Serial 12-lead Electrocardiograms Research Articles

Utilizing median and maximum QTc values improves prediction of breakthrough cardiac events in pediatric long QT syndrome.

Although prior studies indicate that a QTc > 500 ms on a single baseline 12-lead electrocardiogram (ECG) is associated with significantly increased risk of arrhythmic events in long QT syndrome (LQTS), less is known about the risk of persistent QT prolongation. We sought to determine QTc persistence and its prognostic effect on breakthrough cardiac events (BCEs) among pediatric patients treated for LQTS. We performed a retrospective analysis of 433 patients with LQTS evaluated, risk-stratified, and undergoing active guideline-based LQTS treatment between 1999 and 2019. BCEs were defined as arrhythmogenic syncope/seizure, sudden cardiac arrest (SCA), appropriate VF-terminating ICD shock, and sudden cardiac death (SCD). During the median follow-up of 5.5 years (interquartile range [IQR] = 3-9), 32 (7%) patients experienced a total of 129 BCEs. A maximum QTc threshold of 520 ms and median QTc threshold of 490 ms were determined to be strong predictors for BCEs. A landmark analysis controlling for age, sex, genotype, and symptomatic status demonstrated models utilizing both the median QTc and maximum QTc demonstrated the highest discriminatory value (c-statistic = 0.93-0.95). Patients in the high-risk group (median QTc > 490 ms and maximum QTc > 520 ms) had a significantly lower BCE free survival (70%-81%) when compared to patients in both medium-risk (93%-97%) and low-risk (98%-99%) groups. The risk of BCE among patients treated for LQTS increases not only based upon their maximum QTc, but also their median QTc (persistence of QTc prolongation). Patients with a maximum QTc > 520 ms and median QTc > 490 ms over serial 12-lead ECGs are at the highest risk of BCE while on guideline-directed medical therapy.

Does Speckle Tracking Transthoracic Echocardiography Indicate Subtle Changes in Left Ventricular Function in Heart Failure Patients with Reduced Ejection Fraction Treated by Sacubitril-valsartan?

In heart failure patients and reduced ejection fraction (HFrEF), assessing subtle changes in left ventricle (LV) function is crucial for monitoring treatment efficacy. This study aims to determine the effect of valsartan/sacubitril on LV ejection fraction (EF) assessed by two-dimensional (2D) transthoracic echocardiography (TTE) in comparison to that assessed by 2D TTE speckle tracking in patients with HFrEF ≤35% after 6 months of treatment. A prospective study will be conducted on 200 heart failure patients with reduced EF (HFrEF) undergoing sacubitril-valsartan treatment. Each participant underwent a comprehensive evaluation, including physical examination, history taking, serial 12-lead electrocardiogram, and 2D echo to evaluate cardiac parameters. In addition, 2D speckle tracking echocardiography (STE) assessments were conducted before and after 6 months of valsartan/sacubitril treatment. The enrolled patients had an average age of 48 years with 63% females. At the beginning of the study, 9 (4.5%) patients were classified as New York Heart Association (NYHA) FC I, 120 (60%) as NYHA FC II, 64 (32%) as NYHA FC III, and 7 (3.5%) as FC IV. Following treatment, 82 (41%) patients improved to NYHA FC I, and 118 (59%) were in NYHA FC II. Notably, 82 (41%) patients showed improved left ventricular EF (LVEF), detected either by traditional TTE or STE, whereas 118 (59%) showed no improvement in EF through traditional TTE. In addition, 74 (37%) patients demonstrated improvement detected by STE. In contrast, 44 (22%) patients demonstrated no improvement in EF detected by either TTE or STE. STE was a more reliable diagnostic method for seeing early LVEF improvement in patients with HFrEF receiving valsartan/sacubitril treatment not seen by conventional TTE.

