Comparison of Baseline and Post-Nitrate Exercise Testing in Patients with Angina but Non-Obstructed Coronary Arteries with Different Acetylcholine Test Results

Background: Intracoronary acetylcholine testing may induce epicardial coronary artery spasm (CAS) or coronary microvascular spasm (CMVS) in patients with angina syndromes but non-obstructive coronary artery disease, but their causal role in individual patients is not always clear. In this prospective, observational single-center study, we aimed to assess whether (1) the induction of myocardial ischemia/angina by electrocardiogram (ECG) exercise stress test (EST) differs between patients showing different results in response to acetylcholine testing (i.e., CAS, CMVS, or no spasm); (2) the preventive administration of short-acting nitrates has any different effects on the EST of those patients who showed a positive basal EST. We expected that if exercise-induced angina and/or ischemic ECG changes are related to CAS, they should improve after nitrates administration, whereas they should not significantly improve if they are caused by CMVS. Methods: We enrolled 81 patients with angina syndromes and non-obstructive coronary artery disease, who were divided into three groups according to acetylcholine testing: 40 patients with CAS (CAS-group), 14 with CMVS (CMVS-groups), and 27 with a negative test (NEG-group). All patients underwent a basal EST (B-EST). Patients with a positive B-EST repeated the test 24-48 h later, 5 min after the administration of short-acting nitrates (N-EST). Results: There were no significant differences among the groups in terms of the B-EST results. B-EST was positive in eight (20%) patients in the CAS-group, seven (50%) in the CMVS-group, and six (22%) in the NEG-group (p = 0.076). N-EST, performed in eight, six, and five of these patients, also showed similar results in the three groups. Furthermore, the N-EST results also did not significantly differ compared to B-EST in any group, remaining positive in seven (87.5%), four (66.7%), and four (80%) patients in the CAS-group, CMVS-group, and NEG-group, respectively (p = 0.78). Conclusions: Our data show that patients with angina and non-obstructive coronary artery disease show largely comparable results of the ECG exercise stress test and similar poor effects of short-acting nitrates on abnormal ECG exercise stress test results. On the whole, our findings suggest caution in attributing to the results of Ach testing a definite causal role for the clinical syndrome in individual patients.

The combination of high-frequency QRS and ST-segment alterations during exercise stress tests enhanced the diagnostic efficacy for coronary artery disease

BACKGROUND

High-frequency QRS (HF-QRS) manifests as a novel adjunct electrocardiographic marker with potential utility in coronary artery disease (CAD) detection.

HYPOTHESIS

We hypothesize that HF-QRS analysis may be superior to conventional ST-segment analysis in detecting CAD, and the combination of these two analyses in the exercise stress test may enhance the diagnostic efficacy for CAD.

METHODS

The study incorporated a sample of 157 patients (mean age 62 ± $\pm $  9 years) referred for nonemergent angiography. Before angiography, patients underwent exercise stress testing utilizing an upright bicycle. High-resolution electrocardiogram (ECG) data were collected during the exercise test, facilitating both HF-QRS and conventional ST-segment analyses. The diagnostic efficacy of HF-QRS and ST-segment analysis were compared, utilizing angiographic outcomes as the gold standard. The study design integrated HF-QRS analysis and ST-segment analysis via sequential and concurrent testing protocols.

RESULTS

In terms of CAD detection, HF-QRS analysis displayed superior sensitivity compared to conventional ST-segment analysis (63% vs. 37%, p = .002). The serial test significantly increased specificity from 79% to 97% (p = .002) compared to ST-deviation analysis alone. It showed a markedly low sensitivity of 26%. The parallel test significantly increased sensitivity from 37% to 77% (p < .001), while retaining a moderate level of specificity of 51%. The quantity of ECG leads exhibiting a positive HF-QRS response demonstrated a correlation with the severity of CAD (p < .001).

CONCLUSIONS

HF-QRS analysis exhibited superior sensitivity in detecting angiographically confirmed CAD relative to conventional ST-segment analysis. Moreover, the combination of HF-QRS and ST-segment alterations during exercise stress test enhanced the diagnostic efficacy for CAD.

Proceed with caution: Standard protocol exercise stress tests fail to replicate the diagnostic utility of supine-stand tests for long QT syndrome

BACKGROUND

Long QT syndrome (LQTS) is a sudden death predisposing condition characterized by ECG-derived prolongation of the QT interval. Previous studies have demonstrated that the supine-stand test may aid in the diagnosis of LQTS as patients fail to shorten their QT interval in response to standing up. The aim of this study was to evaluate the diagnostic accuracy of ECG data derived from standard protocol, clinically performed treadmill exercise stress tests (TESTs) in their ability to mimic the formal supine-stand test.

METHODS

We performed a retrospective review of 478 TESTs from patients evaluated for LQTS. Patients referred for evaluation of LQTS but who were dismissed as normal served as controls. Heart rate & QT values were obtained from standard protocol TESTs.

RESULTS

Overall, 243 patients with LQTS (125 LQT1, 63 LQT2, 55 LQT3; 146 [60%] female, mean age at TEST 30 ± 17 years) and 235 controls (142 [60%] female, mean age 24 ± 15 years) were included. The paired ΔQTc (QTcStand -QTcSupine ) was similar between LQTS (-5 ± 26) and controls (-2 ± 25; p = .2). During position change, the QT interval shortened by ≥20 ms in 33% of LQTS patients, remained unchanged in 62%, and increased in 5% of LQTS patients which was similar to controls (shortened in 40%, unchanged in 54%, and increased in 6% of controls; p = .2). Receiver-operator curve analysis to test the diagnostic ability of supine-stand ΔQT performed poorly in differentiating LQTS from controls with an of AUC 0.52 (p = .4).

CONCLUSION

TESTs should be used with caution when trying to interpret supine-stand changes for diagnosis of LQTS.

Rethinking False Positive Exercise Electrocardiographic Stress Tests by Assessing Coronary Microvascular Function

BACKGROUND

Exercise electrocardiographic stress testing (EST) has historically been validated against the demonstration of obstructive coronary artery disease. However, myocardial ischemia can occur because of coronary microvascular dysfunction (CMD) in the absence of obstructive coronary artery disease.

OBJECTIVES

The aim of this study was to assess the specificity of EST to detect an ischemic substrate against the reference standard of coronary endothelium-independent and endothelium-dependent microvascular function in patients with angina with nonobstructive coronary arteries (ANOCA).

METHODS

Patients with ANOCA underwent invasive coronary physiological assessment using adenosine and acetylcholine. CMD was defined as impaired endothelium-independent and/or endothelium-dependent function. EST was performed using a standard Bruce treadmill protocol, with ischemia defined as the appearance of ≥0.1-mV ST-segment depression 80 ms from the J-point on electrocardiography. The study was powered to detect specificity of ≥91%.

RESULTS

A total of 102 patients were enrolled (65% women, mean age 60 ± 8 years). Thirty-two patients developed ischemia (ischemic group) during EST, whereas 70 patients did not (nonischemic group); both groups were phenotypically similar. Ischemia during EST was 100% specific for CMD. Acetylcholine flow reserve was the strongest predictor of ischemia during exercise. Using endothelium-independent and endothelium-dependent microvascular dysfunction as the reference standard, the false positive rate of EST dropped to 0%.

CONCLUSIONS

In patients with ANOCA, ischemia on EST was highly specific of an underlying ischemic substrate. These findings challenge the traditional belief that EST has a high false positive rate.

Prognostic Impact of a Routine Six-Month Exercise Stress Test after Complex Left Main Bifurcation Percutaneous Intervention

The prognostic value of exercise stress test after complex left main (LM) coronary artery bifurcation (LM) stenting has been poorly investigated. To partially fill this gap in knowledge, we retrospectively analyzed the procedural and medical data of consecutive patients referred to our center for complex LM bifurcation disease between January 2008 and May 2018 who were treated using either single- or dual-stenting techniques. The prognostic impact of an exercise stress test, performed 6 months after the coronary intervention, was evaluated in 502 patients (316 males, mean age 70.3 ± 12.8 years, mean Syntax score 31.6 ± 6.3). At follow up after a mean of 37.1 ± 10.8 months (range 22.1-47.3 months), the target lesion failure (TLF) rate was 10.1% while stent thrombosis and cardiovascular mortality were 1.2 and 3.6%, respectively. A positive exercise stress test was detected at 6-month follow up in 42 out of 502 patients (8.4%); the incidence of a significant restenosis was 7.6% (n = 38). Patients with a negative exercise stress test at 6-month follow up had higher freedom from TLF and improved survival compared to those with a positive exercise stress test.

