients with chronic renal failure.

OBJECTIVES: This study sought to define the value of dobutamine echocardiography (DbE) for cardiac risk stratification in patients with chronic renal failure (CRF). DESIGN: Outcome study correlating results of DbE with late cardiac events in patients with CRF. SETTING: Academic medical centre. SUBJECTS: All patients with CRF (serum creatinine > 2.5 mg dL-1) undergoing DbE were studied; we analysed 193 consecutive patients (aged 63 +/- 13 years, 73 men). INTERVENTIONS: A standard dobutamine-atropine stress was administered until attainment of peak dose, or the development of severe ischaemia or side-effects. The electrocardiogram (ECG) and echocardiogram were obtained before, during and after stress. Ischaemia was identified by new or worsening wall-motion abnormalities with stress. OUTCOME MEASURES: Patients were followed up after 38 +/- 14 months for cardiac death, myocardial infarction or coronary disease progression requiring revascularization. RESULTS: DbE demonstrated ischaemia in 36 patients (19%), scar in 36 (19%) and a normal study in 121 patients. The heart-rate response to dobutamine was submaximal (< 85% age-predicted heart rate) in the absence of wall-motion abnormalities in 69 patients (36%), 54 of whom completed the protocol. Follow-up data were complete in 191 patients (99%); cardiac events occurred in 33 patients (17%), including 17 with cardiac death, 7 with infarction, and 9 requiring late revascularization. Spontaneous events occurred in 7 patients with ischaemia, 3 with scar (8%), 11 with a nondiagnostic study (16%) and 3 patients with a normal study (6%). Over the entire follow-up, the event-free survival in patients with ischaemia (66%) was markedly lower than those without ischaemia (84%, P = 0.006). However, the event rate in patients with nonischaemic responses increased from 8% to 16% between 24 and 40 months, and whilst ischaemia was an independent predictor of outcome at 24 months, it was not at 40 months. CONCLUSIONS: In patients with CRF, the identification of ischaemia at DbE is associated with a significant risk of adverse cardiac events. Patients with nonischaemic scans have a low frequency of events over short-term follow-up, but this increases at later follow-up. These later events may reflect progressive coronary disease, attributable to the atherogenic milieu of these patients, and imply that repeated testing may be required to maintain cardiac risk stratification in patients with CRF.

Adrenergic beta-Agonists↗
PubMed1997

Incremental value of rubidium-82 positron emission tomography for prognostic assessment of known or suspected coronary artery disease.

Myocardial perfusion imaging using positron emission tomography (PET) may be more accurate for the diagnosis of coronary artery disease (CAD) than conventional imaging. The purpose of this study was to evaluate the prognostic implications of perfusion abnormalities in 685 patients (age 62 +/- 11 years, 199 women) studied by PET, and to assess the incremental value of these data in relation to prognostic implications of clinical and angiographic findings. Rubidium (Rb)-82 PET was performed before and after dipyridamole stress. Transient defects were detected in 227 patients (33%), and were moderate or greater in severity (> 15% of the left ventricle) in 84 (12%). Resting defects were present in 435 (64%) and were moderate or greater in severity in 216 (32%). The total extent of abnormally perfused myocardium was small (< 15% of the left ventricle) in 198 (29%), moderate in 216 (32%), and extensive in 105 (15%). Clinic review or standardized phone interview in 657 patients (96%) identified 151 cardiac events, including 81 cardiac deaths, 16 patients with myocardial infarction, 7 with unstable angina, and 47 with late revascularization (> 3 months after PET). Normal scans had a 90% event-free survival, compared with 87% in patients with small, 75% with moderate, and 76% with extensive defects (log rank chi-square 30, p <0.0001). Functional class, extent of CAD, and the presence and extent of perfusion defects (both at rest and during stress) were independent predictors of cardiac death and total cardiac events. In sequential Cox proportional-hazards models, the results of PET were incremental to those of clinical and angiographic evaluation. Thus, the presence and extent of damaged and jeopardized myocardium are independent and incremental predictors of outcome in patients undergoing Rb-82 PET.

Aged↗
PubMed1997

Influence of gender on physiologic response and accuracy of dobutamine echocardiography.