Incorporation of Serial 12-Lead Electrocardiogram With Machine Learning to Augment the Out-of-Hospital Diagnosis of Non-ST Elevation Acute Coronary Syndrome

Ischemic electrocardiogram (ECG) changes are subtle and transient in patients with suspected non-ST-segment elevation (NSTE)-acute coronary syndrome. However, the out-of-hospital ECG is not routinely used during subsequent evaluation at the emergency department. Therefore, we sought to compare the diagnostic performance of out-of-hospital and ED ECG and evaluate the incremental gain of artificial intelligence-augmented ECG analysis. This prospective observational cohort study recruited patients with out-of-hospital chest pain. We retrieved out-of-hospital-ECG obtained by paramedics in the field and the first ED ECG obtained by nurses during inhospital evaluation. Two independent and blinded reviewers interpreted ECG dyads in mixed order per practice recommendations. Using 179 morphological ECG features, we trained, cross-validated, and tested a random forest classifier to augment non ST-elevation acute coronary syndrome (NSTE-ACS) diagnosis. Our sample included 2,122 patients (age 59 [16]; 53% women; 44% Black, 13.5% confirmed acute coronary syndrome). The rate of diagnostic ST elevation and ST depression were 5.9% and 16.2% on out-of-hospital-ECG and 6.1% and 12.4% on ED ECG, with ∼40% of changes seen on out-of-hospital-ECG persisting and ∼60% resolving. Using expert interpretation of out-of-hospital-ECG alone gave poor baseline performance with area under the receiver operating characteristic (AUC), sensitivity, and negative predictive values of 0.69, 0.50, and 0.92. Using expert interpretation of serial ECG changes enhanced this performance (AUC 0.80, sensitivity 0.61, and specificity 0.93). Interestingly, augmenting the out-of-hospital-ECG alone with artificial intelligence algorithms boosted its performance (AUC 0.83, sensitivity 0.75, and specificity 0.95), yielding a net reclassification improvement of 29.5% against expert ECG interpretation. In this study, 60% of diagnostic ST changes resolved prior to hospital arrival, making the ED ECG suboptimal for the inhospital evaluation of NSTE-ACS. Using serial ECG changes or incorporating artificial intelligence-augmented analyses would allow correctly reclassifying one in 4 patients with suspected NSTE-ACS.

Change in out-of-hospital 12-lead ECG diagnostic classification following resuscitation from cardiac arrest

IntroductionWe evaluated the incidence of change in serial 12-lead electrocardiogram (ECG) diagnostic classifications in patients resuscitated from out-of-hospital (OH) cardiac arrest (OHCA) comparing OH to emergency department (ED) ECGs. MethodsThis retrospective case series included: 1) adults (≥ 18 years old), 2) resuscitated from OHCA, 3) ≥ 1 OH and 1 ED ECG/patient, and 4) emergency medical services (EMS) transport to the study hospital. OH and ED ECGs were classified as: 1) STEMI (ST-segment Elevation Myocardial Infarction), 2) Ischemic, and 3) Non-ischemic. Two ED physicians and one cardiologist independently classified all ECGs, then generated a consensus opinion classification for each ECG based on American Heart Association’s 2018 Expert Consensus criteria. The most ischemic OH ECG classification was compared with the last ED ECG classification. ResultsFrom 7/27/12 to 7/18/19, 176 patients were entered with a mean age of 61.2 ± 16.6 years; 102/176 (58%) were male. Overall, 504 OH and ED 12-lead ECGs were acquired (2.9 ECGs/patient). ECG classification inter-rater reliability kappa score was 0.63 ± 0.02 (substantial agreement). Overall, 86/176 (49%) changed ECG classification from the OH to ED setting; 69/86 (80%) of these ECGs changed from more to less ischemic classifications. Of 49 OH STEMI ECG classifications, 33/49 (67%) changed to a less ischemic (non-STEMI) ED ECG classification. ConclusionsChange in 12-lead ECG classification from OH to ED setting in patients resuscitated from OHCA was common (49%). The OH STEMI classification changed to a less ischemic (non-STEMI) ED classification in 67% of cases.

Lessons Learned During the Pandemic: Correlation of QT Intervals Between Telemetry and 12-Lead Electrocardiogram.