Spatiotemporal repolarization dispersion before and after exercise in patients with long QT syndrome type 1 versus controls: probing into the arrhythmia substrate

Congenital long QT syndrome (LQTS) carries an increased risk for syncope and sudden death. QT prolongation promotes ventricular extrasystoles, which, in the presence of an arrhythmia substrate, might trigger ventricular tachycardia degenerating into fibrillation. Increased electrical heterogeneity (dispersion) is the suggested arrhythmia substrate in LQTS. In the most common subtype LQT1, physical exercise predisposes for arrhythmia and spatiotemporal dispersion was therefore studied in this context. Thirty-seven patients (57% on β-blockers) and 37 healthy controls (mean age, 31 vs. 35; range, 6-68 vs. 6-72 yr) performed an exercise test. Frank vectorcardiography was used to assess spatiotemporal dispersion as Tampl, Tarea, the ventricular gradient (VG), and the Tpeak-end interval from 10-s signal averages before and 7 ± 2 min after exercise; during exercise too much signal disturbance excluded analysis. Baseline and maximum heart rates as well as estimated exercise intensity were similar, but heart rate recovery was slower in patients. At baseline, QT and heart rate-corrected QT (QTcB) were significantly longer in patients (as expected), whereas dispersion parameters were numerically larger in controls. After exercise, QTpeakcB and Tpeak-endcB increased significantly more in patients (18 ± 23 vs. 7 ± 10 ms and 12 ± 17 vs. 2 ± 6 ms; P < 0.001 and P < 0.01). There was, however, no difference in the change in Tampl, Tarea, and VG between groups. In conclusion, although temporal dispersion of repolarization increased significantly more after exercise in patients with LQT1, there were no signs of exercise-induced increase in global dispersion of action potential duration and morphology. The arrhythmia substrate/mechanism in LQT1 warrants further study.NEW & NOTEWORTHY Physical activity increases the risk for life-threatening arrhythmias in LQTS type 1 (LQT1). The arrhythmia substrate is presumably altered electrical heterogeneity (a.k.a. dispersion). Spatiotemporal dispersion parameters were therefore compared before and after exercise in patients versus healthy controls using Frank vectorcardiography, a novelty. Physical exercise prolonged the time between the earliest and latest complete repolarization in patients versus controls, but did not increase parameters reflecting global dispersion of action potential duration and morphology, another novelty.

Assessment of paediatric exertional or peri-exertional syncope: does the story matter?

Exertional syncope has been suggested to correlate with a cardiac aetiology, particularly when occurring in mid-stride. The aim of the study is to evaluate the incidence of cardiac disease among children presenting with exertional syncope, determine the influence of timing within activity, and determine the utility of genetic testing and implantable event monitors in the evaluation of cardiac syncope. The patients ≤18 years old with exertional syncope who underwent exercise stress testing between 2008 and 2019 were retrospectively included. Patients were assessed to be in one of three groups: mid-exertion (mid-stride syncope), peri-exertion (syncope during activity but not moving), and post-exertion (within minutes of the activity). A total of 334 patients were included; 46 % were mid-exertion, 18 % were peri-exertion, and 36 % were post-exertion. Thirteen patients (3.8 %) were diagnosed with cardiac syncope; n = 9 (69 %) mid-exertion. Only mid-exertional syncope was significantly associated with a cardiac diagnosis (OR: 2.6). Cardiac diagnoses included inherited arrhythmia syndromes (n = 9), abnormal coronary origins (n = 2), and supraventricular tachycardia (n = 2). Only catecholaminergic polymorphic ventricular tachycardia (n = 5) was associated with mid-exertional syncope (OR: 1.4). The definitive diagnostic test was exercise testing (n = 8), echocardiogram (n = 2), genetic testing (n = 1), ambulatory monitor (n = 1), and EKG (n = 1). Mid-stride syncope was more likely to result in a cardiac diagnosis, and exercise testing is the most common definitive test as catecholaminergic polymorphic ventricular tachycardia was the primary aetiology of exertional syncope in our cohort. Implantable event monitors and genetic testing could be helpful in ruling out cardiac disease.

Moderators of peak respiratory exchange ratio during exercise testing in children and adolescents with Fontan physiology

OBJECTIVES

Many patients with Fontan physiology are unable to achieve the minimum criteria for peak effort during cardiopulmonary exercise testing. The purpose of this study is to determine the influence of physical activity and other clinical predictors related to achieving peak exercise criteria, signified by respiratory exchange ratio ≥ 1.1 in youth with Fontan physiology.

METHODS

Secondary analysis of a cross-sectional study of 8-18-year-olds with single ventricle post-Fontan palliation who underwent cardiopulmonary exercise testing (James cycle protocol) and completed a past-year physical activity survey. Bivariate associations were assessed by Wilcoxon rank-sum test and simple regression. Conditional inference forest algorithm was used to classify participants achieving respiratory exchange ratio > 1.1 and to predict peak respiratory exchange ratio.

RESULTS

Of the n = 43 participants, 65% were male, mean age was 14.0 ± 2.4 years, and 67.4% (n = 29) achieved respiratory exchange ratio ≥ 1.1. Despite some cardiopulmonary exercise stress test variables achieving statistical significance in bivariate associations with participants achieving respiratory exchange ratio > 1.1, the classification accuracy had area under the precision recall curve of 0.55. All variables together explained 21.4% of the variance in respiratory exchange ratio, with peak oxygen pulse being the most informative.

CONCLUSION

Demographic, physical activity, and cardiopulmonary exercise test measures could not classify meeting peak exercise criteria (respiratory exchange ratio ≥ 1.1) at a satisfactory accuracy. Correlations between respiratory exchange ratio and oxygen pulse suggest the augmentation of stroke volume with exercise may affect the Fontan patient's ability to sustain high-intensity exercise.

Unknown QRS Morphology Change at Peak Exercise: To Stop or to Continue?

Electrocardiogram changes during stress tests are well standardized and understood. We present and explain a reversible QRS morphology change at peak exercise previously unreported. (Level of Difficulty: Intermediate.).

Surrogates of Muscle Mass on Cardiac MRI Correlate with Exercise Capacity in Patients with Fontan Circulation

BACKGROUND

Sarcopenia is an increasingly recognized marker of frailty in cardiac patients. Patients with a history of congenital heart disease and Fontan procedure have a higher risk of developing progressive muscle wasting. Our objective was to determine if we could use routine cardiac MRI (CMR) for the surveillance of muscle wasting.

METHODS

A retrospective study of all Fontan patients (n = 75) was conducted at our institution, with CMR performed from 2010 to 2022 and exercise stress testing performed within 12 months (4.3 ± 4.2 months). The skeletal muscle area (SMA) for the posterior paraspinal and anterior thoracic muscles were traced and indexed for body surface area (BSA). Patients were stratified by percentile into the upper and lower quartiles, and the two groups were compared. Multivariable regression was performed to control for sex and age.

RESULTS

There was a significant positive association of both anterior (r = 0.34, p = 0.039) and paraspinal (r = 0.43, p = 0.007) SMA to peak VO2. Similarly, paraspinal but not anterior SMA was negatively associated with the VE/VCO2 (r = -0.45, p = 0.006). The upper quartile group had significantly more males (18/19 vs. 8/20; p = 0.0003) and demonstrated a significantly higher peak VO2 (32.2 ± 8.5 vs. 23.8 ± 4.7, p = 0.009), a higher peak RER (1.2 ± 0.1 vs. 1.1 ± 0.04, p = 0.007), and a significantly lower VE/VCO2 (32.9 ± 3.6 vs. 40.2 ± 6.2, p = 0.006) compared to the lowest quartile. The association of SMA to VO2 peak and VE/VCO2 was redemonstrated after controlling for sex and age.

CONCLUSION

Thoracic skeletal muscle area may be an effective surrogate of muscle mass and is correlated to several measures of cardiorespiratory fitness post-Fontan. CMR would be an effective tool for the surveillance of sarcopenia in post-Fontan patients given its accessibility and routine use in these patients.

Effect of treadmill exercise stress testing on troponin levels in children and adolescents

BACKGROUND

Chest pain is a common complaint among paediatric patients and cardiac troponin (cTn) level is often part of the initial emergency department evaluation. It is well known that after intense endurance exercise cTn levels can be elevated in patients with otherwise healthy hearts, however the effect shorter duration exercise has on cTn levels in this population is not known.

OBJECTIVE

Determine the behaviour of cTn levels in healthy children and adolescent patients after short burst, high-intensity aerobic exercise.

METHODS

Patients without haemodynamically significant heart disease referred for a treadmill exercise stress test (EST) were recruited over a 6-month period. cTn levels were measured prior to exercise and 4 hours after exercise.

RESULTS

Thirteen patients enrolled. Indications for EST were exertional syncope (six), chest pain (four), and long QT syndrome (three). The median exercise time was 12.9 (9.9-13.7) minutes with an average endurance at the fiftieth percentile for age and maximum heart rate rose to an average of 92 (74-98)% of the predicted peak for age. cTn levels prior to exercise were undetectable in all patients. There was no cTn rise in any patient after exercise. There were no ischaemic changes or arrhythmias on exercise electrocardiograms.

CONCLUSION

Serum cTn levels do not rise significantly in healthy children after short duration, high-intensity aerobic exercise. Physicians evaluating paediatric patients with an elevated cTn level after less than prolonged strenuous activity likely cannot attribute this lab value solely to exercise and may need to undertake further cardiac investigation.

Exercise-induced change in circulating NT-proBNP could not distinguish between patients with and without coronary artery disease: the CADENCE study

Objective. In patients with chest pain, exercise stress test has a moderate accuracy for coronary artery disease (CAD). Adding a reliable cardiac biomarker to the exercise test could potentially improve the precision of the test. We investigated circulating NT-proBNP levels before and during exercise stress test in patients with and without angiographically verified CAD. We hypothesized that NT-proBNP would give an additive diagnostic value to the exercise stress test. Methods. In patients presenting with symptoms of stable CAD, venous blood samples were taken at rest and within 5 min of termination of a maximal stress test on a bicycle ergometer. All study participants underwent coronary angiography. Significant CAD was defined as ≥75% stenosis in one or more segments of the coronary arteries. Results. Of the 297 participants, significant CAD was found in 111 (37%) patients. Resting levels of NT-proBNP were significantly higher in patients with CAD compared with patients without CAD (74.18 vs. 56.03 ng/L), p = .005. During exercise, NT-proBNP levels increased in the total population (p < .001). The rise was, however, not significantly different between the two groups (8.24 vs. 8.51 ng/L), p = .700. Combining resting NT-proBNP with positive exercise stress test was superior to exercise test alone in predicting CAD, AUC = 0.68 vs. 0.64. Conclusion. Exercise-induced change in circulating NT-proBNP could not distinguish between patients with or without CAD. However, resting levels of NT-proBNP were significantly higher in patients with CAD than those without CAD.

