Impact of imaging protocol on left ventricular ejection fraction using gated-SPECT myocardial perfusion imaging.

BACKGROUND: There are limited data on the impact of the imaging protocol (single-day stress-rest, SD, vs. dual-day, DD) on the change in left ventricular (LV) ejection fraction (EF) (post-stress-rest) in relation to ischemia and on outcome. METHODS: Using propensity score matching procedure, 490 of 1121 patients with known CAD, undergoing a SD or a DD in a multicenter study, were evaluated. Stress and rest gated-SPECT myocardial perfusion imaging was used to quantify LV perfusion, EF, and volumes. Outcome was assessed at an average follow-up time of 3.2 years. RESULTS: Post-stress LVEF in SD and DD were comparable across all degrees of ischemia. The change in LVEF in patients with severe ischemia was, however, higher in the DD protocol, independent of the extent of CAD. At follow-up, 240 patients (49.0%) required coronary revascularization (CR) and 52 patients (10.6%) had hard events. The ischemic burden was independently associated with CR and hard-events; the post-stress LVEF was associated with CR but the change in EF was not predictive of either CR or hard events. CONCLUSIONS: In patients with severe ischemia, underestimation of post-stress myocardial stunning could be observed with the SD protocol. Post-stress LVEF and the extent ischemia, but not the change in EF, are predictive of CR and hard events.

Greater functional improvement in patients with diabetes after rehabilitation following cardiac surgery.

BACKGROUND: Diabetes increases the risk of in-hospital complications in medical or surgical patients. Few data are available in the rehabilitation phase after cardiac surgery. AIM: To assess the influence of diabetes on outcome and complication rate in the rehabilitation phase after cardiac surgery. METHODS: Data prospectively recorded in the Hospital Information System from 5261 patients consecutively admitted between 1 January 2008 and 31 May 2013 for a comprehensive cardiac rehabilitation programme directly after cardiac surgery were analysed retrospectively. RESULTS: The study cohort included 1285 (24%) patients with diabetes and 3976 (76%) without. Coronary artery bypass graft (CABG) was more frequent in patients with diabetes (58% vs. 37%, P < 0.01), and valvular surgery was more frequent in patients without diabetes (37% vs. 22%, P < 0.01). Patients with diabetes were more disabled after surgery, with severe disability (Barthel Index < 60) observed in 22% (vs. 17% in patients without diabetes, P < 0.001). During rehabilitation, complications were more frequent in patients with diabetes than those without (28% vs. 21%, P < 0.01); in particular, patients with diabetes had more infections, heart failure and more difficult surgical wound healing. However, the improvement in the Barthel Index was greater in patients with diabetes (+16 ± 15) than without (+13 ± 15, P < 0.001). CONCLUSIONS: In a large cohort of patients directly admitted to an early inpatient rehabilitation programme after cardiac surgery, those with diabetes were more disabled. Nonetheless, and despite the higher rate of complications, patients with diabetes had the greatest benefit in terms of functional improvement.

Applicability of the appropriate use criteria for SPECT myocardial perfusion imaging in Italy: preliminary results.