Dobutamine echocardiography (DE) has been shown to be safe, feasible, and accurate for identification of coronary artery disease (CAD) in mixed populations. The purpose of this study was to examine gender differences in physiologic response and accuracy of DE. We studied 2,886 consecutive DEs, performed in 2,748 patients, 1,209 of whom (44%) were women. A standard incremental protocol (5 to 40 microg/kg/min in 3-minute stages) was followed by atropine and/or an additional stage with 50 microg/kg/min, if the heart rate response was inadequate. Hemodynamic and echocardiographic findings were recorded at each stage. Three hundred sixty-nine patients without previous cardiac intervention (including 135 women) also underwent cardiac catheterization within 1 year of DE. Significant coronary stenoses (defined angiographically as >50% diameter) were present in 67% of women and 65% of men, of whom 55% and 65%, respectively, had multivessel disease. Women had a higher baseline heart rate (76 +/- 13 vs 73 +/- 14 beats/min, p <0.0001), and showed a more rapid increase in heart rate at low dose, with a higher age-predicted maximum heart rate at peak. This led to test termination at target heart rate but a submaximum dose in 22% of women versus 15% of men (p <0.0001) and less frequent administration of atropine (29% vs 34%, p <0.01). Dose-limiting side effects (8% vs 7%) and submaximum heart rate responses (14% vs 17%) were comparable in men and women. Even after the exclusion of negative DE at submaximal heart rate responses, the overall sensitivity was significantly lower in women than men (78% vs 88%, p <0.05), both for single (72% vs 78%, p <0.05) and for multivessel disease (82% vs 93%, p <0.05). The low specificity in both genders (55% vs 46%) probably reflected post-test referral bias. Thus, physiologic responses to dobutamine stress are comparable in men and women, except for a more rapid heart rate response in women, but the accuracy of DE for diagnosis of CAD in women is less than in men.

Aged↗
PubMed1997

Cardiac outcomes in coronary patients with submaximum dobutamine stress echocardiography.

This study evaluated the prediction of cardiac events (cardiac death, myocardial infarction, unstable angina, or late myocardial revascularization) in patients with submaximum responses to dobutamine stress, defined by attainment of <85% age-predicted heart rate. Of 1,772 patients undergoing dobutamine echocardiography over a 2-year period, 425 had a submaximum heart rate response. After exclusion of patients treated with beta-adrenoceptor blocking agents, 255 patients formed the study group. In these patients, the test was terminated after administration of the maximum dose of 40 microg/kg/min of dobutamine with atropine (end of protocol, n = 186), severe angina, ischemic ST-segment changes, or intolerable side effects (n = 69). Dobutamine-induced changes (ischemia, viability, or both) were detected in 46 patients, involving ischemia in 133 segments, viability in 23, and ischemia and viability in 16 segments. Patients were followed for an interval of 28 +/- 17 months; 5 (1.2%) were lost to follow-up. Of the medically treated patients, cardiac events occurred in 73 of 228 (31%), including cardiac death in 25 (11%), nonfatal myocardial infarction in 11 (4.8%), severe unstable angina in 35 (15%), and late revascularization in 2 (0.9%). Cardiac events occurred in 11 of 30 (36%) with inducible abnormalities, and 62 of 198 without inducible abnormalities (31%, p = NS). Thus, cardiac event rates are high in patients with inadequate chronotropic responses to dobutamine stress, irrespective of whether stress-induced changes are detected. A negative dobutamine echocardiogram at submaximum heart rate should be considered nondiagnostic.

Aged↗
PubMed1997

Determinants of functional capacity in chronic mitral regurgitation unassociated with coronary artery disease or left ventricular dysfunction.

Impaired functional capacity is common in patients with mitral regurgitation (MR), but the determinants of functional capacity in patients with normal left ventricular (LV) function are unclear. Forty patients with chronic, isolated, nonrheumatic MR with no coronary artery disease underwent exercise echocardiography with continuous expired gas analysis. Cardiac output and regurgitant stroke volume were measured at rest and immediately after exercise by pulsed-wave Doppler echocardiography. For controls, 17 healthy volunteers without MR were also studied. Patients achieved a significantly lower VO2max compared with controls (25.6 +/- 7.7 vs 31.7 +/- 7.7 ml/kg/min, p = 0.008). VO2max showed better correlations with exercise cardiac output than with cardiac output at rest in both patients and controls. Multiple linear regression identified exercise cardiac output (partial r = 0.65), patient age (partial r = -0.56), and gender as independent determinants of VO2max (multiple R = 0.85, p <0.001). Cardiac output at rest, LV ejection fraction, regurgitant stroke volume, and fraction were not significant determinants. With exercise, the regurgitant stroke volume increased in 13 patients and decreased in 27 patients. The former 13 patients had a significantly lower exercise cardiac output (7.4 +/- 2.5 vs 9.4 +/- 2.6 L/min, p = 0.026). Patients who stopped exercise due to dyspnea (n = 7) had a significantly lower exercise cardiac output and VO2max compared with those who stopped due to fatigue (n = 33), with no differences in resting or exercise regurgitant volume. Patients with an increase in LV end-systolic volume with exercise (n = 8) also had a significantly lower exercise cardiac output (6.9 +/- 1.9 vs 9.2 +/- 2.7 L/min, p = 0.037) and showed a trend toward a lower VO2max (21 +/- 7.5 vs 26 +/- 6.4 ml/kg/min, p = 0.07). In patients with chronic MR, exercise cardiac output is the major determinant of VO2max. Regurgitant volume and fraction are not related to functional capacity. Limitations in functional capacity in these patients may be more related to a diminished cardiac reserve than to a large regurgitant volume.