Exercise Stress Test Late after Arrhythmic versus Nonarrhythmic Presentation of Myocarditis

Background. Exercise stress test (EST) has been scarcely investigated in patients with arrhythmic myocarditis. Objectives. To report the results of EST late after myocarditis with arrhythmic vs. nonarrhythmic presentation. Methods. We enrolled consecutive adult patients with EST performed at least six months after acute myocarditis was diagnosed using gold-standard techniques. Patients with ventricular arrhythmia (VA) at presentation were compared with the nonarrhythmic group. Adverse events occurring during follow-up after EST included cardiac death, disease-related rehospitalization, malignant VA, and proven active myocarditis. Results. The study cohort was composed of 128 patients (age 41 ± 9 y, 70% males) undergoing EST after myocarditis. Of them, 64 (50%) had arrhythmic presentation. EST was performed after 15 ± 4 months from initial diagnosis, and was conducted on betablockers in 75 cases (59%). During EST, VA were more common in the arrhythmic group (43 vs. 4, p < 0.001), whereas signs and symptoms of ischemia were more prevalent in the nonarrhythmic one (6 vs. 1, p = 0.115). By 58-month mean follow-up, 52 patients (41%) experienced adverse events, with a greater prevalence among arrhythmic patients (39 vs. 13, p < 0.001). As documented both in the arrhythmic and nonarrhythmic subgroups, patients had greater prevalence of adverse events following a positive EST (40/54 vs. 12/74 with negative EST, p < 0.001). Electrocardiographic features of VA during EST correlated with the subsequent inflammatory restaging of myocarditis. Nonarrhythmic patients with uneventful EST both on- and off-treatment were free from subsequent adverse events. Conclusions. Late after the arrhythmic presentation of myocarditis, EST was frequently associated with recurrent VA. In both arrhythmic and nonarrhythmic myocarditis, EST abnormalities correlated with subsequent adverse outcomes.

Effect of Revascularization on Exercise-Induced Changes in Cardiac and Prothrombotic Biomarkers in Patients with Coronary Artery Disease

We examined whether resting levels and exercise-induced changes during exercise ECG stress test (EST) of cardiac Troponin T (cTnT), NT-proBNP and prothrombotic markers were affected by revascularization in patients with coronary artery disease (CAD).

EST1 was performed before coronary angiography and revascularization, and patients (n  =  20) with confirmed CAD, performed another EST (EST2) 9 weeks later. Blood samples were drawn at rest and within five min after termination of ESTs.

cTnT and NT-proBNP increased during exercise at both ESTs (p < 0.001, all). Resting cTnT levels at EST2 versus EST1 were significantly higher (p  =  0.02) whereas NT-proBNP did not differ. At both visits, increased D-dimer (p  =  0.008 and <0.001), pro-thrombin fragment 1  +  2 (p  =  0.009 and 0.001) and tissue factor pathway inhibitor (TFPI) (p < 0.001 and 0.001) during exercise were demonstrated. Resting levels of endogenous thrombin potential (ETP) and TFPI were reduced at EST2 versus EST1 (p < 0.01).

Revascularization did not affect exercise-induced release of cardiac and prothrombotic biomarkers and did not reduce resting levels of cTnT or NT-proBNP, suggesting revascularization per se not to prevent secretion of biomarkers. The lower resting levels of ETP and TFPI after revascularization may however, be indicative of reduced thrombin generation and endothelial activation.

Clinicaltrials.gov, CADENCE, NCT01495091 https://clinicaltrials.gov/ct2/show/NCT01495091?term = 01495091&draw = 2&rank = 1.

A Stepwise Guide to the Diagnosis and Treatment of Heart Failure with Preserved Ejection Fraction

Heart failure with a preserved ejection fraction (HFpEF) is a growing epidemic owing to an increasingly obese and aging patient population. Making the diagnosis of HFpEF is often challenging as patients frequently have multiple co-morbidities and alternative reasons for exercise intolerance that is hallmark to the disease. Additionally, a universal diagnostic algorithm and definition of HFpEF is lacking. The treatment of HFpEF is equally challenging as there has been significant difficulty in identifying therapies to improve survival in HFpEF, and management to date requires intensive optimization of HFpEF risk factors. In this review, we highlight a stepwise approach to the diagnosis and management of HFpEF inclusive of 1) how to establish a clinical diagnosis of HFpEF, 2) when to refer for invasive testing, 3) treatment of HFpEF including pharmacologic, non-pharmacologic, and risk factor modification interventions, and 4) when to refer to a dedicated HFpEF center or advanced heart failure specialist. With this systematic stepwise approach to HFpEF management, we aim to improve accurate diagnosis of the disease as well as raise awareness of all available therapeutic options for this challenging patient population. Heart failure with preserved ejection fraction (HFpEF) is becoming increasingly common due to our aging patient population with a higher prevalence of hypertension, diabetes, and obesity. Accurate diagnosis is important, particularly to ensure that an alternative heart failure diagnosis is not missed. We highlight a stepwise approach to the diagnosis of HFpEF, including when to pursue exercise or invasive hemodynamic testing. We also discuss pertinent treatment options by both medication class and co-morbidity status.

Correlation of heart rate recovery and heart rate variability with atrial fibrillation progression

Objective

To examine the combination of heart rate recovery (HRR) and heart rate variability (HRV) in predicting atrial fibrillation (AF) progression.

Methods

Data from patients with a first detected episode of AF who underwent treadmill exercise testing and 24-h Holter electrocardiography were retrospectively analysed. Autonomic dysfunction was verified using HRR values. Sympathetic and parasympathetic modulation was analysed by HRV. AF progression was defined as transition from the first detected paroxysmal episode to persistent/permanent AF.

Results

Of 306 patients, mean LF/HF ratio and HRR did not differ significantly by AF progression regardless of age (< or ≥65 years). However, when the LF/HF ratio was divided into tertiles, in patients aged <65 years, the mid LF/HF (1.60–2.40) ratio was significantly associated with lower AF progression rates and longer maintenance of normal sinus rhythm. For patients aged <65 years, less metabolic equivalents were related to higher AF progression rates. For patients aged ≥65 years, a low HRR was associated with high AF progression rates.

Conclusion

In relatively younger age, high physical capacity and balanced autonomic nervous system regulation are important predictors of AF progression. Evaluation of autonomic function assessed by age could predict AF progression.

Determinants of Exercise Capacity Following ST-Elevation Myocardial Infarction (STEMI)

BACKGROUND

Abnormal left ventricular systolic and diastolic function and reduced exercise capacity are associated with worse prognosis following ST-elevation myocardial infarction (STEMI). However, evidence is lacking on the determinants of exercise capacity following STEMI. We sought to determine the impact of systolic and diastolic dysfunction on exercise capacity and outcomes following first-ever STEMI.

METHODS

In a retrospective analysis of 139 consecutive STEMI patients who had a transthoracic echocardiogram following STEMI and completed exercise treadmill testing, the primary outcome was to identify clinical and echocardiographic determinants of exercise capacity, and the secondary outcome was to identify determinants of major adverse cardiac events (MACEs).

RESULTS

Mean number of metabolic equivalents (METs > 8) was used as a cut-off. Age, female sex, anterior infarction, abnormal diastolic function, minimum left atrial indexed volume (LAVI_min) ≥ 18 mL/m², average e', and E/e' were associated with METs ≤ 8, but not left ventricular ejection fraction (LVEF). On multivariate analysis, LAVI_min (OR 4.3, 95%CI 1.3-14.2; p = 0.017), anterior infarction (OR 2.6, 95%CI 1.2-5.9; p = 0.022), and abnormal diastolic function (OR 3.73, 95%CI 1.7-8.4; p = 0.001) were independent predictors of METs ≤ 8. On Kaplan-Meier analysis, METs ≤ 8 (p = 0.01) and abnormal diastolic function (p = 0.04) were associated with MACEs (median follow-up 2.3 years). METs ≤ 8 was an independent predictor of MACEs (HR 3.4, 95%CI 1.2-9.8; p = 0.02).

CONCLUSIONS

Following first-ever STEMI, increased LAVI_min, anterior infarction, and abnormal diastolic function were independent predictors of reduced exercise capacity. Furthermore, reduced exercise capacity was an independent predictor of MACEs. These results highlight important prognostic and therapeutic implications related to abnormal diastolic function in STEMI patients that are distinct from those with LV systolic impairment.

Burst Exercise Testing Can Unmask Arrhythmias in Patients With Incompletely Penetrant Catecholaminergic Polymorphic Ventricular Tachycardia

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is characterized by cardiac arrest during sudden exertion. However, standard exercise stress testing (EST) lacks sensitivity, leading to misdiagnosis and undertreatment. After a nondiagnostic standard gradual EST, we report 6 patients who underwent a novel burst exercise test characterized by sudden high workload at the outset of testing. In 5 of 6 patients, the burst EST induced new and more complex arrhythmias versus standard EST, which compelled medication initiation in 3 patients. We postulate that this simple EST modification better mimics a typical CPVT triggering event and could improve diagnostic sensitivity and therapeutic decision making.

