High-sensitivity Troponin Testing Research Articles

Management of myocardial infarction with non-obstructive coronary arteries (MINOCA) in Germany: a single-center study on hospital resources and healthcare economics.

Patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) present as a main feature ≤50% stenosis upon angiography despite clinical symptoms and biomarker elevation related to acute coronary syndrome. Due to broad availability of high sensitivity troponin testing as well as invasive and non-invasive imaging, this clinical entity receives increasing clinical awareness. We aimed to investigate the in-hospital work flow and economic impact of MINOCA vs. MICAD (myocardial infarction with obstructive coronary artery disease) patients and related clinical outcomes in a single-center patient collective of a large university heart center in Germany. We retrospectively screened and analyzed all patients who were admitted to our hospital under the suspicion of an acute coronary syndrome within a 12-month period (2017-2018) for further diagnostics and treatment. All included patients showed a pathological troponin elevation and received invasive coronary angiography for acute coronary syndrome. Associated in-hospital costs, procedural and various clinical parameters as well as timelines and parameters of work-flow were obtained. After screening of 3,021 patients, we included 660 patients with acute coronary syndrome. Of those, 118 patients were attributed to the MINOCA-group. 542 patients presented with a "classical" myocardial infarction (MICAD group). MINOCA patients were less frail, more likely female, but showed no relevant difference in age or other selected comorbidities except for fewer cases of diabetes. In-hospital mortality (11% vs. 0%; p < 0.001) and 30-day mortality (17.3% vs. 4.2%; p < 0.001) after the index event were significantly higher in the "classical" myocardial infarction group (MICAD)- Despite a shorter overall length of hospital stay (9.5 ± 8.7 days vs. 12.3 ± 10.5 days, p < 0.01) with a significantly shorter duration of high care monitoring (intensive/intermediate care or chest pain units) (2.4 ± 2.1 days vs. 4.7 ± 3.3 days, p < 0.01) MINOCA patients consumed a relevant contingent of hospital resources. Thus, in a 12-months period a total sum of almost 300 days was attributed to high care monitoring for MINOCA patients with a mean difference of approximately 50% compared to patients with classical myocardial infarction. With average and median costs of 50% less per index, MINOCA treatment costs were lower compared to the MICAD group in the hospital reimbursement system of Germany. Consequently, MINOCA treatment was not associated with a relevant profit for these expanses and a relevant share of nearly 40% of the total costs was generated due to high care monitoring. In light of lower mortality than MICAD and growing scarcity of staff, financial and capacity resources the clinical symptom complex of MINOCA should be put under particular consideration for refining care concepts and resource allocation.

Predicting troponin biomarker elevation from electrocardiograms using a deep neural network.

Elevated troponin levels are a sensitive biomarker for cardiac injury. The quick and reliable prediction of troponin elevation for patients with chest pain from readily available ECGs may pose a valuable time-saving diagnostic tool during decision-making concerning this patient population. The data used included 15 856 ECGs from patients presenting to the emergency rooms with chest pain or dyspnoea at two centres in Sweden from 2015 to June 2023. All patients had high-sensitivity troponin test results within 6 hours after 12-lead ECG. Both troponin I (TnI) and TnT were used, with biomarker-specific cut-offs and sex-specific cut-offs for TnI. On this dataset, a residual convolutional neural network (ResNet) was trained 10 times, each on a unique split of the data. The final model achieved an average area under the curve for the receiver operating characteristic curve of 0.7717 (95% CI±0.0052), calibration curve analysis revealed a mean slope of 1.243 (95% CI±0.075) and intercept of -0.073 (95% CI±0.034), indicating a good correlation between prediction and ground truth. Post-classification, tuned for F1 score, accuracy was 71.43% (95% CI±1.28), with an F1 score of 0.5642 (95% CI±0.0052) and a negative predictive value of 0.8660 (95% CI±0.0048), respectively. The ResNet displayed comparable or surpassing metrics to prior presented models. The model exhibited clinically meaningful performance, notably its high negative predictive accuracy. Therefore, clinical use of comparable neural networks in first-line, quick-response triage of patients with chest pain or dyspnoea appears as a valuable option in future medical practice.

