Ischemia at rest is independent of the extent of ventricular dysfunction and arrhythmias in patients with coronary artery disease

To assess the relation between myocardial ischemia, ventricular arrhythmias (VA), and left ventricular (LV) dysfunction, we evaluated 74 patients with coronary artery disease (CAD) using radionuclide angiography (to determine the resting ejection fraction [EF]), resting thallium-201 scintigraphy (to ascertain the extent of resting ischemia), and 24-hour Holter monitoring (to assess VA). Thirty patients had resting ischemia, 26 had resting EF less than 30%, and 27 had repetitive VA. Patients with and without ischemia had similar EFs (36 +/- 14 vs 38 +/- 14, p = NS). Further, patients with and without repetitive forms of VA had a similar number of resting ischemic segments (1.1 +/- 1.7 vs 1.1 +/- 2.2, p = NS). Patients with EFs less than 30 had more VA than patients with EFs greater than or equal to 30 (Holter class 4.3 +/- 2.3 vs 3.0 +/- 1.8, p less than 0.01) but a similar extent of ischemia (1.4 +/- 2.2 vs 1.0 +/- 1.7, p = NS). Thus, while patients with lower EFs have more repetitive forms of VA, ischemia at rest is independent of VA and EF. These data suggest that prognostic stratification of patients with CAD for intervention studies should include a separate consideration of ischemia.     

A study of the variations in myocardial perfusion induced by systemic thrombolysis in acute myocardial infarct using sequential scintigraphy with 201-thallium

To assess scintigraphic changes induced by intravenous streptokinase therapy, serial rest redistribution thallium-201 perfusion imaging was performed in 62 patients with acute myocardial infarction lasting less than 6 hours. Twenty-seven patients randomized to treatment with intravenous streptokinase (group A) and 35 to conventional therapy (group B) underwent thallium-201 scintigraphy as soon as possible after admission to the coronary care unit (early study). Regional myocardial perfusion was assessed using thallium-201 scintigraphy 7-9 days later in each patient (late study). The size of the perfusion defect was evaluated using a semi-quantitative score. The size of the perfusion defect decreased in serial scans in both group A (preintervention score: 12.1 +/- 6.8; redistribution score: 11.4 +/- 6.8; late study: 8.8 +/- 7.0) and group B (12.8 +/- 6.5; 12.3 +/- 6.7; 10.6 +/- 7.5, respectively). No statistical difference in myocardial perfusion was found between the two groups, on late study. Peak serum creatine kinase MB (CKMB) was earlier in group A than in group B (1030.8 +/- 326.6 vs 1361.0 +/- 271.1: p less than 0.001). The fast CKMB release group (onset of symptoms-peak of CKBM less than or equal to 900 minutes) exhibited higher thallium-201 uptake when compared to the slow CKMB release group, at the time of late study (perfusion defect score: 6.1 +/- 5.7 vs 10.7 +/- 7.3: p = 0.03). Reversibility was observed in 21/62 patients (34%). Reversibility corresponded to unchanged or improved perfusion defect score on late study in 18/21 patients (86%). Nevertheless 20/41 (49%) patients not showing redistribution of thallium-201 within pre-treatment defect had an improvement in regional perfusion on late study. Reversibility was observed in 9/14 (64%) patients with fast CKMB release and in 12/47 (26%) patients with slow CKMB release. We conclude that the early peak of CKMB is associated with a higher uptake of thallium-201 on late study. Furthermore, the reversibility of perfusion defect on redistribution imaging forecasts evolution of scintigraphic perfusion, but, when this is not present, it doesn't rule out late improvement of thallium-201 myocardial uptake. The low sensitivity and specificity of redistribution imaging and the procedure related delay in instituting therapy make thallium-201 scintigraphy unreliable in the evaluation of myocardial reperfusion following thrombolysis.     