Comparison of left ventricular mechanical dyssynchrony parameters between exercise and adenosine triphosphate stress tests using gated single-photon emission computed tomography myocardial perfusion imaging

BACKGROUND

Left ventricular mechanical dyssynchrony (LVMD) can be induced after stress test. However, no studies have compared the influence of different stress‑inducing methods on LVMD parameters.

AIMS

The aim of the study was to determine whether there is a difference between exercise and adenosine triphosphate (ATP) stress tests in terms of changes in LVMD parameters assessed using gated single‑photon emission computed tomography myocardial perfusion imaging (GSPECT MPI).

METHODS

A total of190 patients who underwent 99mTc ‑sestamibi GSPECT MPI were consecutively enrolled. Treadmill exercise and ATP stress tests were performed in 95 patients each. Normal myocardial perfusion was defined as the summed stress score (SSS) ≤3 and summed rest score (SRS) ≤3, myocardial ischemia as SSS >3 and SRS ≤3, and myocardial infarction as SSS >3 and SRS >3. Parameters of LVMD, including phase standard deviation (PSD), phase bandwidth (PBW), skewness, and kurtosis were compared. Subtraction was made between values during stress and rest phases to acquire ∆PSD, ∆PBW, ∆skewness, and ∆kurtosis Results: There were no differences in LVMD parameters between the exercise and ATP groups. The same results were obtained in the normal perfusion, ischemia, and infarction subgroups. Furthermore, no differences were observed in ∆PSD (median [interquartile range, IQR], 0.25 [-2.3 to 3.1] vs 0.42 (-1.7 to 3.1]; P = 0.73), ∆PBW (median [IQR], 1 [-7 to 11] vs 1 [-6 to 11]; P = 0.95), ∆skewness (mean [SD], -0.06 [0.63] vs 0 [0.81]; P = 0.53), and ∆kurtosis (median [IQR], -0.47 [-4.2 to 4.3] vs -0.42 [-4.8 to 5.2]; P = 0.73) between the exercise and ATP stress‑inducing methods.

CONCLUSIONS

There are no differences between the exercise and ATP stress tests in terms of changes in LVMD parameters. Thus, the 2 methods can be used alternatively.

Potential overdiagnosis of long QT syndrome using exercise stress and QT stand testing in children and adolescents with a low probability of disease

BACKGROUND

Long QT syndrome (LQTS) is a dangerous arrhythmia disorder that often presents in childhood and adolescence. The exercise stress test (EST) and QT-stand test may unmask QT interval prolongation at key heart rate transition points in LQTS, but their utility in children is debated.

OBJECTIVE

To determine if the QT-stand test or EST can differentiate children with a low probability of LQTS from those with confirmed LQTS.

METHODS

This retrospective study compares the corrected QT intervals (QTc) of children (<19 years) during the QT-stand test and EST. Patients were divided into three groups for comparison: confirmed LQTS (n = 14), low probability of LQTS (n = 14), and a control population (n = 9).

RESULTS

Using the Bazett formula, confirmed LQTS patients had longer QTc intervals than controls when supine, standing, and at 3-4 min of recovery (p ≤ .01). Patients with a low probability of LQTS had longer QTc duration upon standing (p = .018) and at 1 min of recovery (p = .016) versus controls. There were no significant QTc differences at any transition point between low probability and confirmed LQTS. Using the Fridericia formula, differences in QTc between low probability and confirmed LQTS were also absent at the transition points examined, except at 1 min into exercise, where low probability patients had shorter QTc intervals (437 vs. 460 ms, p = .029).

CONCLUSION

The diagnostic utility of the QT stand test and EST remains unclear in pediatric LQTS. The formula used for heart rate correction may influence accuracy, and dynamic T-U wave morphology changes may confound interpretation in low probability situations.

False-positive electrocardiographic changes during exercise test in a patient with pectus excavatum

Exercise-induced ST-segment changes simulating myocardial ischemia have been described in otherwise normal subjects during hyperventilation. We present the case of a 60-year-old man with pectus excavatum showing significant exercise-induced "pseudo-ischaemic" ST-segment changes with neither coronary artery disease nor anxiety-induced hyperventilation. We found no report of the possible causative role of a narrow antero-posterior chest diameter in inducing "pseudo-ischaemic" ST-segment changes during exercise stress test in the literature.

The incidence of arrhythmias during exercise stress tests among children with Kawasaki disease: A single-center case series

OBJECTIVE

Based on 2017 guidelines, participation in competitive sports with prior history of Kawasaki Disease (KD) requires those with coronary artery aneurysms (CAA) z score ≥ 5 to undergo evaluation for evidence of inducible ischemia or arrhythmias. The use of exercise stress testing (EST) to evaluate arrhythmias among KD patients has never been reported. This retrospective single-center case series study sought to describe the presence of inducible arrhythmias during EST in KD patients with or without CAA.

METHODS

Single-center retrospective review of medical records of patients diagnosed with KD between 1989-2015 at Texas Children's Hospital, Houston, Texas who underwent EST were included.

RESULTS

Among 1007 patients diagnosed with KD, 95 (9%) underwent 165 ESTs at a median time of 9.6 years (IQR 5.8-11.3 years) from diagnosis. Of these 95 patients, 37 had normal coronaries, 21 dilated (z score 2 to <2.5), 10 small (5 >z ≥2.5), 12 medium (10>z ≥ 5 absolute dimension <8 mm), 10 large (z ≥10 or absolute dimension ≥8 mm), 5 severe (myocardial infarct or bypass graft). Supraventricular tachycardia was not seen. Ventricular arrhythmias during EST were uncommon and seen only among patients with CAA z ≥5. Ventricular tachycardia occurred in a single patient with a large CAA, known VT and ICD. High-grade ventricular ectopy was seen in one patient who had severe CAA and underwent bypass grafting.

CONCLUSIONS

Arrhythmias on EST were noted only among patients with CAA z ≥5. The current guidelines are a reasonable approach to increasing healthy activity among KD patients. Clarification regarding which inducible arrhythmias meet criteria for activity restriction may be helpful to guide sport participation.

Identifying Patients With Coronary Artery Disease Using Rest and Exercise Seismocardiography

Coronary artery disease (CAD) is the most common cause of death globally. Patients with suspected CAD are usually assessed by exercise electrocardiography (ECG). Subsequent tests, such as coronary angiography and coronary computed tomography angiography (CCTA) are performed to localize the stenosis and to estimate the degree of blockage. The present study describes a non-invasive methodology to identify patients with CAD based on the analysis of both rest and exercise seismocardiography (SCG). SCG is a non-invasive technology for capturing the acceleration of the chest induced by myocardial motion and vibrations. SCG signals were recorded from 185 individuals at rest and immediately after exercise. Two models were developed using the characterization of the rest and exercise SCG signals to identify individuals with CAD. The models were validated against related results from angiography. For the rest model, accuracy was 74%, and sensitivity and specificity were estimated as 75 and 72%, respectively. For the exercise model accuracy, sensitivity, and specificity were 81, 82, and 84%, respectively. The rest and exercise models presented a bootstrap-corrected area under the curve of 0.77 and 0.91, respectively. The discrimination slope was estimated 0.32 for rest model and 0.47 for the exercise model. The difference between the discrimination slopes of these two models was 0.15 (95% CI: 0.10 to 0.23, p < 0.0001). Both rest and exercise models are able to detect CAD with comparable accuracy, sensitivity, and specificity. Performance of SCG is better compared to stress-ECG and it is identical to stress-echocardiography and CCTA. SCG examination is fast, inexpensive, and may even be carried out by laypersons.

Chronotropic incompetence as a risk predictor in children and young adults with catecholaminergic polymorphic ventricular tachycardia

INTRODUCTION

Risk stratification tools for catecholaminergic polymorphic ventricular tachycardia (CPVT) are limited. The exercise stress test (EST) is the most important diagnostic and prognostic test. We aimed to determine whether heart rate (HR) and blood pressure (BP) response during EST were associated with the risk of arrhythmias.

MATERIALS AND METHODS

We studied the association between HR and BP response and ventricular arrhythmia burden on EST in 20 CPVT patients. HR reserve values <80% and ≤62% were used to define chronotropic incompetence (CI) off and on therapy, respectively. Symptoms and ventricular arrhythmia score (VAS) in all patients with respect to CI and BP during index EST off therapy and on maximal therapy were compared.

RESULTS

CI in CPVT patients off therapy was associated with a worse VAS during EST (P = .046). Patients with CI also more frequently presented with syncope and/or cardiac arrest compared to patients with a normal chronotropic response (P = .008). Once on therapy, patients with CI had similar VAS compared to patients without CI (P = .50), suggesting that treatment attenuates risk related to CI. Patients with CI also had a lower peak systolic BP (P = .041) which persisted on maximal therapy (P = .033).

CONCLUSION

Untreated CPVT patients with CI have more ventricular arrhythmias than those without CI. This may serve as a simple disease prognosticator that can be modified by antiarrhythmic therapy. A mechanistic link between CI and arrhythmia susceptibility remains unknown. Larger studies are needed to confirm and establish the mechanism of these findings.