PURPOSE: Clinical applicability of the appropriate use criteria for SPECT myocardial perfusion imaging has not yet been evaluated in Italy. We investigated the applicability of the Appropriate Use Criteria (AUC) in Italy. METHODS: The indications for testing were prospectively recorded in three different nuclear cardiology laboratories: a general hospital, an academic hospital, and a tertiary centre. Indications were categorized as appropriate, uncertain or inappropriate according to the 2009 AUC; the specialty of the ordering physician was also noted. SPECT results were classified as: normal, probably normal, uncertain, probably abnormal, abnormal. The presence and severity of ischaemia were also noted. RESULTS: Over a 9-month period, 2,134 patients (age 67 ± 10 years, 68 % men) were evaluated (62 % exercise stress test). On average, there were 700 (84 %) appropriate, 73 (7 %) inappropriate and 93 (9 %) uncertain tests. The rates for the appropriateness of indications were comparable in men and women (84 % and 83 %, not significant). As expected, the rate of nonnormal studies was higher (58 %) for appropriate than for inappropriate (33 %) indications. Appropriateness was lower in the tertiary centre (74 %), and uncertain (16 %) and inappropriate (10 %) indications were more common; this was related to the higher rate of outpatients scheduled by nonhospital cardiologists (37 %). The most common indications associated with inappropriate testing were: chest pain, low likelihood of coronary artery disease, interpretable ECG and able to exercise (29 %), and asymptomatic <2 years after percutaneous coronary intervention (24 %). CONCLUSION: In this preliminary evaluation of the AUC in Italy, the majority of studies were classified as appropriate, but a consistent proportion of scheduled SPECT studies, particularly by nonhospital cardiologists, were still categorized as uncertain or inappropriate. Educational approaches should be implemented to reduce the rate of less appropriate examinations. However, a substantial proportion (33 %) of inappropriate studies were classified as nonnormal, with 26 % of these patients having ischaemia.

Temporal evolution of administered activity in cardiac gated SPECT and patients' effective dose: analysis of an historical series.

PURPOSE: Myocardial perfusion imaging contributes >20 % of the average medical radiation exposure to the population in the USA. Imaging protocols able to achieve a radiation exposure ≤9 mSv in 50 % of the studies by 2014 have been recommended. The aim of this study was to analyse the temporal evolution of administered activities in patients scheduled for dual-day (99m)Tc tracer gated single photon emission computed tomography (SPECT) and to compare different dose administration protocols in terms of patients' effective dose. METHODS: Patients evaluated from 1 July 2002 to 31 January 2012 were allocated according to the protocol adopted: group 1: fixed activity according to diagnostic reference level: 740 MBq up to 80 kg (adapted for weight <60 kg); 900 MBq 80-100 kg, 1,110 MBq >100 kg, standard filtered back-projection (FBP) reconstruction; group 2: weight-adjusted activity: 8 MBq/kg up to 1,110 MBq, standard FBP reconstruction; and group 3: 4 MBq/kg, UltraSPECT wide beam reconstruction (WBR) reconstruction. A dual-head Anger camera (GE Helix) was used. RESULTS: A total of 9,060 patients were allocated to different groups: 4,751 in group 1, 2,844 in group 2 and 1,465 in group 3. The stress + rest administered activity was 1,617 ± 180 in group 1, 1,136 ± 260 in group 2 and 682 ± 164 MBq in group 3 (all p < 0.001). Patients' effective dose was 13.7 ± 3 in group 1, 9.5 ± 2.8 in group 2 and 5.7 ± 1.6 mSv in group 3 (all p < 0.001). The 50th percentile was 12.6 in group 1, 9.1 in group 2 and 5.3 mSv in group 3. The effective dose received by the dedicated cardiologists was 2.1, 1.5 and 1.0 µSv/exam in group 1, group 2 and group 3 periods, respectively (all p < 0.001). CONCLUSION: A significant reduction over time in the administered activity for gated SPECT was achieved; accordingly, a significant reduction in patients' exposure was obtained. A simple weight-adjusted strategy with 8 MBq/kg immediately fulfils the recommendations to limit exposure. In selected group 3 patients, a stress-only strategy allows for studies with <3 mSv exposure. Thus, at least the adoption of a new reconstruction algorithm is strongly encouraged, and suggested tracer activities for cardiac gated SPECT are to be revised.

The regulatory background of nuclear cardiology in Europe: a survey by the European Council of Nuclear Cardiology.