Utility of rest magnetocardiography in patients presenting to the emergency department with chest pain: A case series on the CardioFlux MCG

BackgroundMagnetocardiography (MCG) may provide a rapid diagnostic option for patients presenting with chest pain in the emergency department (ED). Case summariesThis case series presents two instances from a multicenter study, where MCG could have served as a rapid, non-invasive diagnostic tool for chest pain patients. In both cases, multiple high-sensitivity troponin (hsTn) tests yielded incorrect evidence of ischemia. In the first case, multiple positive hsTn tests led to the patient requiring 23 h of observation care, while MCG rapidly ruled out acute coronary syndrome (ACS). In the second case, MCG revealed findings indicative of cardiac ischemia where serial ECGs did not indicate ischemia and serial hsTns were normal. Subsequent cardiac catheterization confirmed 99 % stenosis in the patient's left main and left anterior descending arteries, necessitating coronary artery bypass grafting (CABG). ConclusionMCG offers a rapid, painless, non-invasive, radiation free assessment for patients presenting with acute chest pain. Integrating MCG into ED workflows has the potential to improve throughput, reduce the need for subsequent patient observation or inpatient admission, and minimize or eliminate the need for other more expensive non-invasive cardiac testing. MCG avoids some of the problems associated with other methods for diagnosing ischemia. MCG does not involve radiation or the use of pharmacologic agents which have a risk for allergic reactions and anaphylaxis, or the need for an intravenous line. Stress tests are frequently contraindicated or unable to be performed in patients on various medications, may require patient cooperation and in the case of exercise stress tests, the patient's capability to exercise. MCG requires no special patient preparation.

Could paramedics use the HEART Pathway to identify patients at low-risk of myocardial infarction in the prehospital setting?

In the Emergency Department, patients with suspected myocardial infarction can be risk stratified using the HEART pathway, which has recently been amended for prehospital use and modified for the incorporation of a high-sensitivity cardiac troponin test. In a prospective analysis, the performance of both HEART pathways in the prehospital setting, with a high-sensitivity cardiac troponin test using 3 different thresholds, was evaluated for major adverse cardiac events at 30 days. We found that both low-risk HEART pathways, when using the most conservative cardiac troponin thresholds, approached but did not reach accepted rule-out performance in the Emergency Department.

From chest pain to coronary functional testing: Clinical and economic impact of coronary microvascular dysfunction

BackgroundCoronary functional testing to formally diagnose coronary microvascular dysfunction (CMD) reduces cardiovascular events and alleviates angina. This study aims to investigate the extensive and complex journey that patients with CMD undergo, from the onset of chest pain to eventual diagnosis. MethodsData from the Coronary Microvascular Disease Registry (CMDR) were analyzed, including information on the date of first documentation of chest pain, number of non-invasive and invasive tests the patient underwent, emergency department visits, and hospitalizations. In addition, we estimated the total cost per patient. A total of 61 patients with CMD diagnosis were included in this analysis. ResultsMost patients in our cohort were older than 50 years of age. The median time from initial chest pain symptoms to diagnosis was 0.62 (interquartile range [IQR]: 0.06–2.96) years. During this period, patients visited the emergency department a median of 1.0 (IQR: 0.0–2.0) times. Diagnostic tests included 3.0 (IQR: 2.0–6.0) electrocardiograms, 3.0 (IQR: 0.0–6.0) high-sensitivity troponin tests, and 1.0 (IQR: 1.0–2.0) echocardiograms. Prior to diagnosis of CMD, 13 (21.3 %) patients had left heart catheterization without coronary functional testing. Non-invasive testing for ischemia was conducted in 43 (70.5 %) patients. Alternative non-cardiac diagnoses were given to 11 (18.0 %) patients during the diagnostic process, with referrals made to gastroenterology for 16 (26.2 %) and pulmonology for 10 (16.4 %) patients. The cost was almost $2000/patient. ConclusionTimely identification of CMD offers promising opportunities for prompt symptom alleviation, accompanied by reduced visits to the emergency department, cardiovascular testing, invasive medical procedures, and consequently reduced healthcare expenses.

