Stress 201Tl Research Articles

Optimization of 201Tl Dosage in a Simultaneous Acquisition Rest 99mTc/Stress 201Tl Dual-Isotope Myocardial Perfusion Single-Photon Emission Computed Tomography with Semiconductor Gamma Camera.

Background: The use of 201Tl in myocardial perfusion single-photon emission computed tomography (SPECT) is predominantly not recommended because of the higher radiation exposure of 201Tl compared to 99mTc agent. However, the advent of new gamma cameras with semiconductor detectors has made it possible to reduce the 201Tl dose and lower radiation exposure. In our hospital, the dose of 201Tl is adjusted according to the patient's body mass index (BMI), with 50 MBq for BMI<25 and 74 MBq for BMI≥25. The dose of 201Tl during simultaneous acquisition dual-isotope myocardial perfusion SPECT (MPS; stress 201Tl and rest 99mTc agent) exceeds 9 mSv/examination when 74 MBq of 201Tl is administered. In order to further reduce the radiation dose, optimization of the 201Tl dose was investigated. Methods: Two hundred and eighty consecutive patients who underwent stress MPS using simultaneous acquisition dual-isotope protocol (SDI protocol) for the estimation of ischemic heart disease were included. Patients with prior myocardial infarction were excluded. Correlations between BMI and acquisition time were determined in patients receiving 50 MBq (n=154) or 74 MBq (n=126) of 201Tl. In addition, linear regression analysis was used to determine the slope and intercept to derive a linear functional equation, and the theoretically optimal 201Tl dose was evaluated. Results: The correlation coefficient between BMI and acquisition time in the 201Tl 50 MBq group was 0.532 (P< 0.00001) and in the 201Tl 74 MBq group was 0.478 (P<0.00001), both showing a positive correlation. Linear regression analysis yielded two equations: y=0.52x-0.32 (201Tl 50 MBq group) and y=0.41x-0.69 (201Tl 74 MBq group). Linear function equation results indicated that patients with BMI between 25 and 30 could be examined within approximately 15 minutes with 50 MBq of 201Tl. Conclusion: Considering examination efficiency, a single acquisition time of less than 15 minutes is ideal. Theoretically, patients with BMI less than 30 could be examined within approximately 15 minutes with 50 MBq of 201Tl.

Asymptomatic Coronary Artery Disease in Japanese Patients With the Acute Ischemic Stroke

ObjectiveTo investigate the prevalence and outcomes of asymptomatic coronary artery disease (CAD) in patients with the first episode of ischemic stroke. MethodsPatients admitted to our hospital between November 2001 and January 2009 for the episode of an acute ischemic stroke/transient ischemic attack were included. Stress-Tl-201 scintigraphy was performed and followed by coronary angiography (CAG). The prevalence and risks for asymptomatic CAD, and long-term outcomes were studied. ResultsOf 1309 patients, only 15 (1.1%) patients presented with a history of CAD. Excluding 406 patients because of severity, systemic infection, early transfer to another hospital, or a refusal to participate, myocardial scintigraphy was performed in 903 patients (mean age, 72 ± 10 years, male 63.9%), and myocardial ischemia was diagnosed in 214 patients (23.7%). Of these patients, 76 patients underwent CAG, and showed significant stenosis (>75%) of a coronary artery in 61 (80.3%) patients. The risk factors for positive scintigraphy findings and CAG were high-grade premature complexes via Holter monitoring (P < .0001), enlarged left ventricle (P = .0051) and wall motion abnormalities (P = .0014) observed on echocardiography, and carotid artery stenosis observed in magnetic resonance angiography imaging (P < .0001). During the follow-up periods of 83 ± 47 months and of 91 ± 47 months, 17.2% of scintigraphy-positive and 2.8% of scintigraphy-negative patients developed episodes of myocardial ischemia, respectively (P < .001). ConclusionsSymptomatic CAD was rare in Japanese patients with the first episode of ischemic stroke, but asymptomatic CAD was identified by stress Tl-201 myocardial scintigraphy in one-quarter of the patients. Positive scintigraphy was associated with asymptomatic CAD and future cardiac events.

