Comparison based on age of baseline electrocardiographic abnormalities in non-Q-wave myocardial infarction. VANQWISH Trial Research Investigators. Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital.

OBJECTIVE: To compare the incidence of electrocardiographic abnormalities between older (age > or = 70 years) and younger patients presenting with acute non-Q-wave myocardial infarction. DESIGN: Retrospective review of qualifying electrocardiograms in 918 patients enrolled in the multicenter Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) study. SETTING: Seventeen Department of Veterans Affairs medical centers. PARTICIPANTS: A total of 918 patients (224 > or = 70 years old) with acute non-Q-wave myocardial infarction. MEASUREMENTS: Comparison of electrocardiograms in patients aged > or = 70 years and younger patients for presence of left ventriculary hypertrophy, widened QRS complex, ST and T wave abnormalities, rhythm other than sinus, heart rate > or = 80 beats/minute, and location of acute non-Q-wave myocardial infarction. RESULTS: Left ventricular hypertrophy and ST depression > or = 1 mm were significantly more frequent in older than in younger patients. CONCLUSIONS: Older patients presenting with non-Q-wave myocardial infarction have a greater incidence of left ventricular hypertrophy and ST depression on their electrocardiograms than younger patients. Both of these electrocardiographic findings have previously been associated with increased risk of death and recurrent myocardial infarction and may help account for the worse prognosis of non-Q-wave myocardial infarction in older patients.

Technetium Tc 99m sestamibi myocardial perfusion imaging: current role for evaluation of prognosis.

Like 201Tl imaging, technetium Tc 99m sestamibi (MIBI) myocardial imaging can be used with exercise and pharmacologic testing to assess the presence of coronary artery disease. An increasing body of literature indicates that MIBI can also be used to assess risk of future cardiac events such as myocardial infarction or death. This article summarizes the current status of MIBI imaging for evaluating prognosis in patients with known or suspected coronary artery disease.

Risk stratification with pre-hospital discharge exercise technetium-99m sestamibi myocardial tomography in men after acute myocardial infarction.

BACKGROUND: Exercise thallium-201 imaging early after acute myocardial infarction (MI) may provide information concerning risk of future cardiac events. The prognostic value of exercise technetium-99m sestamibi (MIBI) single-photon emission computed tomography in such patients has not been established. METHODS AND RESULTS: Submaximal exercise stress testing with MIBI tomography was done before hospital discharge in 134 consecutive men after acute MI. Patients were monitored for occurrence of late cardiac events (nonfatal MI or cardiac death). Coronary revascularization was done in 31 patients (23%) < or = 3 months after testing. Nonfatal MI or cardiac death occurred in 30 (23%) of the overall group of 133 patients monitored (mean 35+/-19 months) and in 25 (25%) of the 102 patients treated medically. A history of congestive heart failure, failure to reach 85% of age-predicted maximal heart rate, and an isolated fixed MIBI defect were associated with significantly increased risk (p < 0.05) of a late cardiac event in both groups of patients. A reversible MIBI defect was not associated with increased risk. In a multivariable Cox proportional hazards model, only a history of congestive heart failure (relative risk 4.2, 95% confidence interval [CI] 1.7 to 10.4, p < 0.002) and an isolated fixed MIBI defect (relative risk 2.1, 95% CI 1.1 to 4.3, p < 0.05) were independent predictors of increased risk in the total group of 133 patients. In the 102 patients treated medically, only a history of congestive heart failure (relative risk 4.9, 95% CI 1.9 to 13.1) and achievement of 85% of age-predicted maximal heart rate (relative risk 0.13, 95% CI 0.02 to 0.9) were independent predictors of risk. CONCLUSIONS: Early post-MI submaximal exercise testing with MIBI tomography provides limited prognostic information for late cardiac events. An isolated fixed MIBI defect is associated with increased risk but not as strongly as other variables, particularly a history of congestive heart failure.

Influence of race on the prediction of cardiac events with stress technetium-99m sestamibi tomographic imaging in patients with stable angina pectoris.

