Abnormal Exercise Stress Test Research Articles

Aortic Stenosis: Risk Stratification and Timing of Surgery.

This review summarizes the current management of patients with newly diagnosed aortic stenosis. Recent developments include detection of early myocardial dysfunction using serum B-type natriuretic peptide levels and global longitudinal strain, as well as ongoing trials of transcatheter aortic valve replacement in asymptomatic patients and patients with moderate aortic stenosis complicated by symptoms or left ventricular systolic dysfunction. Given the high mortality associated with severe symptomatic aortic stenosis, all symptomatic patients should be referred for aortic valve replacement. Asymptomatic patients with left ventricular systolic dysfunction, abnormal exercise stress test, high degree of stenosis, rapid disease progression, or elevated serum B-type natriuretic peptide level may also have an indication for valve replacement, based on established criteria. The progress in management of severe aortic stenosis has been in the direction of earlier detection and earlier valve replacement.

Abstract 11615: The Prevalence and Association of Exercise Test Abnormalities With Sudden Cardiac Death and Transplant-Free Survival in Childhood Hypertrophic Cardiomyopathy

Introduction: Hypertrophic cardiomyopathy (HCM) can be associated with an abnormal exercise response. In adults with HCM, an abnormal exercise stress test (EST) is predictive of heart failure outcomes. Our goal was to determine if an abnormal exercise response is associated with adverse outcomes in pediatric HCM patients. Methods: : In an international cohort study with 20 centers (PRIMaCY), children <18 years with primary HCM were included. Abnormal EST was defined as an abnormal heart rate or blood pressure response, arrhythmias and/or ischemic ECG changes on exercise. Sudden cardiac death (SCD) events were defined as a composite of SCD and aborted SCD including appropriate implantable cardioverter defibrillator discharges. Using Kaplan-Meier survival analyses, we analyzed the association of abnormal EST with SCD and transplant-free survival. Results: Of 724 eligible patients, 604 underwent at least one EST on follow-up. There were no differences in clinical characteristics between those with or without an EST. The median age at EST was 13.8yrs (IQR 11.0-15.7yrs), 76% were male, 55% were on beta-blockers. 299 (49.5%) had an abnormal EST. Patients with an abnormal EST had more severe septal hypertrophy, higher left atrial diameter z-scores, higher resting LV outflow gradient at first evaluation, and a higher proportion were genotype-positive (p<0.05) compared to those with a normal EST. An abnormal EST was associated with lower 5-year transplant-free survival (99% vs. 95%, p=0.0082) and lower 5-year freedom from SCD events (96% vs. 92%, p=0.025) (Figure 1). Conclusions: Exercise abnormalities are common in childhood HCM. An abnormal EST in children with HCM was associated with lower transplant-free survival and more SCD events. Further analysis will determine if the inclusion of EST results can increase the predictive accuracy of current pediatric SCD risk prediction models.

Abstract 17409: Improved Diagnosis of Coronary Artery Disease Using Cardiac CT Compared With Exercise Stress Testing in an Urban Public Hospital Patient Population

Introduction: Heart disease remains the leading cause of death in the United States, with the disease burden particularly high in various racial and ethnic groups. In serving an underserved population comprised largely of Hispanic and African American individuals, it is crucial for an urban public hospital to diagnose heart disease in a resource-efficient and cost-effective manner. The greater positive predictive value of cardiac CT relative to exercise stress testing presents the opportunity for such hospitals to optimize resource utilization in identifying patients with coronary artery disease (CAD). Hypothesis: The positive predictive value of cardiac CT in diagnosing CAD is greater than that of exercise stress testing in the patient population served by an urban public hospital. Methods: Patients at Harbor-UCLA Medical Center (Torrance, California) were identified for inclusion in this observational study on the basis of a positive (i.e., abnormal) exercise stress test result or a positive cardiac CT result, during the period between January 2015 and September 2019. These patients were subsequently referred for invasive coronary artery angiography, with the diagnosis of obstructive CAD established by an indication for revascularization via percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). Data were analyzed using a two-tailed Z-test for two proportions. Results: Seventy-six catheterization laboratory results were analyzed. Fifteen subjects with an abnormal exercise stress test result, out of a total of 41 (36.6%), had an indication for PCI or CABG. Twenty-five cardiac CT imaging subjects, out of a total of 35 (71.4%), had an indication for PCI or CABG. The proportion of positive cardiac CT results with an indication for PCI or CABG was significantly higher than the abnormal exercise stress test proportion (p=0.0024). Conclusions: Among urban public hospital patients who were referred for invasive coronary artery angiography, it was determined that cardiac CT provides a greater positive predictive value in the diagnosis of obstructive CAD than exercise stress testing. This result may help guide the optimal allocation of diagnostic resources in an urban public hospital.

