Myocardial Imaging In Patients Research Articles

Magnetic Resonance Myocardial Imaging in Patients With Implantable Cardiac Devices: Challenges, Techniques, and Clinical Applications.

Cardiovascular magnetic resonance imaging (MRI) in patients with cardiac implants, such as pacemakers and defibrillators, has gained importance in recent years with the development of modern cardiac implantable electronic devices. The increasing clinical need to perform MRI examinations in patients with cardiac implants has driven the development of new advanced MRI sequences to mitigate image artifacts associated with cardiac implants. More specifically, advances in imaging techniques, such as wideband late gadolinium enhancement imaging, wideband T1 mapping, and wideband perfusion, have been designed to improve image quality and examinations in patients with cardiac implants, enabling a comprehensive and more reliable diagnosis, which was previously unattainable in these patients. This review article explores recent developments and applications of wideband techniques in the field of cardiovascular MRI, offering insights into their transformative potential. Clinical applications of wideband cardiovascular MRI are highlighted, particularly in assessing myocardial viability, guiding ventricular tachycardia ablation, and characterizing myocardial tissue.

GW24-e2437 Prognostic value of 99mTcMIBI SPECT exercise myocardial imaging in patients with suspected or known coronary artery disease

ObjectivesTo examine the prognostic value of 99mTC–MIBI SPECT in patients with suspected or known coronary artery disease.MethodsThe study group consisted of 116 patients with suspected or known CAD. All patients...

220 Contribution of the spect myocardial imaging in the detection of the viability of myocardium in the comment infarct before a gesture of revascularisation

A viable myocardium is able of functional recovering. The existence of a viability is thus an a posteriori observation, of a functional recovery after revascularisation. The aim of our study is to identify myocardial viability after post myocardial infarct with SPECT myocardial imaging in patients proposed for a revascularization procedure. This prospective study looked at patients who experienced previous infarct and in whom we performed a SPECT Thalium 201. The myocardial viability at SPECT was revealied by a residual ischaemia higher than 50% within a necrosed territory. The segmentar kinetics abnormalities were studied by echocardiography before revascularisation procedure then at 6 and 12 months after to estimate a recovery or at least an improvement of the kinetics after the procedure. The Segmentar kinetics study was made by qualitative analysis having allowing a codification of segments according 3 grades. We had 138 patients who benefit from revascularization procedure after detection of myocardial viability by SPECT in the territory of the MI (71 transluminale coronary angioplasty (TCA) and 67 aorto-coronary bypasses). We then confronted viable territories with the segmentar kinetics of these same territories at echocardiography, before and at the 6th and 12th month after the procedure. A functional recovery in term of improvement of the segmentar kinetics at the 6th or the 12th month is held as assessment criterion confirming the myocardial viability. 75% patients have improved their kinetics at 6 or 12 months The SPECT in the TL 201 allowed to detect a myocardial viability and thus to predict a functional recovery in post myocardial infarct period with a 96% sensitivity, a 80% specificity, a positive predictive value of 94% and a negative predictive value of 86%. The SPECT myocardial imaging is a good tool in the detection of the myocardial viability in the post myocardial infarct period.

Left atrial strain as predictor of successful outcomes in catheter ablation for atrial fibrillation: a two-dimensional myocardial imaging study

The objective of this study was to investigate atrial myocardial properties through two-dimensional (2D) myocardial imaging in patients with atrial fibrillation (AF) and its predictive role for recurrence after catheter ablation. Echocardiographic examinations were performed in 40 patients with paroxysmal AF before catheter ablation and 40 age- and gender-matched healthy control subjects. Using a software package, bidimensional acquisitions were analyzed to measure longitudinal strain and strain rate for the left atrium (LA). Systolic strain and strain rate in all eight segments, and its average values, were significantly reduced in AF patients compared to controls. During 9 months of follow-up after catheter ablation for AF, 11 of 40 AF patients had AF recurrence. AF recurrence was associated with gender, LA volume index, and average values of systolic strain and strain rate. By multivariate analysis, only average strain was an independent predictor of AF recurrence (OR = 0.88, 95% CI 0.79-0.98, p = 0.018). Lower systolic strain of LA was strongly associated with recurrence after catheter ablation. Thus, diverse adjunctive ablation strategies should be considered to reduce recurrence in patients with lower systolic strain.