Background and objectiveQT prolongation is associated with an increased risk of ventricular arrhythmias. Since some patients on contact or droplet precautions require QT-prolonging medications, monitoring the QT interval may become imperative to prevent fatal arrhythmias. To limit the exposure of staff to patients during and even after the coronavirus disease 2019 (COVID-19) pandemic and judiciously use personal protective equipment (PPE), it is important to find alternatives to frequent 12-lead electrocardiograms (ECG). The objective of this study was to compare QT intervals measured on telemetry to those measured on 12-lead ECG to determine whether telemetry QT interval measurements could be used in place of 12-lead measurements.MethodsSimultaneous telemetry recordings via a Philips telemetry monitoring system (Philips Healthcare, Eindhoven, Netherlands) and 12-lead ECGs were obtained from 50 patients. Patients were from cardiac telemetry and cardiac intensive care units. QT interval from the telemetry system was compared to the QT interval on the 12-lead ECG. QT intervals on two telemetry strips were uninterpretable as the termination of the T-wave could not be defined appropriately; therefore, these patients were excluded.ResultsIn 33 of 48 patients (69%), QT intervals from the telemetry studies matched the QT intervals measured by 12-lead ECG. The intraclass correlation coefficient (ICC) between telemetry QT and 12-lead ECG QT was 0.887 (95% CI: 0.809-0.934; p<0.001). In 15 of 48 patients (31%), the QT intervals measured from telemetry were different from those measured by 12-lead ECG. These patients either had an abnormal rhythm, conduction abnormalities, or repolarization abnormalities at baseline.ConclusionTelemetry is a suitable alternative for measuring QT intervals in the majority of patients. However, those with baseline ECG abnormalities should have serial 12-lead ECGs. This can reduce the risk of staff exposure to pathogens and prevent overuse of PPE during the COVID-19 pandemic and for other patients in isolation.

Importance of myocardial ischemia detected with protocol-based measurements of high-sensitivity troponin, ECG and echocardiography in critically ill patients without acute coronary syndrome—a prospective study

Elevated cardiac troponin is detected in the majority of critically ill patients. This study aimed to evaluate the prognostic value of protocol-guided detection of myocardial ischemia (MI) (serial 12-lead electrocardiograms (ECG), high-sensitivity troponin T (hsTnT) measurements, and echocardiography) and compare it with a retrospective cohort with only clinically driven detection of MI. In a prospective observational study, 95 patients hospitalized ≥48 hours for reasons other than acute coronary syndrome in medical or surgical intensive-care unit (ICU) were enrolled. A protocol-based approach, with regular 12-lead ECG recordings, hsTnT measurements and admission echocardiography was conducted. All events possibly indicating MI were documented, and ECG, hsTnT, echocardiography were repeated. The protocol-based approach was compared to a retrospective group with only clinically driven detection of MI. In the prospective group, 95.8% of patients had at least one elevated hsTnT value. A hsTnT ＞70 ng/L was associated with the use of inotropes (OR 3.35 (95% CI: 1.184, 9.472), p = 0.022), left ventricular ejection fraction &lt;30% (OR 9.65 (95% CI: 1.172, 76.620), p = 0.035), regional wall motion abnormalities (OR 3.87 (95% CI: 1.032, 14.533), p = 0.045), ICU mortality (OR 8.38 (95% CI: 1.004, 69.924), p = 0.0495), hospital mortality (OR 3.05 (95% CI: 1.133, 8.230), p = 0.027) and 1-year mortality (OR: 5.43 (95% CI: 2.1099, 13.971), p = 0.005). The incidence of MI was higher in the prospective, as compared to the retrospective group (22.1% vs 5.3%; p = 0.001). MI, compared to the high “hsTnT positive only” group, predicted hospital mortality (OR 3.33 (95% CI: 1.190, 9.329), p = 0.02) and 1-year mortality (OR 4.66 (95% CI: 1.647, 13.222), p = 0.0037). A protocol-based compared to a clinically driven approach for the detection of MI reveals more patients with MI. The majority of critically ill patients have elevated hsTnT levels. Detected MI additionally stratifies patients with elevated hsTnT to higher hospital and 1-year mortality.

Atypical chest pain with precordial T wave inversions

A 74-year-old woman with a prior history of coronary artery disease presented to the emergency department with intermittent, burning epigastric pain. Five months prior, she had a stress echocardiogram that showed no signs of ischemia. On presentation, her cardiac exam was normal, chest auscultation revealed wheezes, and the chest wall was tender. Her chest pain resolved on admission. A complete blood count, comprehensive metabolic panel, and serial troponin levels were normal. Serial 12-lead electrocardiograms (ECGs) demonstrated dynamic T wave inversions in the precordial leads, most notably in leads V2-V3 (Figure 1A-B).

Atrial fibrillation trial to evaluate real-world procedures for their utility in helping to lower stroke events: A randomized clinical trial.