A COMBINATION OF 123I-BMIPP SPECT AND STRESS 201TL MYOCARDIAL PERFUSION SPECT AS A USEFUL PROGNOSTIC MARKER OF ASYMPTOMATIC PATIENTS WITH NON-OBSTRUCTIVE HYPERTROPHIC CARDIOMYOPATHY

Reduced coronary flow reserve (CFR) indicates adverse clinical outcome in hypertrophic cardiomyopathy (HCM). 123I-BMIPP (BMIPP) SPECT and stress 201Tl (TL) SPECT has been used to evaluate coronary microvascular dysfunction in HCM. We investigated the long-term prognostic value of BMIPP and stress TL

Diagnostic Accuracy of Electrocardiographic ST-Segment Depression in Patients With Rapid Atrial Fibrillation for the Prediction of Coronary Artery Disease

BackgroundWe aimed to examine the diagnostic value of ST-segment depression in patients with rapid atrial fibrillation (AF) for the prediction of coronary artery disease (CAD). MethodsHemodynamically stable patients with AF, and a heart rate > 80% of their maximum predicted according to their age, were allocated to 2 groups according to their electrocardiographic findings on admission: group A included patients without any ST-segment abnormalities and group B, patients with downward or horizontal ST-segment depression ≥ 1 mm in 2 or more contiguous leads. Group A patients were subjected to a dobutamine stress echo or Tl-201 myocardial single-photon emission computed tomography, followed by coronary angiography in case of abnormal results and Group B patients to coronary angiography. CAD was defined angiographically as stenosis of ≥ 50% in any major epicardial coronary vessel. ResultsOut of 115 consecutive patients, with a mean age of 65.9 ± 10.2 years, 42.6% were male, 18.3% smokers, 68.7% hypertensive, 21.7% had diabetes, and 40% had hyperlipidemia. We enrolled 71 and 44 patients in group A and B, respectively. Prevalence of significant CAD among studied patients was 21.7%, 3/71 (4.2%) and 22/44 (50.0%) in group A and B, respectively. Overall ST-segment depression during rapid AF had 88.0% sensitivity (95% confidence interval [CI], 67.7%-96.8%) and 75.6% specificity (95% CI, 65.2%-83.7%) in predicting presence of CAD, and positive and negative predictive value was 50.0% (95% CI, 34.8%-65.2%) and 95.8% (95% CI, 87.3%-98.7%), respectively. ConclusionsIn consecutive patients with rapid AF, the absence of ST-segment depression might indicate absence of CAD.

Post-exercise diastolic stunning detected by velocity vector imaging is a useful marker for induced ischemia in ischemic heart disease.

Recently, post-exercise diastolic stunning (PES) has been reported as a new clinical marker of induced ischemia. Velocity vector imaging (VVI) has been developed to visualize regional wall motion abnormalities based on vectors detected by the tissue tracking technique, which has the potential to visualize PES. Thus, the aim of this study was to evaluate the usefulness of PES detection by VVI as an objective marker of ischemia compared to stress thallium-201 (Tl-201) single photon emission computed tomography (SPECT). We studied consecutive patients who were scheduled to undergo exercise stress Tl-201 SPECT for the diagnosis of ischemic heart disease. Transthoracic echocardiography was recorded digitally before and 20min after exercise for Tl-201 SPECT, and the data were used subsequently for VVI analysis. We defined PES regions as those with new abnormal vectors observed during isovolumic relaxation. After excluding 14 patients with old myocardial infarction and/or atrial fibrillation, echocardiograms suitable for VVI analysis were obtained from 62 of 65 patients (feasibility, 95%; 44 men; mean age, 64±11years). SPECT revealed induced ischemia in 20 patients, whereas VVI identified PES in 18 patients. VVI detected inducible ischemia with 85% sensitivity and 98% specificity compared to SPECT. VVI detection of PES is a new clinical tool for induced ischemia. Regional diastolic wall motion abnormalities following induced ischemia can be noninvasively detected by VVI.

