The effectiveness of coronary computed tomography angiography and functional testing for the diagnosis of obstructive coronary artery disease: results from the individual patient data Collaborative Meta-Analysis of Cardiac CT (COME-CCT).

AIM: To determine the effectiveness of functional stress testing and computed tomography angiography (CTA) for diagnosis of obstructive coronary artery disease (CAD). METHODS AND RESULTS: Two-thousand nine-hundred twenty symptomatic stable chest pain patients were included in the international Collaborative Meta-Analysis of Cardiac CT consortium to compare CTA with exercise electrocardiography (exercise-ECG) and single-photon emission computed tomography (SPECT) for diagnosis of CAD defined as ≥ 50% diameter stenosis by invasive coronary angiography (ICA) as reference standard. Generalised linear mixed models were used for calculating the diagnostic accuracy of each diagnostic test including non-diagnostic results as dependent variables in a logistic regression model with random intercepts and slopes. Covariates were the reference standard ICA, the type of diagnostic method, and their interactions. CTA showed significantly better diagnostic performance (p < 0.0001) with a sensitivity of 94.6% (95% CI 92.7-96) and a specificity of 76.3% (72.2-80) compared to exercise-ECG with 54.9% (47.9-61.7) and 60.9% (53.4-66.3), SPECT with 72.9% (65-79.6) and 44.9% (36.8-53.4), respectively. The positive predictive value of CTA was ≥ 50% in patients with a clinical pretest probability of 10% or more while this was the case for ECG and SPECT at pretest probabilities of ≥ 40 and 28%. CTA reliably excluded obstructive CAD with a post-test probability of below 15% in patients with a pretest probability of up to 74%. CONCLUSION: In patients with stable chest pain, CTA is more effective than functional testing for the diagnosis as well as for reliable exclusion of obstructive CAD. CTA should become widely adopted in patients with intermediate pretest probability. SYSTEMATIC REVIEW REGISTRATION: PROSPERO Database for Systematic Reviews-CRD42012002780. CRITICAL RELEVANCE STATEMENT: In symptomatic stable chest pain patients, coronary CTA is more effective than functional testing for diagnosis and reliable exclusion of obstructive CAD in intermediate pretest probability of CAD. KEY POINTS: Coronary computed tomography angiography showed significantly better diagnostic performance (p < 0.0001) for diagnosis of coronary artery disease compared to exercise-ECG and SPECT. The positive predictive value of coronary computed tomography angiography was ≥ 50% in patients with a clinical pretest probability of at least 10%, for ECG ≥ 40%, and for SPECT 28%. Coronary computed tomography angiography reliably excluded obstructive coronary artery disease with a post-test probability of below 15% in patients with a pretest probability of up to 74%.

The Role of Electrocardiographic Exercise Testing for the Possibility of Permanent Pacemaker Implantation in Patients with Sinus Bradycardia.

Objective: Study on the role of electrocardiographic (ECG) exercise testing for the possibility of permanent pacemaker implantation (PPI) in patients with sinus bradycardia (SB). Methods: Cross-sectional descriptive, prospective study. The study on 60 patients with SB below 50 beats/minute on 12-lead electrocardiogram at rest, with or without symptoms of SB, conducted at the Vietnam National Heart Institute and Hanoi Heart Hospital from January 2020 to September 2021. Results: Sixty patients with SB were studied, 36 male (60%) and 24 female patients (40%), p > 0.05. The average age was 55.12 ± 13.89 years old. Maximum exercise capacity (MEC) is low and only reaches 7.78 ± 3.59 metabolic equivalents (METs); Not reaching 85% of predicted MEC accounts for 53.5%; Maximum exercise time is 10.53 ± 0.46 minutes; Impaired heart rate (HR) variability in patients with SB is high: Chronotropic Index <0.8 accounts for 53.5%, not reaching 85% of predicted HR max accounts for 45%. The average HR max was 129.90 ± 29.22 beats per minute (BPM). The average maximum workload systolic blood pressure was 155.23 ± 20.59 mmHg. The average value of maximum exercise diastolic blood pressure was 88.10 ± 9.11 mmHg. The HR decreased by 27.87 ± 16.82 BPM in the first minute. Not achieving 85% of predicted MEC (p = 0.062), so it is not an independent factor predicting the ability for PPI. Only the HR variability index <0.8 is an independent predictor for PPI in bradycardic patients, which has OR = 21.521 (95% CI: 2.27-04.34, p < 0.05). Conclusion: Results can be seen that Chronotropic Index <0.8 is an important marker for physicians to decide on PPI in ECG during exercise testing in SB patients and is a potential prognostic factor for the need for PPI.