PURPOSE: Nuclear cardiology is a well-validated, non-invasive imaging modality that is highly cost-effective as a diagnostic and prognostic tool in the evaluation of patients with known or suspected coronary artery disease. However, the number of procedures in Europe is very far from that which would be expected on the basis of epidemiological data, particularly when comparison is made with the USA. As a preliminary step for future action aimed at improving and increasing nuclear cardiology practice in Europe, the European Council of Nuclear Cardiology performed a survey to identify the regulatory issues and the training components pertaining to the practice of nuclear cardiology. METHODS: a questionnaire was sent to 31 national nuclear medicine societies and to 40 national cardiology societies. The main areas covered by the survey were: (1) the license requirements, (2) the theoretical and practical aspects of training and (3) supervision of the stress test during a nuclear cardiology study. RESULTS: The results show that, in a setting of wide heterogeneity of national regulations, education and professional practice, nuclear medicine is a restricted and closely regulated specialty. This situation guarantees the quality and safe use of radionuclides; at the same time, however, it limits integration of nuclear medicine into the clinical arena. CONCLUSION: Cardiologists should become more involved in nuclear cardiology, to further stimulate the use of this powerful diagnostic and prognostic imaging modality.

Independent and incremental prognostic value of (201)Tl lung uptake at rest in patients with severe postischemic left ventricular dysfunction.

BACKGROUND: An elevated (201)Tl lung uptake after stress is related to an adverse prognosis. METHODS AND RESULTS: The functional and prognostic significance of resting (201)Tl lung uptake was assessed in 124 consecutive patients with ischemic heart disease and ejection fraction 0.61 best separated patients with and without events (ROC area under curve 0.82). Event-free survival was significantly lower in patients with L/H >0.61 (P:<0. 001); L/H >0.61 (chi(2)=10.8; P:<0.001) and a restrictive filling pattern (chi(2)=3.6; P:<0.05) were independent predictors of events. The prognostic value of L/H was incremental over that obtained by clinical, echographic and Doppler data (global chi(2)=20.8). CONCLUSIONS: In patients with severe postischemic left ventricular dysfunction undergoing rest-redistribution (201)Tl imaging, an increased lung tracer uptake showed incremental prognostic value over clinical and other imaging findings, providing clinically useful risk assessment.

Ischemic burden in silent and painful myocardial ischemia: a quantitative exercise sestamibi tomographic study.

OBJECTIVES: We sought to determine whether the amount of myocardial ischemic burden differs in patients with painful or silent myocardial hypoperfusion during exercise testing. BACKGROUND: Whether a lack of symptoms during ischemia reflects an alteration in pain perception or less myocardium in jeopardy remains a controversial issue. METHODS: We studied 300 consecutive patients with a well established history of ischemic heart disease and reversible hypoperfusion on exercise sestamibi tomography. Rest and stress sestamibi defects were quantitatively assessed and indexes of exercise left ventricular dilation derived. RESULTS: Painful and silent reversible ischemia was observed in 97 (32%) and 203 (68%) patients, respectively. Patients with painful ischemia had lower values for work load, exercise time and peak rate-pressure product (p < 0.01) and more frequently showed significant ST segment depression during exercise than did patients with silent ischemia (69% vs. 40%, p < 0.001). On sestamibi tomography, patients with painful ischemia had more reversible hypoperfusion than did patients with silent ischemia (mean +/- SD 16 +/- 10% vs. 11 +/- 7%, p < 0.001), despite a comparable extent of stress hypoperfusion (22 +/- 12% vs. 22 +/- 13%); they also had a higher endocardial dilation index (1.32 +/- 0.32 vs. 1.10 +/- 0.26, p < 0.001). By multivariate logistic analysis, the most powerful correlate of painful ischemia was a history of effort angina; the extent of reversible perfusion defect was the sole independent scintigraphic correlate of painful ischemia. CONCLUSIONS: To our knowledge, this is the largest study comparing the degree of hypoperfusion and the presence of symptoms during exercise stress testing in a consecutive cohort of patients with ischemic heart disease and reversible hypoperfusion. The results suggest that the ischemic burden is greater in painful than in silent ischemia.