117: Direct comparison of stress Thallium-201/Rest Technetium-99m dual isotope perfusion imaging with Cadmium-Zinc-Telluride detector versus standard dual detector camera

Recent advances in nuclear myocardial perfusion imaging (MPI) have provided opportunity for improved image information with an important reduction of exam time and radiation. This technology can be used to explore novel protocols (dual isotope high-speed MPI). Today, two devices exist: D-SPECT and Discovery NM 530c (DNM) camera. With D-SPECT, it was showed that rapid stress Tl-201/rest Tc-99m protocol for use with high-speed MPI has offered the superior qualities of Tl-201 for stress imaging and of the Tc-99m agents for rest imaging can be preserved. However, no study has evaluated the same dual-isotope protocol with the other system. A total of 38 consecutive patients underwent simultaneous dual-radionuclide (stress thallium-201/rest technetium-99m) perfusion imaging with a DNM camera and standard dual dectector camera (S-SPECT) during the month of May 2011. All patients successfully underwent stress/rest MPI with both cameras. In 38 patients (50%) pharmacological stress was induced with dipyridamole. DNM SPECT SSS and SRS correlated linearly with conventional S-SPECT respective scores (r=0.84, p<0.0001 for SSS, and r=0.94, p<0.0001 for SRS). On Bland-Altman analysis there was good agreement between the two imaging methods with a shift for both SSS and SRS (mean difference = 1, 95% confidence interval = −3.74 – 5.74 for SSS; mean difference = −3.0, 95% confidence interval = −3.13 – 3.91 for SRS). The analyze revealed a perfusion defect in both the S-SPECT and DNM scans but systematically perfusionnels defects or scars were more extensive with the DNM-camera. Overall image quality was good to excellent. Our study showed a clinical agreement of 96% between the DNM camera and S-SPECT MPI. The effective dose was 11.9 mSv for the study protocol, with 9.7 mSv coming from the Tl-201. The DNM camera such as D-SPECT camera provides clinical information equivalent to conventional standard SPECT MPI.

The prognosis of a normal Tl-201 stress-only SPECT MPI study

BackgroundStress-only Tc-99m SPECT myocardial perfusion imaging (MPI) decreases test time and patient radiation exposure with a proven benign prognosis of a normal study. The imaging sequence of Tl-201 MPI always starts with the stress portion; therefore, no pre-test decisions are needed regarding the imaging sequence. The recent intermittent Tc-99m shortage afforded the unique opportunity to study an unselected group of patients undergoing Tl-201 imaging. MethodsWe retrospectively reviewed all the patients who had SPECT MPI with Tc-99m or Tl-201 over a 1-year period. When Tc-99m was not available, patients received Tl-201. All stress Tl-201 images were routinely processed, and if normal, rest imaging was not done. When Tc-99m was used, patients with lower pre-test probability were selected for a stress-first protocol. We compared the all-cause mortality of patients with normal Tl-201 studies to those with normal stress-only and rest-stress Tc-99m studies using the Social Security Death Index. Unadjusted and risk-adjusted survival analysis was performed. Specific causes of death (cardiac or non-cardiac) were determined by medical record review and contact with treating physicians. ResultsA total of 3,658 patients underwent stress MPI during this time period. Of the 1,215 patients who had Tl-201 MPI, 716 (67%) had a normal stress-only study. Out of 2,443 patients who underwent Tc-99m MPI, 70% had normal perfusion with 1,098 normal stress-only studies and 493 normal rest-stress studies. The average follow-up was 23.3 ± 5.3 months. Unadjusted all-cause mortality at the end of follow-up was 7.1% in the Tl-201 stress-only group, 6.3% for Tc-99m stress-only patients, and 4.3% in the Tc-99m rest-stress cohort. After controlling for confounding variables, survival was similar in the three groups (HR 1.07, 95% CI 0.62-1.82, P = .82 for normal Tl-201 stress-only compared to normal Tc-99m rest-stress). The risk-adjusted 1-year survival was between 98.5 and 98.8% in the three groups. ConclusionsNormal stress-only Tl-201 SPECT MPI study has a similarly benign prognosis when compared to Tc-99m rest-stress and Tc-99m stress-only normal SPECT MPI studies. The stress-first design allowed for early triage of over 60% of patients and marked improvement in laboratory efficiency due to shortened test time.