The prognostic value of myocardial perfusion imaging in African-Americans is unknown. This study compared the prediction of cardiac events of stress technetium-99m (Tc-99m) sestamibi single-photon emission computed tomography (SPECT) imaging in symptomatic Caucasian and African-American patients. Prospectively collected stress Tc-99m sestamibi tomographic imaging data from 4 medical centers, with follow-up information in 1,086 Caucasian and African-American patients, were analyzed in a core statistical laboratory. Primary events of cardiac death and nonfatal myocardial infarction and secondary events of all-cause mortality were analyzed using Kaplan-Meier survival analysis and Cox proportional-hazards multivariable model. Normal images in both African-Americans and Caucasians were associated with a low-annual cardiac event rate, whereas abnormal images were significantly associated with a higher cardiac event rate. The highest predictor of cardiac events was multivessel abnormality in both races. Use of this technique could identify patients at high risk and potentially reduce the high-cardiac event rate in African-Americans by utilizing appropriate therapies.

Effect of the stress level achieved during symptom-limited exercise technetium-99m sestamibi myocardial tomography on the detection of coronary artery disease.

BACKGROUND: The stress level achieved during exercise thallium 201 myocardial imaging may influence its sensitivity for detecting coronary artery disease (CAD). The effect of exercise adequacy on the accuracy of technetium-99m sestamibi (MIBI) imaging has not been studied. HYPOTHESIS: The study was undertaken to assess the effect of exercise level achieved on sensitivity for detecting CAD. METHODS: A consecutive series of 250 patients (mean age 60 +/- 10 years) with CAD by angiography underwent symptom-limited exercise MIBI single-photon emission computed tomography. Single-vessel CAD was found in 66 patients, double-vessel CAD in 84, triple-vessel CAD in 80, and left main disease in 20. RESULTS: No significant differences were found in sensitivities of an abnormal MIBI scan or a reversible defect among 102 patients reaching 85% of age-predicted heart rate and 148 who did not (82 vs. 89% and 66 vs. 70%, respectively, p = NS). Patients (n = 128) able to exercise < or = 6 min had a higher incidence of abnormal scans and reversible defects than 122 patients with a greater exercise duration (91 vs. 82% and 75 vs. 61%, respectively, both p < 0.05). Sensitivity of an abnormal MIBI scan for multivessel disease was greater than for single-vessel disease in patients who achieved > or = 85% of age-predicted heart rate (91 vs. 59%, p < 0.01) and in those who exercised > 6 min (89 vs. 66%, p < 0.01). No significant differences in the sensitivities of an abnormal MIBI study for multivessel versus single-vessel CAD were seen in patients achieving lower peak levels of exercise. Sensitivity of ischemic ST depression was lower than that of MIBI tomography at all levels of exercise. CONCLUSIONS: The sensitivity of exercise MIBI tomography for angiographic CAD is relatively independent of the peak heart rate achieved. Exercise duration of > 6 min is associated with a significantly higher MIBI abnormality rate than a duration of > 6 min, possibly reflecting the effect of myocardial ischemic burden on exercise ventricular function. Regardless of level of stress or its duration, exercise MIBI tomography improves the sensitivity for CAD detection compared with stress-induced ischemic ST depression.

Dipyridamole technetium 99m sestamibi myocardial tomography for preoperative cardiac risk stratification before major or minor nonvascular surgery.