Anaerobic Threshold↗
PubMed1997

Accuracy and cost-effectiveness of exercise echocardiography for detection of coronary artery disease in patients with mitral valve prolapse.

Mitral valve prolapse is sometimes associated with chest pain, but this symptom may also be caused by coexisting coronary disease. The accuracy of exercise echocardiography in diagnosing coronary disease in these patients and the most cost-efficient diagnostic approach are unclear. We studied 96 patients (aged 59 +/- 12 years; 70 men) with mitral valve prolapse who underwent exercise electrocardiography, exercise echocardiography, and coronary angiography. The accuracies of seven diagnostic strategies based on the current and expected use of exercise electrocardiography and exercise echocardiography in patients with mitral valve prolapse were examined, with the costs calculated based on Medicare reimbursement. Thirteen (13.5%) patients had significant coronary artery disease. The sensitivity and specificity of exercise electrocardiography in the 71 patients with interpretable electrocardiograms were 50% and 72%, respectively. For the 73 patients who achieved >85% of maximal heart rate, 52 had interpretable exercise electrocardiograms (sensitivity 50%; specificity 69%). Exercise echocardiography had a sensitivity of 69% and a specificity of 98% in the 96 patients and a sensitivity of 82% and a specificity of 96% in patients who achieved >85% of maximal heart rate. Approaches adopting Bayes' theorem and restricting further investigation to patients with at least intermediate pretest probability of coronary disease were the least costly. When combined with exercise echocardiography as the initial test, clinical stratification was associated with a false-negative rate of 21%. The utility of exercise electrocardiography is limited by the high prevalence of resting electrocardiographic abnormalities and suboptimal sensitivity and specificity. The best balance of cost and diagnostic accuracy is to perform exercise echocardiography in patients with at least intermediate probability of coronary artery disease.

Aged↗
PubMed1997

Outcomes and cost implications of a clinical-based algorithm to guide the discriminate use of stress imaging before noncardiac surgery.

Approximately 8 million patients at risk for coronary artery disease undergo noncardiac surgery annually in the United States. This study defined the appropriateness and cost of evaluating these patients with stress imaging tests. Before noncardiac surgery, 178 consecutive patients were prospectively studied by stress imaging. Pretest cardiac risk (low, intermediate, high) was established by interviewing the referring physician and separately by a cardiologist on the basis of the nature of noncardiac surgery and Eagle's clinical criteria. Patients were followed-up for alterations in management and perioperative events until hospital discharge. Referring physicians and cardiologists identified low risk in 24% and 54% of patients, respectively (p < 0.0001). Of 96 patients identified as low risk by cardiologists, 75 had minor surgery and 21 had major surgery, but no clinical risk factors. In the remaining 82 patients with major surgery, ischemia and other severe abnormalities were detected in 19 (23%) patients. At follow-up, no perioperative complications occurred in minor surgery; one patient with major surgery but no clinical risk factors died from complications related to hypertrophic cardiomyopathy. Patients with at least one clinical risk factor undergoing major surgery but who did not have ischemia on stress testing (n = 63) had two complications (infarction and unstable angina). Intervention (revascularization and surgical cancellation) was probably the explanation for the absence of events in 19 patients with ischemia. With a weighted mean Medicare reimbursement ($386), the use of a simple selection algorithm based on noncardiac surgery and clinical risk to avoid testing low-risk patients would have an average cost of $214 per patient, representing a 45% savings.

Adult↗
PubMed1997

Increased left ventricular cavity size, not wall thickness, potentiates myocardial ischemia.

