Myocardial Perfusion Imaging Ischemia Research Articles

Myocardial Perfusion Imaging and C-Reactive Protein in Myocardial Ischemia: A Retrospective Single-Center Study.

Inflammation is an important mechanism in atherosclerosis and plaque formation. C-reactive protein (CRP) is a common inflammatory biomarker associated with the risk of coronary heart disease. We investigated the relationship of CRP with findings from myocardial perfusion imaging (MPI). In this retrospective study, 102 consecutive patients (mean age 71 years, 68% males) who underwent MPI (for diagnostic reasons or quantification of myocardial ischemia) and CRP determination (upper limit: 6 mg/L) within 1 month from MPI were included. The patients had no infection or recent acute coronary syndrome. The median CRP level was 4 mg/L (2, 10) among the study population. Patients with raised CRP had higher summed stress score (SSS) (p = 0.006) and summed rest score (SRS) (p = 0.001) and higher risk for SSS > 3 (OR 9.25, 95% CI 2.03-42.13, p = 0.001) compared to those with low CRP. The association of SSS and SRS with CRP levels was more evident in patients over 70 years (p = 0.027 and p = 0.005, respectively). No significant difference in summed difference score was shown. The two groups had no difference in other risk factors (p > 0.05 for all comparisons). a high level of CRP was associated with the presence and extent of stress-induced myocardial ischemia in MPI.

High Grade AV Block Associated with Dipyridamole Infusion

The use of dipyridamole for thallium imaging has proved very successful in demonstrating coronary arterial disease [1]. Dipyridamole causes coronary arteriolar vasodilation by increasing interstitial adenosine levels by inhibition of both adenosine deaminase and facilitated cellular adenosine uptake. Differential flow changes occur in coronary arteries if a significant luminal stenosis exists [2]. Intravenous infusion of dipyridamole is safe although transient noncardiac side effects are common. These side effects are mostly mild and not need to treat although can be treated with aminophylline [5]. High-grade AV block after dipyridamole has been described in few case reports and mostly was associated with transient myocardial ischemia [2-4]. We describe a case of long-lasting high grade AV block following dipyridamole infusion. In context of near normal baseline ECG. In our case the AV block occurred without evidence of ischemia in myocardial perfusion imaging and we think it can be an unexpected adverse effect of dipyridamole and clinicians should be aware of AV block as a possible adverse effect of dipyridamole.

Body Mass Index Is Independently Associated with the Presence of Ischemia in Myocardial Perfusion Imaging.

Background and Objectives: Obesity has been linked to various cardiovascular risk factors, increased incidence of coronary artery disease, and myocardial perfusion defects. The aim of this study was to investigate if body mass index (BMI) and waist circumference (WC) were associated with myocardial perfusion defects. Materials and Methods: A total of 308 consecutive patients who had myocardial perfusion imaging (MPI) with single photon emission computed tomography (SPECT) and a complete medical record on file were studied retrospectively. Results: The median age was 69 (61–76) years, the BMI was 27.6 (24.4–30.7) kg/m2, and the WC was 110 (102–118) cm. Of the 308 patients, 239 patients (77.6%) had myocardial ischemia. A positive test for ischemia was more frequent in men compared to women (72 vs. 28%, p < 0.001). Within the male group, BMI and WC were not significantly different between the ischemia and non-ischemia groups. In contrast, within the female group, both BMI (30.2 vs. 27.1 kg/m2, p = 0.002) and WC (112 vs. 105.5 cm, p = 0.020) were significantly higher in the ischemia group. Multivariable logistic regression showed that male sex and BMI were the only two independent predictors of ischemia in our patient population. Conclusions: This study showed that BMI was an independent predictor of ischemia in our patient population.

Atrioventricular (AV) block and sinus arrest associated with dipyridamole infusion.