The value of dipyridamole technetium 99m sestamibi (MIBI) tomography for preoperative cardiac risk stratification was assessed in 285 consecutive patients being considered for nonvascular surgery. A "major" (n = 140) or "minor" (n = 89) nonvascular procedure was later done in 229 of these patients < or = 4 months after dipyridamole testing. Perioperative cardiac events (unstable angina, acute ischemic pulmonary edema, nonfatal myocardial infarction, or cardiac death) occurred in 11 (8%) patients undergoing major nonvascular surgery and 1 (1%) undergoing a minor procedure. The only clinical or scintigraphic variables associated with significantly increased perioperative cardiac risk in patients having major surgery were Goldman class > or = II, an abnormal MIBI scan, and a fixed perfusion defect. In these patients, cardiac events occurred in 1% of those who had a normal MIBI study, 14% of those with an abnormal scan (p < 0.01), 12% with a reversible MIBI defect (p = 0.29), and 17% with a fixed MIBI defect (p < 0.01). In the 60 patients whose Goldman class was > or = II, only an abnormal MIBI study and a fixed perfusion defect were associated with incremental risk of a perioperative cardiac event. The incidence of perioperative cardiac events in these patients was 4% with a normal MIBI scan, 27% with an abnormal study (p < 0.05), 24% with a reversible MIBI defect (p = 0.45), and 37% with a fixed defect (p < 0.01). Event rates were low in patients having minor nonvascular surgery; none of the 25 with a normal MIBI study and only 1 of the 64 with an abnormal scan had a perioperative cardiac event (p = not significant (NS). We conclude that dipyridamole MIBI tomography can provide important prognostic information in patients having major nonvascular surgery. A normal MIBI study indicates a low risk of perioperative cardiac events, whereas an abnormal study in patients with Goldman class > or = II undergoing major surgery is associated with significantly increased risk. The prognostic value of MIBI tomography in patients at low clinical risk undergoing minor surgery is limited.

Dipyridamole technetium-99m sestamibi myocardial tomography in patients evaluated for elective vascular surgery: prognostic value for perioperative and late cardiac events.

Dipyridamole thallium-201 myocardial imaging can provide information regarding risk of perioperative cardiac events in patients being considered for vascular surgery. The value for this purpose of myocardial imaging with technetium-99m sestamibi (MIBI), a radiotracer with biokinetic and imaging properties different from thallium-201, has not been established. To this end the prognostic value of dipyridamole MIBI tomography for perioperative and late cardiac events was evaluated in 229 consecutive patients being considered for elective vascular surgery. Vascular surgery was done < or = 3 months after testing in 197 of these patients. Perioperative cardiac events (cardiac death, nonfatal myocardial infarction, unstable angina, or ischemic pulmonary edema) occurred in 9 (5%) patients. The rate of such events was 3% in patients with normal MIBI results, 5% in those with abnormal results, and 6% in patients with a reversible MIBI defect (both p = NS). When patients with abnormal MIBI results who had preoperative cardiac interventions (coronary revascularization or an increase in antiischemic medical therapy) were compared with with those who did not, no significant differences in the occurrence of perioperative cardiac events were found between these two groups either. A group of 172 medically treated patients who survived vascular surgery and did not have a nonfatal perioperative cardiac event was then monitored (mean 21 +/- 14 months) for the occurrence of a serious late cardiac event (nonfatal myocardial infarction or cardiac death). Event-free survival (Mantel-Cox) was significantly less in patients with abnormal studies compared with those with normal scan results. Late cardiac events occurred in 26 (15%) patients, with those having an abnormal MIBI result showing a significantly greater event rate than those with normal results (26% vs 4%, p < 0.0001). The rate of late cardiac events was 33% in patients with a reversible MIBI defect (p < 0.001) and 23% in those with a fixed defect (p < 0.03). Independent Cox multivariable predictors of increased risk of late cardiac events were a history of diabetes mellitus (relative risk [RR] 2.2, 95% confidence interval [CI] 1.0 to 4.9), an abnormal MIBI study (RR 3.7, 95% CI 1.2 to 11.4), and a reversible MIBI defect (RR 2.7, 95% CI 1.2 to 6.1). We conclude that, although its ability to assess increased perioperative cardiac risk remains uncertain, dipyridamole MIBI tomography does provide important prognostic information regarding the risk of serious cardiac events in patients having vascular surgery. The presence of an abnormal MIBI result, specifically one demonstrating a reversible perfusion defect, is associated with significantly increased risk.