Impact of Mitral Regurgitation Severity and Cause on Effort Tolerance-Integrated Stress Myocardial Perfusion Imaging and Echocardiographic Assessment of Patients With Known or Suspected Coronary Artery Disease Undergoing Exercise Treadmill Testing

Background Mitral regurgitation ( MR ) has the potential to impede exercise capacity; it is uncertain whether this is because of regurgitation itself or the underlying cause of valvular insufficiency. Methods and Results The population comprised 3267 patients who underwent exercise treadmill myocardial perfusion imaging and transthoracic echocardiography within 6±8 days. MR was present in 28%, including 176 patients (5%) with moderate or greater MR . Left ventricular systolic function significantly decreased and chamber size increased in relation to MR , paralleling increments in stress and rest myocardial perfusion deficits (all P<0.001). Exercise tolerance (metabolic equivalents of task) decreased stepwise in relation to graded MR severity ( P<0.05). Workload was significantly lower with mild versus no MR (mean±SD, 9.8±3.0 versus 10.1±3.0; P=0.02); magnitude of workload reduction significantly increased among patients with advanced versus those with mild MR (mean±SD, 8.6±3.0 versus 9.8±3.0; P<0.001). MR -associated exercise impairment was accompanied by lower heart rate and blood pressure augmentation and greater dyspnea (all P<0.05). Both functional and nonfunctional MR subgroups demonstrated significantly decreased effort tolerance in relation to MR severity ( P≤0.01); impairment was greater with functional MR ( P=0.04) corresponding to more advanced left ventricular dysfunction and dilation (both P<0.001). Functional MR predicted reduced metabolic equivalent of task-based effort (B=-0.39 [95% CI, -0.62 to -0.17]; P=0.001) independent of MR severity. Among the overall cohort, advanced (moderate or greater) MR was associated with reduced effort tolerance (B=-1.36 [95% CI, -1.80 to -0.93]; P<0.001) and remained significant ( P=0.01) after controlling for age, clinical indexes, stress perfusion defects, and left ventricular dysfunction. Conclusions MR impairs exercise tolerance independent of left ventricular ischemia, dysfunction, and clinical indexes. Magnitude of exercise impairment parallels severity of MR .

HEART Score and Stress Test Emergency Department Bayesian Decision Scheme: Results from the Acute Care Diagnostic Collaboration

BACKGROUND

Accurate identification of patients at risk of major adverse cardiac events (MACE) places a substantial burden on emergency physicians (EPs). Bayesian nomogram for risk stratification in low- to intermediate-risk cardiovascular patients has not been investigated previously.

OBJECTIVE

The objective of this study was to develop a comparative diagnostic model using Bayesian statistics for exercise treadmill test (ETT) and stress echocardiogram (ECHO) to calculate post-test diagnostic risk of MACE using HEART (history, electrocardiogram, age, risk factors, and troponin) risk score as predictor of pretest probability.

METHODS

Stratification was made by applying HEART scores for the prediction of MACE. Likelihood ratios (LR) were calculated using pooled sensitivity and specificity of ETT and ECHO from the American College of Cardiology Foundation/American Heart Association systematic review. Post-test probabilities were obtained after inserting HEART score and LR into Bayesian nomogram. Analysis of variance was used to assess statistical association.

RESULTS

Positive LR (LR+) for ETT was 4.56 and negative LR (LR-) was 0.27; for ECHO, LR+ 5.65 and LR- 0.15. Bayesian statistical modeling post-test probabilities for LR+ and low HEART risk yielded a post-test probability for ETT of 7.75% and 9.09% for ECHO; intermediate risk gave 47.62% and 52.63%, respectively. For LR-, low HEART risk post-test probability for ETT was 0.46% and for ECHO 0.26%; intermediate risk probabilities were 4.48% and 2.49%, respectively. LR- was statistically significant in ruling out MACE with ECHO (p < 0.001), but no significant differences were seen for LR+ (p = 0.64).

CONCLUSIONS

This Bayesian analysis demonstrated slight superiority of stress ECHO over ETT in low- and intermediate-risk patients in ruling out MACE.

The role and outcome of cardiac rehabilitation program in patients with atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is associated with diminished cardiac function, and exercise tolerance.

HYPOTHESIS

We sought to investigate the role of cardiac rehabilitation program (CR) in patients with AF.

METHODS

The study included 2165 consecutive patients that participated in our CR program between the years 2009 to 2015. All were evaluated by a standard exercise stress test (EST) at baseline, and upon completion of at least 3 months of training. Participants were dichotomized according to baseline fitness and the degree of functional improvement. The combined primary end point was cardiac related hospitalization or all-cause mortality.

RESULTS

A total of 292 patients had history of AF, with a mean age of 68 ± 9 years old, 76% of which were males. The median predicted baseline fitness of AF patients was significantly lower compared to non-AF patients (103% vs 122%, P < 0.001, respectively). Prominent improvement was achieved in the majority of the patients in both groups (64% among AF patients and 63% among those without AF). Median improvement in fitness between stress tests was significantly higher in patients with AF (124% vs 110%, P < 0.001, respectively). Among AF patients, high baseline fitness was associated with a lower event rates (HR 0.40; 95%CI 0.23-0.70; P = 0.001). Moreover, prominent improvement during CR showed a protective effect (HR 0.83; 95% CI 0.69-0.99; P = 0.04).

CONCLUSION

In patients with AF participating in CR program, low fitness levels at baseline EST are associated with increased risk of total mortality or cardiovascular hospitalization during long-term follow-up. Improvement on follow-up EST diminishes the risk.

Relative Handgrip Strength as a Simple Tool to Evaluate Impaired Heart Rate Recovery and a Low Chronotropic Index in Obese Older Women

The aim of the present study was to compare differences in heart rate response following a treadmill exercise test in elderly obese women categorized into groups based on relative handgrip strength. Eighty-eight obese elderly women who were between the ages of 60 and 87 participated in the study and were categorized and enrolled to one of two groups based on lower (< 1.51 m2) or higher (≥ 1.51 m2) relative handgrip strength, respectively. The heart rate recovery in the first and second minutes following the treadmill exercise test and the chronotropic index were compared between groups. The higher relative handgrip strength group presented a significantly higher peak heart rate during exercise and a quicker heart rate recovery following exercise versus the lower relative handgrip strength group (p<0.05). Furthermore, there was a tendency (p=0.059) toward a significantly greater chronotropic index in the higher versus the lower relative handgrip strength group. In conclusion, elderly women with greater relative handgrip strength also demonstrated a better heart rate response during and following exercise, possibly indicating better autonomic balance. The relative handgrip strength might be an important and inexpensive tool for the elderly obese women to indirect assess cardiovascular health.

Effects of Lifestyle Modification on an Exaggerated Blood Pressure Response to Exercise in Normotensive Females

BACKGROUND

This study was designed to examine the effects of a lifestyle modification on the improvement in an exaggerated systolic blood pressure (SBP) response to exercise in normotensive females.

METHODS

The subjects were 78 normotensive females with (n = 25) and without (n = 53) an exaggerated SBP response to exercise who were not taking any medications. An exaggerated SBP response to exercise was defined according to the criteria of the Framingham Study (peak SBP: ≥190 mm Hg). A lifestyle modification program consisting of aerobic exercise and diet counseling was conducted for 12 weeks. The brachial-ankle pulse wave velocity (baPWV), plasma nitrate/nitrite (NOx), plasma thiobarbituric acid-reactive substances (TBARS), high-sensitivity C-reactive protein, fibrinogen levels, and the white blood cell (WBC) counts were measured before and after 12-week intervention.

RESULTS

After 12-week intervention, the exercise-induced SBP elevation decreased in an exaggerated SBP response group (P < 0.05). In addition, the plasma NOx significantly increased, and the WBC counts and plasma TBARS decreased in an exaggerated SBP response group (P < 0.05). In an exaggerated SBP response group, a stepwise multiple regression analysis showed that the percent change in exercise-induced SBP elevation was independently associated with the percent changes in the plasma NOx level and baPWV (r2 = 0.647, P < 0.0001).

CONCLUSIONS

These results suggest that a lifestyle modification is considered to be important for reducing an exaggerated SBP response to exercise by improving the arterial stiffness and nitric oxide bioavailability.

Wolff-Parkinson-White syndrome: a single exercise stress test might be misleading

Risk stratification of patients with Wolff-Parkinson-White syndrome for sudden death is a complex process, particularly in understanding the utility of the repeat exercise stress test. We report a case of an 18-year-old patient who was found to have a high-risk pathway by both invasive and exercise stress testing after an initial exercise stress test showing beat-to-beat loss of pre-excitation.

Risk stratification for large artery or chronic coronary artery disease-related ischemic stroke in octogenarians undergoing exercise stress myocardial perfusion imaging: A cohort study

OBJECTIVES

To test, if in octogenarians, treadmill exercise with myocardial perfusion imaging (exercise-MPI) can risk stratify for large artery or chronic CAD-related ischemic stroke (LACCIS).

METHODS

Exercise-MPI-related data of 237 octogenarians (55% prior MI or revascularization) without previous stroke were registered and prospective follow-up was performed to document LACCIS. LACCIS was defined as acute onset of neurological symptoms with CT/MRI findings of non-lacunar-type infarcts in the absence of atrial fibrillation or intracardiac embolic sources.

RESULTS

After 7.3 years, 10 LACCIS were documented. SSS [HR 1.08 (1.02-1.13 95% CIs), SDS [HR 1.1 (1.04-1.16 95% CIs)], and non-sustained VT or transient AV block during exercise [HR 3.9 (1.7-9.0 95% CIs)] were predictors of LACCIS (P < .01 for all). A SSS threshold of 16 had 81% specificity for identification of future LACCIS and risk groups formed according to this cut-off had significantly different LACCIS-free survival (P = .015).

CONCLUSION

Exercise-MPI in octogenarians can provide risk stratification markers for LACCIS.