Screening Sportsmen and Sportswomen Over Age 35: The Relevance of an Exercise Electrocardiogram. Data From the SEEPRED Study.

INTRODUCTION: The importance of exercise electrocardiogram (ECG) is still controversial in the prevention of cardiovascular events among sportsmen and sportswomen. The aim of this study was to assess the relevance of exercise ECG as a screening tool to prevent cardiovascular events when any cardiovascular disease (CVD) risk factors are present. METHODS: The study included leisure time asymptomatic sportsmen and sportswomen over age 35 evaluated from 2011 to 2016 at the University Hospital of Saint-Etienne (France). Major adverse cardiovascular events (MACE) and atrial fibrillation were collected at 3 years. RESULTS: Of the cohort of 2457 sportsmen and sportswomen (mean age 50.2 ± 9.4 years), 50 (2%) had a high-risk SCORE2. A total of 256 exercise ECGs (10%) were defined as positive, most of them due to silent myocardial ischemia (SMI) (n = 196; 8%). These 196 SMI cases led to 33 coronary angiograms (1%), which revealed 23 significant coronary stenoses requiring revascularization. In multivariate logistic regression analysis, having at least two CVD risk factors was independently associated with (1) positive exercise ECG (OR = 1.80 [95% CI: 1.29-2.52], p = 0.0006), with (2) suspected SMI (OR = 2.57 [95% CI: 1.10-6.02], p = 0.0304), with (3) confirmed SMI (OR = 8.20 [95% CI: 3.46-19.46], p < 0.0001) and with (4) cardiovascular events (MACE or atrial fibrillation) (OR = 6.95 [95% CI: 3.49-13.81], p < 0.0001) at 3 years (median). CONCLUSIONS: The study supports the European recommendations for the use of exercise ECG in evaluation of asymptomatic leisure time sportsmen over age 35. Having at least two CVD risk factors was the best predictor for presence of coronary artery stenosis that may increase the risk for adverse events. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT06024863.

Exercise-Induced QRS Prolongation in Brugada Syndrome: Implications for Improving Disease Phenotyping and Diagnosis.

BACKGROUND: Abnormal ventricular activation at rest is reported in Brugada syndrome (BrS). OBJECTIVES: The aim of this study was to evaluate the usefulness of dynamic changes in ventricular activation during exercise to improve disease phenotyping and diagnosis of BrS. METHODS: Digital 12-lead electrocardiograms during stress testing were analyzed retrospectively at baseline, peak exercise, and recovery in 53 patients with BrS and 52 controls. Biventricular activation was assessed from QRS duration (QRSd), whereas right ventricular activation was assessed from S wave duration in the lateral leads (I and V6) and terminal R wave duration in aVR. Exercise-induced changes in QRS parameters to predict a positive procainamide response were assessed in separate test and validation cohorts with suspected BrS. RESULTS: Baseline electrocardiogram parameters were similar between BrS and controls. QRSd shortened with exercise in all controls but prolonged in all BrS (-6.1 ± 6.0 ms vs 7.1 ± 6.5 ms [P < 0.001] in V6). QRSd in recovery was longer in BrS compared with controls (90 ± 12 ms vs 82 ± 11 ms in V6; P = 0.002). Both groups demonstrated exercise-induced S duration prolongation in V6, with greater prolongation in BrS (8.2 ± 14.3 ms vs 1.2 ± 12.4 ms; P < 0.001). Any exercise-induced QRSd prolongation in V6 differentiated those with a positive vs negative procainamide response with 100% sensitivity and 95% specificity in the test cohort, and 87% sensitivity and 93% specificity in the validation cohort. CONCLUSIONS: Exercise-induced QRSd prolongation is ubiquitous in BrS primarily owing to delayed right ventricular activation. This electrocardiogram phenotype predicts a positive procainamide response and may provide a noninvasive screening tool to aid in the diagnosis of BrS before drug challenge.