BackgroundEnhancing detection of unrecognized atrial fibrillation among acute ischemic stroke patients is crucial for secondary stroke prevention.AimTo evaluate whether the detection rate of new atrial fibrillation in acute ischemic stroke patients without known atrial fibrillation could be improved by doing serial 12-lead electrocardiograms once daily for five days, compared with conventional 24-h Holter monitoring (24-h Holter).MethodsWe conducted a randomized clinical trial to compare the detection rates of paroxysmal atrial fibrillation between serial electrocardiograms versus 24-h Holter from October 2015 to October 2018 at six hospitals. Eligible participants were acute ischemic stroke patients with aged ≥65 years, with neither atrial fibrillation history nor any presence of atrial fibrillation on baseline electrocardiogram at admission. The primary outcome was newly detected electrocardiogram in the serial electrocardiograms and 24-h Holter group.ResultsAmong 826 patients, baseline characteristics were similar between both groups. In the intention-to-treat analysis, there was no statistical difference between serial electrocardiograms versus 24-Holter to detect atrial fibrillation (8.4% vs. 6.9%; adjusted odds ratio 1.17, 95% confidence interval 0.69–2.01). Stepwise multivariate logistic regression revealed age ≥80 years and history of heart failure were associated with detection of paroxysmal atrial fibrillation whereas patients with lacunar infarction had lower odds for detection of paroxysmal atrial fibrillation.ConclusionsSerial electrocardiograms had comparable detection rate of paroxysmal atrial fibrillation compared with 24-h Holter and might be a viable alternative to 24-h Holter as a first-line approach to survey for potential paroxysmal atrial fibrillation among elderly patients with acute ischemic stroke.Clinical Trial Registration: URL https://clinicaltrials.gov/ct2/show/NCT02578979Unique Identifiers: NCT02578979

Enhanced Response to Drug-Induced QT Interval Lengthening in Patients with Heart Failure with Preserved Ejection Fraction

Patients with heart failure (HF) with reduced ejection fraction demonstrate enhanced response to drug-induced QT interval lengthening and are at increased risk for torsades de pointes. The influence of HF with preserved ejection fraction (HFpEF) on response to drug-induced QT lengthening is unknown. We administered intravenous ibutilide 0.003 mg/kg to 10 patients with HFpEF and 10 age- and sex-matched control subjects without HF. Serial 12-lead electrocardiograms were obtained for determination of QT intervals. Demographics, maximum serum ibutilide concentrations, area under the serum ibutilide concentration vs time curves, and baseline Fridericia-corrected QT (QTF) (417 ± 14 vs 413 ± 15 ms, P = .54) were similar in the HFpEF and control groups. Area under the effect (QTFvs time) curve (AUEC) from 0 to 1.17 hours during and following the ibutilide infusion was greater in the HFpEF group (519 ± 19 vs 497 ± 18 ms·h, P= .04), as was AUEC from 0 to 8.17 hours (3576 ± 125 vs 3428 ± 161 ms·h, P = .03) indicating greater QTF interval exposure. Maximum QTF (454 ± 15 vs 443 ± 22 ms, P = .18) and maximum percent increase in QTF from baseline (8.2 ± 2.1 vs 6.7 ± 1.9%, P = .10) in the 2 groups were not significantly different. HFpEF is associated with enhanced response to drug-induced QT interval lengthening.

A proposal for a reconstruction (derivation) of V1-V6 using leads I, II, and a “sternal notch lead”: A solution to the problem of non-reproducibility of precordial leads in serial 12-lead standard electrocardiograms

Variation of the amplitude and morphology of V1-V6 leads in serial ECGs, due to variation in the placement of V1-V6 recording electrodes, and the noncompliance in placing the V1-V6 electrodes at the recommended thoracic loci, are 2 problems which have defied solution since the advent of electrocardiography. A proposal is presented herein of a set of 3 recorded leads (conventional limb leads I and II, and a lead recorded via an electrode adjacent to the sternal notch [SNL]), aimed at reconstructing the V1-V6 leads, as a function of the 3 recorded leads, employing patient-specific and general (population) coefficients. The SNL electrode is expected to be placed at a designated thoracic site without ambiguity, and thus in conjunction with the limb leads I and II, to yield a hybrid 12-lead ECG with the conventional 6 limb leads and 6 derived V1-V6 leads. The SNL will result in the elimination of the problems of variation in the placement of V1-V6 electrodes, and the noncompliance of placing the V1-V6 electrodes at the recommended thoracic sites, and the resultant variation in the amplitude and morphology of the V1-V6 leads in serial ECGs.