Combination of change in hematological parameters with exercise stress test to predict coronary artery disease

OBJECTIVE

Treadmill exercise stress testing for identifying patients with a higher likelihood of coronary artery disease (CAD) before elective coronary angiography is recommended in the current guidelines. In this study, we aimed to evaluate the changes in the hematological parameters before and after exercise stress test in relation with the presence of CAD.

METHODS

A total of 113 patients with chest pain who underwent treadmill exercise testing and coronary angiography were included in this study.

RESULTS

Neutrophil count (4.38±0.99 vs 5.19±0.93, P<.001), and neutrophil to lymphocyte ratio (NLR) (2.04±0.63 vs 2.41±0.78, P<.001) were significantly elevated after treadmill exercise test in all the patients. Increase in the NLR after exercise test was significantly higher in patients with positive exercise test (n=68) than negative exercise test (n=45) (0.49±0.58 vs 0.19±0.44, P=.016). The sensitivity and specificity of treadmill exercise testing according to coronary angiography was 79% and 64%, respectively. A cut-off point of 0.2 for the change in the NLR in addition to positive treadmill exercise testing had 91% sensitivity and 92% specificity in predicting significant coronary artery stenosis (AUC:0.913, 95% CI: 0.805-1.000, P<.001).

CONCLUSIONS

Neutrophil to lymphocyte ratio is an important inflammatory marker that can contribute to treadmill ECG testing in predicting CAD.

Reproducibility of corrected QT interval in pediatric genotyped long QT syndrome

Reproducibility of corrected QT interval (QTc), especially QTc after exercise, has not been thoroughly investigated. We reviewed charts of pediatric patients who underwent treadmill-exercise stress testing without medication multiple times within 1 year. In patients with long-QT syndrome (LQTS; n = 22), the discrepancy in QTc between two treadmill exercise stress tests using Fridericia's formula was 14 ± 12 ms at rest, 13 ± 12 ms 4 min after exercise, with a maximum of 14 ± 12 ms after exercise. There was no statistically significant difference in QTc between the two tests. Intraclass correlation coefficients (ICC) were 0.84, 0.85, and 0.85, respectively. In controls (n = 13), the discrepancy in QTc was 18 ± 12 ms at rest, 14 ± 7 ms 4 min after exercise, with a maximum of 14 ± 9 ms after exercise. There was no significant difference in QTc between the two tests. ICC were 0.78, 0.80, and 0.80, respectively. QTc calculated using Bazett's formula also showed high reproducibility. Reproducibility of QTc in children is high at rest and after exercise.

Influence of cardiac stress protocol on myocardial perfusion imaging accuracy: The role of exercise level on the evaluation of ischemic burden

BACKGROUND

Some specifics of cardiac stress protocols, i.e., stressor used or exercise level achieved, may impact myocardial perfusion imaging (MPI) accuracy.

METHODS

Four-hundred and seventy-five patients were submitted to MPI and coronary angiography. MPI was performed after exercise (303 patients) or dipyridamole stress (172 patients). A coronary stenosis ≥70% was considered significant. In case of exercise test, a peak heart rate (HR) <85% of the maximal age predicted was considered submaximal and categorized as follows: >75% and <85% ("Group 1"); <75% ("Group 2").

RESULTS

At coronary angiography, 312/475 (66%) patients showed significant stenosis. In the overall population, MPI showed a high accuracy in unmasking significant coronary stenosis, independently of the stress protocol adopted (AUC .76 for exercise vs .78 for vasodilator; P = NS). However, in case of an exercise stress test, a significant interaction between peak %HR and MPI diagnostic power was evident. While an elevated accuracy was still maintained in "Group 1" patients (AUC .79; P vs maximal exercise = NS), a significant drop was demonstrated in "Group 2" patients (AUC .66; P vs maximal exercise = .012, and P vs "Group 1" = .042).

CONCLUSIONS

The accuracy of MPI is not influenced by the stress protocol adopted. Exercise MPI maintains an elevated accuracy as long as the %HR remains >75%.

Exercise performance in young patients with complete atrioventricular block: the relevance of synchronous atrioventricular pacing

At present, there are many pacing strategies for young patients with complete atrioventricular block. The most frequent policy is to attempt placing a dual-chamber system when possible; however, there is a group of patients that is functioning with a non-synchronous ventricular pacing, raising the question of the ideal timing to upgrade their systems. We investigated the exercise performance of a group of children and young adults with complete atrioventricular block and dual-chamber pacemakers in both single- and dual-chamber pacing modalities. A total of 15 patients performed maximal exercise stress testing after programming the VVIR or DDD modes with 2 hours of interval in a double-blind study protocol. Compared with VVIR pacing, DDD pacing resulted in increase in the peak VO2, longer test duration, major increase in the heart rate achieved during peak exercise, decreased systemic non-invasive arterial blood pressure measured at maximal exercise, higher maximal workload, prolongation of the anaerobic threshold timing, and better self-rated performance perception in all the patients. Synchronous atrioventricular pacing contributes to an increase in both the exercise performance and the performance perception in 100% of the patients. This difference contributes to create a sense of "fitness" with repercussions in the overall health, self-esteem, and life quality, as well as encourages youngster to practice sports. Our experience tends to favour upgrading patients' systems to dual-chamber systems before reaching the adolescent years, even if the centre policy is to prolong as long as possible the epicardial site in order to avoid long years of right ventricular pacing.

Athens QRS Score as a Predictor of Coronary Artery Disease in Patients With Chest Pain and Normal Exercise Stress Test

Background

The diagnostic value of the Athens QRS score to detect obstructive coronary artery disease CAD in patients with otherwise normal exercise stress test remains unclear.

Methods and Results

We analyzed 458 patients who underwent exercise stress test with or without myocardial perfusion imaging within 2 months of coronary angiography from 2008 to 2011. Patients (n=173) with abnormal stress test based on ST segment criteria were excluded. The Athens QRS score ≤5 was defined as abnormal. In our study cohort, 285 patients met the inclusion criteria and were divided into 2 groups: low Athens QRS score (LQRS, n=56), with QRS score ≤5 and normal Athens QRS score normal Athens QRS score, n=229), with QRS score >5. The presence of single‐vessel and multivessel obstructive CAD was higher in LQRS than in normal Athens QRS score patients (47% versus 7.5% and 30% versus 3.8%, respectively, all P<0.001). Logistic regression analysis showed that the likelihood of CAD was strongly and independently associated with LQRS (odds ratio=36.81, 95% CI: 10.77–120.47), diabetes (odds ratio=6.49, 95% CI: 2.41–17.49), lower maximum heart rate (odds ratio=0.92, 95% CI: 0.88–0.95, all P<0.001), and older age (odds ratio=1.93, CI: 1.88–1.97, P=0.002).

Conclusions

In a clinical cohort of patients with chest pain and normal exercise stress test, LQRS score is a strong independent predictor of presence of CAD. LQRS patients have a 6‐fold higher prevalence of CAD and may warrant further evaluation even with reassuring exercise stress test.

Health-related variables and predictors of Health-promoting Lifestyle in cardiovascular disease patients

INTRODUCTION

The principal cause for death in the world is cardiovascular disease. Poor lifestyle is a contributing element in this regard. The objective of this study was to estimate the effects of health-related variables and lifestyle variables on the results of exercise stress tests in patients with cardiovascular disease in Iran.

METHODS

The study population in this case-control study was 220 patients who were candidates for exercise stress tests in Mazandaran Province (Iran) in 2015. The patients were divided randomly into two groups based on the results of their exercise stress tests, i.e., positive (110 patients) and negative (110 patients). The data collection tool was a standard questionnaire entitled "Health promotion lifestyle profile-II." The data were analyzed using mean, standard deviation, the chi-squared test, and logistic regression by SPSS version 22 software.

RESULTS

The risk of a positive exercise stress test increases with age. The age group above 65 was 1.049 times more at risk of a positive exercise stress test than the age group of less than 45. The people with dyslipidemia had 1.635 times greater risk of positive exercise stress tests than the group without dyslipidemia. In addition, patients with hypertension had 1.579 times greater risk of positive exercise stress tests than the group without hypertension. The lack of individual health responsibility (Odds ratio (OR): 1.622), stress management (OR: 1.592), and physical activity (OR: 1.245) contributed more to positive exercise tests than the other risk factors.

CONCLUSION

Educational interventions can improve the responsibility for health, physical activity, and stress management among people with the risk of cardiovascular disease.

The association of clinical indication for exercise stress testing with all-cause mortality: the FIT Project

INTRODUCTION

We hypothesized that the indication for stress testing provided by the referring physician would be an independent predictor of all-cause mortality.

MATERIAL AND METHODS

We studied 48,914 patients from The Henry Ford Exercise Testing Project (The FIT Project) without known congestive heart failure who were referred for a clinical treadmill stress test and followed for 11 ±4.7 years. The reason for stress test referral was abstracted from the clinical test order, and should be considered the primary concerning symptom or indication as stated by the ordering clinician. Hierarchical multivariable Cox proportional hazards regression was performed, after controlling for potential confounders including demographics, risk factors, and medication use as well as additional adjustment for exercise capacity in the final model.

RESULTS

A total of 67% of the patients were referred for chest pain, 12% for shortness of breath (SOB), 4% for palpitations, 3% for pre-operative evaluation, 6% for abnormal prior testing, and 7% for risk factors only. There were 6,211 total deaths during follow-up. Compared to chest pain, those referred for palpitations (HR = 0.72, 95% CI: 0.60-0.86) and risk factors only (HR = 0.72, 95% CI: 0.63-0.82) had a lower risk of all-cause mortality, whereas those referred for SOB (HR = 1.15, 95% CI: 1.07-1.23) and pre-operative evaluation (HR = 2.11, 95% CI: 1.94-2.30) had an increased risk. In subgroup analysis, referral for palpitations was protective only in those without coronary artery disease (CAD) (HR = 0.75, 95% CI: 0.62-0.90), while SOB increased mortality risk only in those with established CAD (HR = 1.25, 95% CI: 1.10-1.44).