The use of dipyridamole for thallium-201 imaging has proved very successful in demonstrating coronary arterial disease, and a combination of dipyridamole and dynamic exercise is becoming widely used. Dipyridamole is safe when given intravenously, although transient noncardiac side effects are common; side effects such as chest pain, headache, and dizziness. These side effects are mostly mild, and can be treated with aminophylline. We describe a 45-year-old woman with normal baseline electrocardiography (ECG) and unremarkable physical examination, referred for myocardial thallium scan with dipyridamole. A few seconds after infusion of dipyridamole, her ECG developed first-degree atrioventricular (AV) block, then, 2:1 AV block, complete heart block (CHB), and sinus arrest. After aminophylline infusion, junctional escape rhythm was seen, and a few seconds later, rhythm changed to sinus rhythm. Thallium scan was negative for ischemia. High-grade AV block after dipyridamole has been described in few case reports, and mostly was associated with transient myocardial ischemia; it seems that the presence of conduction abnormalities at baseline is a risk factor. But in our case, the sinus arrest and AV block occurred without evidence of ischemia in myocardial perfusion imaging, and we think it can be an unwanted complication of dipyridamole; clinicians should be aware of bradyarrhythmia as a possible complication of dipyridamole. An alternative explanation is that this arrhythmia can be caused by vagal activity; and another possibility is that the imaging study was false negative.

Left ventricular mechanical dyssynchrony in patients with chest pain and normal epicardial coronary arteries

BackgroundTo detect ischemia in patients with angina and normal coronaries frequently represents a complex diagnosis. MethodsTo investigate whether left ventricular mechanical dyssynchrony by phase analysis contributes in the evaluation of patients with chest pain and normal coronaries, gated-SPECT myocardial perfusion imaging (MPI) at rest and 30 minutes post-stress was performed in 218 patients with normal epicardial coronaries, who were divided into two groups: those with summed difference score (SDS) ≥ 4 (54 patients, Group 1), and those with SDS < 4 (164 patients, Group 2). Intraventricular synchronism-phase standard deviation (PSD) and histogram bandwidth (HBW)—was evaluated by phase analysis. ResultsWomen were significantly more frequent in Group 2 (those without ischemia in SPECT MPI): 113 (69%) vs 25 (46%), P = .00001. In males, left ventricular ejection fraction (LVEF) and ventricular volumes were not significantly different between patients with or without ischemia. However, ischemic females showed significantly higher ventricular volumes, minor post-stress LVEF and more negative delta LVEF (− 3.9 vs 0.34, P = .0008) than the non-ischemic ones. There was a significant post-stress increase of PSD and HBW among males, although not among females. According to SSS (≥ 4, with ischemia/necrosis; < 4, without ischemia/necrosis), post-stress PSD and HBW significantly increase both in male and female, and PSD and HBW were significantly higher in females with SSS ≥ 4 compared to those with SSS < 4 (PSD rest: 19.04° vs 11.72°, P < .0001; HBW rest: 58.85° vs 38.21°, P < .0001). PSD and HBW were also higher among males with SSS ≥ 4 compared to those with SSS < 4, although not significantly. ConclusionHigher ventricular volumes in females and dyssynchrony are associated with inducible ischemia in MPI in patients with chest pain and normal coronaries. Stress-induced ischemia increases degree of dyssynchrony.

Predictors of Myocardial Ischemia in Preoperative Oncology Patients Who Underwent Fluorodeoxyglucose-Positron Emission Tomography Study.

Background:Coronary artery calcification (CAC) can be visually estimated on computed tomography (CT) attenuation correction (CTAC) of positron emission tomography (PET). The visual estimation of CAC from CTAC scans performed for PET/CT is comparable to the standard CAC score scan. Myocardial perfusion imaging (MPI) with single-photon emission CT (SPECT) is commonly performed for risk stratification before oncologic surgery.Objective:We investigated the value of visual estimation of CAC from CTAC of PET/CT as well as other factors such as coronary artery disease (CAD) risk factors and type of cancer as predictors of MPI ischemia.Methods:Retrospectively, we identified 268 patients who underwent PET/CT and MPI for preoperative cardiac evaluation. Visual estimation of CAC was performed and classified into four categories.Results:The results of visual CAC were as follows: 47.8% – zero CAC, 32.8% – mild CAC, 14.2% – moderate CAC, and 5.2% – severe CAC. The majority of patients (85.8%) had normal MPI, whereas 14.2% were abnormal. There was a strong association between ischemia on MPI and CAC seen on CTAC (P < 0.01), dyslipidemia (P < 0.01), family history of CAD (P < 0.05), smoking (P < 0.01), and type of malignancy (P < 0.01).Conclusion:A strong association exists between visual estimation of CAC on CTAC and MPI. Zero is highly associated with normal MPI, but moderate-to-severe CAC is associated with abnormal MPI, in addition smoking, dyslipidemia, and certain cancer are associated with ischemic MPI; subsequently, preoperative cardiac testing is warranted in these subsets of patients.