Left ventricular (LV) hypertrophy increases the vulnerability of the myocardium to ischemia. The purpose of this study was to determine whether LV diameter or wall thickness was the principal determinant of the effect of LV mass on the development of ischemia, measured by exercise thallium perfusion imaging, in a population with coronary artery disease (CAD). We studied 109 patients with CAD but no prior myocardial infarction who underwent exercise thallium imaging within 1 year of coronary angiography. Thallium perfusion defects were present in 76% of patients. LV mass index was associated with thallium perfusion abnormalities (odds ratio 2.09 for 50 gm increments), an association that persisted after adjusting for extent of CAD. LV end-diastolic diameter had a strong correlation with a thallium defect (odds ratio 3.7 for 10 mm increments), but LV wall thickness had no correlation (odds ratio 1.0 for 5 mm increments). In a stepwise regression model that included extent of CAD and other potential clinical variables, LV end-diastolic diameter was the strongest predictor of thallium defects (adjusted odds ratio 4.5). This study confirms the association of LV hypertrophy with ischemia in patients with CAD, specifically in patients with eccentric hypertrophy.

Coronary Angiography↗
PubMed1997

Age and referral to coronary angiography after an abnormal treadmill thallium test.

This study investigated the association between age and referral to coronary angiography among ambulatory adults with an abnormal treadmill thallium scan. The subjects studied were 416 consecutive adults who were > or = 30 years old, under the care of cardiologists, and had an abnormal treadmill thallium scan between 1990 and 1993 at the Cleveland Clinic Foundation. The primary end point was performance of coronary angiography within 90 days of the treadmill test. Coronary angiography was performed in 163 subjects. Coronary angiography was performed in 46% of patients aged 30-49 years, in 53% of those aged 50 to 64 years, in 33% of those aged 65 to 74 years, and in only 18% of those aged > or = 75 years (chi2 test for trend, p < 0.0001). After adjustment for potential confounders, age remained associated with a lower rate of referral to angiography (p < 0.0001). During 2 years of follow-up 34 deaths occurred (14 cardiac), with particularly high mortality rates among those aged >74 years (cumulative rate 31%, 95% confidence interval 16% to 47%). The number of abnormal thallium scan segments was predictive of death (p = 0.02). These data suggest that increasing age is associated with a lower rate of referral to coronary angiography after an abnormal treadmill thallium test.

Adult↗
PubMed1997

Sex and diagnostic evaluation of possible coronary artery disease after exercise treadmill testing at one academic teaching center.

Controversy exists as to whether a sex bias exists that affects the diagnostic approach to suspected coronary artery disease: previous studies have used coronary angiography, but not other noninvasive testing, as a primary end point. This investigation examined posttest sex differences in diagnostic evaluation after exercise treadmill testing according to a broader end point than just coronary angiography alone. The design was a cohort analytic study with a 90-day follow-up. The study was done at the Cleveland Clinic Foundation, an academic group practice. Patients included consecutive adults (1023 men and 579 women) with chest pain but no documented coronary disease who were referred for symptom-limited exercise treadmill testing without adjunctive imaging; none had undergone prior invasive cardiac procedures. Main outcome measures included (1) performance of any subsequent diagnostic study (invasive or noninvasive) and (2) performance of coronary angiography as the next diagnostic study. During follow-up, 89 (8.7%) men and 48 (8.3%) women underwent a second diagnostic study (odds ratio 0.95; 95% confidence interval 0.66 to 1.37; p > 0.8), whereas 64 (6.3%) men and 21 (3.6%) women went straight to coronary angiography (odds ratio 0.56; 95% confidence interval 0.34 to 0.93; p = 0.02). In multivariable logistic regression analyses, which considered baseline clinical characteristics, the ST-segment response, and other prognostically important exercise responses, women tended to be less likely than men to be referred to any second test (adjusted odds ratio 0.70; 95% confidence interval 0.42 to 1.19; p > 0.1) but were markedly and significantly less likely to be referred straight to coronary angiography (adjusted odds ratio 0.33; 95% confidence interval 0.17 to 0.65). After exercise treadmill testing, women were only slightly less likely than men to be referred for subsequent diagnostic testing; they were, however, much less likely to be referred straight to coronary angiography as opposed to another noninvasive study.

Academic Medical Centers↗
PubMed1997

Evolution of dobutamine echocardiography protocols and indications: safety and side effects in 3,011 studies over 5 years.