Changed diastolic function at rest in patients with perfusion defects in exertion myocardial scintigraphy with TI-201

Myocardial perfusion scintigraphy with TI-201 after exercise allows distinction between areas of scar (irreversible defect) and areas of ischemia (reversible defects). Accordingly 4 major groups of patients can be identified: with normal perfusion pattern (Group I); with reversible ischemia (Group II); with scar of previous myocardial infarction (Group III); with both evidence of scar and ischemia (Group IV). Sixty-nine patients (59 m; 10 f; mean age 55.7 +/- 9 years) with suspected or demonstrated ischemic heart disease underwent stress TI-201 myocardial scintigraphy and on the basis of the scintigraphic results were assigned as follows: 11 to group 1, 14 to group II, 31 to group III and 13 to group IV. In order to investigate the behaviour of ventricular diastolic function in these different subsets, all the patients underwent subsequently a radionuclide angiography at rest (both first pass and equilibrium gated blood pool studies), which allowed the assessment of left ventricular ejection fraction (EF), peak filling rate (PFR)--as expression of diastolic function--and regional wall motion pattern. The values of EF and PFR were significantly reduced (p less than 0.05) in the patients with defects of perfusion (Groups II, III and IV) in comparison to the patients with normal perfusion (Group I); abnormal wall motion was found in 0 (I), 8 (II), 22 (III) and 7 (IV) patients. The diastolic function was more frequently altered (PFR less than 2.5 EDV/sec) than the systolic function (EF less than 50%) or regional wall motion, mainly in patients with reversible scintigraphic defects (prevalence of alterations in the groups II and IV: PFR: 78%, EF: 22%, abnormal wall motion: 56%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Myocardial perfusion in silent myocardial ischemia: investigation by exercise stress myocardial tomography with thallium-201

To investigate myocardial perfusion in silent myocardial ischemia, we performed exercise stress myocardial tomography with thallium-201 (T1) in 85 patients with coronary artery disease (CAD). Exercise stress myocardial tomography was obtained both immediately after exercise and three hours later. Patients were classified into two groups according to the presence (Symptomatic Group, n = 36) or absence (Silent Group, n = 49) of chest pain during exercise stress. Clinical features (age, gender and history of myocardial infarction) and arteriographically determined severity of CAD were the same in both groups. The extent of myocardial ischemia (% Ischemia) estimated by exercise stress myocardial tomography was the same in each group (30 +/- 10% in Silent Group, 28 +/- 12% in Symptomatic Group, NS). The severity of exercise-induced myocardial ischemia was expressed as a minimal value of myocardial T1 washout rate (minimal WOR) of each patient. Although exercise heart rate was identical in both groups, minimal WOR in Silent Group was significantly higher than that of Symptomatic Group (4 +/- 10% vs -16 +/- 14%, p less than 0.001). The study in patients who exhibited both silent and symptomatic ischemia showed same results. These findings suggest that the severity of ischemia is a fundamental factor in determining the presence or absence of pain during exercise induced ischemia.     

Influence of the postexercise acquisition delay on the detection of functional abnormalities in sestamibi-gated SPECT.

BACKGROUND: Gated single photon emission computed tomography (SPECT) identifies functional changes produced by ischemia, but the influence of acquisition delay on their detection is not established. METHODS AND RESULTS: In 80 patients with known or suspected coronary artery disease, gated SPECT was acquired twice: first, less than 30 minutes after peak exercise (stress 1), and second, more than 45 minutes after peak exercise (stress 2). End-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) were compared with perfusion. The relationship between the DeltaEF (stress EF - resting EF) and the summed difference score (SDS) was -0.443 (P < .0001) for stress 1 and -0.416 (P < .0001) for stress 2. In stress 1, EF increased in patients without inducible ischemia (SDS = 0) (57% +/- 10% vs 54% +/- 9% at rest, P < .02) and decreased in those with an SDS of 1 or greater (53% +/- 10.8% vs 55% +/- 9.6% at rest, P < .05). In stress 2, EF was unchanged in patients without ischemia (55.8% +/- 9.7%, P = .06) and decreased in the other patients (52.8% +/- 10.2%, P < .01). In patients without ischemia, both the EDV and ESV decreased significantly in stress 1 and were unchanged in stress 2. In patients with an SDS of 1 or greater, the EDV remained unchanged and the ESV minimally decreased in stress 1, whereas both volumes clearly and significantly increased in stress 2. CONCLUSIONS: The early acquisition of postexercise gated SPECT is slightly more effective in detecting ischemia-related functional changes; however, a delayed acquisition within 60 minutes still permits the detection of functional abnormalities in most patients.     