P145Trends in frequency of stress induced ischemia in myocardial perfusion imaging in a southeast asian population

P145Trends in frequency of stress induced ischemia in myocardial perfusion imaging in a southeast asian population

Temporal trends in stress Myocardial Perfusion Imaging (MPI) studies in patients with Coronary Artery Disease (CAD) and with no CAD among Saudi Arabian’s population

Introduction Previous studies showed that lower risk patients are being referred to stress testing. Few studies suggested that the frequency of abnormal myocardial perfusion imaging (MPI) studies have declined over the past two decades to even less than 10%. However, it is not clear if this is a universal observation. The aim of this analysis is to assess the temporal trends of the prevalence of abnormal and ischemic MPI studies among large consecutive cohort of Saudi Arabia’s population over a period of 11 years. Methodology From a high volume single center registry, we assessed all patients who undergone stress MPI studies between Octobers 2007 to June 2017 for changes in their demographics, baseline clinical information, past cardiac history, and cardiac risk factors. We also compared the trends of the frequency of abnormal and ischemic MPI. The sample was divided into 5 successive temporal subgroups for the purposes of analysis: 2007 to 2008; 2009 to 2010; 2011 to 2012; 2013 to 2014; and 2015 to 2017. Results A total of 13,786 MPI studies were analysed over the specified duration. There was a progressive decline in the prevalence of abnormal MPI in all patients, from 50.8% in 2007 to 32.3% in 2017, (P Conclusion There has been a temporal decline in the prevalence of abnormal and ischemic MPI studies over a period of 11 years. However, this decline is significantly lower than the previously reported from western cohorts.

Temporal Trends in the Prevalence, Severity, and Localization of Myocardial Ischemia and Necrosis at Myocardial Perfusion Imaging After Myocardial Infarction

The definition, presentation, and management of myocardial infarction (MI) have changed substantially in the last decade. Whether these changes have impacted on the presence, severity, and localization of necrosis at myocardial perfusion imaging (MPI) has not been appraised to date. Subjects undergoing MPI and reporting a history of clinical MI were shortlisted. We focused on the presence, severity, and localization of necrosis at MPI with a retrospective single-center analysis. A total of 10,476 patients were included, distinguishing 5 groups according to the period in which myocardial perfusion scintigraphy had been performed (2004 to 2005, 2006 to 2007, 2008 to 2009, 2010 to 2011, 2012 to 2013). Trend analysis showed over time a significant worsening in baseline features (e.g., age, diabetes mellitus, and Q waves at electrocardiogram), whereas medical therapy and revascularization were offered with increasing frequency. Over the years, there was also a lower prevalence of normal MPI (from 16.8% to 13.6%) and ischemic MPI (from 35.6% to 32.8%), and a higher prevalence of ischemic and necrotic MPI (from 12.0% to 12.7%) or solely necrotic MPI (from 35.7% to 40.9%, p <0.001). Yet the prevalence of severe ischemia decreased over time from 11.4% to 2.0%, with a similar trend for moderate ischemia (from 15.9% to 11.8%, p <0.001). Similarly sobering results were wound for the prevalence of severe necrosis (from 19.8% to 8.2%) and moderate necrosis (from 8.5% to 7.8%, p = 0.028). These trends were largely confirmed at regional level and after propensity score matching. In conclusion, the outlook of stable patients with previous MI has substantially improved in the last decade, with a decrease in the severity of residual myocardial ischemia and necrosis, despite an apparent worsening in baseline features.