Multicenter analysis to assess risk of major adverse cardiac events in patients undergoing high-sensitivity troponin testing in the emergency department.

Our objective was to evaluate 30-day major adverse cardiac events (MACE) in emergency department (ED) patients with normal high-sensitivity troponins (hs-trop). We hypothesized that MACE rates would be<1% in patients with (1) two normal troponins regardless of change in troponin (delta) and (2) index hs-trop below the limit of quantitation (LOQ) regardless of the institution modified HEART score. This was a multicenter, retrospective, cohort study of adult patients who presented to 1 of 18 EDs between July 2020 and April 2021 with acute coronary syndrome as defined by an institutional-modified HEART score completed by their treating physician or midlevel, no evidence of ST-elevation myocardial infarction, and an index or serial gender-adjusted hs-trop within normal limits. The primary outcome was MACE within 30 days of index ED encounter. A detailed case review was then performed for those patients experiencing a MACE. Of the 9084 patients who had single or serial normal troponins, 31 (0.34%; confidence interval [CI] 0.23%-0.48%) experienced MACE. Of the 6140 patients with 2 normal hs-trop and a delta (change in troponin)<4, 27 patients (0.44%; CI 0.29%-0.64%) experienced MACE. Only 1 of the 69 patients with 2 normal hs-trop results but delta (change in troponin) ≥ 4 (1.45%; CI 0.04%-7.81%) suffered MACE. This patient was classified as non-low risk by our institutional HEART score. Of 7498 patients with an index hs-trop<LOQ, 14 (0.19%; CI 0.10%-0.31%) experienced MACE, with 57% (N=8) deemed non-low risk by HEART score. Patients with 2 normal hs-trop values in the ED are unlikely to suffer 30-day MACE. Although it remains unclear whether patients with delta (change in troponin) ≥4 despite normal troponins will have a 30-day MACE, this situation is rare. Additionally, a single index hs-trop<6ng/L demonstrated a low risk for 30-day MACE independent of the institutional HEART score.

A-010 Systemwide Implementation of High Sensitivity Troponin T in a Multi-center Hospital Set Up with Instrument Variability: The Baystate Health Experience

Abstract Background High-sensitivity cardiac troponin (hs-cTn) testing helps in rapid risk stratification in patients with acute coronary syndromes resulting in early identification of low-risk patients eligible for early discharge. A high sensitivity troponin test can measure the 99th percentile upper reference limit with an analytical imprecision ≤10% and it can measure cTn above the limit of detection in ≥50% of healthy subjects. We carried out method validation of the Elecsys Gen 5 hsTnT assay with variable instrument capacities like Roche cobas e801, e601, and e411 in our health system. The analytical variability of these instruments was studied and standardized to implement the Gen 5 hsTnT assay systemwide for clinical use in four hospitals. Methods The cTnT control samples with low, medium, and high concentrations were used for precision studies (N = 20). The calibration materials at five levels ranging from 8 ng/L to 10 000 ng/L were used for evaluating linearity, accuracy, and analytical measurement range. The observed and assigned values were compared using linear regression analysis. Heparinized plasma samples were tested using the Gen 5 hsTnT assay. Method comparisons were carried out on different Roche cobas analyzers in each hospital splitting remnant specimens. Analyzer e801 performance was compared with a reference laboratory. Simultaneously, the e601 and e411 analyzers were compared with the e801. Statistical analysis was carried out using EP Evaluator and GraphPad Prism. Results The Roche e801 demonstrated imprecision of 0.5%–2.2% (N = 20), the e601 had imprecision of 0.4%–1.4% (N = 20) and the e411 had 0.8%–4.8% (N = 20) across the three levels of control samples tested. These were well below the expected imprecision criteria of ≤10% for troponins. Deming regression analysis of the 5th GEN assays showed linear relationship across platforms: y (e801 5th GEN) = 1.007x (Reference Lab 5th GEN) + 50.65, R = 0.9899 with positive bias of 8% (N = 45); y (e601 5th GEN) = 0.929x(e801 5th GEN) + (−1.426), R = 0.9995 with negative bias of 7% (N = 48); y (e411 5th GEN) = 0.942x(e801 5th GEN) + (−7.044), R = 1.000 with negative bias of 7% (N = 49). The accuracy, reportable range, and linearity of Gen 5 hsTnT were tested on e801, e611 and e411 analyzers over a measured range of 8–10 000 ng/L. Allowable systematic error (SEa) was 1.5 ng/L (conc) or 5.0% (e801); 1.5 ng/L (conc) or 7.5% (e611 and e411). The maximum deviation for a mean recovery from 100% was 2.4% (e801), 2.7% (e601) and 6.2% (e411). The 5 of 5 mean recoveries were accurate within the SEa for all the three analyzers. The 15 out of 15 results were accurate within the allowable total error (TEa) of 3 ng/L (conc) or 10.0% (e801), 3 ng/L (conc) or 15.0% (e601 and e411). The three analyzers passed reportable range and accuracy tests, and the results were linear. Conclusion The TEa was determined from instrument specific imprecision, systemwide medical decision limits and parameters of rule out criteria. The standardization of analytical performance characteristics is important in a large health system with instrument variability and provision of transfer of care across health systems.