Assessing the accuracy of an automated atrial fibrillation detection algorithm using smartphone technology: The iREAD Study

The Kardia Mobile Cardiac Monitor (KMCM) detects atrial fibrillation (AF) via a handheld cardiac rhythm recorder and AF detection algorithm. The algorithm operates within predefined parameters to provide a "normal" or "possible atrial fibrillation detected" interpretation; outside of these parameters, an "unclassified" rhythm is reported. The system has been increasingly used, but its performance has not been independently tested. The objective of this study was to evaluate whether the KMCM system can accurately detect AF. A single-center, adjudicator-blinded case series of 52 consecutive patients with AF admitted for antiarrhythmic drug initiation were enrolled. Serial 12-lead electrocardiograms (ECGs) and nearly simultaneously acquired KMCM recordings were obtained. There were 225 nearly simultaneously acquired KMCM and ECG recordings across 52 enrolled patients (mean age 68 years; 67% male). After exclusion of unclassified recordings, the KMCM automated algorithm interpretation had 96.6% sensitivity and 94.1% specificity for AF detection as compared with physician-interpreted ECGs, with a κ coefficient of 0.89. Physician-interpreted KMCM recordings had 100% sensitivity and 89.2% specificity for AF detection as compared with physician-interpreted ECGs, with a κ coefficient of 0.85. Sixty-two recordings (27.6%) were unclassified by the KMCM algorithm. In these instances, physician interpretation of KMCM recordings had 100% sensitivity and 79.5% specificity for AF detection as compared with 12-lead ECG interpretation, with a κ coefficient of 0.71. The KMCM system provides sensitive and specific AF detection relative to 12-lead ECGs when an automated interpretation is provided. Direct physician review of KMCM recordings can enhance diagnostic yield, especially for unclassified recordings.

Utility of serial 12-lead electrocardiograms in children with Marfan syndrome.

The goal of this study was to assess the utility of serial electrocardiograms in routine follow-up of paediatric Marfan patients. Children ⩽18 years who met the revised Ghent criteria for Marfan syndrome and received a 12-lead electrocardiogram and echocardiogram within a 3-month period were included. Controls were matched by age, body surface area, gender, race, and ethnicity, and consisted of patients assessed in clinic with a normal cardiac evaluation. Demographic, clinical, echocardiographic, and electrocardiographic data were collected. A total of 45 Marfan patients (10.8 [2.4-17.1] years) and 37 controls (12.8 [1.3-17.1] years) were included. Left atrial enlargement and left ventricular hypertrophy were more frequently present on 12-lead electrocardiogram of Marfan patients compared with controls (12 (27%) versus 0 (0%), p<0.001; and 8 (18%) versus 0 (0%), p=0.008, respectively); however, only two patients with left atrial enlargement on 12-lead electrocardiogram were confirmed to have left atrial enlargement by echocardiogram, and one patient had mild left ventricular hypertrophy by echocardiogram, not appreciated on 12-lead electrocardiogram. QTc interval was longer in Marfan patients compared with controls (427±16 versus 417±22 ms, p=0.03), with four Marfan patients demonstrating borderline prolonged QTc intervals for gender. While Marfan patients exhibited a higher frequency of left atrial enlargement and left ventricular hypertrophy on 12-lead electrocardiograms compared with controls, these findings were not supported by echocardiography. Serial 12-lead electrocardiograms in routine follow-up of asymptomatic paediatric Marfan patients may be more appropriate for a subgroup of Marfan patients only, specifically those with prolonged QTc interval at their baseline visit.