Exercise electrocardiography for pre-test assessment of the likelihood of coronary artery disease.

OBJECTIVES: To develop a tool including exercise electrocardiography (ExECG) for patient-specific clinical likelihood estimation of patients with suspected obstructive coronary artery disease (CAD). METHODS: An ExECG-weighted clinical likelihood (ExECG-CL) model was developed in a training cohort of patients with suspected obstructive CAD undergoing ExECG. Next, the ExECG-CL model was applied in a CAD validation cohort undergoing ExECG and clinically driven invasive coronary angiography and a prognosis validation cohort and compared with the risk factor-weighted clinical likelihood (RF-CL) model for obstructive CAD discrimination and prognostication, respectively.In the CAD validation cohort, obstructive CAD was defined as >50% diameter stenosis on invasive coronary angiography. For prognosis, the endpoint was non-fatal myocardial infarction and death. RESULTS: The training cohort consisted of 1214 patients (mean age 57 years, 57% males). In the CAD (N=408; mean age 55 years, 53% males) and prognosis validation (N=3283; mean age 57 years, 57% males) cohorts, 11.8% patients had obstructive CAD and 4.4% met the endpoint. In the CAD validation cohort, discrimination of obstructive CAD was similar between the ExECG-CL and RF-CL models: area under the receiver-operating characteristic curves 83.1% (95% CIs 77.5% to 88.7%) versus 80.7% (95% CI 74.6% to 86.8%), p=0.14. In the ExECG-CL model, more patients had very low (≤5%) clinical likelihood of obstructive CAD compared with the RF-CL (42.2% vs 36.0%, p<0.01) where obstructive CAD prevalence and event risk remained low. CONCLUSIONS: ExECG incorporated into a clinical likelihood model improves reclassification of patients to a very low clinical likelihood group with very low prevalence of obstructive CAD and favourable prognosis.

The Value of Exercise Electrocardiography in Outpatients with Stable Chest Pain and Low Pre-Test Probability of Significant Coronary Artery Disease.

The role of exercise electrocardiography (ECG) in the investigation of stable chest pain has been questioned. The American Heart Association guidelines suggest the use of exercise ECG in patients with stable chest pain and low pre-test probability (PTP) of significant coronary artery disease, while the European Society of Cardiology Guidelines does not. This retrospective observational study aimed to assess the usefulness of exercise ECG in the low-PTP population with stable chest pain. We reviewed the medical records for all outpatient exercise ECGs conducted because of stable chest pain at the Department of Medicine and Emergency, Sahlgrenska University Hospital, Mölndal, Sweden, during 2016-2018. The identified patients were categorized in low-, intermediate-, or high-risk pre-test probability of significant coronary artery disease. All low-PTP patients were followed for one year post investigation for the incidence of acute coronary syndrome and all-cause mortality. Thus, 505 patients (mean age 60 years, 56% women) with low PTP were included in the study. Only four patients (0.6%) experienced incident myocardial infarction (three patients) or all-cause mortality (one patient). The negative predictive value of exercise ECG was 99.7%, and the positive predictive value was 28.6%. In this low-PTP population, exercise ECG yields a good negative predictive value and a poor positive predictive value.

Incremental Value of Exercise ECG to Myocardial Perfusion Single-Photon Emission Computed Tomography for Prediction of Cardiac Events.