OBJECTIVES: This study sought to document the safety of dobutamine stress echocardiography as it has evolved at a single center and to define predictors of adverse events. BACKGROUND: The indications and protocol for dobutamine stress testing have evolved over 5 years of clinical use, but the influence of these changes on the safety and side effects of the test is undefined. METHODS: Over 5 years, 3,011 consecutive dobutamine stress studies were performed in 2,871 patients, using an incremental protocol from 5 to 40 micrograms/kg body weight per min in 3-min stages, followed by atropine or an additional stage with 50 micrograms/kg per min, if required. Clinical data were gathered prospectively, and hemodynamic and echocardiographic findings were recorded at each stage, including recovery. Dobutamine echocardiography was defined as positive for ischemia in the presence of new or worsening wall motion abnormalities; in the absence of ischemia, failure to attain 85% of age-predicted maximal heart rate was identified as a nondiagnostic result. RESULTS: Studies were performed for risk assessment (70%) and symptom evaluation (30%); over the study period, there was an increment in the use of dobutamine echocardiography for preoperative evaluation. Most tests (n = 2,194 [73%]) were terminated due to attainment of peak dose with achievement of target heart rate (> 85% maximal age-predicted heart rate); 455 patients (15%) failed to achieve > 85% maximal predicted heart rate despite maximal doses of dobutamine and atropine. The protocol was stopped prematurely in 230 patients (7.6%) because of side effects, including ventricular (n = 27 [0.9%]) and supraventricular rhythm disorders (n = 22 [0.7%]), severe hypertension (n = 24 [0.8%]) and hypotension or left ventricular outflow tract obstruction (n = 112 [3.8%]). Noncardiac symptoms, such as headache, nausea or anxiety, caused early test termination in 45 patients (1.6%). The remaining tests were stopped because of severe chest pain (n = 106 [3.5%]) or severe ischemia by echocardiography (n = 26 [0.9%]). Serious complications occurred in nine patients, including sustained ventricular tachycardia in five, myocardial infarction in one and other conditions in three requiring hospital admission (sustained supraventricular tachycardia, hypotension, suspected myocardial infarction), but neither ventricular fibrillation nor death occurred. Independent predictors of serious complications could not be defined. Over 5 years, higher dose protocols and more frequent use of atropine have raised the number of diagnostic protocols from 59% to 80%, without increasing the incidence of major side effects. CONCLUSIONS: Despite the use of more aggressive protocols and alterations of the indications for testing to include sicker patients, major side effects are a rare complication of dobutamine echocardiography.

Adrenergic beta-Agonists↗
PubMed1997

Use of exercise echocardiography for prognostic evaluation of patients with known or suspected coronary artery disease.

OBJECTIVES: This study prospectively compared the incremental prognostic benefit of exercise echocardiography with that of exercise testing in a large cohort. BACKGROUND: Exercise echocardiography is widely accepted as a diagnostic tool, but the prognostic information provided by this test, incremental to clinical and stress testing evaluation, is ill-defined. METHODS: Clinical, exercise and echocardiographic variables were studied in a consecutive group of 500 patients undergoing exercise echocardiography. After exclusion of patients who underwent revascularization within 3 months of the stress test (n = 16, 3%) and those lost to follow-up (n = 21, 4%), the remaining 463 patients (mean [+/-SD] age 57 +/- 12 years, 302 men) were followed-up for 44 +/- 11 months. Outcome was related to the exercise and echocardiographic findings, and the incremental prognostic benefit of exercise echocardiography was compared with that of standard exercise testing. RESULTS: Cardiac events occurred in 81 patients (17%), including 33 (7%) with spontaneous events (cardiac death, myocardial infarction and unstable angina) and 48 with late revascularizations due to progressive symptoms. In a multivariate Cox proportional hazards model, the likelihood of any cardiac event was increased in the presence of ischemia (relative risk [RR] 5.06, 95% confidence interval [CI] 3.09 to 8.29, p < 0.001) and lessened by more maximal stress, measured as percent age-predicted maximal heart rate (RR per 5% increment 0.84, 95% CI 0.77 to 0.92, p < 0.001). Spontaneous events were more strongly predicted by ischemia (RR 8.20, 95% CI 3.41 to 19.71, p < 0.001) and percent age-predicted maximal heart rate (RR per 5% increment 0.78, 95% CI 0.67 to 0.91, p < 0.001). An interactive logistic regression model showed that the addition of echocardiographic to exercise and clinical data offered incremental predictive value. CONCLUSIONS: The presence of ischemia on the exercise echocardiogram can predict whether patients will experience an event. This relation is independent of, and incremental to, clinical and exercise data.

Aged↗