A-164 Key Performance Indicators (KPIs) Can be Polluted by Add-on Tests

Abstract Background Key Performance Indicators (KPIs) are a measurement of service performance which are measured frequently and can demonstrate the clinical effectiveness of services. We undertook a review of a subset of KPIs following feedback from clinicians in the emergency department that was at odds to our reported KPIs. Our reported KPIs suggested that we were not meeting the turnaround times (TATs) required (1 h from receipt in the laboratory to result availability), however the view of the clinicians was that we were achieving the KPIs needed to manage their patients. We undertook an exercise to quantify the impact of add-on tests to our published KPIs as our laboratory information systems are not able to discriminate tests that are added on at a later time from those that go though as a first pass. Methods We reviewed all data (February 2022) for 4 common tests requested in the Emergency Department at King’s College NHS Foundation Hospital: amylase, CRP, paracetamol and high sensitivity troponin. Through a laborious process, we reviewed all records where a test had been added on to compare the turnaround time (TAT) for tests that pass through the first time and those that are added on so that we could quantify the impact of add-ons. Results In the month of February 2022, we processed 754 amylase, 4014 CRP, 121 paracetamol and 1414 high sensitivity troponin tests. The highest proportion of add-on tests was experienced with troponin (9.7%), amylase (9.4%) and paracetamol (8.3%). The lowest percentage of add-on tests was CRP (1.9%). Figures to be presented will demonstrate the impact of add-on tests as compared to those that go through as a first pass yield in whisker box plot format, non-truncated. Conclusion Add-on tests were polluting the KPIs that we were reporting. The service was delivering a TAT that the clinicians required, however our legacy internal reporting systems were not able to discern the date/time of add-on from that of the receipt of the tube into CSR or strip out the add-ons from the KPI reports and hence the negative impact that they have on reporting.

Results from healthy donors for novel point-of-care high-sensitivity troponin test