Background Both myocardial perfusion single-photon emission computed tomography (MPS) and exercise ECG (Ex-ECG) carry prognostic information in patients with stable chest pain. However, it is not fully understood if combining the findings of MPS and Ex-ECG improves risk prediction. Current guidelines no longer recommend Ex-ECG for diagnostic evaluation of chronic coronary syndrome, but Ex-ECG could still be of incremental prognostic importance. Methods and Results This study comprised 908 consecutive patients (age 63.3±9.4 years, 49% male) who performed MPS with Ex-ECG. Subjects were followed for 5 years. The end point was a composite of cardiovascular death, acute myocardial infarction, unstable angina, and unplanned percutaneous coronary intervention. National registry data and medical charts were used for end point allocation. Combining the findings of MPS and Ex-ECG resulted in concordant evidence of ischemia in 72 patients or absence of ischemia in 634 patients. Discordant results were found in 202 patients (MPS-/Ex-ECG+, n=126 and MPS+/Ex-ECG-, n=76). During follow-up, 95 events occurred. Annualized event rates significantly increased across groups (MPS-/Ex-ECG- =1.3%, MPS-/Ex-ECG+ =3.0%, MPS+/Ex-ECG- =5.1% and MPS+/Ex-ECG+ =8.0%). In multivariable analyses MPS was the strongest predictor regardless of Ex-ECG findings (MPS+/Ex-ECG-, hazard ratio [HR], 3.0, P=0.001 or MPS+/Ex-ECG+, HR,4.0, P<0.001). However, an abnormal Ex-ECG almost doubled the risk in subjects with normal MPS (MPS-/Ex-ECG+, HR, 1.9, P=0.04). Conclusions In patients with chronic coronary syndrome, combining the results from MPS and Ex-ECG led to improved risk prediction. Even though MPS is the stronger predictor, there is an incremental value of adding data from Ex-ECG to MPS, especially in patients with normal MPS.

The Predictive Value of Combining Symptoms, Residual Syntax Score and Non-Invasive Tests in the Diagnosis of Significant Coronary Artery Disease in Elderly Post-PCI Patients.

Purpose: To assess the diagnostic efficiency of a combination of symptoms, residual Syntax score (rSS) and non-invasive tests in elderly post-PCI patients. Patients and Methods: This was a retrospective study that consecutively enrolled patients ≥60 years old with chronic coronary syndrome and previous stent implantation without lesions requiring further revascularization between March 2013 and June 2020. The patients were scheduled for exercise ECG, CCTA and invasive coronary angiography within 4 weeks. The study then calculated rSS and the sensitivity, specificity, positive and negative predictive values (PPV and NPV) and accuracy of symptoms, rSS, exercise ECG and CCTA, taking computational pressure-flow dynamics derived fractional flow reserve (caFFR) as the standard reference. Results: A total of 114 patients were enrolled in this study, including 75 patients with caFFR-positive and 39 patients with caFFR-negative. The caFFR-positive group had more patients with typical angina. Furthermore, the rSS in the caFFR-positive group was higher than that in the caFFR-negative category (7.33 ± 6.56 vs 3.34 ± 4.26, p < 0.001). There was no significant difference in exercise ECG results between the two groups. However, the rate of positive CCTA in the caFFR-positive group was higher than that in the caFFR-negative category (89.33% vs 46.15%, p < 0.001). In addition, after combining symptoms, rSS and CCTA, the sensitivity, specificity, PPV, NPV and accuracy for diagnose were 77.5%, 84.2%, 90.2%, 66.7% and 79.8%, respectively. Conclusion: The findings showed that exercise ECG had limited power to diagnose significant CAD in elderly post-PCI patients, but CCTA was more efficient. Moreover, combining symptoms, rSS and CCTA provided more accurate diagnostic performance with feasibility and safety.

[Clinical study on the diagnostic value of cardiopulmonary exercise test for coronary atherosclerotic heart disease].