606 Formation of Coronary Artery Fistula After Mitral Valve Repair

We report a case of a 72-year-old male, who was incidentally found to have developed a coronary artery fistula (CAF) following cardiac surgery. The patient had undergone mitral valve (MV) repair, left atrial appendage excision and AF ablation for management of mitral regurgitation secondary to bileaflet MV prolapse 3 years prior. He reported intermittent exertional dyspnoea and underwent coronary angiography following an abnormal exercise stress test. At coronary angiography, a CAF between the right atrial branch artery of the right coronary artery (RCA) and the right atrium was demonstrated. No CAF was present on angiography preoperatively. As there was no echographic evidence of haemodynamic significance, the CAF was managed conservatively. The cause of CAF formation at this specific site is hypothesised to be due to injury to the right atrial branch artery by cannulation of the right atrium for cardiopulmonary bypass, a rarely described occurrence in the literature [[1]Lee R.M. Colucci G. W Coronary artery fistula after mitral valve surgery.American Heart Journal. 1988; 115: 1128-1130Crossref PubMed Scopus (17) Google Scholar]. Coronary artery fistulae are anomalous connections between the coronary arteries and other vessels or cardiac chambers (coronary-cameral fistula). The population incidence is estimated at 0.2% and is most often due to a congenital malformation. Invasive procedures including coronary angiography and cardiac surgery are known to cause CAF. The incidence of CAF in the post cardiac surgery population has been reported in case series of up to 2.3% post coronary artery bypass grafting (CABG) and 8.9% following CABG and valve surgery [[2]Young A, Cheng R, Wei J, Esmailian F, Currier J, Azarbal B. Prevalence of coronary artery fistulae after cardiac surgery. Comparison between coronary artery bypass grafting, valve surgery, and orthotopic heart transplantation. Herz 2015;40 Suppl 1:51-5.Google Scholar]. Importantly, this case highlights that CAF can occur, following cardiac surgery, at a site distant to the operative region.

542 Review of Efficacy and Outcomes of Preventing Hospital Admissions by Use of Quick-Access Chest Pain Clinic for Low-Moderate Risk Chest Pain Presentations

Chest pain clinics have been increasingly utilized around the world as an effective way of assessing patients with low-to-moderate risk chest pain. To review the clinical utility of our outpatient chest pain clinic. Consecutive patients referred to the chest pain clinic over a six-month period in 2019 in a single-centre tertiary hospital were retrospectively reviewed. 507 patients were referred during the six-month period, of which 382 patients were assessed. Of these, 237 patients (62%) had an exercise stress test (EST) and 46 patients (12%) had an alternative functional study. 13 patients (3.4%) were referred for angiogram. Of these, 3 patients were referred directly, whilst 10 were referred after abnormal EST. Of the latter 10, 5 patients (50%) who had strong initial clinical suspicion for CAD had significant disease on angiography requiring intervention. This represents 0.01% of patients reviewed in the chest pain clinic requiring invasive intervention. The other 5 patients with low clinical suspicion had no significant CAD on angiography. 72 of the 382 reviewed patients (19%) were deemed to not need any cardiac investigations. This retrospective analysis confirms the utility of chest pain clinic in preventing hospital admissions for low-moderate risk chest pain patients. However, it also highlights the low-specificity that standard EST has in predicting significant CAD, with high false positivity. Further it demonstrates that initial high clinical suspicion is very important in predicting significant coronary disease.

The utility of combined cardiopulmonary exercise stress testing in the evaluation of pediatric patients with chest pain.