Impact of incomplete revascularization of coronary artery disease on long-term cardiac outcomes. Retrospective comparison of angiographic and myocardial perfusion imaging criteria for completeness

BackgroundCoronary revascularization in patients with coronary artery disease may be guided by coronary angiography (CA) or alternatively by ischemia on stress myocardial perfusion imaging (MPI). Which strategy leads to optimal cardiac outcomes is uncertain. MethodsWe performed a retrospective analysis of 170 patients with MPI ischemia and percutaneous coronary intervention. The primary endpoint was all-cause mortality at a mean follow-up of 47 ± 21 months; the secondary end point was the composite of deaths, nonfatal myocardial infarction, and repeat coronary revascularization (MACE). The coronary revascularization was defined as complete (CCR) or incomplete (ICR) as judged by CA criteria and by MPI ischemia matched with CA criteria. ResultsNighty-two patients (54%) had ICR by CA criteria (ICR-CA) and 84 (49%) had ICR by MPI criteria (ICR-MPI). Mortality and MACE were lower in patients with CCR-MPI than with ICR-MPI (P = .048, and P = .025). Survival of patients with CCR-CA and ICR-CA was not different (P = .081). Patients with both ICR-MPI and ICR-CA had the worst survival, whereas patients with CCR-MPI and CCR-CA had the best survival (P = .047). By multivariate analysis, ICR-MPI + ICR-CA was an independent predictor of death (P = .025). ConclusionPatients with ICR by MPI were at higher risk than those with CCR. Patients with both ICR by MPI and CA were at the highest risk, while patients with CCR by both MPI and CA had the best long-term event-free survival.

Temporal trends of stress myocardial perfusion imaging: Influence of diabetes, gender and coronary artery disease status

IntroductionTemporal trends of myocardial perfusion imaging (MPI) among diabetics and non-diabetics and the influence of gender and prior coronary artery disease (CAD) status has not been previously investigated. Materials and methodsConsecutive patients who underwent clinically indicated stress-MPI over a 17-year period (1996 through 2012) were studied. Data were collected prospectively as a part of the ongoing clinical databases. Study patients were divided into 4 temporal subgroups (1996 to 2000, 2001 to 2004, 2005 to 2008 and 2009 to 2012) to compare the trends of cardiac risk factors and the frequency of abnormal and ischemic MPI. ResultsOf 78,344 total stress MPI studies, 30.2% were in diabetics. The frequency of abnormal MPI studies, while substantially higher in diabetics, significantly declined over time both in diabetics (53.6% in 1996 to 39.8% in 2012) and non-diabetics (37% in 1996 to 27.4% in 2012), despite an increase in the cardiac risk factor profile. Furthermore, among patients with no known CAD, the temporal prevalence of abnormal MPI was highest in diabetic men (57.5% in 1996 to 31.9% in 2012), lowest in non-diabetic women (18.8% in 1996 to 11% in 2012), and both intermediate and comparable in non-diabetic men and diabetic women (36.4% and 35.7% in 1996 and 20.7% and 17.5% in 2012, respectively). ConclusionsDespite a temporal reduction in the prevalence of abnormal studies from 1996 through 2012, stress MPI continues to play an important clinical role, particularly in diabetics, men and patients with known-CAD.

A multi-center assessment of the temporal trends in myocardial perfusion imaging

BackgroundRecent literature suggests that the frequency of abnormal SPECT myocardial perfusion imaging (MPI) has decreased over the past two decades despite an increase in the prevalence of many cardiac risk factors. This study examined the trends in the prevalence of obstructive coronary artery disease (CAD) by abnormal and ischemic MPI and invasive angiography. MethodsWe analyzed all patients who underwent stress MPI or invasive angiography at two academic centers between January 1996 and December 2012, for their demographic data and study results. ResultsA total of 108,654 MPI studies were performed. Over time, the percentage of patients with hypertension, hyperlipidemia, diabetes, and a history of smoking increased. There was a decline in the prevalence of abnormal MPI studies in all patients as well as in those with and without known CAD (from 47.2%, 71.8%, and 31.4% in 1996 to 33.9%, 64.8%, and 18.8% in 2012, respectively, all P < .0001). Similarly, there was a decline in the prevalence of ischemic MPI studies in all patients as well as in those with and without known CAD. A total of 142,924 invasive angiograms were performed. There was a decline in the prevalence of one-vessel and multi-vessel coronary disease (from 29.1% and 53.6% in 1996 to 22.4% and 35.9% in 2012, respectively, all P < .0001). ConclusionsThere has been a temporal decline in the prevalence of abnormal and ischemic MPI studies as well as the frequency and extent of obstructive CAD on angiography. However, this decline was not to the same extent as previously reported, and the overall 34% abnormal MPI rate, with 19% in patients with no known CAD and 65% in patients with known CAD, remains a clinically relevant percentage of patients tested.