CONCLUSIONS

The indication for stress testing is an independent predictor of mortality, showing an interaction with CAD status. Importantly, SOB may be associated with higher mortality risk than chest pain, particularly in patients with CAD.

Plasma B-type natriuretic peptide levels are poorly related to the occurrence of ischemia or ventricular arrhythmias during symptom-limited exercise in low-risk patients

INTRODUCTION

The usefulness of B-type natriuretic peptide (BNP) as a marker of ischemia is controversial. BNP levels have predicted arrhythmias in various settings, but it is unknown whether they are related to exercise-induced ischemic ventricular arrhythmias.

MATERIAL AND METHODS

We analyzed in 63 patients (64 ±14 years, 65% male, 62% with known coronary disease) undergoing exercise stress single-photon emission computed tomography (SPECT) the association between plasma BNP values (before and 15 min after exercise) and the occurrence of ischemia or ventricular arrhythmias during the test.

RESULTS

Exercise test (8.1 ±2.7 min, 7.4 ±8.1 metabolic equivalents, 82 ±12% of maximal predicted heart rate) induced reversible perfusion defects in 23 (36%) patients. Eight (13%) patients presented significant arrhythmias (≥ 7 ventricular premature complexes/min, couplets, or non-sustained ventricular tachycardia during exercise or in the first minute of recovery). Median baseline BNP levels were 17.5 (12.4-66.4) pg/ml in patients developing scintigraphic ischemia and 45.6 (13.2-107.4) pg/ml in those without ischemia (p = 0.137). The BNP levels increased after exercise (34.4 (15.3-65.4)% increment over baseline, p < 0.001), but the magnitude of this increase was not related to SPECT positivity (35.7 (18.8-65.4)% vs. 27.9 (5.6-64.0)% in patients with and without ischemia, respectively, p = 0.304). No significant association was found between BNP values (at baseline or their change during the test) and ventricular arrhythmias.

CONCLUSIONS

Plasma BNP values - at baseline or after exercise - were not associated with myocardial ischemia or with ventricular arrhythmia during exercise SPECT. These results highlight the limited usefulness of this biomarker to assess acute ischemia.

Coronary Flow Reserve Predicts Longitudinal Myocardial Deformation Capacity in Heart-Transplanted Patients

AIMS

This study aimed to evaluate the role of microvascular dysfunction on left ventricular (LV) longitudinal deformation, filling pressures, and exercise capacity in heart-transplanted (HTx) patients.

METHODS AND RESULTS

Fifty-seven HTx patients underwent comprehensive echocardiographic graft function assessment during symptom-limited, semisupine exercise test with simultaneous right heart catheterization. Coronary flow velocity reserve (CFVR) was measured in the left anterior descending artery using pulsed Doppler echocardiography. We divided patients into two groups based on upper and lower median of CFVR. Twenty-six healthy subjects served as controls. Compared with healthy controls, HTx patients had reduced CFVR (P < 0.0001), exercise capacity (P < 0.0001), and LV longitudinal deformation capacity (P < 0.0001). HTx patients in the reduced CFVR group (CFVR < 2.73) were more symptomatic (P < 0.0001) and had higher prevalence of coronary cardiac allograft vasculopathy (CAV) (P < 0.0001) than patients in the high CFVR group. Systolic function improved in both HTx groups during exercise. However, LV longitudinal myocardial deformation improved significantly more in the high CFVR group (P < 0.0001). Peak exercise LV global longitudinal strain and CFVR were strongly correlated (r = 0.8, P < 0.0001). A weak correlation was observed between CFVR and invasive cardiac index at peak exercise (r = 0.35, P < 0.01) and CFVR and LV filling measured by E/e' ratio (r = -0.41, P < 0.01) and pulmonary capillary wedge pressure (r = -0.30, P < 0.05).

CONCLUSION

HTx patients have reduced CFVR, exercise capacity, and LV longitudinal myocardial deformation capacity compared with healthy individuals. HTx patients with reduced CFVR are more symptomatic and have increased prevalence of CAV. Furthermore, reduced CFVR is correlated with reduced LV longitudinal myocardial deformation and exercise capacity.

Real-time aortic pulse wave velocity measurement during exercise stress testing

BACKGROUND

Pulse wave velocity (PWV), a measure of arterial stiffness, has been demonstrated to be an independent predictor of adverse cardiovascular outcomes. This can be derived non-invasively using cardiovascular magnetic resonance (CMR). Changes in PWV during exercise may reveal further information on vascular pathology. However, most known CMR methods for quantifying PWV are currently unsuitable for exercise stress testing.

METHODS

A velocity-sensitive real-time acquisition and evaluation (RACE) pulse sequence was adapted to provide interleaved acquisition of two locations in the descending aorta (at the level of the pulmonary artery bifurcation and above the renal arteries) at 7.8 ms temporal resolution. An automated method was used to calculate the foot-to-foot transit time of the velocity pulse wave. The RACE method was validated against a standard gated phase contrast (STD) method in flexible tube phantoms using a pulsatile flow pump. The method was applied in 50 healthy volunteers (28 males) aged 22-75 years using a MR-compatible cycle ergometer to achieve moderate work rate (38 ± 22 W, with a 31 ± 12 bpm increase in heart rate) in the supine position. Central pulse pressures were estimated using a MR-compatible brachial device. Scan-rescan reproducibility was evaluated in nine volunteers.

RESULTS

Phantom PWV was 22 m/s (STD) vs. 26 ± 5 m/s (RACE) for a butyl rubber tube, and 5.5 vs. 6.1 ± 0.3 m/s for a latex rubber tube. In healthy volunteers PWV increased with age at both rest (R(2) = 0.31 p < 0.001) and exercise (R(2) = 0.40, p < 0.001). PWV was significantly increased at exercise relative to rest (0.71 ± 2.2 m/s, p = 0.04). Scan-rescan reproducibility at rest was -0.21 ± 0.68 m/s (n = 9).

CONCLUSIONS

This study demonstrates the validity of CMR in the evaluation of PWV during exercise in healthy subjects. The results support the feasibility of using this method in evaluating of patients with systemic aortic disease.

Chronotropic Incompetence and Dynamic Postexercise Autonomic Dysfunction Are Associated with the Presence and Severity of Erectile Dysfunction

BACKGROUND

Exercise stress testing (EST) is crucial to determine cardiovascular (CV) risk in men with erectile dysfunction (ED). Low exercise workload, a slower rate of recovery following exercise, and an impaired capacity to increase heart rate (HR) during exercise testing (chronotropic incompetence) are independent predictors of adverse CV outcomes. Aim of this study was to investigate the association between ED and EST parameters.

METHODS

A total of 180 ED patients and 50 men without ED underwent maximal EST. Exercise parameters including exercise capacity (metabolic equivalents, METS), peak exercise time, HR at six METS, peak exercise, HR recovery (HRR) at 1 and 2 minutes and chronotropic index (CI) were evaluated in all individuals. Endothelial function was evaluated with flow-mediated dilatation (FMD) of the brachial artery.

RESULTS

ED patients had lower peak exercise time and thus lower calculated exercise capacity (P < 0.001) and reduced CI (P < 0.01) compared to men without ED. There was a significant association of ED severity with duration of exercise, peak workload, HRR 2 minutes after exercise, and CI (all P < 0.05). There also was a positive relation of HRR and CI with FMD (all P < 0.05).

CONCLUSIONS

This study shows interrelationships between exercise capacity, HRR, CI, and ED. Abnormal HRR and CI are associated with systemic endothelial dysfunction. These findings imply pathophysiological links and may have important implications for the estimation of cardiovascular risk in ED patients.

Fragmented QRS Is Associated with Improved Predictive Value of Exercise Treadmill Testing in Patients with Intermediate Pretest Likelihood of Significant Coronary Artery Disease

BACKGROUND

The predictive value of exercise treadmill testing (ETT) remains inadequate in diagnosing patients with suspected coronary artery disease (CAD) and needs to be improved.

OBJECTIVE

The aim of this study was to investigate whether the presence of FQRS on 12-lead ECG would increase the PPV of ETT in patients with an intermediate likelihood of CAD.

METHODS

fQRS, defined as the presence of notched R or S waves without accompanying typical bundle branch block or the existence of an additional wave-like RSR' pattern in the original QRS complex (with a duration of <120 ms), was assessed in 95 patients with positive ETT. Coronary angiogram (CA) was performed in all patients, divided into two groups as the significant CAD group and nonsignificant CAD group according to coronary artery lesions. The differences between the groups in terms of the presence of fQRS and clinical characteristics were investigated.

RESULTS

The mean age of patients was 51.3 ± 11.3 years, and 74 of them were males (77.9%). FQRS was present in 47 (49.5%) patients, and significant CAD was demonstrated in 51 subjects (53.7%) among the enrolled subjects. fQRS was more prevalent in the significant CAD group compared to nonsignificant CAD group (P < 0.001). The presence of FQRS increased the PPV of positive ETT from 53.7% to 85.1%. In addition, FQRS was associated with the increased risk of significant CAD in multivariate analysis (OR = 2.839, P < 0.001).

CONCLUSION

In clinical practice, the presence of fQRS in patients with positive ETT may support clinicians during the decision-making process with regard to the referral for a coronary angiography.