Effect of long-term exercise training on regional myocardial perfusion changes in patients with coronary artery disease

The cardiac rehabilitation of patients with coronary artery disease (CAD) promotes exercise tolerance, improves left ventricular function, and decreases the heart rate and systolic blood pressure at the same load intensity. Several studies have shown that cardiac rehabilitation improves myocardial perfusion in CAD patients. However, the long-term (> or = 1 year) effect of cardiac rehabilitation on myocardial perfusion is still controversial. The effect of long-term exercise training on myocardial perfusion in CAD patients was assessed using thallium-201 (201Tl) exercise studies at a baseline (4 months after the onset of CAD) and at a 1-year or more follow-up in 58 patients with stable CAD. The subjects had been divided into a training group (n=35) participating in supervised exercise 2 times per week for the follow-up period, and the control group (n=23). There was an improvement in the myocardial perfusion on stress 201Tl scintigraphy in 20 of the 35 (57.1%) trained patients and in 3 of the 23 (13.0%) of the control patients (p<0.001). The number of 201Tl stress myocardial perfusion defect segments was significantly decreased after the cardiac rehabilitation training (231 to 153 segments), but showed no change in the control group (158 to 156 segments) (p<0.01). In spite of no significant differences in the number of involved coronary arteries, it improved (12/17 patients: 70.6%) more in the patients who had trained for more than 2 years compared to the patients who had trained for less than 2 years. The exercise tolerance increased in 25 of the 35 training group patients (71.4%), and in only 3 of the 23 control group patients (13.0%). The peak double products increased from 20,131+/-6,010 to 28,370+/-5,600 (p<0.01) in the training group, and showed no change in the control group (20,567+/-5,112 to 20,964+/-7,728 (NS)). The results indicated that the long-term physical training increased exercise tolerance and the double products of CAD patients. In addition, the training resulted in improved cardiac perfusion as evidenced by 201Tl scintigraphy. The findings suggest that exercise training is an advisable and effective treatment for patients with CAD.     

Clinical significance of improved persistent defect by thallium-201 reinjection imaging in the subacute phase of myocardial infarction

The clinical significance of new fill-in observed by thallium-201 (201Tl) reinjection in myocardial segments with persistent defect in the subacute phase of myocardial infarction was investigated. Seventy-five patients with subacute phase (mean 20th day) of first myocardial infarction underwent stress-redistribution-reinjection 201Tl single photon emission computed tomography (SPECT) imaging. Percentage 201Tl uptake was calculated and classified as persistent defect without fill-in even after reinjection (PD group, n = 26, 35%), persistent defect with new fill-in after reinjection [REINJ (+) group, n = 19, 25%] and reversible defect [RD (+) group, n = 24, 32%]. The clinical features and angiographic findings were assessed in the same phase in each group. Diameter stenosis of the infarction-related arteries by coronary angiography was 68 +/- 34% in the PD group, 31 +/- 23% in the REINJ (+) group and 83 +/- 27% in the RD (+) group [p < 0.01, REINJ (+) group vs PD group and RD (+) group]. Wall motion of the infarcted myocardial segments significantly improved and the mean left ventricular ejection fraction (EF) was higher in the REINJ (+) group than in the PD group (mean EF 51% vs 43%, p < 0.01). Post infarction angina was more frequent in the RD (+) group than in the REINJ (+) group (38% vs 5%, p < 0.05). Although new fill-in-after 201Tl reinjection has been considered to indicate severe myocardial ischemia in chronic coronary disease, these results indicate that this phenomenon in viable myocardium in patients with subacute phase of myocardial infarction is not always related to residual ischemia in the infarcted myocardial area.     

Thallium-201 myocardial SPECT in left bundle branch block: diagnosis of myocardial ischemia with a disease-specific reference database.