Residual exertional ischemia and unfavorable left ventricular remodeling in patients with systolic dysfunction after anterior myocardial infarction.

OBJECTIVES: This study investigated whether exercise-induced myocardial ischemia influences left ventricular remodeling after anterior myocardial infarction. BACKGROUND: The effects of acute and recurrent ischemia on ventricular function are well established. However, to our knowledge the role of exertional ischemia in the remodeling response after infarction has not been investigated. METHODS: Ninety-one patients with a first anterior Q wave myocardial infarction were studied at 5 weeks by rest echocardiography and exercise scintigraphy. The echocardiographic examination was repeated 6 months later. On the basis of the presence and extent of reversible perfusion defects on exercise scintigraphy, patients were assigned to groups with no exertional ischemia (group 1, n = 20 [22%], mild to moderate ischemia (group 2, n = 45 [49%]) and severe exertional ischemia (group 3, n = 26 [29%]). RESULTS: Initial left ventricular volumes were similar, and no differences were found among the three groups in the remodeling response over the 6-month period of the study. However, patients in groups 2 and 3 with an ejection fraction < or = 40% showed significant (p < 0.01) ventricular enlargement over time, which was similar between the two groups (end-diastolic volume [mean +/- SD] from 74 +/- 13 to 80 +/- 17 ml/m2 in group 2 and from 72 +/- 11 to 81 +/- 19 ml/m2 in group 3; regional dilation from 42 +/- 16% to 52 +/- 22% in group 2 and from 38 +/- 18% to 46 +/- 27% in group 3). In contrast, ventricular dimensions did not change in group 1 patients with an ejection fraction < or = 40% as well as in patients in all three groups with an ejection fraction > 40%. CONCLUSIONS: Exercise-induced myocardial ischemia may contribute to progressive ventricular enlargement in patients with poor left ventricular function after a large anterior myocardial infarction.

Accuracy and safety of technetium-99m hexakis 2-methoxy-2-isobutyl isonitrile (Sestamibi) myocardial scintigraphy with high dose dipyridamole test in patients with effort angina pectoris: a multicenter study. Italian Group of Nuclear Cardiology.

Clinical and physiologic evidence indicates that maximal coronary vasodilation is not achieved in a large number of patients with use of the standard dose of dipyridamole (0.56 mg/kg body weight over 4 min). The feasibility, safety and accuracy of technetium-99m hexakis 2-methoxy-2-isobutyl isonitrile (Sestamibi) scintigraphy associated with intravenous high dose dipyridamole (0.56 mg/kg over 4 min followed 4 min later by an additional 0.28 mg/kg over 2 min) were evaluated in a multicenter study. Planar myocardial perfusion images were obtained at rest and after dipyridamole in 101 patients with effort chest pain and no prior myocardial infarction. High dose dipyridamole (62 patients) was used when typical chest pain or electrocardiographic (ECG) signs of ischemia, or both, did not occur during or after the standard dose (39 patients). With high dose dipyridamole, 34 patients had pain (18 patients) or ECG signs of ischemia (ST depression greater than or equal to 2 mm) (8 patients), or both (8 patients), whereas the other 28 patients had Sestamibi injection in the absence of symptoms or ECG changes. All patients underwent coronary angiography: 81 had significant coronary artery disease (greater than or equal to 50% reduction of lumen diameter) (affecting one vessel in 38, two vessels in 19 and three vessels in 24 patients) and 20 patients had normal coronary arteries. The overall sensitivity, specificity and predictive accuracy of Sestamibi scintigraphy were 81%, 90% and 83%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Technetium-99m sestamibi tomographic evaluation of residual ischemia after anterior myocardial infarction.