A cardiac cause is an extremely rare etiology of pediatric chest pain. Despite its low sensitivity/specificity, exercise stress testing (EST) is widely used to determine the prognosis in patients with suspected/established coronary disease. We aimed to look at the utility of a combined cardiopulmonary EST in the evaluation of pediatric patients with chest pain. After institutional review board approval, a retrospective chart review was performed of all pediatric patients who were referred for an EST for chest pain from January 2014 to 2017. Patients with incomplete records, severe congenital heart disease, and a prior EST were excluded. A total of 389 patients met the inclusion criteria. Echocardiogram (ECHO) was performed on 333 (85.6%) patients and 43 (11%) previously unknown structural cardiac anomalies were identified. A total of 76 (19.5%) patients had an abnormal EST with the 3 most common causes being related to the respiratory system. Only four patients had both an abnormal exercise stress test and an incidental structural anomaly on ECHO but none of them had their symptoms recreated during the EST. Only 1% of patients previously undiagnosed with heart disease had an abnormal stress test and an incidental anomaly on ECHO. These ECHO anomalies were unlikely to be the cause of chest pain. Furthermore, since the majority of abnormal stress tests were secondary to a pulmonary cause, a complete cardiopulmonary EST may be an effective screening tool for certain patients presenting with chest pain. Our study emphasizes the need for performing a complete cardiopulmonary EST instead of an isolated cardiac stress test to maximize diagnostic efficiency and yield.

Effect of Ranolazine in Patients with Chest Pain and Normal Coronaries- A Hospital Based Study.

There is an important role of coronary microcirculation in the clinical presentation and prognosis of patients who have typical chest pain despite normal epicardial coronary arteries (microvascular angina). Treatment of these patients is empirical because of the incomplete knowledge of its cause. Limited data has shown that ranolazine reduces angina and improves exercise performance in such patients with frequent angina. To evaluate the effect of ranolazine in patients with chest pain and normal epicardial coronaries (micro-vascular angina). Sixty-five patients with anginal symptoms with abnormal exercise stress test and normal epicardial coronaries were enrolled for the study. All participants had baseline demographic and health history questionnaires, including Seattle Angina Questionnaire (SAQ) and Duke Activity Status Index (DASI). After enrolment, patients were randomly divided into two groups. One group (group 1) was assigned to ranolazine for six weeks along with other indicated anti-anginal drugs. The other group (group 2) was assigned to anti-anginal drugs other than ranolazine. Patients were reassessed for symptomatic and functional improvement (SAQ, DASI) at six weeks. Mean age of patients examined were 49.03 years in group 1 and 49.77 years in group 2. Approximately 42.9% of patients in group 1 and 40% in group 2 were male. Despite current anti-anginal therapy, patients in both the groups were symptomatic. At six weeks, 60% of patients in group 1 had angina as compared to 88.6% at baseline (p<0.05). Similarly, scores of domains of SAQ were higher at six weeks as compared to baseline (p<0.05) except for treatment satisfaction. No improvement of DASI score and functional capacity were seen in either group at six weeks as compared to baseline (p>0.05). At six weeks, angina was significantly lower in group 1 as compared to group 2 (60 % vs 86.7%; p<0.05). Four out of five SAQ subscale score were higher in ranolazine group as compared to the other group (p<0.05). Treatment satisfaction trended lower on ranolazine group (p<0.05). There was no significant differences in DASI in the two groups (DASI score 30.59 vs 29.85, p>0.05). Ranolazine is safe and improves symptoms significantly in patients with micro-vascular angina.

Stress Testing After Complete and Successful Coronary Revascularization

BackgroundNoninvasive stress tests play a determinant role in the initial management of patients with chronic angina. Nonetheless, their use in the same patient population is considered inappropriate within 2 years after percutaneous coronary intervention (PCI). Indeed, early abnormal results correlate less well with angiographic control and are attributed to a number of confounding factors. We prospectively assessed prevalence and impact on the quality of life of abnormal stress test results in a highly selected patient population. MethodsPatients with no cardiac comorbidities who underwent successful and complete PCI with stenting for typical angina and had an abnormal exercise stress test (EST) under guideline-directed medical treatment were administered the Seattle Angina Questionnaire (SAQ). Clinical evaluation, EST, and the SAQ were repeated at 1, 6, and 12 months after the index PCI. ResultsOne hundred ninety-eight patients qualified and were included in the study (mean age, 64 years; 79% men). Although the majority had normal EST results or an increased threshold to angina, at 1 month after the index PCI, 29% of patients still had an abnormal result. At 6 and 12 months, 31% and 29% of patients had abnormal results, respectively. Quality-of-life assessment by the SAQ showed consistent results, with persistent angina in one third of patients. Control angiography documented a critical lesion, attributable to in-stent coronary restenosis, in only 8% of patients. ConclusionsWhen stress testing is systematically performed after PCI, the prevalence of abnormal results is high and is associated with impaired quality of life. Prognostic significance along with the underlying pathophysiological mechanisms of such findings should be investigated.