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction This study evaluates healthy donor values of a novel high-sensitivity troponin test, an 8-minute whole blood assay performed with fingerstick or Lithium-heparin samples using a handheld sized platform designed for Point-of-Care or in-lab measurements. In accordance with the Fourth Universal Definition of Myocardial Infarction, whole blood 99th percentile upper reference limits (URLs) and 50th percentile (median) values for healthy individuals were characterised per gender; values were established for fingerstick, venous whole blood, and plasma. Purpose To determine 99th percentile URLs for hs-cTnI in healthy donors as myocardial injury cut-off for use in clinical trials and clinical practice. The median values were determined to confirm high-sensitivity performance in all matrices. Methods Whole blood from consented healthy subjects, 22 to 85 years (n=810), were collected across 5 clinical sites. Subjects taking cardiac history/medications or having abnormal hemoglobin A1c, NT-proBNP, and eGFR values were excluded. hs-cTnI values were determined in capillary (fingerstick), Li-Heparin venous whole blood, and venous Li-Heparin plasma matrices. Sex-specific and overall 99th percentile URLs using the recommended non-parametric approach and median values for each sample matrix were determined. Results Statistical outliers were eliminated by the Dixon-Reed test, prior to calculating the 99th percentile and median values. There was no significant difference between the three sample types. The median results are tabulated below: as expected, the female values are lower than the male values (p &amp;lt;0.01). These data additionally show that &amp;gt;50% of results exceed the assays limit of detection [ref .1] for all matrices, confirming this assay is a high-sensitive assay for troponin-I. Conclusion The novel hs-cTnI system is the first that demonstrates high-sensitivity cTnI performance in fingerstick, whole blood and plasma matrices. Quality measurements in all three matrices translates to use with confidence in emergency department and other diagnosis and triage settings. Hence, the data presented here are of relevance to current and future studies and clinical implementation of this device. Table 1: median hs-cTnI values in healthy subject, % of subjects above LoD (limit of detection) and %CV at 99th URL.

152 EXPLORATORY ANALYSIS OF TROPONIN AS BIOMARKER OF ACUTE ISCHAEMIC STROKE SUBTYPES IN A GROUP OF PATIENTS RECRUITED TO THE MIND STUDY

Abstract Background Stroke is a major common cause of acquired disability and death worldwide. Atrial dysfunction or cardiomyopathy, defined by the presence of specific serum biomarkers, ECG findings, or echocardiographic findings, increases the risk of atrial fibrillation, which has been implicated as a key risk factor for ischaemic stroke. There is now growing body of evidence which suggests that early positive troponin after ischaemic stroke may be independently associated with a cardiac embolic source. miRNA as Novel Diagnostic biomarker (MiND) is a current Irish-led research study whose aim is to discover a unique highly diagnostic and prognostic biomarker expressed in acute ischaemic stroke. Methods Data were retrospectively extracted from patients recruited to the MiND study with confirmed diagnosis of acute ischaemic stroke within 12 hours of symptoms onset having also undergone high-sensitivity troponin testing from July 2019 to November 2021. Stroke subtypes were classified as per ESUS criteria. Statistical analysis was carried out using STATA/SE, version 16.0. Results We identified 52 patients who had troponin performed within 12 hours of symptoms onset. Twenty-two patients were identified as having cardioembolic stroke (CE), 17 as non-cardioembolic stroke (NCE) and 13 as Embolic stroke of unknown source (ESUS). The mean age for each group was 77.5 (±9.8), 65.5 (±12.8) and 66.3 (±11.7) years, respectively. The rate of troponin positivity for each group was 55% (12/22), 29% (5/17) and 15% (2/13), respectively. The unadjusted logistic analysis revealed a positive association between CE stroke subtype and elevated troponin (OR 3.94, 95% 1.20-12.98, p = 0.024) and an inverse association between ESUS stroke subtype and elevated troponin (OR 0.24, 95% CI 0.05-1.21, p = 0.083). Conclusion Our analysis reveals that early positive troponin after ischaemic stroke is a strong predictor of CE stroke subtype but not of ESUS stroke subtype.

Clinical Applications of High-Sensitivity Troponin Testing: From Diagnosis to Prognosis.

High-sensitivity cardiac troponin (hs-cTn) is critical in the diagnosis of acute coronary syndrome. However, it can also inform risk of cardiovascular events and mortality. Patients with unstable angina and normal-range hs-cTn have a very favorable short-term prognosis and do not appear to suffer increased risk of cardiovascular events and mortality. Such patients can often be treated in the outpatient setting.