Prognostic value of predischarge dipyridamole technetium 99m sestamibi myocardial tomography in medically treated patients with unstable angina.

Recently developed unstable angina clinical practice guidelines have recommended risk stratification with dipyridamole thallium-201 myocardial imaging in patients at "intermediate" pretest clinical risk who cannot exercise maximally. The prognostic value of predischarge dipyridamole technetium 99m sestamibi (MIBI) tomography has not been assessed in this clinical setting. To this end, 128 medically treated patients with unstable angina at intermediate pretest clinical risk underwent follow-up for 16 +/- 11 (mean +/- SD) months after predischarge intravenous dipyridamole MIBI tomography. An abnormal MIBI scan result was present in 99 patients (77%), of whom 47 had one or more reversible and 76 had one or more fixed perfusion defects. Cardiac events occurred in 68 (53%) patients after dipyridamole testing: recurrent unstable angina (n = 36), nonfatal acute myocardial infarction (n = 6), or death (n = 26). A cardiac event occurred in 10% of patients with normal MIBI tomography results compared with 69% of those with abnormal results (p < 0.01). Event rates associated with specific perfusion defects were similar (reversible = 68%; fixed = 71%) and were greater than rates in patients without defects (both p < 0.05). Clinical variables associated with increased risk of cardiac events by univariate analysis included a history of congestive heart failure, prior myocardial infarction, and diabetes mellitus (all p < 0.05). Independent multivariable predictors (Cox proportional hazards model) of any cardiac event were an abnormal result of MIBI scan (relative risk [RR] = 4.3, 95% confidence interval [CI] 1.5 to 12.0) and a reversible (RR = 1.8, 95% CI 1.1 to 2.9) or a fixed perfusion defect (RR = 2.9, 95% CI 1.6 to 5.4).(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise technetium-99m myocardial tomography for the risk stratification of men with medically treated unstable angina pectoris.

The prognostic value of predischarge maximal exercise stress testing with technetium-99m sestamibi (MIBI) myocardial tomography was assessed in 126 consecutive men hospitalized with a diagnosis of unstable angina pectoris who were medically stabilized. None had coronary revascularization for < or = 6 months after testing. Over a mean follow-up of 12 +/- 7 months (range 1 to 29), 35 patients (28%) had a cardiac event--nonfatal acute myocardial infarction (n = 6), cardiac death (n = 5), or rehospitalization for unstable angina (n = 24). Any type of cardiac event occurred in 12% of patients with normal MIBI scans, compared with 39% of those with an abnormal MIBI scan (p < 0.001) and 60% of those with a reversible perfusion defect (p < 0.0001). Only 2% of patients with normal scans had either a nonfatal myocardial infarction or cardiac death, compared with 14% of those with abnormal MIBI scans (p < 0.05) and 25% with a reversible defect (p < 0.001). A fixed perfusion defect was not associated with increased cardiac risk. With use of multivariable Cox proportional-hazards modeling, the only scintigraphic variable with independent predictive value was the presence of a reversible MIBI defect, with a relative risk of 3.8 (95% confidence interval 1.6 to 8.6, p < 0.05) for any cardiac event, and 19.2 (95% confidence interval 2.2 to 167.0, p < 0.05) for a nonfatal myocardial infarction or cardiac death. Cardiac event-free survival was also significantly decreased in patients with a reversible perfusion defect (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic value of dipyridamole technetium-99m sestamibi myocardial tomography in patients with stable chest pain who are unable to exercise.