Limited Utility of Exercise Stress Tests in the Evaluation of Children with Chest Pain

The objective of this study was to assess the utility of the exercise stress test (EST) in pediatric patients without previously diagnosed heart disease who present with chest pain and to correlate EST results with echocardiographic findings. Retrospective chart review over a 14-month period. Cardiology clinic at an academic children's hospital. Two hundred three pediatric patients who presented to a pediatric cardiologist and had an EST for chest pain. Correlate EST results with echocardiographic findings and the patient's ultimate diagnosis. Retrospective review of patients who presented to cardiology clinic for chest pain, analysis of medical records, EST, echocardiograms, and other downstream testing. Of 433 patients who presented to a pediatric cardiologist for chest pain, 203 (47%) had an EST performed. One hundred seventy-six (87%) patients did not have a prior diagnosis of congenital heart disease and made up our study population. Mean age was 13.2 ± 3 years. Of the patients who had an EST, 139 (79%) had chest pain with exercise. Echocardiography was performed in 124 (70%) of the patients who had an EST. Of patients undergoing echocardiography, 17/124 (14%) had abnormalities, but none of the abnormalities found were thought to contribute to the patients' chest pain. There were only four (2%) abnormal EST, and none were thought to be diagnostic for the patients' symptoms of chest pain. The most common diagnoses were musculoskeletal chest pain in 34 patients (19%) and reactive airway disease in 27 patients (15%). In children referred to pediatric cardiology clinic for chest pain, EST has a low yield in identifying cardiac abnormalities.

Left Main Coronary Artery Compression Long Term After Repair of Conotruncal Lesions: The Bow String Conduit

We report 4 cases of left main coronary artery (LMCA) compression after remote repair of conotruncal lesions and their successful surgical management.

Coronary tortuosity: a long and winding road

Coronary tortuosity is a phenomenon often encountered by cardiologists performing coronary angiography. The aetiology and clinical importance of coronary tortuosity are still unclear. Coronary tortuosity without fixed atherosclerotic stenosis in patients with angina pectoris and an abnormal exercise stress test has never been described in the literature.This article describes three cases of patients with anginal complaints, an abnormal exercise stress test and coronary angiography without the presence of a fixed atherosclerotic lesion.It is hypothesised that coronary tortuosity leads to flow alteration resulting in a reduction in coronary pressure distal to the tortuous segment of the coronary artery, subsequently leading to ischaemia. Future studies will be necessary to elucidate the actual mechanism of coronary tortuosity and its clinical significance. (Neth Heart J 2007;15:191-5.).

Global risk scores and exercise testing for predicting all-cause mortality in a preventive medicine program

ContextThe usefulness of exercise stress test results and global cardiovascular risk systems for predicting all-cause mortality in asymptomatic individuals seen in clinical settings is unclear.ObjectivesTo determine the validity for prediction of all-cause mortality of the Framingham Risk Score and of a recently described European global scoring system Systematic Coronary Risk Evaluation (SCORE) for cardiovascular mortality among asymptomatic individuals evaluated in a clinical setting and to determine the potential prognostic value of exercise stress testing once these baseline risks are known.Design, Setting, and ParticipantsProspective cohort study of 3554 asymptomatic adults between the ages of 50 and 75 years who underwent exercise stress testing as part of an executive health program between October 1990 and December 2002; participants were followed up for a mean of 8 years.Main Outcome MeasuresGlobal risk based on the Framingham Risk Score and the European SCORE. Prospectively recorded exercise stress test result abnormalities included impaired physical fitness, abnormal heart rate recovery, ventricular ectopy, and ST-segment abnormalities. The primary end point was all-cause mortality.ResultsThere were 114 deaths. The c-index, which corresponds to receiver operating characteristic curve values, and the Akaike Information Criteria found that the European SCORE was superior to the Framingham Risk Score in estimating global mortality risk. In a multivariable model, independent predictors of death were a higher SCORE (for 1% predicted increase in absolute risk, relative risk [RR], 1.07; 95% confidence interval [CI], 1.04-1.09; P<.001), impaired functional capacity (RR, 2.95; 95% CI, 1.98-4.39; P<.001), and an abnormal heart rate recovery (RR, 1.59; 95%, 1.04-2.41; P = .03). ST-segment depression did not predict mortality. Among patients in the highest tertile from the SCORE, an abnormal exercise stress test result, defined as either impaired functional capacity or an abnormal heart rate recovery, identified a mortality risk of more than 1% per year.ConclusionExercise stress testing when combined with the European global risk SCORE may be useful for stratifying risk in asymptomatic individuals in a comprehensive executive health screening program.