OBJECTIVES: This study investigated the value of sestamibi scintigraphy in assessing residual ischemia after anterior myocardial infarction. BACKGROUND: Serial imaging with sestamibi, the uptake and retention of which correlate with regional myocardial blood flow and viability, has been used to estimate salvaged myocardium and risk area after acute infarction. We recently documented that recovery of perfusion and contraction in the infarcted area may continue well after the subacute phase, suggesting myocardial hibernation. Some underestimation of viability in the setting of hibernating myocardium by sestamibi imaging has been reported. METHODS: We studied 58 patients in stable condition after Q wave anterior infarction. Regional perfusion and function were quantitatively assessed by sestamibi tomography and two-dimensional echocardiography at 4 to 6 weeks and at 7 months after infarction. In sestamibi polar maps, abnormal areas with tracer uptake > 2.5 SD below our reference values were computed at rest and after symptom-limited exercise. On two-dimensional echocardiography the ejection fraction and extent of rest wall motion abnormalities were assessed by a computerized system. All patients had coronary angiography between the two studies. RESULTS: At 7 months the extent of rest sestamibi defect was significantly reduced in 40 patients (69%, group 1) and unchanged in 18 (31%, group 2). Rest wall motion abnormalities and ventricular ejection fraction significantly improved in group 1 but not in group 2. Underlying coronary disease, patency of the infarct-related vessel and rest sestamibi defect extent at 5 weeks were comparable between the two groups. At 7 months, an increase in the reversible (stress-rest defect) tracer defect was observed in group 1 (p < 0.05) despite a smaller stress-induced hypoperfusion (p < 0.05). Reversible sestamibi defects and stress hypoperfusion were unchanged in group 2. In 38 (95%) of 40 group 1 patients, the area showing reversible sestamibi defects at 7 months matched the area showing fixed hypoperfusion at 5 weeks. CONCLUSIONS: The reduction in the rest tracer uptake defect that can occur late after infarction may affect the assessment of ischemic burden by sestamibi imaging early after anterior myocardial infarction.

Polymyalgia rheumatica: inflammation suppression with low dose of methylprednisolone or modified-release prednisone.

OBJECTIVE: Polymyalgia rheumatica (PMR) is an inflammatory disease that affects people aged > 50 years, and is characterised by pain and morning stiffness in the shoulder and pelvic girdle with synovitis of the proximal joints and extra-articular synovial structures. It is currently mainly treated with glucocorticoids (GCs). The aim of the study was to evaluate changes in inflammatory markers and their correlations with cortisol levels after treatment with 6-methylprednisolone (6-MP) or modified-release prednisone (MR-P) in patients with "early" PMR. PATIENTS AND METHODS: The study involved 81 GC-naïve with "early" PMR diagnosed on the basis of the 2012 EULAR/ACR criteria: 38 treated with 6-MP at a starting dose of 12 mg at 8.00 a.m, gradually tapered to 8, 4 and 2 mg/day, and 43 treated with MR-P at a starting dose of 10 mg at 10 p.m, tapered to 7, 5, 3, 2 and 1 mg. The markers of inflammation (ESR mm/h, CRP mg/dL and fibrinogen mg/dL), the circulating serum levels of cytokines (TNFa and IL-6), and morning serum cortisol levels were evaluated at baseline and during GC treatment. RESULTS: There were significant differences between baseline and the end of treatment in the serum levels of IL-6 (5.3 ± 9.3 vs 2.8 ± 3.3 pg/mL; p < 0.05) and CRP (2.1 ± 3.3 vs 0.9 ± 1.7 mg/dL; p < 0.01) in the patients treated with MR-P, and in serum cortisol levels (15.8±6.4 vs 13.6+5.6 µg/dL; p < 0.01) in the patients treated with 6-MP. After the first month of treatment, 76.7% of the patients treated with MR-P had IL6 levels at or below the upper normal limit, whereas 52.6% of those treated with 6-MP had normal IL6 levels (p < 0.05). There was also a significant difference in the percentage of patients in whom the daily GC dose was tapered within eight months (6.7% in the MR-P group vs 25% in the 6-MP group; p < 0.001) and, by the end of the study, respectively 59.5% vs 35.1% patients were receiving a low GC dose or had discontinued treatment altogether (OR 2.7, 95% CI 1.0-6.77; p < 0.001). After six and 12 months, respectively 10.3% and 14.3% of the patients had discontinued MR-P, as against none of the patients treated with 6-MP (p < 0.05). CONCLUSIONS: In this prospective observational study of PMR patients receiving low-dose GCs, the changes in inflammatory markers were similar in those treated with 6-MP or MR-P, whereas morning cortisol levels remained unchanged only in the MR-P group. During the first month of treatment, MR-P chronotherapy given at bedtime significantly decreased IL-6 levels. The percentage of patients stopping GC treatment was higher in the MR-P group than in the 6-MP group.