Unlike dipyridamole testing with thallium-201, the ability of technetium-99m sestamibi (MIBI) myocardial imaging to evaluate risk of later cardiac events has not been established. In this study, the prognostic value of dipyridamole MIBI myocardial tomography (same-day, rest-stress protocol) was assessed in 534 patients with stable chest pain consistent with angina pectoris. During follow-up (mean 13 +/- 5 months), 58 patients (11%) had a major cardiac event--nonfatal myocardial infarction (n = 14) or cardiac death (n = 44). A history of congestive heart failure, prior myocardial infarction or diabetes mellitus, and either a reversible or fixed myocardial perfusion defect on MIBI scans were univariate and multivariate predictors of increased cardiac risk. Cardiac events occurred in 2% of patients with normal MIBI scans, compared with 15% with abnormal scans, 17% with reversible perfusion defects and 16% with fixed defects (all p < 0.01). Relative risks (univariate Cox analysis) associated with an abnormal MIBI scan, a reversible perfusion defect and a fixed defect were 8.4 (95% confidence interval [CI] 2.6 to 26.8), 1.9 (95% CI 1.1 to 3.2) and 2.4 (95% CI 1.4 to 4.3), respectively. Patients with any kind of perfusion abnormality (reversible or fixed) had a significantly lower cardiac event-free survival than those with normal scans (all p < 0.0001). It is concluded that, as with thallium-201 myocardial scintigraphy, a normal MIBI scan is associated with low cardiac risk, whereas dipyridamole-induced myocardial perfusion defects identify patients with significantly increased risk.

Exercise technetium-99m sestamibi tomography for cardiac risk stratification of patients with stable chest pain.

BACKGROUND: This study was designed to evaluate the prognostic value of symptom-limited maximal exercise treadmill testing with tomographic technetium-99m sestamibi (MIBI) myocardial imaging in patients referred for evaluation of stable angina. Exercise stress thallium-201 myocardial imaging provides prognostic information in coronary artery disease subsets including patients with stable chest pain. The prognostic value of exercise technetium-99m MIBI myocardial tomography has not been established. METHODS AND RESULTS: Of 548 consecutive patients with stable angina pectoris who underwent maximal exercise treadmill stress testing in combination with a same-day "rest-stress" tomographic technetium-99m MIBI myocardial imaging protocol, 521 patients were followed for 13 +/- 5 months to determine the univariate and multivariate variables associated with cardiac events and to define their cardiac event-free survival. Ten patients were lost to follow-up (98% complete), and 17 who had coronary revascularization within 6 months of testing were excluded. Major cardiac events occurred in 24 patients (9%)--nonfatal myocardial infarction in 11 and cardiac death in 13. Univariate Cox survival analysis demonstrated significant relative risk (RR) and 95% confidence intervals (CI) for exercise ST segment depression (RR = 2.3; 95% CI, 1.0 to 5.3), an abnormal MIBI scan (RR = 13.8; 95% CI, 1.9 to 102.3), and a reversible MIBI perfusion defect (RR = 3.2; 95% CI, 1.4 to 7.5). Multivariate models demonstrated that both exercise MIBI perfusion abnormalities (RR = 11.9; 95% CI, 1.6 to 89.4) and reversible MIBI perfusion defects (RR = 2.9; 95% CI, 1.2 to 7.0) had independent predictive value. During 1 year of follow-up, cardiac events occurred in only 0.5% of patients with normal MIBI scans compared with 7% of those with abnormal MIBI scans (P < .001). One-year, cardiac event-free survival was 92% in patients with reversible MIBI perfusion defects (P < .01 versus normal), 96% in patients with fixed defects (P < .01), and 93% in patients with combined reversible and fixed MIBI myocardial perfusion abnormalities (P < .02). CONCLUSIONS: As with exercise thallium-201 myocardial imaging, exercise stress technetium-99m MIBI myocardial tomography provides significant independent information concerning the subsequent risk of serious cardiac events (death, myocardial infarction) in patients with stable angina pectoris. The identification of MIBI perfusion abnormalities, in particular, the presence of reversible MIBI defects, was associated with reduced 1-year, event-free survival. The recognized imaging and radiotracer biokinetic differences between thallium-201 and MIBI do not appear to modulate the prognostic value associated with scintigraphic evidence of ischemic myocardial jeopardy in the stable angina population.

Dipyridamole technetium 99m sestamibi myocardial tomography as an independent predictor of cardiac event-free survival after acute ischemic events.