Osborn waves following out-of-hospital cardiac arrest—Effect of level of temperature management and risk of arrhythmia and death

BackgroundThe Osborn or J-wave, an upright deflection of the J-point on the electrocardiogram (ECG), is often observed during severe hypothermia. A possible relation between Osborn waves (OW) and increased risk of ventricular arrhythmia has been reported. We sought to determine whether the level of targeted temperature management (TTM) following out-of-hospital cardiac arrest (OHCA) affects the prevalence of OW and to assess the associations between OW and risk of ventricular arrhythmia and death. Methods and resultsThe present study is part of the TTM-trial ECG-substudy (including OHCA-patients randomized to TTM at 33 °C vs. 36 °C from 24 of 36 sites). Serial 12-lead ECGs from 680 (94%) patients were analysed and stratified by OW at predefined time-points (0, 4, 28, 36, 72-h after admission).On admission, the overall prevalence of OW was 16%, increasing to 32% at target temperature, with higher prevalence in the 33 °C-group (40% vs. 23%, p < 0.0001). No difference in prevalence was found between the 33 °C- and 36 °C-groups on admission (18% vs. 14%, p = .11) or after rewarming (13% vs. 10%, p = .44). OW were not associated with increased risk of ventricular arrhythmia (Odds ratio = 0.78 (0.51–1.20), p = .26), but associated with significantly lower 180-day mortality as compared to no OW (38% vs. 52%, plog-rank = 0.001) in univariable analyses only. ConclusionOW are frequent during TTM, particularly in patients treated with 33 °C. OW are not associated with increased risk of ventricular arrhythmia, and may be considered a benign physiological phenomenon, associated with lower mortality in univariable analyses.

Usefulness of Serial 12-Lead Electrocardiograms in Predicting 30-Day Outcomes in Patients With Undifferentiated Chest Pain (the ASAP CATH Study)

An initial electrocardiogram (ECG) and serial troponin measurements are both independently and incrementally predictive of acute coronary syndrome in patients presenting with undifferentiated chest pain in the Emergency Department (ED). However, it is unclear if serial (ECGs) add significant to the contemporary diagnostic evaluation of this patient group. The ASAP CATH study was a single center, prospective study that enrolled patients presenting to an ED with undifferentiated chest pain. In addition to standard clinical evaluation, serial ECGs were performed at 90-minute intervals to evaluate whether serial changes suggestive of ischemia developed (Q waves, ST elevation or depression, or T-wave inversion). Total 365 subjects were enrolled from March 2014 to May 2015. Serial ECG changes developed in 6.6% (n = 24 of 365), the most common being the development of T-wave inversion (66.7%, n = 16 of 24). The sensitivity and positive predictive value of serial ECG changes were poor (<30%), with a less areas under the curve (0.55) compared with serial troponins alone (0.83). The addition of serial ECG changes to Thrombolysis In Myocardial Infarction risk scoring showed a decrease in the net reclassification index for major adverse cardiovascular events (-0.04, p <0.1) and was not significant for the prediction of major adverse cardiovascular events and/or acute coronary syndrome in 30 days (-0.003, p = 0.94). In conclusion, routine serial ECG evaluation for patients presenting with undifferentiated chest pain in the ED may not significantly improved diagnostic prognosis beyond current standard evaluation modalities.

Detection of STEMI Using Prehospital Serial 12-Lead Electrocardiograms

Objective: Repeated or serial 12-lead electrocardiograms (ECGs) in the prehospital setting may improve management of patients with subtle ST-segment elevation (STE) or with a ST-segment elevation myocardial infarction (STEMI) that evolves over time. However, there is a minimal amount of scientific evidence available to support the clinical utility of this method. Our objective was to evaluate the use of serial 12-lead ECGs to detect STEMI in patients during transport in a Canadian emergency medical services (EMS) jurisdiction. Methods: We performed a retrospective study of suspected STEMI patients transported by EMS in the Chaudière-Appalaches region (Québec, Canada) between August 2006 and December 2013. Patients were monitored by a serial 12-lead ECG system where an averaged ECG was transmitted every 2 minutes. Following review by an emergency physician, ECGs were grouped as having either a persistent STE or a dynamic STE that evolved over time. Results: A total of 754 suspected STEMI patients were transported by EMS during the study period. Of these, 728 patients met eligibility criteria and were included in the analysis. A persistent STE was observed in 84.3% (614/728) of patients, while the remaining 15.7% (114/728) had a dynamic STE. Among those with dynamic STE, 11.1% (81/728) had 1 ST-segment change (41 no-STEMI to STEMI; 40 STEMI to no-STEMI) and 4.5% (33/728) had ≥ 2 ST-segment changes (17 no-STEMI to STEMI; 16 STEMI to no-STEMI). Overall, in 8.0% (58/728) of the cohort, STEMI was identified on a subsequent ECG following an initial no-STEMI ECG. Conclusions: Through recognition of transient ST-segment changes during transport via the prehospital serial 12-lead ECG system, STEMI was identified in 8% of suspected STEMI patients who had an initial no-STEMI ECG. Key words: electrocardiography; emergency medical services; ST-elevation myocardial infarction; prehospital dynamic ECG

Diagnostic Value of D-Dimer in Acute Myocardial Infarction Among Patients With Suspected Acute Coronary Syndrome.