Finding acute coronary syndrome with serial troponin testing for rapid assessment of cardiac ischemic symptoms (FAST-TRAC): a study protocol

ObjectiveTo determine the utility of a highly sensitive troponin assay when utilized in the emergency department.MethodsThe FAST-TRAC study prospectively enrolled >1,500 emergency department patients with suspected acute coronary syndrome within 6 hours of symptom onset and 2 hours of emergency department presentation. It has several unique features that are not found in the majority of studies evaluating troponin. These include a very early presenting population in whom prospective data collection of risk score parameters and the physician’s clinical impression of the probability of acute coronary syndrome before any troponin data were available. Furthermore, two gold standard diagnostic definitions were determined by a pair of cardiologists reviewing two separate data sets; one that included all local troponin testing results and a second that excluded troponin testing so that diagnosis was based solely on clinical grounds. By this method, a statistically valid head-to-head comparison of contemporary and high sensitivity troponin testing is obtainable. Finally, because of a significant delay in sample processing, a unique ability to define the molecular stability of various troponin assays is possible.Trial registrationClinicalTrials.gov Identifier NCT00880802

Adoption of High-sensitivity Troponin Testing and Emergency Physician Ordering Behavior

IntroductionEmergency departments (ED) are rapidly replacing conventional troponin assays with high-sensitivity troponin tests. We sought to evaluate emergency physician utilization of troponin tests before and after high-sensitivity troponin introduction in our ED.MethodsWe retrospectively examined 9,477 ED encounters, identifying the percentage in which physicians ordered a serum troponin both before and after our institution adopted a high-sensitivity troponin test.ResultsAfter introduction of high-sensitivity troponin testing, the percentage of ED encounters in which physicians ordered troponin studies decreased (28.3% before vs 22% after; P <.001), with the drop most pronounced in admitted patients (decrease of 10.9% [95% confidence interval [CI]: 7.3%–14.5%] in admitted patients vs decrease of 3.6% [95% CI: 1.7%–5.4%] in discharged patients; P<.001)ConclusionIntroduction of high-sensitivity troponin testing was associated with a decrease in troponin ordering. While the reasons for this are unclear, it is possible that physicians became more selective in their ordering behavior because of the lower specificity of high-sensitivity troponin.

Prognostic implications of serial high-sensitivity cardiac troponin testing among patients with COVID-19: A Danish nationwide registry-based cohort study

BackgroundAlthough troponin elevation is associated with worse outcomes among patients with coronavirus disease 2019 (COVID-19), prognostic implications of serial troponin testing are lacking. We investigated the association between serial troponin measurements and adverse COVID-19 outcomes. MethodsUsing Danish registries, we identified COVID-19 patients with a high-sensitivity troponin measurement followed by a second measurement within 1–24 h. All measurements during follow-up were also utilized in subsequent time-varying analyses. We assessed all-cause mortality associated with the absence/presence of myocardial injury (≥1 troponin measurement >99th percentile upper reference limit) and absence/presence of dynamic troponin changes (>20% relative change if first measurement elevated, >50% relative change if first measurement normal). ResultsOf 346 included COVID-19 patients, 56% had myocardial injury. Overall, 20% had dynamic troponin changes. In multivariable Cox regression models, myocardial injury was associated with all-cause mortality (HR = 2.56, 95%CI = 1.46–4.51), as were dynamic troponin changes (HR = 1.66, 95%CI = 1.04–2.64). We observed a low incidence of myocardial infarction (4%) and invasive coronary procedures (4%) among patients with myocardial injury. ConclusionsMyocardial injury and dynamic troponin changes determined using serial high-sensitivity troponin testing were associated with poor prognosis among patients with COVID-19. The risk of developing myocardial infarction requiring invasive management during COVID-19 hospitalization was low.