Reduced heart rate response to dipyridamole in patients undergoing myocardial perfusion SPECT

A mild decrease in blood pressure and increase in heart rate (HR) are considered normal hemodynamic responses to dipyridamole. In this study, we tried to investigate HR response to dipyridamole and its predictors in patients undergoing gated myocardial perfusion single photon emission computed tomography (SPECT). 201 consecutive patients undergoing dipyridamole stress Tc99m-MIBI or Tl-201 gated myocardial perfusion SPECT were prospectively enrolled. Dipyridamole was infused over 4 min and radiopharmaceutical was injected 3 min after the end of infusion. A reduced heart rate response to dipyridamole considered if the HR ratio (peak HR/rest HR) was 1.20 or less. Stress (sLVEF), rest (rLVEF) left ventricular ejection fractions, stress and rest motion (SMS, RMS) and thickening scores (STS, RTS) were derived automatically by QGS. Summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) for myocardial perfusion were calculated. Patients were grouped according to HR response and groups were compared. A logistic regression analysis was used to determine independent predictors of reduced HR response. Reduced HR response was found in 78 % of patients. Patients with abnormal HR response were more frequently had a history of diabetes mellitus, chronic renal failure, and had lower high-density lipoprotein (HDL) levels. Peak HR, SSS, SRS, sLVEF and rLVEF were lower; rest HR, RTS, and the number of patients with ≤ 45 % sLVEF and rLVEF were higher in reduced HR response group (all p < 0.05). There was no difference between groups by means of gender, rest and peak systolic or diastolic tension, SDS, SMS, STS, RMS, history of hypertension, peripheral arterial disease, metabolic syndrome, coronary interventions, digoxin, calcium channel blocker or beta blocker usage. Multivariable logistic regression analysis demonstrated that the independent predictors of reduced HR response were HDL, rest HR and SSS. When HDL was removed from the model, chronic renal failure also emerged as an independent predictor. Reduced HR response to dipyridamole is associated with ventricular dysfunction, cardiac autonomic neuropathy. Low HDL levels also seem to be related with reduced HR response.

Stress Thallium-201/Rest Technetium-99m Sequential Dual Isotope High-Speed Myocardial Perfusion Imaging

Our purpose was to describe a novel, rapid stress thallium-201 (Tl-201)/rest technetium-99m (Tc-99m) agent myocardial perfusion imaging (MPI) protocol (Tl/Tc) with a high-speed MPI scanner and to compare this protocol with a standard rest/stress Tc-99m agent protocol (Tc/Tc) with respect to image quality and radiation dosimetry. Recent advances in gamma camera technology have provided opportunity for improved SPECT MPI protocols. A rapid Tl/Tc protocol that could improve image information while maintaining a low radiation burden for the patient would be desirable. We compared high-speed SPECT MPI studies in 374 consecutive patients undergoing exercise or pharmacologic Tl/Tc protocol to those of 262 patients undergoing rest/stress Tc/Tc protocol. Tl/Tc imaging was accomplished in <20 min. Overall image quality was good to excellent in 96% and 98% of patients with the Tl/Tc and the Tc/Tc protocols, respectively (p = ns). Beginning rest imaging within 2 min after rest injection with the Tl/Tc protocol did not result in reduced confidence in image interpretation. Early rest Tc images of the Tl/Tc protocol showed less extracardiac activity than was observed on standard rest imaging used in the Tc/Tc protocol (84% vs. 61%), respectively (p < 0.01). The normalcy rate was high in both groups (100% vs. 92%). Radiation burden was similar between the Tl/Tc and Tc/Tc protocols. A rapid stress Tl-201/rest Tc-99m protocol for use with high-speed SPECT MPI has image quality and radiation dosimetry similar to those observed with a conventional rest/stress Tc-99m protocol. The Tl/Tc protocol offers promise as an efficient and relatively low radiation dose method, in which the superior qualities of Tl-201 for stress imaging and of the Tc-99m agents for rest imaging can be preserved. The findings also suggest that with rapid imaging rest MPI immediately after Tc-99m agent injection may be superior to standard delayed image initiation.

Abstract 5818: Stress Thallium-201/Rest Tc-99m Sequential Dual Isotope High-Speed Myocardial Perfusion Imaging