Assessing Clinical Impact of Myocardial Perfusion Studies: Ischemia or Other Prognostic Indicators?

One of the major strengths of nuclear myocardial perfusion imaging (MPI) is the robust prognostic databases from observational studies demonstrating significantly different outcomes in patients with low-risk vs high-risk scans. The severity of the MPI defect can be semi-quantitated using the summed stress score (SSS) and summed difference score (SDS). SSS is more strongly associated with mortality, whereas SDS is the better predictor of subsequent coronary angiography and revascularization. The strength of MPI variables as prognostic indicators decreases when adjusted for prognostically important clinical and stress test variables. Nonetheless, most studies of general patient populations have demonstrated that MPI adds incremental prognostic value to clinical and stress test information. In contrast to these positive results from observational studies, the application of MPI ischemia as a treatment guide in several recent trials (DIAD, WOMEN, COURAGE, BARI 2D, STICH) has largely failed to identify patient subsets with improved outcome. This issue will continue to be investigated in the ongoing PROMISE and ISCHEMIA trials.

Coronary artery and thoracic aorta calcification is inversely related to coronary flow reserve as measured by 82Rb PET/CT in intermediate risk patients

BackgroundThe strength and nature of the relationship between myocardial perfusion imaging (MPI), coronary flow reserve (CFR), and coronary artery calcium (CAC) and thoracic aorta calcium (TAC) remain to be clarified. MethodsDynamic rest-pharmacological stress 82Rb positron emission tomography/computed tomography MPI with CFR, CAC, and TAC was performed in 75 patients (59 ± 13 years; F/M = 38/37) with intermediate risk of coronary artery disease. ResultsA total of 29 (39%) patients had ischemic and 46 (61%) had normal MPI. CAC was correlated with TAC (ρ = 0.7; P < .001), and CFR was inversely related with CAC and TAC (ρ = −0.6 and −0.5; P < .001, respectively). By gender-specific univariate analysis, age (P = .001), CAC (P = .004), and CFR (P = .008) in males, but CFR (P = .0001), age (P = .002), and TAC (P = .01) in females were significant predictors of ischemic MPI. By multiple regression, the most potent predictor was CFR [odds ratio (OR) = 0.17, P = .01), followed by age (OR = 1.07, P = .02), gender (OR = 4.01, P = .03), and CAC (OR = 1.002, P = .9). ConclusionsCombination of MPI, CFR, CAC, and TAC has complementary roles in intermediate risk patients.

Prevalence and Predictors of Ischemia and Outcomes in Outpatients With Diabetes Mellitus Referred for Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging

Background- The prevalence of ischemia and its prediction of events are unclear in outpatients with diabetes mellitus in the modern era of intensive medical management. We sought to identify the prevalence of ischemia, subsequent cardiac events, and impact of sex, stress type, and symptom status on these findings in a cohort of stable outpatients with diabetes mellitus referred for single-photon emission computed tomography myocardial perfusion imaging (MPI). Methods and Results- The study cohort included 575 consecutive outpatients with diabetes mellitus who underwent quantitative, gated single-photon emission computed tomography MPI. Clinical information, stress MPI variables, and cardiac events were prospectively collected and analyzed. The study population was at intermediate risk of coronary artery disease or had known coronary artery disease (40.3%); 29% of patients were asymptomatic at the time of stress testing. Scintigraphic ischemia and significant (≥10%) left ventricular ischemia were present in 126 patients (21.9%) and 29 patients (5.0%), respectively, and <1% of patients had early revascularization. The risk of ischemia was increased >2-fold by male sex (P<0.001), but was not impacted by pharmacological stress (P=0.15) or presence of symptoms (P=0.89). During a median 4.4 years follow-up, the rate of cardiac death/nonfatal myocardial infarction was moderate at 2.6%/y (cardiac death 0.8%/y) in the total cohort, but was 5.7%/y in those with ischemia (P<0.001). Pharmacological stress predicted a higher cardiac event rate (P<0.001) but symptoms did not (P=0.55). Conclusions- This cohort of stable outpatients with diabetes mellitus referred for single-photon emission computed tomography had low rates of significant ischemia and early revascularization; an initially low cardiac event rate increased after 2 years. Independent predictors of cardiac death/nonfatal myocardial infarction were known coronary artery disease, pharmacological stress, and MPI ischemia. Nearly one third of those with events had a normal MPI, indicating a need for improved risk stratification.