Evidence of Impaired Left Ventricular Systolic Function by Doppler Myocardial Imaging in Patients With Systemic Amyloidosis and No Evidence of Cardiac Involvement by Standard Two-Dimensional and Doppler Echocardiography

We examined the potential role of Doppler myocardial imaging for early detection of systolic dysfunction in patients with systemic amyloidosis (AL) but without evidence of cardiac involvement by standard echocardiography. We identified 42 patients without 2-dimensional echocardiographic or Doppler evidence of cardiac involvement. These patients had normal ventricular wall thickness and normal velocity of the medial mitral annulus. Myocardial images were obtained in these patients and in 32 age- and gender-matched healthy controls. Peak longitudinal systolic tissue velocity (sTVI), systolic strain rate (sSR), and systolic strain (sS) were determined for 16 left ventricular segments. Radial and circumferential sSR and sS were also measured. Compared with controls in this group of patients with AL, peak longitudinal sSR (-1.0 +/- 0.2 vs -1.4 +/- 0.2, p <0.001) and peak longitudinal sS (-15.6 +/- 3.3 vs -22.5 +/- 2.0 p <0.001) were significantly decreased. In conclusion, the mean sS from all 6 basal segments, or from all 16 left ventricular segments differentiated patients with AL with normal echocardiography from controls, with similar accuracy for the mean sSR from the 6 basal segments. This distinction was not apparent from peak longitudinal sTVI or from radial or circumferential sSI or sSR.

129 A characteristic and potentially diagnostic abnormality of systolic myocardial deformation at Doppler myocardial imaging in patients with hypertrophic cardiomyopathy

129 A characteristic and potentially diagnostic abnormality of systolic myocardial deformation at Doppler myocardial imaging in patients with hypertrophic cardiomyopathy

Diagnostic Significance of Positive I-123 BMIPP Despite Negative Stress Tl-201 Myocardial Imaging in Patients With Suspected Coronary Artery Disease

There is frequently discordance in the interpretation of myocardial single-photon emission computed tomography images using both rest iodine-123 15-(p-iodophenyl)-3-(R,S) methylpentadecanoic acid (BMIPP) and stress thallium-201 ((201)Tl); that is, negative BMIPP vs positive (201)Tl studies. However, little attention has been paid to reverse discordance (ie, positive BMIPP despite negative stress (201)Tl). In the present study 105 consecutive patients with suspected coronary artery disease (CAD) who underwent both rest BMIPP and stress (201)Tl imaging were evaluated. No patient with previous myocardial infarction was included. Scintigraphic studies revealed that BMIPP was in concordance with (201)Tl in 71 patients: both were positive in 38 and negative in 33, whereas both were discordant in 20 and reverse discordant in 14. In patients with reverse discordance, the pattern of BMIPP abnormality was segmental in 8 and spotty in 6; the former was related to coronary territory. Based on the BMIPP findings and clinical symptoms, 7 patients with positive BMIPP despite negative (201)Tl underwent coronary angiography: 3-vessel CAD was found in 3 patients, 2-vessel CAD in 1, coronary spasm in 2, and insignificant lesions in 1. In the remaining 7 patients, no cardiac event was observed during 2-year follow-up. In patients showing positive BMIPP despite negative (201)Tl, a segmental BMIPP perfusion abnormality indicates a high likelihood for CAD, despite normal stress (201)Tl imaging. Thus, adding BMIPP to (201)Tl imaging may help to better identify patients with significant CAD, including multivessel disease.