BACKGROUND: The aim of this study was to assess the value of a myocardial perfusion single photon emission computed tomography (SPECT) reference file for patients with left bundle branch block (LBBB). METHODS AND RESULTS: Tl-201 stress-redistribution myocardial perfusion SPECT studies of patients with complete, permanent LBBB were reviewed retrospectively. To develop a reference database, 18 patients with a low likelihood of coronary artery disease (CAD) were selected. Left ventricular regional average and standard deviation (SD) values of the reference file images were calculated. The diagnostic performance was tested on perfusion images of 49 patients with LBBB, undergoing both scintigraphic and coronary angiographic evaluation, and was compared with a commercial quantitative analysis system using a general reference database. The LBBB reference file performed significantly better in detecting epicardial CAD than did the general reference database (receiver operating characteristic area under the curve 0.835 +/- 0.06 vs 0.580 +/- 0.08, p < .01). Disease localization also was improved significantly in the territory of the left anterior descending and of the right coronary arteries. CONCLUSIONS: The use of a reference file of patients with LBBB and a low likelihood of CAD aids the detection and the localization of myocardial ischemia on Tl-201 myocardial SPECT images of this patient group.     

Relation between electrocardiographic and scintigraphic location of myocardial ischemia during exercise in one-vessel coronary artery disease

The purpose of this study was to determine the usefulness of exercise electrocardiography in predicting the site of myocardial ischemia. Fifty-two patients were studied who had angiographically documented 1-vessel coronary artery disease (CAD) and exercise-induced reversible thallium-201 perfusion defects. The patients were divided into 2 groups: group I (28 patients) had left anterior descending CAD and group II (24 patients) had left circumflex or right CAD. There were no significant differences between the 2 groups in severity of coronary stenosis, heart rate and systolic blood pressure during exercise. The size of the perfusion defect was larger in group I than II (28 +/- 12% vs 19 +/- 10%, p less than 0.02). There was no significant difference between the 2 groups in the frequency of ST depression in the anterior, inferior or lateral electrocardiographic leads. ST depression occurred in 16 patients (57%) in group I and 11 patients (46%) in group II (difference not significant). The sensitivity of the exercise electrocardiogram was 52% using 12 leads, 50% using 3 leads (V3, V5 and aVF) and 50% using V5 alone (difference not significant). Thus, the site of ST depression during exercise is not a good predictor of the site of exercise-induced perfusion defect or anatomic site of CAD. The use of 12 leads does not improve the sensitivity of exercise electrocardiography in patients with CAD.     

Impact of left ventricular ejection fraction on endothelial function in patients with coronary artery disease

BACKGROUND: Endothelial dysfunction is present in patients with coronary artery disease (CAD) or with congestive heart failure. HYPOTHESIS: This study was performed to evaluate the impact of systolic heart function on endothelial function in patients with CAD. METHODS: The study population consisted of 283 consecutive patients (mean age 59 years, 176 men) undergoing coronary angiography. Endothelial function was assessed by measuring flow-mediated vasodilation (FMD) of the brachial artery. RESULTS: Patients (n = 236) with an ejection fraction (EF) > or = 55% on routine echocardiogram were younger (mean age 58 vs. 62 years), showed a lower prevalence of diabetes (15 vs. 38%) and myocardial infarction (13 vs. 66%), and showed a higher FMD (4.8 +/- 2.4 vs. 4.0 +/- 2.0%, p < 0.05) than patients (n = 47) with an EF < 55%. The correlation coefficient between FMD/endothelial function and EF/systolic heart function was 0.149 (p < 0.02) in the overall study population. Multivariate analysis showed that of age, gender, frequency of diabetes mellitus, myocardial infarction, and CAD extent, EF was the only significant independent parameter correlating with FMD in patients with CAD. CONCLUSIONS: Compared with the other tested risk factors, EF surprisingly was the only significant independent parameter correlating with endothelial function in patients with CAD. Our results support the view that endothelial function is an independent prognostic factor in patients with CAD.     

Effect of coronary artery bypass surgery on myocardial perfusion and ejection fraction response to inotropic stimulation in patients without improvement in resting ejection fraction