Global risk scores and exercise testing for predicting all-cause mortality in a preventive medicine program.

The usefulness of exercise stress test results and global cardiovascular risk systems for predicting all-cause mortality in asymptomatic individuals seen in clinical settings is unclear. To determine the validity for prediction of all-cause mortality of the Framingham Risk Score and of a recently described European global scoring system Systematic Coronary Risk Evaluation (SCORE) for cardiovascular mortality among asymptomatic individuals evaluated in a clinical setting and to determine the potential prognostic value of exercise stress testing once these baseline risks are known. Prospective cohort study of 3554 asymptomatic adults between the ages of 50 and 75 years who underwent exercise stress testing as part of an executive health program between October 1990 and December 2002; participants were followed up for a mean of 8 years. Global risk based on the Framingham Risk Score and the European SCORE. Prospectively recorded exercise stress test result abnormalities included impaired physical fitness, abnormal heart rate recovery, ventricular ectopy, and ST-segment abnormalities. The primary end point was all-cause mortality. There were 114 deaths. The c-index, which corresponds to receiver operating characteristic curve values, and the Akaike Information Criteria found that the European SCORE was superior to the Framingham Risk Score in estimating global mortality risk. In a multivariable model, independent predictors of death were a higher SCORE (for 1% predicted increase in absolute risk, relative risk [RR], 1.07; 95% confidence interval [CI], 1.04-1.09; P<.001), impaired functional capacity (RR, 2.95; 95% CI, 1.98-4.39; P<.001), and an abnormal heart rate recovery (RR, 1.59; 95%, 1.04-2.41; P =.03). ST-segment depression did not predict mortality. Among patients in the highest tertile from the SCORE, an abnormal exercise stress test result, defined as either impaired functional capacity or an abnormal heart rate recovery, identified a mortality risk of more than 1% per year. Exercise stress testing when combined with the European global risk SCORE may be useful for stratifying risk in asymptomatic individuals in a comprehensive executive health screening program.

Improving coronary heart disease risk assessment in asymptomatic people: role of traditional risk factors and noninvasive cardiovascular tests.

At least 25% of coronary patients have sudden death or nonfatal myocardial infarction without prior symptoms.1 Therefore, the search for coronary patients with subclinical disease who could potentially benefit from intensive primary prevention efforts is critically important. The American Heart Association’s (AHA) Prevention V Conference, “Beyond Secondary Prevention: Identifying the High Risk Patient for Primary Prevention,” addressed ways to identify more patients who are asymptomatic and clinically free of coronary heart disease (CHD) but at sufficiently high risk for a future coronary event to justify more intensive risk reduction efforts.2 In this report, we amplify on key findings and recommendations of the AHA Prevention V conference, highlight new research since the conference, and propose an approach to the use of office-based testing and additional noninvasive procedures in selected patients to better define their coronary event risk. The recommendations are concordant with the recently released approach to risk assessment and management from the third report of the Adult Treatment Panel of the National Cholesterol Education Program (ATP-III).3 Enthusiasm for primary prevention and risk assessment in asymptomatic people has been spurred by recent advances in prevention research. Lipid-lowering trials demonstrated that primary prevention of coronary events is feasible, evidenced by the West of Scotland Coronary Primary Prevention Study (WOSCOPS) trial4 of hypercholesterolemic men and by the Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS) trial5 in average or typical risk men and women with only moderate lipid abnormalities. Aspirin6 or ACE inhibitors7 can also reduce risk in selected asymptomatic, high-risk people. Emerging coronary risk factors have been described including inflammatory, infectious, and thrombotic markers,8 and there has been a steady flow of reports that focus attention on potential new ways of predicting coronary risk.9 In addition, noninvasive tests for subclinical atherosclerotic disease are available …