Use of Electrocardiographic Depolarization Abnormalities for Detection of Stress-Induced Ischemia as Defined by Myocardial Perfusion Imaging

High-frequency mid-QRS (HFQRS) analysis was recently introduced as a tool for identification of stress-induced ischemia. The diagnostic performance of this electrocardiographic technique has not been determined in a large cohort of patients. This study compared the diagnostic performance of HFQRS analysis to conventional ST-segment analysis in detecting exercise-induced ischemia. The study included 996 patients (56 ± 10 years of age, 670 men) referred for exercise myocardial perfusion imaging (MPI), which served as the gold standard of ischemia. High-resolution electrocardiogram was used for computer analysis of HFQRS signals. Number of electrocardiographic leads with ≥50% decrease of HFQRS intensity (L(50%)) was used as an index of ischemia. Perfusion images were evaluated semiquantitatively. Receiver operating characteristic analysis demonstrated an L(50%) ≥3 as the criterion that yielded optimal sensitivity and specificity for diagnosing moderate/severe ischemia. Compared to ST-segment analysis HFQRS analysis was more sensitive (69% vs 39%, p <0.005) and more specific (86% vs 82%, p <0.05). L(50%) correlated with amount of MPI ischemia (R(2) = 0.75, p <0.0001). Multivariate logistic regression analysis demonstrated a significant incremental diagnostic value for the addition of HFQRS data to a model containing pretest and conventional exercise parameters. L(50%) was the best predictor of mild or moderate/severe MPI ischemia. In conclusion, computerized HFQRS analysis improved the diagnostic performance of conventional stress electrocardiogram in detecting exercise-induced ischemia. Thus, this technique might aid in the noninvasive evaluation of coronary artery disease.

The relationship between stress-induced myocardial ischemia and coronary artery atherosclerosis measured by hybrid SPECT/CT camera

The coronary artery calcium (CAC) score and myocardial perfusion imaging can now be detected simultaneously using a hybrid SPECT/CT camera. However, there has been little evaluation on the relationship between stress-induced ischemia and coronary artery calcification in a Japanese population. The aim of this study was to investigate the relationship between these parameters and to elucidate the diagnostic value of the CAC score as an adjunct to myocardial perfusion imaging (MPI) for the assessment of coronary artery disease (CAD) in an intermediate-risk population. We retrospectively analyzed 105 patients (63% men, mean age 71 years) with CAD or suspected CAD who underwent MPI using SPECT/CT. CAC scanning was performed using a SPECT/CT camera. There was a significant difference in the CAC score between patients with ischemia (n = 42) and those without ischemia (n = 63) (1353 ± 1524 vs. 332 ± 554, p < 0.01). The frequency of ischemic MPI determined by summed difference score tended to be higher in patients with high CAC (CAC = 0; 0.8 ± 1.3 vs. CAC > 1000; 3.0 ± 2.0). Higher age is related roughly with higher CAC score with no statistical significance (r(2) = 0.1) (<60 years old; 200 ± 692, vs. >80 years old; 1258 ± 1546, ns). The location of calcification was not related to the ischemic area. In a population with a predominately intermediate likelihood of CAD, a calcium score of zero has a possibility of excluding inducible ischemia on MPI. In part, ischemic MPI is associated with a high likelihood of subclinical atherosclerosis as detected by CAC. Hybrid SPECT/CT might be useful for diagnostic assessment and coronary artery with known or suspected CAD.

Detection of stress-induced myocardial ischemia from the depolarization phase of the cardiac cycle—a preliminary study