The aim of this study was to assess the effect of coronary artery bypass grafting (CABG) on myocardial perfusion and left ventricular (LV) contractile reserve in patients with reduced ejection fraction (EF). We studied 57 patients (age 59 +/- 8 years, 46 men and 11 women) with EF < or = 40% referred for CABG with dobutamine (up to 40 microg/kg/min) stress-reinjection thallium-201 single-photon emission computed tomography, and radionuclide ventriculography at rest and at low-dose dobutamine before and 3 months after CABG. An increase in resting EF > or = 5% occurred in 12 patients (group A) after CABG (EF 34% before and 46% after CABG), whereas no increase occurred in the remaining 45 patients (group B) (EF 34% before and 32% after CABG). A significant increase in EF from rest to low-dose dobutamine radionuclide ventriculography occurred before and after CABG. The magnitude of increase was more significant after than before CABG in group A (12% vs 7%) as well as in group B (13% vs 7%, both p <0.001). Patients in both groups had a significant reduction in stress, rest, and ischemic perfusion scores after CABG. However, the percentage of reduction in resting perfusion defect score was more significant in group A than in group B (60% vs 30%, respectively, p <0.01). It is concluded that CABG induces a significant improvement in resting myocardial perfusion and EF response to inotropic stimulation, even in the absence of improved EF at rest. Patients without improvement in resting EF after CABG have mild improvement in resting myocardial perfusion that may be sufficient to increase EF after CABG during inotropic stimulation, but not at rest. We describe the myocardium with these characteristics as "the reactive myocardium."     

Cholesterol reduction improves myocardial perfusion abnormalities in patients with coronary artery disease and average cholesterol levels

OBJECTIVES: We sought to evaluate whether pravastatin treatment increases myocardial perfusion, as assessed by thallium-201 single-photon emission computed tomographic (SPECT) dipyridamole testing, in patients with coronary artery disease (CAD) and average cholesterol levels. BACKGROUND: Previous studies in hypercholesterolemic patients have demonstrated that cholesterol reduction restores peripheral and coronary endothelium-dependent vasodilation and increases myocardial perfusion. METHODS: This was a randomized, placebo-controlled study with a cross-over design. Twenty patients with CAD were randomly assigned to receive 20 mg of pravastatin or placebo for 16 weeks and then were crossed over to the opposite medication for a further 16 weeks. Lipid and lipoprotein analysis and dipyridamole thallium-201 SPECT were performed at the end of each period. The SPECT images were visually analyzed in eight myocardial segments using a 4-point scoring system by two independent observers. A summed stress score and a summed rest score were obtained for each patient. Quantitative evaluation was performed by the Cedars-Sinai method. The magnitude of the defect was expressed as a percentage of global myocardial perfusion. RESULTS: Total and low density lipoprotein cholesterol levels during placebo were 214 +/- 29 mg/dl and 148 +/- 25 mg/dl, respectively. These levels with pravastatin were 170 +/- 23 mg/dl and 103 +/- 23 mg/dl, respectively. The summed stress score and summed rest score were lower with pravastatin than with placebo (7.2 +/- 2.3 vs. 5.9 +/- 2.3, p = 0.012 and 3.2 +/- 1.6 vs. 2.4 +/- 2.2, p = 0.043, respectively). Quantitative analysis showed a smaller perfusion defect with pravastatin (29.2%) as compared with placebo (33.8%) (p = 0.021) during dipyridamole stress. No differences were found at rest. CONCLUSIONS: Reducing cholesterol levels with pravastatin in patients with CAD improves myocardial perfusion during dipyridamole stress thallium-201 SPECT.     

The clinical and prognostic significance of dipyridamole Tl-201 emission computed tomography in patients with dilated cardiomyopathy

To clarify the clinical significance of regional myocardial perfusion abnormality of the left ventricle in dilated cardiomyopathy (DCM), 20 patients with DCM underwent dipyridamole Tl-201 emission computed tomography (ECT). The subjects were divided into 2 groups: group 1 had (n = 9) reversible defects and group 2 (n = 11) had persistent defects only. Group 2 patients significantly advanced heart failure and significantly poorer prognoses than group 1 (55% vs 11% in 2 years survival rate, p less than 0.05). The echocardiographic left ventricular end-diastolic dimension was larger in group 2 than group 1 (68.3 +/- 8.2 mm vs 61.9 +/- 4.0 mm, p less than 0.05) and % fractional shortening was smaller in group 2 than group 1 (18.0 +/- 4.5% vs 24.5 +/- 6.9%, p less than 0.05). Moreover, 12 of the 13 segments with reversible defect showed fairly well preserved left ventricular wall motion, whereas 35 of 58 segments with persistent defect had severely impaired wall motion (1/13 vs 35/58, p less than 0.01). Dipyridamole Tl-201 ECT demonstrated conclusively that the two types of defects (reversible and persistent) are useful to evaluate not only the abnormal myocardial perfusion but also myocardial damage and the prognosis in DCM.     