Recent advances in gamma camera technology are providing opportunities for novel high-speed myocardial perfusion imaging (HS-MPI) protocols. We aimed to develop and evaluate a stress thallium-201 (Tl-201) and rest Tc-99m sestamibi or tetrofosmin imaging protocol that could reduce imaging time and radiation burden. Methods: We studied 410 consecutive patients undergoing exercise or pharmacologic low-dose stress Tl-201 HS-MPI (4 min/acquisition) in the semi-upright and supine positions (D-SPECT, Spectrum-Dynamics) followed by rest Tc-99m sestamibi (n= 139) or tetrofosmin (n= 271) with immediate post-injection rest imaging. Of 330 patients with no known coronary artery disease (CAD), 29 patients also underwent invasive coronary angiography (ICA) or coronary computed tomography angiography (CCTA) within a three month period and 36 had a &lt; 5% pre-test likelihood of CAD (LLk). Despite low injected doses [Tl-201 (2.2± 0.3 mCi) and Tc-99m sestamibi or tetrofosmin (8.9± 2.4 mCi), the 3 acquisition MPI protocol (2 stress/1 rest) was accomplished &lt; 20 minutes. The quality of stress and resting image was good to excellent in &gt;96% of cases; importantly, no or minor extracardiac activity was seen on 99% of stress and 93% of rest images. HS-MPI was nondiagnostic or uninterpretable in only 2/410 patients. In the 29 patients with CCTA or ICA, the sensitivity and specificity for the detection of ≥70% stenosis were 73% and 89%, respectively, and in 15 patients with ICA, the sensitivity was 89%. The normalcy rate in the LLk group was 100%. A fast stress Tl-201/rest Tc-99m HS-MPI protocol offers promise as a time-efficient, low radiation dose method, in which the superior qualities of Tl-201 for stress imaging and of Tc-99m agents for rest imaging can be utilized.

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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.

Assessment of contractile response to dobutamine stress by means of ECG-gated myocardial SPECT: Comparison with myocardial perfusion and fatty acid metabolism

The present study assessed left ventricular performance during dobutamine stress measured using gated SPECT, and compared the results to myocardial perfusion and fatty acid metabolism. Thirty-six patients with myocardial infarction given (99m)Tc-sestamibi or (99m)Tc-tetrofosmin were examined by gated SPECT at rest and during dobutamine stress (4-20 microg x kg(-1) x min(-1)). After acquiring data at the highest dose, 201TlCl was injected and dual-isotope SPECT was performed to assess myocardial ischemia. Thirty of 36 patients also underwent myocardial SPECT with 123I-BMIPP. Regional wall motion changes during dobutamine infusion were determined from the gated SPECT data and classified as: (1) Improvement, (2) Worsening, (3) No change, and (4) Biphasic response. For myocardial segments of each infarct area, stress 201Tl, rest (99m)Tc and (123)I-BMIPP uptakes were graded on a five-point scoring system of defects from 0 (normal) to 4 (grossly defective). Rest 99mTc defect score index (DSI) in No change area was significantly higher than that in Biphasic area. The ADSI (stress 201Tl - rest (99m)Tc) in Biphasic area was significantly higher than those in Improvement and No change areas. The deltaDSI (BMIPP - (99m)Tc) in Worsening area tended to be higher than that in No Change area. Regional contractile response to dobutamine stress analyzed by gated SPECT showed that the response in-myocardial infarct areas could be classified by rest and stress myocardial perfusion and BMIPP accumulation.

Diagnostic Accuracy of Stress First-Pass Contrast-Enhanced Myocardial Perfusion MRI Compared with Stress Myocardial Perfusion Scintigraphy

The purpose of this study was to determine the diagnostic accuracy of stress perfusion MRI acquired with saturation-recovery prepared turbo fast low-angle shot (turbo FLASH) compared with stress myocardial perfusion scintigraphy. Recent studies show that first-pass contrast-enhanced myocardial perfusion MRI can provide noninvasive detection of low-limiting stenosis in the coronary artery. First-pass contrast-enhanced MR images were acquired at rest and during stress in 40 patients with suspected coronary artery disease. All patients underwent thallium-201 SPECT without attenuation correction and coronary angiography. Two reviewers independently assigned one of five confidence grades without knowing the results of coronary angiography for receiver operating characteristic (ROC) analysis. Luminal stenosis >70% on coronary angiography was used as a reference standard. On coronary angiography, 70% or greater diameter stenosis of the coronary artery was observed in 21 (52.5%) of 40 patients. The areas under the ROC curve for detection of significant stenosis in the individual coronary artery were 0.86 (observer 1) and 0.84 (observer 2) for MRI. These values were 0.79 (observer 1, p = not significant) and 0.72 (observer 2, p = not significant) for 201Tl SPECT. The diagnostic accuracy of stress perfusion MRI acquired with saturation-recovery-prepared turbo FLASH was comparable with that of stress 201Tl SPECT. Stress first-pass contrast-enhanced MRI is a noninvasive technique that can be used as an alternative to stress myocardial perfusion scintigraphy.