Cardiac energy metabolism in patients with chest pain and normal coronary angiograms

In 70 patients (94% were a consecutive series) with angina pectoris and normal coronary angiograms, we measured cardiac exchange of lactate, glucose, free fatty acids (FFAs), glutamate, alanine, citrate, and oxygen together with coronary sinus blood flow and blood pressure in response to pacing (150 beats/min). Twelve patients had an abnormal exercise stress test; 26 developed ST depression and 46 had chest pain in response to pacing. Sixteen patients had no ST changes (exercise/pacing) and no pain during pacing. Pacing induced an increase in cardiac carbohydrate extraction and a decrease in FFA extraction in the entire group of patients. Less than 3% of patients had significant cardiac lactate release in response to pacing, and there were no consistent differences in the cardiac metabolic or hemodynamic responses between patient groups. The pacing-induced shift from FFA to carbohydrate extraction probably reflects the cardiac response to an acute workload. A definite sign of cardiac ischemia (lactate production) was a rare finding in these patients and not confined to the demonstration of electrocardiographic signs of ischemia.

The prognostic role of normal thallium myocardial imaging in asymptomatic patients with abnormal exercise stress test

The prognostic role of normal thallium myocardial imaging in asymptomatic patients with abnormal exercise stress test

Diabetes Mellitus in Saudi Arabia: The Clinical Pattern and Complications in 1,000 Patients

A retrospective and prospective study of 1,000 ambulatory and hospitalized diabetic patients was done in Riyadh, Saudi Arabia. Saudis completed 777 (77.7%) and non-Saudis 223 (22.3%). Sex distribution was equal among Saudis, males 389 (50.1%) and females 388 (49.9%), but non-Saudi males were predominant at 153 (68.6%), non-Saudi females 70 (31.4%) reflecting the preponderant male expatriate labor force. A proportion of different types of diabetes was: IDDM 115 (11.7%), non-obese non-insulin dependent diabetes mellitus (NIDDM) 405 (41.0%), obese NIDDM 412 (42.1%), and early onset non-insulin dependent diabetes (diagnosis under 30 years of age), 43 (4.4%). Regarding treatment, 388 (40.6%) received insulin followed by sulfonylurea, alone in 330 (33.5%), diet only 117 (12.0%), combination sulfonylurea and biguanide in 113 (11.6%), biguanide alone in 13 (1.3%) and insulin plus tablets in 7 (0.8%). Of 472 and 426 patients, 29.7% and 30.0% had elevated total cholesterol or triglycerides respectively, while 77.2% of 373 patients had elevated glycosylated hemoglobin (HbA1). At least once in 998 patients, diabetic ketoacidosis occurred in 7.6%.

Technetium-99m stannous pyrophosphate scintigrams in normal subjects, patients with exercise-induced ischemia and patients with a calcified valve

Although technetium-99m stannous (99mTc[Sn]) pyrophosphate has been shown to be a specific and sensitive index of myocardial infarction, abnormal images have been reported in patients with unstable angina or ventricular aneurysm. Sixty-one subjects--33 patients subjected to maximal treadmill stress testing, 23 normal subjects and 5 patients with a calcified aortic or mitral valve--underwent imaging with 99mTc(Sn) pyrophosphate to determine whether abnormal images are associated with (1) exercise-induced ischemia, (2) delayed clearance of tracer from the blood pool, or (3) calcified intracardiac structures. Myocardial injury was excluded on the basis of normal MB creatine kinase (CK) values in all patients with stress testing. All eight patients with an abnormal exercise stress test had normal images. Four of 25 patients with a normal exercise stress test had diffusely abnormal images. In some normal subjects diffusely abnormal images were present 60 minutes after injection of the tracer, but became normal 90 to 120 minutes after injection. Variations in clearance of tracer from the blood pool were noted in this group. Patients with a calcified aortic or mitral valve had normal images. We conclude that (1) exercise-induced ischemia is not associated with abnormal 99mTC(SN) pyrophosphate images; (2) images are not necessarily abnormal in patients with a calcified valve; and (3) delayed removal of tracer from the cardiac blood pool may result in diffusely abnormal images even in normal subjects; in these cases, repeat images should be obtained at least 2 hours after injection of the tracer to avoid false abnormal images.