Differences in left ventricular ejection fraction and volumes measured at rest and poststress by gated sestamibi SPECT.

BACKGROUND: Some studies suggested that the poststress left ventricle ejection fraction (LV EF) is lower than rest LV EF in patients with stress-induced ischemia. METHODS AND RESULTS: By using a 2-day protocol and 30 mCi Tc-99m sestamibi, LV EF, end-systolic volume (ESV), and end-diastolic volume (EDV) were measured with gated SPECT. Of 99 eligible patients, 91 had technically adequate studies. Poststress LV EF minus rest LV EF was defined as DeltaLV EF. DeltaEDV and DeltaESV were similarly defined. Rest and poststress LV EF (r = 0.89), EDV (r = 0.78), and ESV (r = 0.93) were highly correlated (P <.001). Rest LV EF, EDV, and ESV were not significantly different between patients with and without stress-induced ischemia. DeltaLV EF was significantly lower in patients with stress-induced ischemia (-3.5% +/- 4.5% vs -1.1% +/- 4.7%, P = .02). Mean LV EF poststress in ischemic patients was 55.0% +/- 10.5% vs 61.2% +/- 10.0% in nonischemic patients (P = .008). However, only 1 patient (3%) with ischemia had DeltaLV EF that exceeded the 95% confidence limit of DeltaLV EF for normal patients. Ischemia was significantly associated with increased DeltaEDV and DeltaESV (P < .01). CONCLUSIONS: Stress-induced ischemia is associated with poststress reduction in LV EF and increased poststress EDV and ESV. However, the effect of ischemia on the difference between poststress and rest EF measurements is modest and rarely exceeds the confidence limits in normal patients undergoing 2-day protocols. In most patients, poststress LV EF is an accurate reflection of rest LV EF.     

Percutaneous transluminal coronary angioplasty in patients with reduced left ventricular ejection fraction: effects on myocardial perfusion and left ventricular response to exercise

Many patients with coronary artery disease treated by percutaneous transluminal coronary angioplasty (PTCA) have a history of previous myocardial injury resulting in a reduced left ventricular ejection fraction (EF). The effects of successful PTCA on myocardial perfusion and left ventricular function in these patients were compared to treatment in patients with normal left ventricular EF. There were 21 patients with a normal EF (mean EF 59 +/- 2%) (Group I) and 15 patients with reduced EF (mean EF 43 +/- 1%) (Group II). Before PTCA a similar degree of reversible myocardial ischemia was present on thallium scintigraphy. At peak exercise left ventricular EF in the Group I patients decreased by 4 +/- 1% compared to 8 +/- 1% in Group II. At one month following successful PTCA there was resolution of reversible myocardial ischemia in both groups. No changes in EF at rest were observed. At the same level of exercise as before PTCA the mean EF was 5 +/- 1% higher than the pretreatment value in Group I and 10 +/- 1% higher in Group II. Thus in this study reversible myocardial ischemia was associated with severe compromise in the left ventricular response to exercise which was substantially improved by PTCA.     

Gender differences in the relation between ST-T-wave abnormalities at baseline electrocardiogram and stress myocardial perfusion abnormalities in patients with suspected coronary artery disease.

The presence of ST-T-wave abnormalities in the resting electrocardiogram was reported as a predictor of coronary artery disease (CAD) and increased morbidity and mortality. However, the independent value of ST-T abnormalities for predicting the presence and severity of perfusion abnormalities during stress testing has not been studied in a homogenous patient group without known CAD. We evaluated the relation between resting ST-T abnormalities and myocardial perfusion abnormalities in 246 patients (age 59 +/- 13 years, 114 men and 132 women) without known CAD or previous myocardial infarction referred for evaluation of possible myocardial ischemia by dobutamine (up to 40 microg/kg/min) stress sestamibi or tetrofosmin single-photon emission computed tomographic imaging. Resting ST-T abnormalities were present in 123 patients, whereas 123 patients with normal resting electrocardiograms served as a matched control group. Abnormal myocardial perfusion (fixed or reversible perfusion defects) was detected in 72% of men with and in 35% of men without resting ST-T abnormalities (p <0.0001), whereas the prevalence of myocardial perfusion abnormalities was not different in women with and without resting ST-T abnormalities (27% vs 23%, p = NS). In the entire population, independent predictors of an abnormal perfusion by multivariate analysis of clinical characteristics and risk factors were male gender (p <0.001, chi-square 10.5) and resting ST-T abnormalities (p <0.05, chi-square 3). Separate analysis of patients based on gender revealed resting ST-T abnormalities as independent predictors of abnormal perfusion in men (p <0.05, chi-square 4) but not in women. Stress perfusion defect score was higher in men with than without ST-T abnormalities (887 +/- 545 vs 207 +/- 180, p <0.001). It is concluded that resting ST-T wave abnormalities are associated with a higher prevalence and severity of resting and dobutamine-induced myocardial perfusion abnormalities in men but not in women. Resting ST-T wave abnormalities are powerful predictors of compromised myocardial perfusion independent of other clinical risk factors of CAD in men.     