A new method for noninvasive quantitation of segmental myocardial wall thickening using technetium-99m 2-methoxy-isobutyl-isonitrile scintigraphy--results in normal subjects.

A quantitative index of regional myocardial wall motion obtained from electrocardiogram-gated perfusion images has been assessed. The assumption for the proposed algorithm is that, according to the partial volume effect, the recovery counts by the instrumentation is a function of the object size. Systo-diastolic changes in the detected radioactivity would therefore reflect changes in myocardial wall thickness. Ten normal volunteers were studied in control condition by 99mTc 2-methoxy-isobutyl-isonitrile scintigraphy. Electrocardiogram (ECG)-gated images were acquired in multiple projections. End-diastolic and end-systolic activity was measured along radii from the center to the edge of the left ventricle. Data are displayed as circumferential profiles and the percent systolic thickening determined according to the formula (end-systolic profile--end-diastolic profile) (end-diastolic profile + background) x 100.) The intra- and interobserver variabilities were +/- 5.4% and +/- 4.1%, respectively. Analysis of regional systolic thickening showed a heterogeneous pattern, with a maximal and minimum value of 35% and 27% located to the infero-apical and to the proximal anterior wall, respectively. Our values correlate well with those reported for normals using cine computed tomography or nuclear magnetic resonance.

Rest-redistribution thallium-201 and rest technetium-99m-sestamibi SPECT in patients with stable coronary artery disease and ventricular dysfunction.

UNLABELLED: Resting sestamibi uptake was compared with 201Tl rest-redistribution uptake in 48 patients with ischemic heart disease and regional ventricular asynergies. METHODS: In 48 patients, rest/4-hr redistribution 201Tl and resting sestamibi tomography were closely performed on separate days. Segmental tracer uptake was quantified. Wall motion in corresponding segments was also assessed by two-dimensional echocardiography in 17 patients. RESULTS: Quantitative analysis indicates that the uptake of the two tracers was comparable in normal segments as well as in segments with fixed 201Tl defects. In contrast, in segments with reversible 201Tl defects, sestamibi uptake was significantly lower than redistribution 201Tl uptake. CONCLUSION: In patients with chronic ischemic heart disease and regional asynergies, quantified sestamibi activity parallels 201Tl redistribution activity in normal segments and in those with fixed 201Tl defects. In segments showing reversible 201Tl defects, whether or not dysfunctioning, sestamibi uptake is significantly lower than 201Tl redistribution.

Thallium-201 reverse redistribution at reinjection imaging correlated with coronary lesion, wall motion abnormality and tissue viability.