Value of low-dose dobutamine addition to routine dual isotope gated SPECT myocardial imaging in patients with healed myocardial infarction or abnormal wall thickening by echocardiogram

There is overlap in myocardial viability detection by thallium-201 uptake and contractile reserve (CR) using low-dose dobutamine (LDD). The dual isotope protocol was modified in this study by acquiring thallium-201 images using LDD to enhance viability detection in addition to coronary flow reserve assessment. One hundred twenty-four patients with coronary disease underwent gated single-photon emission computed tomographic thallium-201 imaging at rest with LDD (10 μg/kg/min) during acquisition followed by stress technetium-99m sestamibi myocardial perfusion (MP) imaging with dobutamine, adenosine, or treadmill exercise. F-18-fluorodeoxyglucose (FDG) positron emission tomography was obtained in 41 patients. Myocardial perfusion (MP) imaging was divided into normal, fixed, and ischemic segments, and subclassified by wall motion and/or thickening changes between 1-hour poststress and LDD into normal, fixed, or improved dysfunctional segments (CR present). Mean left ventricular ejection fraction was 39% at 1 hour after stress and 47% with LDD (p <0.001). In dysfunctional myocardium, CR was significantly higher (p <0.001) in ischemic (233 of 368) and fixed segments (150 of 335) than in normal MP segments (43 of 220). Combined MP and CR analysis showed higher accuracy and negative predictive value in identifying FDG-viable myocardium than either method alone, whereas a high positive predictive value was maintained, similar to both markers. Quantitative analysis showed significant increased wall motion and thickening with LDD compared with 1 hour after stress, which was highest in ischemic segments and lowest in fixed segments. Thus, LDD dual isotope is a practical protocol that improves viability detection by simultaneous MP and CR analysis in addition to coronary flow reserve assessment in 1 study. Moreover, it requires no extra imaging time or radioactivity than the routine protocol.

Characteristics of the Doppler Myocardial Imaging in Patients with Myocardial Hypertrophy

Characteristics of the Doppler Myocardial Imaging in Patients with Myocardial Hypertrophy

Doppler myocardial imaging in patients with heart failure receiving biventricular pacing treatment

Background In patients with heart failure, biventricular pacing (BIV) improves left ventricular (LV) performance by counteracting LV unsynchronized contraction caused by the presence of left bundle branch block (LBBB). However, no data are yet available on regional long-axis function in patients with LBBB or on BIV effectiveness in improving such a function in patients with heart failure and LBBB. Methods and Results We studied with standard 2D echocardiography and tissue Doppler imaging (TDI) 21 nonischemic patients in New York Heart Association (NYHA) class III-IV, with LBBB and QRS ≥120 ms, receiving BIV. To assess long-axis function, TDI qualitative analysis at the basal level of each LV wall was performed in M-mode color and pulsed wave Doppler modalities before and after BIV. By analysis of the interventricular septum, the inferior, posterior, lateral, and anterior walls, of 105 basal segments, the following electromechanical patterns were identified: normal (pattern I), mildly unsynchronized (pattern IIA), severely unsynchronized (pattern IIB), reversed early in systole (pattern IIIA), reversed late in systole (pattern IIIB), and reversed throughout all the systole (pattern IV). After BIV, (1) 49 (46.7%) of 105 segments showed unsynchronized contraction of the same degree as before; (2) 36 (34.3%) of 105 and 20 (19%) of 105 showed unsynchronized contraction of lesser and greater degree, respectively, than before; and (3) a preexcitation pattern was found in 11 (10.5%) of 105, but no segment with pattern IV was observed. According to TDI analysis, patients were divided into group 1 (10 of 21), with less severe LV asynchrony than before BIV, and group 2 (11 of 21), with no change or more severe LV asynchrony than before BIV. In group 1, (1) the LV ejection fraction increased significantly (P =.01); (2) the exercise tolerance, expressed as time and work capacity on the bicycle stress testing, increased significantly (P =.01, P =.003, respectively); (3) the 6-minute walked distance increased significantly (P =.01); and (4) the NYHA class decreased significantly (P =.003). In group 2, no significant differences were found either in LV ejection fraction, in NYHA class, or in exercise tolerance data (P = not significant for all). Conversely, the QRS narrowing was significant in both groups (P =.003 in group 1 and P =.01 in group 2). Conclusions TDI is useful in assessing the severity of LV asynchrony in patients with LBBB with heart failure as well as in evaluating the pacing effects on long-axis function in these patients. BIV reduced unsynchronized and/or dyskinetic contraction in at least one third of the LV basal segments, whereas it induced preexcitation in approximately 10%. Such changes were responsible for better LV synchrony in approximately one half of patients. After BIV, LV performance improved significantly in patients with better LV synchrony evaluated by TDI, whereas the QRS narrowing was not predictive of this functional improvement. (Am Heart J 2001;142:881-96.)