Objective: To evaluate the value of cardiopulmonary exercise testing in diagnosing coronary atherosclerotic heart disease（CHD). Methods: A total of 156 patients with suspected CHD（The patient's condition is relatively stable, aged 18 to 80 years）were performed for cardiopulmonary exercise testing, ECG exercise test and coronary angiography. Based on the results of coronary angiography, the sensitivity, specificity and diagnostic value of relevant indicators of cardiopulmonary exercise testing (CPET) parameters (Peak VO2%pred、Peak O2 pulse%pred、ΔVO2/ΔWR) in diagnosing CHD were analyzed by statistical methods based on the results of coronary angiography. Results: Useing the best cut-off point of Peak VO2 ≤69%pred for detecting CHD, the sensitivity was 55.1%, the specificity was 77.0%, and the AUC was 0.698. The sensitivity, specificity and AUC of peak O2 pulse%pred were 50.7%, 72.4% and 0.58 respectively. ΔVO2/ΔWR sensitivity in diagnosing CHD was 44.9%, specificity was 87.4%, AUC was 0.647. The sensitivity of peak O2 pulse%pred and ΔVO2/ΔWR were much higher than the ECG exercise test, the difference was statistically significant (P<0.01). Conclusion: The sensitivity of some indexes of CPET in diagnosing CHD was better than ECG exercise test, the specificity and diagnostic value of the optimal cut-off point are high. CPET has predictive value for the diagnosis of CHD, it can diagnose CHD early and accurately.

Asymptomatic Athlete With Short-Coupled Premature Ventricular Contractions.

We present an asymptomatic 26-year-old athlete, with no family history of sudden cardiac death and no structural heart disease, who displayed short-coupled premature ventricular contractions on exercise test and Holter monitoring. The rarity of the case as well as management dilemmas are discussed. (Level of Difficulty: Intermediate.).

Typical angina during exercise stress testing improves the prediction of future acute coronary syndrome.

INTRODUCTION: The prognostic value of angina during exercise stress testing is controversial, possibly due to previous studies not differentiating typical from non-typical angina. We aimed to assess the prognostic value of typical angina alone, or in combination with ST depression, during exercise stress testing for predicting cardiovascular events. METHODS: We conducted a prospective observational cohort study including all patients who performed a clinical exercise stress test at the department of Clinical Physiology, Kalmar County Hospital between 2005 and 2012. The association between typical angina/ST depression and incident acute coronary syndrome (ACS) and cardiovascular mortality were analysed using Cox regression for long-term and 1-year follow-up. RESULTS: Out of 11605 patients (median follow-up 6.7 years), 623 (5.4%) developed ACS and 319 (2.7%) died from cardiovascular causes. Compared to patients with no angina and no ST depression, typical angina and ST depression were associated with increased risk of future ACS; hazard ratio (HR) 3.5 ([95%CI] 2.6-4.7). This association was even stronger for ACS within one year (typical angina with and without concomitant ST depression; HR 20.8 (13.9-31.3) and 9.7 (6.1-15.4), respectively). Concordance statistics for ST depression in predicting ACS during long-term follow-up was 0.58 (0.56-0.60) and 0.69 (0.65-0.73) for ACS within one year, and 0.64 (0.62-0.66) and 0.77 (0.73-0.81), respectively, when typical angina was added to the model. CONCLUSIONS: Typical angina during exercise stress testing is predictive of future ACS, especially in combination with ST depression, and during the first year after the test.

Recognition System Using Fusion Normalization Based on Morphological Features of Post-Exercise ECG for Intelligent Biometrics.

Although biometrics systems using an electrocardiogram (ECG) have been actively researched, there is a characteristic that the morphological features of the ECG signal are measured differently depending on the measurement environment. In general, post-exercise ECG is not matched with the morphological features of the pre-exercise ECG because of the temporary tachycardia. This can degrade the user recognition performance. Although normalization studies have been conducted to match the post- and pre-exercise ECG, limitations related to the distortion of the P wave, QRS complexes, and T wave, which are morphological features, often arise. In this paper, we propose a method for matching pre- and post-exercise ECG cycles based on time and frequency fusion normalization in consideration of morphological features and classifying users with high performance by an optimized system. One cycle of post-exercise ECG is expanded by linear interpolation and filtered with an optimized frequency through the fusion normalization method. The fusion normalization method aims to match one post-exercise ECG cycle to one pre-exercise ECG cycle. The experimental results show that the average similarity between the pre- and post-exercise states improves by 25.6% after normalization, for 30 ECG cycles. Additionally, the normalization algorithm improves the maximum user recognition performance from 96.4 to 98%.