UNLABELLED: Previous studies based on standard stress-redistribution 201TI scintigraphy provided conflicting results about the clinical significance 201Tl reverse redistribution. Recent observations indicate that the majority of these defects normalize following reinjection reflecting viable myocardium. METHODS: In this study, the meaning of reverse redistribution occurring at reinjection imaging, its relation to standard 4-hr redistribution, coronary lesion, abnormal wall motion and tissue viability were assessed. A region with normal activity in the stress image was considered as having reverse redistribution if 201Tl activity at reinjection imaging was definitely abnormal with a decrease in relative tracer uptake >15% of the peak. From a series of 270 patients, 29 showed reverse redistribution. Of these 29 patients, 27 had evidence of previous myocardial infarction. Coronary lesions were detected in all but 1 patient. Average ejection fraction was 0.38 +/- 0.11. RESULTS: On a segmental basis, 50/377 regions showed the pattern of reverse redistribution. A significant coronary lesion (> or = 50%) was found in 78% of these regions; occlusion rate was 50%, and collateral circulation was found in 35% of occluded vessels. Hypokinesis or akinesis was present in 72% of segments. Tissue viability, defined as an uptake >55% of the peak, was found in 44% of these segments. The 50 segments showing reverse redistribution were divided into two groups according to an abnormal uptake also at 4-hr redistribution (group 1, 25 segments) or appearing only following reinjection (group 2,25 segments). Despite segments of group 1 showing a higher degree of coronary stenosis (80 +/- 32 versus 59 +/- 43%, p < 0.01), a similar rate of coronary occlusion, ventricular dysfunction and maintained viability was found in the two groups. CONCLUSION: Reverse redistribution in chronic coronary artery disease is frequently associated with significant coronary lesion, collateral-dependent dysfunctioning myocardium and preserved tissue viability. The occurrence of reverse redistribution following reinjection expands the indication for viability imaging to all patients with known coronary artery disease and regional wall motion abnormalities who undergo diagnostic and prognostic 201TI scintigraphy.

Heterogeneous fate of perfusion and contraction after anterior wall acute myocardial infarction and effects on left ventricular remodeling.

After acute myocardial infarction, patency of infarct vessel and extent of left venticular (LV) dysfunction are major determinants of ventricular remodeling. Spontaneous, delayed reperfusion in the infarct zone occurs in a sizeable number of patients well after the subacute phase. The aim of this study was to determine the relation between the occurrence of this spontaneous, delayed reperfusion and LV remodeling. In 84 patients, resting LV volumes, topography, regional function, and perfusion were quantitatively evaluated by 2-dimensional echocardiography and sestamibi tomography 5 weeks (study 1) and 7 months (study 2) after anterior Q-wave infarction. At study 2, LV end-diastolic volume increased by > 15% in 17 patients (20%, LV remodeling); they had already had at study 1 significantly larger LV volumes, more severe hypoperfusion and wall motion abnormalities, and greater regional dilation than patients with stable LV volumes. Delayed reperfusion occurred in 8 of 17 patients with and in 42 of 67 patients without LV remodeling (47% vs 63%; p=NS). At study 2, LV regional dilation and end-diastolic volumes were stable in patients with, but increased in patients without, spontaneous reperfusion (from 25+/-24% to 29+/-26% at study 2 [p<0.05] and from 65+/-14 to 68+/-18 ml/m2 [p <0.05]). At multivariate analysis, however, regional ventricular dilation at study 1 was the sole predictor of further LV remodeling. Thus, after acute myocardial infarction, spontaneous reperfusion occurring after 5 weeks plays only a minor role in influencing LV remodeling. Benefits from delayed reperfusion seem limited to patients with preserved LV volumes; patients with an enlarged left ventricle 5 weeks after acute infarction are prone to further LV remodeling, irrespective of delayed reperfusion.

Effects of nitroglycerin by technetium-99m sestamibi tomoscintigraphy on resting regional myocardial hypoperfusion in stable patients with healed myocardial infarction.