Evaluation of Myocardial Flow Reserve Using Pharmacological Stress Thallium-201 Single-Photon Emission Computed Tomography: Is There a Difference between Total Arterial Off-Pump Coronary Artery Bypass Grafting and Conventional Coronary Artery Bypass

The advantage of total arterial off-pump coronary bypass grafting (OPCAB) over conventional onpump coronary artery bypass grafting with 1 internal thoracic artery and veins (CCAB) in terms of myocardial flow reserve has not been studied. We studied these procedures using thallium- 201 perfusion single-photon emission computed tomography (Tl-201 perfusion SPECT). Between 1997 and 2001, 152 patients were recruited from our database (OPCAB, n = 100; CCAB, n = 52). All patients underwent pharmacological stress Tl-201 perfusion SPECT 3 to 12 months after bypass surgery. Myocardial perfusion was analyzed semiquantitatively with a 5-point scoring system in a 20-segment model (0, normal, to 4, absence of uptake). Summed stress (SSS), rest (SRS), and difference score (SDS) of the entire myocardium as well as average scores (ASS, ARS, ADS) of individual walls (anterior, septal, lateral, and inferior) were compared by Student t test as well as by repeated-measures analysis of variance with Bonferroni correction. The SSS, SRS, and SDS of OPCAB versus those of CCAB were 6.86 +/- 0.72 versus 7.17 +/- 0.92, 3.95 +/- 0.57 versus 3.75 +/- 0.73, and 2.91 +/- 0.47 versus 3.42 +/- 0.74 (P > .05). However, the lateral wall showed lower scores in OPCAB (ASS, 0.18 versus 0.41, P = .015; ARS, 0.12 versus 0.20, P = .168; ADS, 0.06 versus 0.21, P = .031). The septal wall had higher scores in OPCAB (ASS, 0.33 versus 0.12, P = .003; ARS, 0.18 versus 0.07, P = .037; ADS, 0.14 versus 0.04, P = .030). The anterior and inferior walls were not different between the 2 groups. OPCAB led to results similar to those of CCAB. The better results in the lateral wall have been the effect of grafting radial artery rather than vein. The similarity in myocardial reserve in the inferior wall between the 2 groups needs further study. There was no deleterious effect of off-pump as opposed to on-pump CAB.

Exercise-induced left bundle branch block accompanied by chest pain: Correlation with coronary artery disease

A case of a 25-year-old woman with familiar hypercholesterolemia, who was admitted complaining for chest pain on exertion, is presented. She underwent a treadmill stress test and during the exercise left bundle branch block with concomitant chest pain in low heart rate (105/min) was demonstrated. After these findings TL-201 scintigraphy with dipyridamole infusion was performed: Chest pain and left bundle branch block appeared again during the test, and the stress TL-201 tomographic images showed reversible defect in the anterior wall. Finally, the young woman underwent coronary arteriography, which showed normal coronary vessels. The ergonovine test for coronary spasm was negative.

Prognostic value of fatty acid imaging in patients with angina pectoris without prior myocardial infarction: comparison with stress thallium imaging

A fatty acid analogue, 123I-labelled beta-methyl iodophenyl pentadecanoic acid (BMIPP), has been used to identify ischaemic and metabolically impaired myocardium. However, the prognostic value of BMIPP imaging, particularly in relation to stress myocardial perfusion imaging, remains unclear. Data from 167 consecutive patients with angina pectoris but without prior myocardial infarction (MI) who had undergone both BMIPP and stress 201Tl (sTL) imaging were analysed. Tracer uptake was graded using a 13-segment, 4-point scoring model. Patients were followed up for 48 months with primary end points (cardiac death, non-fatal MI) as hard cardiac events and with secondary end points (late revascularisation, recurrent angina and heart failure) as soft events. For overall cardiac events (5 hard and 29 soft events), Kaplan-Meier analysis revealed significantly lower event rates in subgroups with normal BMIPP uptake, a summed difference score of sTL (SDS) of <3 or absence of diabetes mellitus when compared to each counterpart. Multivariate Cox's analysis revealed reduced BMIPP uptake, SDS > or =3, diabetes and reduced ejection fraction to be significant predictors. Negative predictive values of normal BMIPP and SDS <3 for all events were 91% and 84%, respectively. No hard event occurred in 66 patients with normal BMIPP uptake, whereas two patients with SDS <3 but impaired BMIPP uptake had hard events. In conclusion, normal BMIPP imaging is an excellent prognostic sign, independently of stress myocardial perfusion imaging, in patients with angina pectoris without prior MI.