Prognostic value of poststress left ventricular volume and ejection fraction by gated myocardial perfusion SPECT in women and men: gender-related differences in normal limits and outcomes.

BACKGROUND: Whether there are gender differences in the prognostic application of gated myocardial perfusion single photon emission computed tomography (SPECT) has not been assessed. METHODS AND RESULTS: Gender-specific normal limits of poststress volume and ejection fraction (EF) were obtained in 597 women and 824 men with a low likelihood of coronary artery disease and normal perfusion and were applied in a prognostic evaluation of 6713 patients (2735 women and 3978 men). Patients underwent rest thallium-201/stress technetium-99m sestamibi gated myocardial perfusion SPECT and were followed up for 35 +/- 14 months. The upper limit of the end-systolic volume (ESV) index was 27 mL/m2 in women and 39 mL/m2 in men, and the upper limit of the end-diastolic volume index was 60 mL/m2 in women and 75 mL/m2 in men. The lower limit of the EF was 51% in women and 43% in men. Gated SPECT variables provided incremental prognostic information in both genders. Women with severe ischemia and an EF lower than 51% or an ESV index greater than 27 mL/m2 were at very high risk of cardiac death or myocardial infarction (3-year event rates of 39.8% and 35.1%, respectively), whereas women with severe ischemia but an EF of 51% or greater or an ESV index of 27 mL/m2 or less were at intermediate or high risk (3-year event rates of 10.8% and 15.2%, respectively). CONCLUSION: Poststress EF and ESV index by gated myocardial perfusion SPECT provide comparable incremental prognostic information over perfusion in women and men. After separate criteria for abnormal EF and ESV index in women are used, the combination of severe ischemia and abnormal EF or ESV index identifies women at very high risk of cardiac events.     

Rate of left ventricular functional recovery by radionuclide angiography after exercise in coronary artery disease

To characterize determinants of the rate of recovery of left ventricular (LV) function after exercise-induced ischemia, sequential postexercise radionuclide angiography was performed prospectively in 38 consecutive patients with documented coronary artery disease (CAD). In each patient new or increased regional asynergy developed or absolute ejection fraction decreased at least 4% during exercise. Twenty patients showed immediate recovery of LV function after exercise (group 1) and 18 showed delayed recovery (group 2). Ejection fraction in the first postexercise period was significantly greater in group 1 (65 +/- 12%) than in group 2 (55 +/- 11%) (p less than 0.01). The mean number of coronary arteries with at least 70% diameter narrowing was greater in group 2 (2.7 +/- 0.5) than in group 1 (2.0 +/- 0.9) (p = 0.026); CAD score was also greater in group 2 than in group 1 (p = 0.005). The increase in LV end-diastolic volume from rest to end exercise was greater in group 2 than in group 1 (p = 0.005); neither the change in LV volume nor the change in heart rate or blood pressure after exercise separated the groups. The only independent predictor of the rate of functional recovery was the degree of exercise-induced regional myocardial asynergy (p less than 0.001). Thus, exercise radionuclide angiography in patients with CAD provides a model for evaluating postischemic myocardial function. Delayed functional recovery is associated with extensive exercise-induced regional asynergy as a result of severe CAD and is not primarily influenced by hemodynamic changes.     