BackgroundThe role of D-dimer as a diagnostic marker in myocardial infarction (MI) and acute coronary syndrome (ACS) is still a question. The aim of this study was to evaluate the diagnostic value of D-dimer in the diagnosis of AMI in patients suspected with ACS.MethodsThis cross-sectional study was conducted on patients suspected with ACS. Serial standard 12-lead electrocardiogram (ECG), D-dimer, and troponin tests were done for all the patients. According to the examinations, ECG changes, and troponin, patients were allocated into two groups of MI and unstable angina (UA). Chi-square, independent t-test, and Pearson correlation test were used by SPSS ver, 17. Cut-off point of D-dimer for MI diagnosis was evaluated by receiver operating characteristic (ROC) curve analysis.ResultsSeventy-five patients with a mean age of 63.1 ± 9.75 years were studied in two groups of MI (n = 34) and UA (n = 41). Patients were homogeneous based on age, gender, and risk factors for diabetes and dyslipidemia. D-dimer in patients with MI patients was higher than in patients with UA (P = 0.001). The optimal cut-off point of D-dimer for diagnosis of MI was 548 mEq/L with sensitivity and specifity of 63.4% and 91.2%, respectively.ConclusionsBased on the results of this study, it seems that the measurement of D-dimer serum level can be appropriate as a marker with high sensitivity and relatively high specificity for differentiating MI from UA in patients with suspected ACS.

Atrial fibrillation trial to evaluate real-world procedures for their utility in helping to lower stroke events (AFTER-PULSE): Study protocol for a randomized controlled trial.

BackgroundEnhancing detection of undiagnosed atrial fibrillation (AF) in hospitalized patients with a recent ischemic stroke is important because of the treatment implications; especially since presence of paroxysmal AF may not be picked up in a single 12-lead electrocardiogram (ECG) test. While several trials have shown improved detection of AF with prolonged ECG monitoring, this strategy is associated with relatively high cost, labor intensity, and patient inconvenience, thereby making it challenging to routinely implement in all hospitals. Fortunately, conventional 24-h Holter monitoring and repeated 12-lead ECGs are readily available to detect paroxysmal AF in all hospitals, but is unclear which is the better strategy for evaluating undiagnosed AF. The objective of his study is to conduct a randomized trial of serial 12-lead ECGs vs. 24-hour Holter monitoring in the detection of AF in ischemic stroke patients without known AF.Methods and analysisWe plan to enroll 1200 participants from six hospitals in Taiwan. Patients will be eligible for enrollment if they are admitted for an acute ischemic stroke within 2 days, are ≥65 years of age, and have no known AF by history or on baseline ECG at admission. We will randomly assign participants in a 1:1 ratio to undergo daily 12-lead ECG once daily for 5 days (intervention group) or 24-h Holter monitoring (control group). Primary outcome is newly detected AF on a 12-lead ECG or AF lasting ≥30 s on Holter monitoring.Trial registration numberClinicalTrials.gov Identifier: NCT02578979.

MP028: Dynamic changes of prehospital serial 12-lead electrocardiogram for remote diagnosis of suspected ST-segment elevation myocardial infarction