A rise in systolic blood pressure during adenosine stress myocardial perfusion imaging does not increase the likelihood of an abnormal scan

Background: The normal physiologic response to vasodilators, such as adenosine, is a fall in systolic blood pressure (SBP). However, in some cases, a patient's SBP rises rather than falls during adenosine stress myocardial perfusion imaging (MPI). It has been anecdotally suggested that this paradoxical response may result from a heightened adrenergic state due to adenosine-induced ischemia. We sought to assess whether ischemia is more common among patients whose SBP rises during adenosine stress MPI. Methods: Scan findings and SBP responses for 866 consecutive patients (age = 65.7±12.6 years; 356 men) undergoing adenosine stress MPI were assessed. Adenosine (140 μg/kg/min) was infused for six minutes (no concomitant exercise). MPI was performed using either a 201Tl stress / redistribution or a dual isotope ( 201Tl rest / 99mTc stress) protocol. Scans were interpreted by experienced readers. Results: A rise in SBP ≥10 mmHg was seen in 61 (7%) patients, while 227 (26%) had a flat response (ΔSBP <10 mmHg) and 578 (67%) had a drop in SBP ≥10 mmHg. The ratio of ischemic to non-ischemic scans in women was the same, irrespective of SBP response. In men there was a trend toward fewer ischemic scans among patients whose SBP rose compared with those whose SBP fell during testing (p = 0.08). Men with a flat SBP response had an intermediate scan ratio. MPI Result SBP Decreased SBP Flat SBP Increased Male Female Male Female Male Female % with any ischemia 42 29 34 25 29 27 % with no ischemia 58 71 66 75 71 73 Conclusion: A rise in SBP during adenosine infusion is not associated with a higher likelihood of ischemia in patients undergoing adenosine stress MPI. In fact, there is a trend toward less ischemia among men who demonstrate such a paradoxical response. It is unlikely that a rise in SBP during adenosine stress MPI is due to an adrenergic surge in response to ischemia. The finding of more ischemia in men with a fall in SBP may help to account for the observation that men with exaggerated SBP responses to adenosine have a higher risk of cardiac death.

Quantitative relationship of stress Tc-99m sestamibi lung uptake with resting Tl-201 lung uptake and with indices of left ventricular dysfunction and coronary artery disease

Background We investigated the relationship of stress technetium 99m sestamibi lung uptake with rest thallium 201 lung uptake and with indices of left ventricular (LV) dysfunction and severity of coronary artery disease (CAD) in patients with known or suspected CAD undergoing stress testing and cardiac catheterization. Stress Tc-99m sestamibi lung uptake and both stress and rest Tl-201 lung uptake are associated with LV dysfunction and extent of CAD. Although the mechanism of lung uptake is thought to be similar for the two isotopes, their physiologic characteristics are different. No direct comparison of lung uptake for the two isotopes has been reported. Methods and results We evaluated 192 consecutive patients who underwent dual-isotope myocardial perfusion imaging and cardiac catheterization within 30 days. We examined the relationship of stress Tc-99m sestamibi lung-to-heart ratio (LHR) with rest Tl-201 LHR, with indices of myocardial perfusion, and with invasive measures of the severity of LV dysfunction and CAD. Stress Tc-99m sestamibi LHR correlated with rest Tl-201 LHR ( r = 0.548, P < .001). Stress Tc-99m sestamibi LHR was positively associated with LV filling pressures and extent of CAD and negatively associated with LV ejection fraction and arterial systolic blood pressure. However, after adjustment for multiple comparisons, stress Tc-99m sestamibi LHR was significantly associated only with LV end-diastolic pressure ( r = 0.287, P = .002) and pulmonary capillary wedge pressure ( r = 0.337, P < .001). Conclusions Increased stress Tc-99m sestamibi LHR correlates with rest Tl-201 LHR in patients with known or suspected CAD. Stress Tc-99m sestamibi lung uptake is also associated with invasively measured LV filling pressures.