BACKGROUND: A total of 137 consecutive patients with recent uncomplicated myocardial infarction (n = 31) or unstable angina (n = 106) were studied to determine the relative prognostic value of predischarge clinical risk stratification and intravenous dipyridamole stress sestamibi (MIBI) myocardial tomography in patients unable to exercise maximally after an acute ischemic coronary event. METHODS AND RESULTS: Patients were followed up after the index study for 10 +/- 5 months (range 1 to 23 months) to ascertain cardiac events that occurred in 20 patients (15%): nonfatal myocardial infarction (n = 5) or cardiac death (n = 15). Cardiac event rates were 35% in patients with a recent myocardial infarction and 8% in the group with unstable angina (p < 0.001). Patients with these cardiac events had more frequent abnormal MIBI study results, fixed defects, and reversible plus fixed (combined) defects (all p < 0.05). The univariate relative risk of death or myocardial infarction associated with an abnormal MIBI study was 6.0 (95% confidence limits 0.8 to 44.7). Multivariate stepwise logistic regression models identified an abnormal MIBI study and either fixed or reversible MIBI defects as being predictive of death or myocardial infarction (all p < 0.05). The Mantel-Haentzel 1-year cardiac event-free survival rate was excellent in 27 patients with a normal MIBI single-photon computed emission tomographic scan (100%) but significantly reduced in the 110 patients with an abnormal MIBI study (80%; p < 0.05 vs normal subjects). The presence of combined MIBI defects was associated with the poorest event-free survival rate (66%; difference not significant vs fixed or reversible defects only). CONCLUSION: We conclude that predischarge dipyridamole MIBI tomography provided independent prognostic information in this population of patients who were unable to exercise after a recent acute ischemic coronary event.

Prognostic value of dipyridamole thallium-201 scintigraphy in patients with stable chest pain.

The usefulness of dipyridamole testing with planar thallium-201 scintigraphy for assessing risk of subsequent cardiac events was evaluated in 373 patients with stable chest pain. Follow-up information was complete in 362 patients (mean age 64 +/- 9 years). During an average follow-up period of 18 months, cardiac events occurred in 59 patients--unstable angina in 27, nonfatal acute myocardial infarction in 11, and death from cardiac causes in 21. A history of previous myocardial infarction, congestive heart failure, or coronary bypass surgery before the study, or the presence of an abnormal scan or one with a fixed perfusion defect was associated with a significantly increased frequency of subsequent cardiac events (p less than 0.05). However, the presence of a reversible perfusion defect was not associated with increased risk (p = 0.1872). Stepwise logistic regression showed that a history of coronary artery bypass surgery before the study and the presence of a fixed perfusion defect were the only variables with independent predictive value for occurrence of a subsequent cardiac event (p less than 0.05). Survival analysis revealed a significantly increased cardiac event rate in patients with abnormal scans compared with those with normal scans over a 30-month follow-up period (p less than 0.01). We conclude that dipyridamole testing with thallium-201 scintigraphy can provide prognostic information concerning risk of future cardiac events in patients with stable chest pain. The presence of a fixed perfusion defect in particular identifies patients at increased risk.

Atrial pacing with two-dimensional echocardiography for evaluation of chest pain: comparison with thallium 201 scintigraphy.