Myocardial imaging in patients with defibrillator patch electrodes

Radionuclide imaging methods such as single-photon emission tomography (SPECT) and positron emission tomography (PET) are well-established techniques to evaluate myocardial ischemia and viability in patients with coronary artery disease. 1‐3 Life-threatening ventricular tachyarrhythmias are frequent findings in these patients. There is growing consensus that implantable cardioverter defibrillator (ICD) therapy reduces the incidence of sudden cardiac death in this group. 4‐8 Considering the progressive nature of the underlying disease, these patients may require radionuclide imaging to guide further therapy. Initiated by anecdotal evidence of a discrepancy between coronary angiography (no significant stenosis), thallium-201 (Tl-201) SPECT (persistent defect), and fluorodeoxyglucose-18 (F-FDG-18) PET (no defect) in patients with epicardially placed ICD leads, we investigated the hypothesis that epicardial ICD patch electrodes cause pseudodefects with SPECT. Therefore, Tl-201 SPECT, technetium-99m (Tc-99m) SPECT, and FFDG-18 PET measurements with a thorax phantom were performed to validate findings in patients and to clarify the effects of photon attenuation in the ICD patch electrode in relation to patch location, patch material composition, and the choice of nuclearcardiologic imaging modality. ICD patch electrodes placed directly on the epicardium were frequently used until recently. 9 ‐11 ••• Three different patch electrodes were examined: model 6897-M (Medtronic, Minneapolis, Minnesota), model L67 (CPI, St. Paul, Minnesota), and model 1501 (Siemens, Erlangen, Germany). The electrodes are shown in Figure 1. Technical specifications and attenuation coefficients for gamma radiation of the Medtronic and the CPI electrodes are listed in Table 1. The Siemens electrode is identical in composition to the CPI electrode.

Examination of left ventricular contractile reserve by Doppler myocardial imaging in patients with dilated cardiomyopathy.

Detection of left ventricular contractile reserve by means of dobutamine stress echocardiography is a well known technique. The aim of the present study was to detect velocity changes during the administration of dobutamine, to establish if Doppler myocardial imaging is a suitable method for determining left ventricular contractile reserve, and to determine if the technique provides more information than traditional stress echocardiography. Twenty-five patients (all males; mean age, 53.4 years) were examined for a clinical diagnosis of idiopathic dilated cardiomyopathy with a poor left ventricular systolic function (ejection fraction less than 30%). Doses of 5-10 and 20 mg/kg/min dobutamine were administered and elevated at 4-minute intervals. Ejection fraction was calculated using the Simpson rule. The peak systolic and the early and late diastolic velocities were measured in the basal segment of the septum and the inferior wall at baseline and at full dose of dobutamine. Results indicated that peak systolic velocity increased significantly, both in the septum (0.11±0.03 vs. 0.20±0.05 m/sec; p=0.001) and in the inferior wall (0.10±0.05 vs. 0.17±0.06 m/sec; p=0.03). Late diastolic velocities also increased significantly, both in the septum (0.17±0.05 vs. 0.22±0.07 m/sec; p=0.01) and in the inferior wall (0.18±0.08 vs.0.21±0.02 m/sec; p=0.01). There was a significant linear correlation between the relative increases in basal ejection fraction value and in peak systolic velocity upon dobutamine stimulation. Patients were divided into responders and nonresponders based on responses in either ejection fraction (25% relative increase) or peak systolic velocity (5 cm/s increase). This study concludes that 1) Doppler myocardial imaging is an adequate and simple technique to examine left ventricular contractile reserve; and 2) measurement of peak systolic velocity during dobutamine stimulation seems to be a simple and good indicator of left ventricular contractile reserve. (c)2001 CHF, Inc.