Impact of type 2 diabetes on myocardial insulin sensitivity to glucose uptake and perfusion in patients with coronary artery disease

BACKGROUND AND HYPOTHESIS: Myocardial insulin resistance (IR) is a feature of coronary artery disease (CAD) with reduced left ventricular ejection fraction (LVEF). Whether type 2 diabetes mellitus (T2DM) with CAD and preserved LVEF induces myocardial IR and whether insulin in these patients acts as a myocardial vasodilator is debated. METHODS: We studied 27 CAD patients (LVEF > 50%): 12 with T2DM (CAD+DM), 15 without T2DM (CAD-NoDM). Regional myocardial and skeletal glucose uptake, myocardial and skeletal muscle perfusion were measured with positron emission tomography. Myocardial muscle perfusion was measured at rest and during hyperemia in nonstenotic and stenotic regions with and without acute hyperinsulinemia. RESULTS: Myocardial glucose uptake was similar in CAD+DM and CAD-NoDM in both nonstenotic and stenotic regions [0.38 +/- 0.08 and 0.36 +/- 0.11 micromol/g.min; P value nonsignificant (NS)] and (0.35 +/- 0.09 and 0.37 +/- 0.13 micromol/g.min; P = NS). Skeletal glucose uptake was reduced in CAD+DM (0.05 +/- 0.04 vs. 0.10 +/- 0.05 micromol/g.min; P = 0.02), and likewise, whole-body glucose uptake was reduced in CAD+DM (4.0 +/- 2.8 vs. 7.0 +/- 2.4 mg/kg.min; P = 0.01). Insulin did not alter myocardial muscle perfusion at rest or during hyperemia. Insulin increased skeletal muscle perfusion in CAD-NoDM (0.11 +/- 0.03 vs. 0.06 +/- 0.03 ml/g.min; P = 0.02), but not in CAD+DM (0.08 +/- 0.04 and 0.09 +/- 0.05 ml/g.min; P = NS). CONCLUSION: Myocardial IR to glucose uptake is not an inherent feature in T2DM patients with preserved LVEF. Acute physiological insulin exposure exerts no coronary vasodilation in CAD patients irrespective of T2DM.     

Correlation between ECG and myocardial perfusion after mechanical reperfusion of acute myocardial infarction

The identification of viable myocardium after myocardial infarction (MI) carries major prognostic impact. Due to myocardial stunning early after successful mechanical reperfusion of acute myocardial infarction, analysis of myocardial perfusion but not of contractile function can be used to differentiate between necrotic and viable myocardium. Although being widely regarded as an indicator of infarct transmurality, the relation between post-infarct Q-wave formation and the amount of viable myocardium has not been studied. We hypothesized that there was a correlation between the extent of Q-wave formation and the extent of perfusion abnormalities on myocardial contrast echocardiography early after successful mechanical reperfusion of first acute myocardial infarction and that the extent of post-infarct Q-wave formation might therefore be used as a simple estimate of the amount of viable myocardium. METHODS AND RESULTS: 47 patients with first MI and treated by direct PCI were enrolled. Patients were divided into 3 groups according the presence and number of abnormal Q waves (group A-no abnormal Q wave; group B-< or =2 abnormal Q waves, group C-> or =3 abnormal Q waves). Left ventricular pump function was defined by ejection fraction (EF) on ventriculography and wall motion score index (WMSI) on echocardiography. Myocardial perfusion was defined by perfusion score index (PSI) on myocardial contrast echocardiography. Patients in group A had significantly better LV function than patients in other groups [EF 57+/-5 vs. 48+/-11% (group B) and 47+/-10% (group C); p<0.05], also WMSI was the best in this group [1.34+/-0.22 vs. 1.67+/-0.39 (group B) and 1.68+/-0.31 (group C); p<0.01]. Myocardial perfusion assessed by PSI was best in group A (1.2+/-0.3, p<0.05). With respect to PSI, there was a significant difference between group B and C (1.41+/-0.21 vs. 1.56+/-0.29; p<0.05), even though EF and WMSI did not differ in these groups. The amount of perfused segments with severe wall motion abnormality was higher in group B compared to group C (47% vs. 25%; p<0.05). CONCLUSION: In patients after successful mechanical reperfusion of first MI, the extent of Q-wave formation on ECG may be regarded as a corollary of the amount of myocardial microvascular damage and may, therefore, be used to estimate the amount of viable myocardium post-infarct.