Atrial pacing was performed with two-dimensional (2-D) echocardiography and thallium 201 scintigraphy in 40 men with stable chest pain. Coronary angiography showed significant (one or more lesions greater than or equal to 50%) coronary artery disease (CAD) in 36 patients and no or insignificant CAD in 4. Two dimensional echocardiography showed a left ventricular wall motion abnormality (WMA) either at rest or with pacing in 28 (78%) patients with CAD, with 17 (47%) showing a new or worsened WMA with pacing. A thallium scan showing abnormality (reversible or fixed perfusion defect) was seen in 26 (72%) patients with CAD; 18 (50%) had a reversible defect. In all, 34 of the 36 patients with CAD (94%) had a WMA, a perfusion defect, or both (specificity 50%). Occurrence of both a WMA and a perfusion defect in individual segments ranged from 10 of 25 patients with septal abnormalities to 0 of 12 with abnormalities of the lateral segment. Sensitivity of 2-D echocardiography for identifying CAD in specific vessels was 81% for the left anterior descending (LAD) artery, 30% for the right coronary artery, and 20% for the circumflex artery (both p less than .001 compared with the LAD artery). Corresponding sensitivities for thallium 201 imaging were 54% (p less than .05 compared with 2-D echocardiography), 27%, and 8% (both p less than .05 compared with the LAD artery). When combined with atrial pacing, 2-D echocardiography and thallium 201 perfusion imaging are of similar value for diagnosing the presence of CAD in patients with stable chest pain. Two-dimensional echocardiography is superior to thallium 201 imaging for identifying the presence of significant CAD in the LAD artery, but both tests are limited in their ability to detect lesions of the right coronary or circumflex arteries.

Thallium-201 perfusion imaging with atrial pacing or dipyridamole stress testing for evaluation of cardiac risk prior to nonvascular surgery.

Preoperative assessment of cardiac risk using thallium-201 scintigraphy and atrial pacing (n = 42) or dipyridamole stress testing (n = 35) was performed in 77 patients (mean age 65 +/- 7 years), who subsequently underwent elective nonvascular surgery. All patients were at low cardiac risk by clinical criteria; none could perform exercise stress testing due to physical limitations. ST depression consistent with ischemia occurred in 11 patients during atrial pacing and in 1 patient during dipyridamole stress testing (p less than 0.01). Nine patients had reversible perfusion defects with atrial pacing, and 10 patients with dipyridamole stress testing; fixed defects were present in 15 and 8 patients, respectively. Only one patient (fixed perfusion defect with atrial pacing, left main disease on coronary angiography) underwent preoperative coronary revascularization. Two patients subsequently had postoperative cardiac events. One patient (reversible perfusion defect with dipyridamole stress testing) experienced sudden death after a nonvascular procedure, while a second patient (normal thallium images with dipyridamole testing) had a nonfatal myocardial infarction. In patients having atrial pacing or dipyridamole stress testing, thallium-201 scans that are normal or show only a fixed perfusion defect confirm a low risk of cardiac complications following nonvascular surgery. The presence of a reversible perfusion defect does not preclude a postoperative course free of cardiac complications in patients at low cardiac risk by clinical criteria.

Prognostic value of atrial pacing and thallium-201 scintigraphy in patients with stable chest pain.

The value of atrial pacing and thallium-201 scintigraphy for assessing risk of subsequent cardiac events was examined in 210 patients with stable chest pain. Follow-up information was complete in 195 patients (mean age 61 years). Over an average follow-up of 19 months, cardiac events occurred in 38 patients--unstable angina in 20, nonfatal acute myocardial infarction in 6 and death from cardiac causes in 12. A history of previous myocardial infarction, diabetes mellitus, systemic hypertension or peripheral vascular disease at the time of pacing was not associated with an increased frequency of subsequent cardiac events. Six of 38 patients with later cardiac events had a history of congestive heart failure, compared with 8 of 157 without cardiac events (p less than 0.05). Neither pacing-induced angina, ST depression, nor the presence of a fixed perfusion defect was significantly more frequent in patients with cardiac events as a whole compared with patients without such events. Reversible defects and abnormal scans (reversible or fixed defects) were present, respectively, in 19 and 31 of 38 patients with cardiac events, compared with 42 and 79 patients, respectively, of the 157 patients without cardiac events (both p less than 0.01). In patients who developed unstable angina, a reversible defect was seen in 13 and an abnormal scan in 16 (both p less than 0.01 compared with patients without cardiac events). In 12 patients who died from a primary cardiac event, fixed defects were present in 8 and an abnormal scan in 11 (p less than 0.05 and p less than 0.01, respectively, compared with patients without cardiac events).(ABSTRACT TRUNCATED AT 250 WORDS)

Preoperative evaluation of cardiac risk by means of atrial pacing and thallium 201 scintigraphy.