Introduction: Accurate and efficient interpretation of prehospital 12-lead electrocardiogram (ECG) in patients with suspected ST-segment elevation myocardial infarction (STEMI) can improve outcomes, especially in rural regions. In the Chaudière-Appalaches region, Quebec, a prehospital serial 12-lead ECG monitoring system is used for remote interpretation of ECG abnormalities by emergency physicians via a telemedicine platform, the Unité de Coordination Clinique des Soins Préhospitaliers d'Urgence (UCCSPU). The objective of the study was to evaluate the use of serial monitoring of dynamic ECG changes in patients with suspected STEMI during emergency medical services (EMS) transport. Methods: A retrospective cohort study with suspected STEMI patients monitored with prehospital serial ECGs was performed from August 2006 to December 2013. The data was extracted from UCCSPU clinical databases and verified by an emergency physician supervisor. During EMS transport, the serial ECG monitoring system automatically produced and transmitted every 2 minutes a 12-lead ECG without artefacts. STEMI criteria were based on the Third Universal Definition of Myocardial Infarction. Dynamic ECG change was defined as an ST-segment elevation or depression that meets diagnostic criteria (eg. initial non STEMI (NSTEMI) changing to STEMI and vice versa). Results: Among the 752 patients identified with suspected STEMI, 728 (96.8%) were included in the study due to missing data. The majority (614/728; 84.3%) had a consistent ST segment without significant dynamic changes throughout transport, of which 521 were identified as STEMI and 93 as NSTEMI. The remaining 114 patients (15.7%) had dynamic ECG changes: 41 (36%) evolved from NSTEMI to STEMI, 40 (35.1%) changed from STEMI to NSTEMI, and 33 (28.9%) had more than one dynamic ST-segment change. Overall, 59 patients (8.1%) had a final STEMI ECG diagnosis after an initial NSTEMI ECG interpretation. Conclusion: In this study, the serial ECG system enabled the remote diagnosis of STEMI in 8.1% of patients during EMS transport following an initial NSTEMI diagnosis. Serial monitoring of dynamic changes can allow for more rapid diversion to primary percutaneous coronary intervention facilities, potentially improving patient outcomes. Further studies are needed to evaluate the clinical impact, and costs and benefits of implementing this technology.

The effect of tafamidis on the QTc interval in healthy subjects.

The transthyretin (TTR) stabilizer, tafamidis, has demonstrated efficacy and safety in the treatment of TTR familial amyloid polyneuropathy (20 mg day(-1) ). Tafamidis use in TTR cardiomyopathy led to the study of the potential effect of tafamidis on the QTc interval in healthy subjects. This randomized, three treatment, three period, six sequence crossover study with placebo, a positive control (moxifloxacin 400 mg) and tafamidis (400 mg, to achieve a supra-therapeutic Cmax of ~20 µg ml(-1) ) was conducted in healthy volunteers at three clinical research units. Oral dosing in each of the three treatment periods was separated by a washout period of ≥ 14 days. Serial triplicate 12-lead electrocardiograms were performed. QTc intervals were derived using the Fridericia correction method. Safety and tolerability were assessed by physical examination, vital signs measurement, laboratory analyses and monitoring of adverse events (AEs). A total of 42 subjects completed the study. The upper limit of the two-sided 90% confidence intervals (CIs) for the difference in baseline-adjusted QTc F between tafamidis 400 mg and placebo was <10 ms (non-inferiority criterion) for all time points. The lower limit of the two-sided 90% CI between moxifloxacin 400 mg and placebo exceeded 5 ms at the pre-specified moxifloxacin tmax of 3 h post-dose, confirming assay sensitivity. Cmax and AUC(0,24 h) for tafamidis were 20.36 µg ml(-1) and 305.4 µg ml(-1) h, respectively. There were no serious/severe AEs or treatment discontinuations due to AEs. This thorough QTc study suggests that a supra-therapeutic single 400 mg oral dose of tafamidis does not prolong the QTc interval and is well-tolerated in healthy volunteers.

The clinical significance of QT interval dispersion in severe acute pancreatitis

Objective To assess the clinical significance of QT interval dispersion (QTd) in the diagnosis and prognosis of early heart damage in patients with severe acute pancreatitis.Methods All patients received complete ECG,There were 58 patients with SAP (the SAP group) and 189 patients with mild acute pancreatitis (the control group).These patients were analyzed retrospectively and 60 normal people were used as the healthy control group.The QT interval were measured respectively in serial 12-lead electrocardiogram and QTd,QTcd were calculated.Result QTd and QTcd were significantly longer in the SAP group than in the MAP group and in the healthy control group (P＜0.01).QTd,QTcd were not remarkably extended in the MAP group than in the healthy control group (P＞0.05).Conclusions QTd and QTcd have clinical values to diagnose and to predict early heart damage in patients with SAP.They might be useful in evaluating the condition of cardiac function in patients with SAP. Key words: Pancreatitis, acute necrotizing; Electrophysiologic technigues, cardiac