Noninvasive Testing for Diagnosis of Stable Coronary Artery Disease in the Elderly.

Efficient diagnostic approaches to detect coronary artery disease (CAD) in elderly patients are necessary to ensure optimal and timely treatment. The population of suspected CAD patients older than 70 years is especially vulnerable and constantly growing. Finding the optimal diagnostic approach is challenging due to certain features of this population, such as high prevalence of comorbidities, existing contraindications to exercise tests or cognitive decline, which hinders correct assessment of the patient's situation. Moreover, some symptoms of CAD can have variable significance in the elderly compared to younger adult groups. In this review, we present current recommendations of the United States (US) and European cardiologists' associations and discuss their applicability for diagnostics in the elderly population. Exercise electrocardiogram (ECG) and exercise stress echocardiography (SE) tests are not feasible for a substantial proportion of elderly patients. Coronary computed tomography angiography (CTA) appears to be an attractive alternative for such patients, but is not universally applicable; for instance, it is problematic in patients with significant calcification of the vessels. Moreover, more studies are needed to compare the results delivered by CTA to those of other diagnostic methods. Future efforts should be focused on comparative studies to better understand the limits and advantages of different diagnostic methods and their combinations. It is possible that some of the currently used diagnostic criteria could be improved to better accommodate the needs of the elderly population.

The Role of Aortic Stiffness Parameters in Evaluating Myocardial Ischemia.

BACKGROUND: Arterial stiffness is a process resulting in deterioration of hemodynamic function of the aorta, a decrease in its compliance and elasticity, caused by the proportional change of components of the extracellular matrix. Although many researches have been done to determine the etiologies of myocardial ischemia in the absence of obstructive coronary artery disease, none of them has investigated the relation between the parameters of aortic stiffness and the myocardial ischemia documented by the exercise stress test. The present cross-sectional study aimed to investigate the difference of aortic stiffness parameters between the groups separated by exercise stress test result as positive and negative ischemic findings in the absence of obstructive coronary artery disease. METHODS: The present study included 79 patients who were admitted to Istanbul Faculty of Medicine, Department of Cardiology with complaint of chest pain. Forty patients (21 women and 19 men) have ischemic findings on the exercise electrocardiography (ECG) test and 39 patients (20 women and 19 men) have normal exercise ECG results. The patients who have positive exercise ECG findings underwent coronary angiography and all the patients had non-obstructive coronary artery disease. Demographic features (age, sex and comorbidities) were statistically similar between the groups. Aortic stiffness measurements (pulse wave velocity, pulse pressure, aortic augmented pressure, augmentation index, systolic pressure-time index, diastolic pressure-time index and subendocardial viability ratio) were done with tonometric methods. RESULTS: There was no significant difference between the two groups in terms of the aortic stiffness parameters. Systolic blood pressure (P = 0.33), diastolic blood pressure (P = 0.24), pulse pressure (P = 0.60), systolic pressure-time index (P = 0.10), diastolic pressure-time index (P = 0.91), subendocardial viability ratio (P = 0.19), aortic augmented pressure (P = 0.87), augmentation index (P = 0.58) and pulse wave velocity (P = 0.56) were detected between the two groups. Biochemical parameters were found similar between the two groups. Only low-density lipoprotein levels were slightly higher in patients with negative exercise stress test result (139 vs. 123 mg/dL, P = 0.02). CONCLUSION: There is no finding supporting that the aortic stiffness identifies the patients with non-obstructive coronary artery disease but with signs of myocardial ischemia and further investigation of other causes of myocardial ischemia is required.

Multi-Beat Averaging Reveals U Waves Are Ubiquitous and Standing Tall at Elevated Heart Rates Following Exercise.