Atrial pacing and thallium 201 scintigraphy were done in 61 patients with known or suspected coronary artery disease referred for evaluation of cardiac risk before elective vascular surgery. All patients had noncardiac limitations precluding performance of an adequate exercise stress test. Before atrial pacing all were considered to be at low risk of a postoperative cardiac event based on assessment of clinical parameters. Vascular surgery was subsequently performed in 47 patients. In these patients, pacing-induced ST segment depression greater than or equal to 1 mm occurred in 18, a fixed perfusion defect occurred in 11, and a reversible defect occurred in six. Two of the six patients with reversible perfusion defects had preoperative coronary angiography; both had significant coronary artery disease (one or more lesions greater than or equal to 50%). Two patients (one of whom had a reversible perfusion defect) underwent preoperative coronary revascularization and tolerated subsequent vascular surgery well. All other patients received only medical therapy. None of the 47 patients undergoing vascular surgery had a postoperative cardiac event (unstable angina, congestive heart failure, myocardial infarction, or cardiac death). Of the 14 patients in whom vascular surgery was deferred or canceled, surgery was canceled for noncardiac reasons in seven. Six of these seven patients had a normal perfusion scan; none had a reversible perfusion defect or marked (greater than or equal to 2 mm) ST segment depression. No cardiac event occurred during a 3-month period after atrial pacing in any of these patients. Six of the remaining seven patients had reversible perfusion defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of coronary artery disease in the patient unable to exercise: alternatives to exercise stress testing.

Exercise stress testing is a well-established method for the diagnostic, prognostic, and functional assessment of patients with known or suspected CAD. A variety of alternative tests have been described in patients unable to perform leg exercise. Atrial pacing and dipyridamole imaging have been evaluated most extensively, and results compare favorably with those of exercise testing for diagnosing the presence of CAD. Both tests may be used to assess prognosis after myocardial infarction, and dipyridamole imaging may be useful in patients undergoing preoperative evaluation. The use of the cold pressor test and isometric handgrip exercise have also been described. However, the value of both tests is limited by a relatively low sensitivity for detecting the presence of CAD. Other testing modalities--arm ergometry, intravenous infusion of beta-adrenergic agonists, and transthoracic pacing--show promise but require further assessment to confirm their value.

Atrial pacing and thallium-201 scintigraphy in patients with chest pain: correlation with coronary anatomy.

Atrial pacing and thallium-201 scintigraphy were performed in 72 patients referred for evaluation of chest pain. Coronary artery disease (CAD) was present in 63 patients, as documented by cardiac catheterization performed at the same time or within 2 months of atrial pacing. Nine patients had no or insignificant (less than 50% stenosis) CAD. The sensitivity of pacing-induced angina for CAD was 51%, and was 49% for ST depression. Specificities were 89% and 78%, respectively. A reversible perfusion defect was seen in 54% of patients with CAD (specificity 89%), and a fixed defect in 29% (specificity 100%). The sensitivity of an abnormal thallium-201 scan (one or more reversible or fixed defects) was 79% (p less than 0.05 compared to angina or ST depression). Combined sensitivity of ST depression and/or an abnormal thallium-201 scan was 87%. There were no significant changes in any of these sensitivities as the number of vessels with CAD increased. Thallium-201 scintigraphy correctly identified 11 of 19 (58%) patients with single-vessel disease as having CAD in only one vessel, but underestimated the extent of disease in all but a few patients with multivessel disease. The sensitivity of perfusion imaging to identify lesions in specific vessels ranged from 27% (circumflex) to 57% (right coronary artery). Specificities were 100% for circumflex, 78% for anterior descending, and 83% for right coronary artery lesions.(ABSTRACT TRUNCATED AT 250 WORDS)