The additional value of gated SPECT myocardial imaging in patients with previous myocardial infarction

The additional value of gated SPECT myocardial imaging in patients with previous myocardial infarction

Comparison of tissue harmonic imaging with contrast (sonicated albumin) echocardiography and Doppler myocardial imaging for enhancing endocardial border resolution

Endocardial resolution during 2-dimensional echocardiography is technically limited in at least 10% to 15% of patients. Recently, several ultrasound imaging innovations have been introduced that may improve endocardial resolution and decrease the proportion of technically difficult studies. This study compares tissue harmonic imaging, intravenous sonicated albumin, and Doppler myocardial imaging in patients with technically difficult echocardiograms. Twenty-eight patients with known or suspected cardiac disease and poor baseline endocardial resolution were studied. Only harmonic imaging (conventional and optimized for tissue) was superior to baseline fundamental imaging (p <0.001). Harmonic imaging was superior to baseline imaging in all myocardial regions and in the majority of patients, including those with the worst baseline studies.

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). Two-year cardiac event-free survival was significantly lower in patients with an abnormal MIBI study result ( p < 0.0002). We conclude that the use of predischarge dipyridamole MIBI myocardial tomography provides prognostic information in medically treated patients with unstable angina beyond that available with clinical risk assessment alone. This application of dipyridamole MIBI myocardial imaging is consistent with the recommended use of dipyridamole thallium-201 imaging in published unstable angina clinical practice guidelines.

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

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. 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). 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.

Thallium-201 Myocardial Imaging in Patients with Coronary Artery Disease: Comparison of Intravenous Adenosine and Oral Dipyridamole

To compare thallium-201 (201Tl) myocardial perfusion imaging following intravenous adenosine and oral dipyridamole. Open-label, randomized, comparison. Outpatient, university-affiliated clinic. Fifteen patients with angiographically documented coronary artery disease. Planar 201Tl myocardial perfusion imaging following both intravenous adenosine 140 micrograms/kg/min for six minutes and oral dipyridamole suspension 300 mg. A comparison between adenosine and dipyridamole was made in the following areas: concordance in interpretation of 201Tl scintigrams, cardiac and noncardiac 201Tl uptake and clearance, hemodynamic and electrocardiographic changes, and adverse effects. The scintigraphic studies showed perfusion defects in 13 patients (87 percent) after dipyridamole and in 15 patients (100 percent) after adenosine. 201Tl uptake and clearance were quantitated in nine myocardial segments and in four extracardiac segments in each patient. 201Tl uptake was not significantly different between adenosine and dipyridamole studies in most cardiac regions. Extracardiac 201Tl uptake was significantly less in the liver and splanchnic regions following adenosine compared with dipyridamole. 201Tl clearance was not significantly different following adenosine and dipyridamole except in the anterolateral region in the anterior view. Hemodynamic changes following administration of intravenous adenosine and oral dipyridamole were not significantly different. Adverse effects were more common with adenosine than with dipyridamole. Adverse effects with adenosine were transient; however, adverse effects with dipyridamole were prolonged and required reversal with aminophylline in 2 patients. No patients required termination of the adenosine infusion or administration of aminophylline. These preliminary data suggest that adenosine 201Tl imaging may be a useful alternative to dipyridamole 201Tl imaging. Although adenosine produces more frequent adverse effects, they are generally better tolerated than those associated with dipyridamole.