Background Electrocardiogram (ECG)-based detection of ischemia is typically dependent on identifying changes in repolarization. Analysis of high-frequency QRS (HFQRS) components, related to the depolarization phase of the cardiac action potential, has been reported to better identify ischemia. Our aim was to test the hypothesis that HFQRS analysis is both more sensitive and specific than standard ECG for detecting exercise-induced ischemia in patients undergoing exercise myocardial perfusion imaging (MPI). Methods Exercise MPI was performed in 133 consecutive patients (age, 63 ± 12; 100 males) and used as the gold standard for ischemia. Patients with QRS duration more than 120 milliseconds (n = 20), technical problems (n = 8), or inconclusive MPI (n = 4) were excluded, leaving 101 patients for analysis. Conventional ECG was combined with high-resolution ECG acquisition that was digitized and analyzed using the HyperQ System (BSP, Tel Aviv, Israel). The relative HFQRS intensity change during exercise was used as an index of ischemia. Results Of the 101 patients who were included in the analysis, 19 exhibited MPI ischemia. The HFQRS index of ischemia was found to be more sensitive (79% vs 41%; P < .05) and more specific (71% vs 57%; P < .05) than conventional ST analysis. Conclusions The HFQRS analysis was more sensitive and specific than conventional ECG interpretation in detecting exercise-induced ischemia and exhibited enhanced diagnostic performance in both women and men. Thus, it may aid in the noninvasive diagnosis of ischemic heart disease.

Dobutamine-induced chest pain does not predict ischemic findings on myocardial perfusion imaging

Chest pain occurs frequently during dobutamine stress testing and is commonly attributed to ischemia. However, the pathophysiologic significance of dobutamine-induced chest pain is uncertain. The purpose of this study is to explore the correlation between dobutamine-induced chest pain and evidence of ischemia on myocardial perfusion imaging (MPI). This study included 1608 patients who underwent dobutamine stress MPI at the Mid America Heart Institute (Kansas City, Mo) and were analyzed retrospectively. Patients were divided into those with chest pain during dobutamine infusion versus those without it. Multivariate and chi(2) analyses were conducted to explore the relationship between chest pain and ischemic changes on MPI. Of 1608 patients, 208 (13%) had chest pain with dobutamine whereas 1400 (87%) did not. MPI ischemia was seen in 47% of patients with chest pain and 43% without chest pain (P = .28). Chest pain was not any more predictive of ischemia when analyzed separately by gender (P = .31). Multivariate analysis did not identify chest pain as a predictor of ischemia (P = .19). Significant predictors of scintigraphic ischemic changes were age (P = .001), gender (P < .0001), smoking (P = .0149), and known coronary artery disease (P < .0001). This large retrospective study suggests that chest pain during dobutamine stress testing is not a predictor of ischemia when analyzed against reversible perfusion defects on SPECT MPI.

Coronary calcium scoring in selected patients after normal or equivocal myocardial perfusion imaging studies, clinical usefulness

Background: Coronary calcium scoring (CCS) by CT after myocardial perfusion imaging (MPI) in selected patients might improve sensitivity for the detection of significant coronary artery disease (CAD), or in patients with symptoms, improve diagnostic confidence for the absence of significant CAD. Methods: We reviewed all 132 patients who were referred for CCS shortly after MPI at our medical center (4-slice MDCT; scan parameters 120 kV, 100 mA, 4 × 2.5 mm slice collimation, 0.375 scan pitch, 3 mm slice thickness, 125–250 ms temporal resolution) (MPI by thallium, sestamibi, or dual isotope SPECT in 124 patients, rubidium PET in 8). Results: No patient had an ischemic MPI, but 15 had chest pain with exercise testing, 15 had an ischemic ECG response, and 8 had an equivocal scintigraphic response. These patients (n=30) thus had a stress response which was considered not to be completely normal. The remaining patients (n=102) had completely non-ischemic stress MPI tests and were referred for CCS in order to improve the diagnostic confidence that CAD was not present. Nine patients (7%) had CCS scores greater than 400 volume units indicating significant CAD and another 11 (8%) patients had CCS 100–400 units indicating CAD which was possibly significant. In addition, 15 patients had mildly abnormal CCS (score 11–100) suggesting early CAD The remainder (n=81) had CCS less than 10 confirming no significant CAD. No patients with CCS >100 were diabetics. Of the 30 patients with not-completely-normal stress studies, 2 were reclassified as having significant CAD based on a CCS > 400, and another 2 had CCS 100–400. Thus, in this series of patients who were referred for CCS after MPI, 29/132 (22%) were reclassified from not having CAD to having CAD based on a CCS > 100. Patients who were reclassified were not easily identifiable based on clinical or stress test parameters. Coronary calcium testing appears to be a promising approach to identifying patients who have significant CAD despite a non-ischemic MPI, and for confirming the absence of CAD in selected patients in whom diagnostic concern persists.