Initial experience regarding the safety and yield of rest-stress myocardial perfusion imaging in emergency department patients with mildly abnormal high-sensitivity cardiac troponins

BackgroundWith high-sensitivity troponin testing, approximately a third of patients presenting to emergency departments (EDs) with suspected acute coronary syndromes will have mildly abnormal values. However, data regarding rest-stress myocardial perfusion imaging (MPI) in these patients are limited. We hypothesize that stress testing is safe and that the yield for detecting myocardial ischemia is associated with risk stratification by the HEART score. Methods and ResultsWe conducted a retrospective cohort study of consecutive patients referred for rest-stress MPI with mildly abnormal high-sensitivity troponin T (hs-cTn) values. Outcomes were adverse events related to stress MPI, defined as myocardial infarction or ventricular tachyarrhythmia, and the presence of ischemia, defined as a reversible perfusion defect. Among 213 patients, the median age was 67, most were male (61.5%, n = 131), and prior CAD was common (53.5%, n = 114). Myocardial ischemia was present in 13.6% (n = 29), and there were no adverse events attributable to stress MPI. A higher HEART score was associated with myocardial ischemia (Odds Ratio [OR] 1.50, 95% Confidence Interval [CI] 1.08 to 2.08, P = .002). ConclusionRest-stress MPI appears safe in patients with mildly abnormal hs-cTn values, and the yield for detecting ischemia is associated with the HEART score, though further validation studies are needed.

Transient Acquired QT Interval Prolongation After Administration of Intravenous Ondansetron

A 62-year-old man with a history of stable ischemic heart disease presented to the emergency room with nausea, vomiting, and chest pain at rest. The chest pain was atypical in nature; it did not respond to nitroglycerin and did not worsen with exertion. He took only aspirin, metoprolol, and ramipril at home. The patient was normotensive and normoxemic. Serial high-sensitivity troponin test results were normal, and other bloodwork (including calcium and magnesium levels) was unremarkable, with the exception of a serum potassium level of 2.4 mmol/L. His presenting electrocardiogram (ECG; Fig. 1A ) showed sinus rhythm with a right bundle branch block and a mildly prolonged QTc interval (450 msec using Bazett’s formula1Bazett H. An analysis of the time-relations of electrocardiograms.Heart. 1920; 7: 353-370Google Scholar). However, conduction delays prolong the QRS interval, which affects the length of the QT interval without significant impact on the repolarization duration. Bogossian’s formula can correct the QTc interval in the presence of bundle branch blocks, and this yielded a normal QTc interval of 302 msec.2Bogossian H. Linz D. Heijman J. et al.QTc evaluation in patients with bundle branch block.Int J Cardiol Heart Vasc. 2020; 30: 100636PubMed Google ScholarFigure 1Electrocardiogram showing (A) sinus rhythm with a right bundle branch block (bbb) and mildly prolonged QTc interval; (B) ST changes with profound QTc interval prolongation; and (C) partial resolution of the ST changes.View Large Image Figure ViewerDownload Hi-res image Download (PPT) During his time in the emergency room, he experienced nausea and was given 4 mg of ondansetron intravenously. He was also given 40 mmol of KCl orally for his hypokalemia. Fifteen minutes later, the patient had a mild recurrence of atypical chest discomfort at rest, and another ECG Fig. 1B) was performed. This showed nonspecific ST changes with profound QTc interval prolongation, using both Bogossian’s formula (562 msec) and Bazett’s formula (628 msec). In addition to QTc interval prolongation, there was a dramatic difference in T wave morphology, including prolongation of the Tpeak–Tend interval. Ten minutes later, an ECG (Fig. 1C) and blood work were repeated, which showed a serum potassium level of 3 mmol/L, and partial resolution of the ST changes. The patient was not given any further QT-prolonging medication, and he was subsequently diagnosed with noncardiac chest pain after undergoing normal stress myocardial perfusion imaging. Severe hypokalemia is a known cause of QT interval prolongation.3Yelamanchi V.P. Molnar J. Ranade V. Somberg J.C. Influence of electrolyte abnormalities on interlead variability of ventricular repolarization times in 12-lead electrocardiography.Am J Ther. 2001; 8: 117-122Crossref PubMed Scopus (35) Google Scholar However, this patient’s initial ECG demonstrates a normal (by Bogossian’s formula) or only modestly prolonged (by Bazett’s formula) QTc interval. Subsequent administration of IV ondansetron resulted in profound transient QTc interval prolongation relative to this patient’s baseline, and marked changes in T wave morphology. It has been previously described that intravenous ondansetron administration can lead to QT interval prolongation and T wave changes. Our patient had a history of ischemic heart disease; the presence of structural heart disease increases the risk for acquired QT interval prolongation. Such prolongations of the QTc and Tpeak–Tend intervals are associated with increased risk of Torsades de Pointes and sudden cardiac death, with the risk increasing proportionally to QTc interval duration.4Thomas S. Behr E. Pharmacologic treatment of acquired QT prolongation and torsades de pointe.Br J Clin Pharmacol. 2016; 81: 420-427Crossref PubMed Scopus (67) Google Scholar, 5Hafermann M. Namdar R. Seibold G. et al.Effect of intravenous ondansetron on QT interval prolongation in patients with cardiovascular disease and additional risk factors for torsades: a prospective, observational study.Drug Healthc Patient Saf. 2011; 3: 53-58PubMed Google Scholar, 6Tse G. Gong M. Meng L. et al.Predictive value of Tpeak-Tend indices for adverse outcomes on acquired QT prolongation: a meta-analysis.Front Physiol. 2018; 9: 1226Crossref PubMed Scopus (18) Google Scholar These images demonstrate the importance of cautious administration of QT interval–prolonging medications, particularly in the presence of other risk factors for QT interval prolongation such as hypokalemia and underlying structural heart disease, even if the baseline QTc interval is not markedly prolonged.Novel Teaching Points•Proper assessment of the QT interval is important in the setting of a bundle branch block, as widening of the QRS will cause subsequent QT interval prolongation without significant impact on the duration of repolarization.•Bogossian’s formula is an alternative method for calculating the QT interval in the setting of a bundle branch block. However, no single formula is perfect for QTc interval calculation in every situation.•Caution is needed when prescribing medications that prolong the QT interval, especially for patients with an underlying predilection for QT interval prolongation.