Acute Effects of Oral Isosorbide Dinitrate on Exercise Thallium-201 Myocardial Imaging in Patients with Stable Angina Pectoris

Acute Effects of Oral Isosorbide Dinitrate on Exercise Thallium-201 Myocardial Imaging in Patients with Stable Angina Pectoris

Serial quantitative planar technetium-99m isonitrile imaging in acute myocardial infarction: Efficacy for noninvasive assessment of thrombolytic therapy

Technetium-99m isonitrile is a new myocardial perfusion imaging agent that accumulates according to the distribution of myocardial blood flow. However, unlike thallium-201, it does not redistribute over time. This imaging agent was used with serial quantitative planar imaging to assess the initial risk area of infarction, its change over time and the relation to infarct-related artery patency in 30 patients with a first acute myocardial infarction. Twenty-three of 30 patients were treated with recombinant tissue-type plasminogen activator (rt-PA) within 4 h after the onset of chest pain. Seven patients were treated in the conventional manner without thrombolytic therapy. Technetium-99m isonitrile was injected before or at the initiation of thrombolytic therapy, and imaging was performed several hours later. These initial images demonstrated the area at risk. Repeat imaging was performed 18 to 48 h later and at 6 to 14 days after the onset of myocardial infarction to visualize the ultimate extent of infarction.The initial area at risk varied greatly (range defect integral 2 to 61) both in patients treated with rt-PA and in those who received conventional treatment. For the total group, the initial imaging defect decreased in size in 20 patients and was unchanged or larger in 10 patients. Patients with a patent infarct-related artery had a significantly greater decrease in defect size than did patients with persistent coronary occlusion (-51 ± 38% versus -1 ± 26%, p = 0.0001). All patients with a decrease in defect size >30% had a patent infarct-related artery. In 12 patients who also had predischarge quantitative exercise thallium-201 imaging, good agreement existed between the extent and severity of myocardial perfusion defect on the last technetium-99m isonitrile study before discharge and that noted on delayed thallium-201 imaging.It is concluded that serial planar technetium-99m isonitrile myocardial imaging in patients with acute myocardial infarction undergoing thrombolytic therapy offers a new quantitative noninvasive approach for assessment of the initial risk zone as well as the success of reperfusion.

Hemodynamic and prognostic value of thallium-201 myocardial imaging in patients with dilated cardiomyopathy

We studied 70 patients with dilated cardiomyopathy to determine whether extent of perfusion defect on thallium imaging could be related to the hemodynamics and prognosis of the patients. Patients were divided into three groups according to the extent of perfusion defect, i.e., Grade I: no perfusion defect ( n = 19), Grade II: apical perfusion defect ( n = 22), and Grade III: extensive perfusion defect ( n = 29). The patients of Grade III demonstrated marked hemodynamic deterioration compared with those of Grade I and II. Three-year survival rate showed lower value in proportion to the extent of perfusion defect ( P < 0.05). Death from progressive heart failure tended to occur in patients with extensive perfusion defect ( P < 0.05). In patients of Grade III, the perfusion defect extended mainly to the posterolateral segment. Although autopsy studies showed increased fibrosis in the left ventricular wall in these patients, the extension of the fibrosis was not related to that of fibrosis. Moreover, the perfusion defect had regressed in three of 18 patients in the follow-up examination. These results indicate that the extent of perfusion defect on thallium imaging may be of value in non-invasive evaluation and prediction of the prognosis in patients with dilated cardiomyopathy. Distribution of the perfusion defect was, however, not related to that of myocardial fibrosis.