The reporting of U wave abnormalities is clinically important, but the measurement of this small electrocardiographic (ECG) feature is extremely difficult, especially in challenging recording conditions, such as stress exercise, due to contaminating noise. Furthermore, it is widely stated that ECG U waves are rarely observable at heart rates greater than 90 bpm. The aims of the study were (i) to assess the ability of multi-beat averaging to reveal the presence of U waves in ECGs contaminated by noise following exercise and (ii) to quantify the effect of exercise on U wave amplitude. The multi-beat averaging algorithm was applied to recover U waves in 20 healthy subjects in pre- and post-exercise recordings. Average beats were generated from 30 beat epochs. The prevalence of U waves and their amplitudes were measured in pre- and post-exercise recordings and changes in amplitude due to exercise were quantified. U waves were present in all subjects in pre-exercise recordings. Following exercise, U waves could not be seen in standard ECG but were observable in all 20 subjects by multi-beat averaging and despite significantly increased mean (±SD) heart rate (63 ± 8 bpm vs. 100 ± 9 bpm, p < 0.0001). Furthermore, U waves were observable in all subjects with heart rates greater than 90 bpm. U waves significantly increased in amplitude following exercise (38 ± 15 µV vs. 80 ± 48 µV, p = 0.0005). Multi-beat averaging is effective at recovering U waves contaminated by noise due to exercise. U waves were measurable in all subjects, dispelling the myth that U waves are rarely seen at elevated heart rates. U waves exhibit increased amplitudes at elevated heart rates following exercise.

Incremental value of high-frequency QRS analysis for diagnosis and prognosis in suspected exercise-induced myocardial ischaemia.

AIM: Exercise stress testing is used to detect myocardial ischaemia, but is limited by low sensitivity and specificity. The authors investigated the value of the analysis of high-frequency QRS components as a marker of abnormal depolarization in addition to standard ST-deviations as a marker of abnormal repolarization to improve the diagnostic accuracy. METHODS AND RESULTS: Consecutive patients undergoing bicycle exercise stress nuclear myocardial perfusion imaging were prospectively enrolled. Presence of myocardial ischaemia, the primary diagnostic endpoint, was adjudicated using MPI and coronary angiography. Automated high-frequency QRS analysis was performed in a blinded fashion. The prognostic endpoint was major adverse cardiac events (MACEs) during two years of follow-up. Exercise-induced ischaemia was detected in 147/662 patients (22%). The sensitivity of high-frequency QRS was similar to ST-deviations (46% vs. 43%, p=0.59), while the specificity was lower (75% vs. 87%, p<0.001). The combined use of high-frequency QRS and ST-deviations classified 59% of patients as 'rule-out' (both negative), 9% as 'rule-in' (both positive) and 32% in an intermediate zone (one test positive). The sensitivity for 'rule-out' and the specificity for 'rule-in' improved to 63% and 97% compared with ST-deviation analysis alone (both p<0.001). MACE-free survival was 90%, 80% and 42% in patients in the 'rule-out', intermediate and 'rule-in' groups (p<0.001). After adjustment for age, gender, ST-deviations and clinical post-test probability of ischaemia, high-frequency QRS remained an independent predictor for the occurrence of MACEs. CONCLUSION: The use of high-frequency QRS analysis in addition to ST-deviation analysis improves the diagnostic accuracy during exercise stress testing and adds independent prognostic information.

The importance of ST elevation in V2-4 ECG leads in athletes.