Cardiac stress test is normal in pre-motor Parkinson's disease

Cardiac sympathetic denervation is an early nonmotor feature of Parkinson's disease (PD). The aim of the current study was to trace evidence for cardiac dysfunction abnormalities in the premotor phase of PD. We retrospectively reviewed treadmill ergometric tests of a large cohort (n = 16,841) between 2000 and 2012, that attended the Executive Screening Survey (ESS) at Sheba Medical Center. Heart rate and blood pressure profiles as well as exercise capacity were compared between subjects who later developed PD and age- and sex-matched subjects (ratio 1:2) who did not. We identified 28 subjects (24 males) who developed PD at follow-up. The PD group was older than the group of subjects who did not develop PD on first ergometric test (64.82 ± 8.82 vs. 48.91 ± 10.60 years, P < 0.001). The time between the first ergometric test and motor symptoms onset was 4.64 ± 2.86 years. Patients who later developed PD had lower maximal heart rate (P < 0.001) and lower heart rate reserve than healthy controls (P < 0.001); however, compared with age- and sex-matched subjects, subjects who developed PD had similar exercise capacity and heart rate profile during rest, exercise, and recovery, even 1 year before diagnosis. In this study, we did not detect significant signs of sympathetic dysfunction during the premotor phase of PD.

High-sensitivity cardiac troponin T and copeptin assays to improve diagnostic accuracy of exercise stress test in patients with suspected coronary artery disease

BACKGROUND

The average diagnostic sensitivity of exercise stress tests (ESTs) is lower than that of other non-invasive cardiac stress tests. The aim of the study was to examine whether high-sensitivity cardiac troponin T (hs-cTnT) or copeptin concentrations rise in response to inducible myocardial ischaemia and may improve the diagnostic accuracy of ESTs.

METHODS AND RESULTS

An EST was performed stepwise on a bicycle ergometer by 383 consecutive patients with suspected or progression of coronary artery disease (CAD). In addition venous blood samples for measurement of hs-cTnT and copeptin were collected prior to EST, at peak exercise, and 4 h after EST. Coronary angiography was assessed for all patients. Patients with significant CAD (n = 224) were more likely to be male and older compared to patients with non-significant CAD (n = 169). Positive EST was documented in 125 (55.8%) patients with significant CAD and in 69 (43.4%) patients with non-significant CAD. Copeptin and hs-cTnT concentrations at baseline were higher in patients with significant CAD (copeptin: 10.8 pmol/l (interquartile range (IQR) 8.1-15.6) vs 9.4 pmol/l (IQR 7.1-13.9); p = 0.04; hs-cTnT: 3.0 ng/l (IQR <3.0-5.4) vs <3.0 ng/l (IQR <3.0); p = 0.006). Hs-cTnT improved sensitivity (61.6% vs 55.8%), specificity (67.7% vs 56.6%) and the positive predictive value (PPV) (72.3% vs 64.4%) and negative (55.2% vs 47.6%) predictive value (NPV) of EST. Copeptin could not improve sensitivity (55.4% vs 55.8%) and reduced specificity, PPV and NPV.

CONCLUSIONS

The measurement of hs-cTnT during EST improves sensitivity, specificity, and positive and negative predictive values. In contrast, measurement of copeptin does not improve diagnostic sensitivity and reduces specificity.

Effects of renal sympathetic denervation on exercise blood pressure, heart rate, and capacity in patients with resistant hypertension

Renal denervation reduces office blood pressure in patients with resistant hypertension. This study investigated the effects of renal denervation on blood pressure, heart rate, and chronotropic index at rest, during exercise, and at recovery in 60 patients (renal denervation group=50, control group=10) with resistant hypertension using a standardized bicycle exercise test protocol performed 6 and 12 months after renal denervation. After renal denervation, exercise blood pressure at rest was reduced from 158±3/90±2 to 141±3/84±4 mm Hg (P<0.001 for systolic blood pressure/P=0.007 for diastolic blood pressure) after 6 months and 139±3/83±4 mm Hg (P<0.001/P=0.022) after 12 months. Exercise blood pressure tended to be lower at all stages of exercise at 6- and 12-month follow-up in patients undergoing renal denervation, although reaching statistical significance only at mild-to-moderate exercise levels (75-100 W). At recovery after 1 minute, blood pressure decreased from 201±4/95±2 to 177±4/88±2 (P<0.001/P=0.066) and 188±6/86±2 mm Hg (P=0.059/P=0.01) after 6 and 12 months, respectively. Heart rate was reduced after renal denervation from 71±3 bpm at rest, 128±5 bpm at maximum workload, and 96±5 bpm at recovery after 1 minute to 66±2 (P<0.001), 115±5 (P=0.107), and 89±3 bpm (P=0.008) after 6 months and to 69±3 (P=0.092), 122±7 (P=0.01), and 93±4 bpm (P=0.032) after 12 months. Mean exercise time increased from 6.59±0.33 to 8.4±0.32 (P<0.001) and 9.0±0.41 minutes (P=0.008), and mean workload increased from 93±2 to 100±2 (P<0.001) and 101±3 W (P=0.007) at 6- and 12-month follow-up, respectively. No changes were observed in the control group. In conclusion, renal denervation reduced blood pressure and heart rate during exercise, improved mean workload, and increased exercise time without impairing chronotropic competence.

Early exercise stress testing is safe after primary percutaneous coronary intervention

BACKGROUND

The optimal timing of exercise stress testing post primary percutaneous coronary intervention is uncertain with anecdotal evidence suggesting an increased risk of acute myocardial infarction and/or death if performed too early. This has translated into a delayed return to normal life activities following an acute myocardial infarction resulting in an increase in socio-economic burden.

AIMS

We hypothesize that early (within 7 days of primary percutaneous coronary intervention) exercise stress testing is safe.

METHODS

A prospective study of consecutive patients enrolled into the Cardiac Rehabilitation Program at a tertiary referral centre that underwent primary percutaneous coronary intervention, and who were able to perform a treadmill stress test were recruited. Timing of exercise stress testing was within 7 days post primary percutaneous coronary intervention and outcomes of death, acute myocardial infarction and other major adverse cardiac event were assessed 24 hours post exercise stress testing.

RESULTS

Recruited patients (n=230) aged between 29 and 78 (mean age 56 ± 10 years) with 191 being males (83%) and 39 being females (17%). While 28 patients had a positive stress test (12.2%), there were no deaths, acute myocardial infarction or any other major adverse cardiac event within 24 hours of performing the exercise stress testing. Mean METS achieved were 8.1 ± 2.3.

CONCLUSIONS

Early exercise stress testing after primary percutaneous coronary intervention appears safe.

Exercise electrocardiogram testing in two brothers with different outcome - a case study exercise testing in master cyclists

The cases of two brothers training and competing as master cyclists and both preparing for a cycling tour are presented. The older brother aged 66 years went first to the primary care physician and presented with an asymptomatic depression in the exercise stress test of the ST segment in V5 and V6 during recovery after complete exhaustion. Coronary angiography revealed a multi vessel coronary artery disease and he underwent bypass surgery. One year later, he successfully completed his planned cycling tour of ~600 km in seven stages and covering ~12,000 m of total ascent. The younger brother aged 59 years went a few months later to the primary care physician and also performed asymptomatic exercise stress testing without changes in the ST segments. Unfortunately, 2 months later he suffered a cardiac arrest during his cycling tour and survived following immediate successful cardiopulmonary resuscitation on the road by his cycling colleagues. Immediate invasive coronary arteriography showed a complete stenosis of the trunk of arteria coronaria sinistra (left coronary artery), a 40%-50% stenosis of ramus circumflexus, and a 20% stenosis of arteria coronaria dextra (right coronary artery). The left coronary artery was dilated and he continued cycling 2 months later. In both brothers, familial hypercholesterolemia was the main cardiovascular risk factor for the multi vessel coronary artery disease. A negative exercise electrocardiogram in siblings with an increased risk for coronary artery disease seemed not to exclude an advanced multi vessel coronary artery disease. In master athletes with asymptomatic exercise electrocardiogram but a positive family history, further examinations should be performed in order to detect relevant stenosis in coronary arteries.

A cohort study of chest pain patients discharged from the emergency department for early outpatient treadmill exercise stress testing

OBJECTIVE

Guidelines on intermediate-risk chest pain, based on consensus alone, recommend inpatient provocative testing after infarct exclusion. Inpatient testing exceeds capacity in many hospitals, so guidelines concede outpatient testing within 72 h is acceptable. We performed a cohort study of chest pain patients having early outpatient treadmill exercise stress testing (EST).

METHODS

All chest pain patients discharged from our emergency with booked outpatient treadmill EST during the 2008 to 2010 calendar years were included. There were no exclusions. The primary outcome was diagnosis of major coronary artery disease among stress test attendees. Secondary outcomes were time to stress test booking, representations with chest pain or death within 30 days.

RESULTS

The cohort consisted of 657 patients: 59% men, mean age 53.2 years. Time from discharge to stress test averaged 10.6 days and 73% of patients attended. Of patients who attended, 14% had a positive test and 13% an inconclusive result. These patients were older than those with negative results (P < 0.001). Four patients (0.8% of attendees) were diagnosed with major coronary artery disease. There were no representations with acute myocardial infarction and no deaths identified.

CONCLUSIONS

Outpatient treadmill EST an average of 10 days post-discharge from emergency with chest pain did not result in adverse events despite reasonably high positive stress test rates. Consensus-based recommendations for inpatient testing or outpatient testing within 72 h of discharge should be reviewed in light of these data.