Reductions in Major Downstream Care After Switch to High-Sensitivity Troponin Test

In 2017, the FDA approved high-sensitivity cardiac troponin (hs-cTn) assays. Clinicians now regularly use these tests that lower the limit of

Инфаркт миокарда без подъема сегмента ST: особенности патогенеза, диагностики, инвазивных вмешательств

The literature review presents data about pathogenesis of non-ST-segment elevation myocardial infarction (non-STEMI), the characteristics of modern high-sensitivity troponin tests, invasive strategy management of patients with non-STEMI.

Distribution of High-Sensitivity Troponin Taken Without Conventional Clinical Indications in Critical Care Patients and Its Association With Mortality.

To describe the distribution of high-sensitivity troponin in a consecutive cohort of patients in critical care units, regardless of clinical indication, and its association with clinical outcomes. Prospective observational study. Single-center teaching hospital. Consecutive patients admitted to two adult critical care units (general critical care unit and neuroscience critical care unit) over a 6-month period. All patients had high-sensitivity troponin tests performed at admission and tracked throughout their critical care stay, regardless of whether the supervising team felt there was a clinical indication. The results were not revealed to patients or clinicians unless clinically requested. There were 1,033 patients in the study cohort (general critical care unit 750 and neuroscience critical care unit 283). The median high-sensitivity troponin was 21 ng/L (interquartile range, 7-86 ng/L), with 560 patients (54.2%) above the upper limit of normal as defined by the manufacturer. Admission high-sensitivity troponin concentrations above the upper limit of normal in general critical care unit and neuroscience critical care unit were associated with increasing age, comorbidity, markers of illness severity, and the need for organ support. On adjusted analysis, the high-sensitivity troponin concentration remained an independent predictor of critical care mortality in general critical care unit and neuroscience critical care unit. High-sensitivity troponin elevation, taken outside the context of conventional clinical indications, was common in the critically ill. Such elevations were associated with increasing age, comorbidity, illness severity, and the need for organ support. Admission high-sensitivity troponin concentration is an independent predictor of critical care mortality and as such may represent a novel prognostic biomarker at admission.

High sensitivity troponin testing: is it what we really wanted?

High sensitivity troponin testing: is it what we really wanted?