BACKGROUND: Early repolarization in the anterior ECG leads (ERV2-4) is considered to be a sign of right ventricular (RV) remodeling, but its etiology and importance are unclear. METHODS: A total of 243 top-level endurance-trained athletes (ETA; 183 men and 60 women, weekly training hours: 15-20) and 120 leisure-time athletes (LTA; 71 men and 49 women, weekly training hours: 5-6) were investigated. The ERV2-4 sign was evaluated concerning type of sport, gender, transthoracic echocardiographic parameters, and ECG changes, which can indicate elevated RV systolic pressure [left atrium enlargement (LAE), right atrium enlargement (RAE), RV conduction defect (RVcd)]. RESULTS: Stroke volume and left ventricular mass were higher in ETAs vs. LTAs in both genders (p < 0.01). Prevalence of the ERV2-4 sign was significantly higher in men than in women [p = 0.000, odds ratio (OR) = 36.4] and in ETAs than in LTAs (p = 0.000). The highest ERV2-4 prevalence appeared in the most highly trained triathlonists and canoe and kayak paddlers (OR = 13.8 and 5.2, respectively). Within the ETA group, the post-exercise LAE, RAE, and RVcd changes developed more frequently in cases with than without ERV2-4 (LAE: men: p < 0.05, females: p < 0.005; RAE: men: p < 0.05, females: p < 0.005; RVcd: N.S.). These post-exercise appearing LAE, RAE, and RVcd are associated with the ERV2-4 sign (OR = 4.0, 3.7, and 3.8, respectively). CONCLUSIONS: According to these results, ERV2-4 develops mainly in male ETAs due to long-lasting and repeated endurance training. The ERV2-4 sign indicates RV's adaptation to maintain higher compensatory pulmonary pressure and flow during exercise but its danger regarding malignant arrhythmias is unclear.

Delayed onset Takotsubo syndrome following exercise ECG: a case report.

BACKGROUND: Takotsubo syndrome usually occurs immediately following a physical or emotional trigger. In some cases, a triggering stress may not be evident. A delayed manifestation of the syndrome may account for such cases. CASE SUMMARY: An asymptomatic 69-year-old woman presented for a routine cardiac check-up, which revealed normal electrocardiogram (ECG), echocardiography, and exercise ECG. She did not complain of any chest pain during or immediately after the tests. After about 24 h, she developed chest pain for which she was admitted with the provisional diagnosis of acute coronary syndrome. ECG showed dynamic T-wave changes with QTc prolongation. Cardiac biomarkers were mildly elevated. Characteristic reversible left ventricular dysfunction in absence of coronary stenosis ultimately led to the diagnosis of Takotsubo syndrome. DISCUSSION: Our case represents a delayed occurrence of Takotsubo syndrome triggered by a treadmill exercise stress test, which manifested about 24 h following the stressor. Such delayed manifestation may account for those cases of Takotsubo syndrome where no immediate triggering stressor is evident.

TWARMI pilot trial: The value and optimal criteria of microvolt T-wave alternans in the diagnosis of reversible myocardial ischemia in patients without structural cardiac disease.

AIMS: Microvolt T-wave alternans (MTWA) testing is a beat-to-beat fluctuation in the amplitude of T wave. We investigated whether: (a) MTWA can be new non-invasive tool for detection of reversible ischemia in patients with suspected CAD without structural heart disease, (b) MTWA can detect ischemia earlier and with greater test accuracy compared with exercise ECG ST-segment testing, and (c) threshold value of MTWA and heart rate at which the alternans is estimated can be different compared to standard values. METHODS: A total of 101 patients with suspected stable coronary disease, but without structural heart disease, were included. Echocardiography, exercise ECG test, MTWA with classical and modified threshold alternans values, and coronary angiography were performed. RESULTS: About 33.3% patients had a false-positive result on exercise ECG test. The sensitivity of exercise ECG ST-segment test in the detection of coronary artery disease was 97.8%, and the specificity was 42.5% (DOR 33.89). In a group of angiographically positive patients, standard MTWA accurately identified 60% of patients, while 40% had a false-negative result. About 91.8% patients with negative angiography result were accurately identified with 8.2% false positives. The sensitivity of MTWA was 59.61% and specificity 91.83%. Best ratio of sensitivity and specificity (86.53% and 95.91%, DOR 151.06) had modified criteria for positive MTWA (MTWA >1.5 µV at heart rate 115-125/min). CONCLUSIONS: This study showed that MTWA can be the new non-invasive tool for the detection of reversible ischemia in patients with suspected CAD without structural heart disease. Also, MTWA can detect ischemia earlier and with greater accuracy compared with exercise ECG testing.