Myocardial sestamibi uptake reflects regional flow distribution and cellular integrity; however, some segments showing reduced tracer uptake at rest may consist of viable, although hypoperfused, myocardium. It is speculated that the administration of nitroglycerin (NTG) before the sestamibi injection would improve the tracer uptake in resting hypoperfused regions. Thirty-six stable patients with previous myocardial infarction (56 +/- 2 years; mean ejection fraction 42 +/- 2%), in whom perfusion defects could be seen at resting sestamibi tomography, repeated the scintigraphic study 2 to 6 days later, receiving NTG (0.3 to 0.6 mg sublingually) before the tracer injection. The size of the tracer uptake defect was quantified from circumferential profiles in 3 short-axis slices by integrating the area below the lower normal limit (mean -2 SD). After NTG, the mean perfusion defect significantly decreased (from 6,324 +/- 619 to 5,365 +/- 516, p < 0.01). The defect was reduced beyond the reproducibility limits in 20 patients (56%, group 1) and was unchanged or increased in 16 (44%, group 2). The resting sestamibi defect size was comparable between the 2 groups. The average percent reduction of the perfusion defect after NTG was 29 +/- 4% (range 7 to 74).(ABSTRACT TRUNCATED AT 250 WORDS)

Multiparametric approach to diagnosis of non-Q-wave acute myocardial infarction.

The present study investigated whether the lack of enzyme increase is reason enough to exclude necrosis in patients with ischemic heart disease who develop electrocardiographic sustained ST-T changes in the absence of Q waves. In 15 consecutive patients with angina who developed sustained ST-T changes during hospitalization, the presence of myocardial necrosis was investigated by a prospective multiparametric approach. Serum enzymes and myoglobin, pyrophosphate uptake, 2-dimensional echocardiography, perfusion scintigraphy, left ventriculography and coronary angiography were evaluated. According to creatine kinase and creatine kinase-MB peak at twice the upper normal value, the diagnosis of acute myocardial infarction applied only to 40% of patients. However, myoglobin was positive in 80% and a perfusion defect could be documented by an electrocardiographic gated microsphere technique in 100% of patients. The positivity of myoglobin increased to 100% and of creatine kinase and creatine kinase-MB to 87 and 60%, respectively, when a peak value twice the individual lowest value was considered for positivity. The 100% presence of perfusion defects associated with the high prevalence of both positive pyrophosphate uptake (87%) and regional dyssynergies (87 and 73%, respectively, by left ventriculography and echocardiography) strongly suggest that sustained (greater than or equal to 7 days) ST-T changes in this population were indicative of myocardial necrosis. Thus, by conventional enzymatic approach, diagnosis of non-Q-wave infarction can be missed in a sizable number of patients and present important clinical implications.

Myocardial perfusion abnormalities in chronic Chagas' disease as detected by thallium-201 scintigraphy.

Most patients with chronic Chagas' heart disease complain of chest pain. The pathophysiology of this symptom is unknown, although myocardial necrosis and fibrosis are frequent necropsy findings and cardiac autonomic impairment is a prominent feature of the disease. To evaluate the possibility of an ischemic cause for these abnormalities in 23 patients (18 men, aged 32 to 60 years, mean 42) with chronic Chagas' disease complaining of chest pain, thallium-201 myocardial scintigraphy was performed after maximal effort and 4-hour redistribution. Regional wall motion was assessed by radionuclide and contrast angiography. Heart rate responses to sinus respiratory arrhythmia, atropine, phenylephrine and Valsalva maneuver were evaluated in all patients and in 22 normal control subjects. Coronary angiography was performed in 16 patients. Only 1 patient had chest pain and no ischemic electrocardiographic changes occurred in any case during the effort test. Scintigraphic analysis of 7 segments per patient showed perfusion defects in at least 1 segment in all patients. Of 161 myocardial segments 16 showed fixed, 10 reversible, and 22 paradox defects (reverse redistribution). The majority (75%) of the fixed perfusion defects occurred in dyssynergic regions, whereas reverse redistribution predominated in regions with normal wall motion (82%). The reversible defects were present in normal or mildly hypokinetic regions. Markedly impaired parasympathetic cardiac control was present but no significant coronary abnormalities were seen in any of the 16 patients undergoing angiography. It is concluded that whereas fixed defects are likely to correspond to fibrotic or necrotic lesions, reversible and paradox perfusion defects may be caused by regional flow or metabolism derangements, possibly related to abnormal parasympathetic control of the coronary microcirculation.