Evaluation of ECG algorithms designed to improve detect of transient myocardial ischemia to minimize false alarms in patients with suspected acute coronary syndrome

Hospital-Based Electrocardiographic Monitoring: The Good, the Not So Good, and Untapped Potential

Continuous electrocardiographic (ECG) monitoring was first introduced into hospitals in the 1960s, initially into critical care, as bedside monitors, and eventually into step-down units with telemetry capabilities. Although the initial use was rather simplistic (ie, heart rate and rhythm assessment), the capabilities of these devices and associated physiologic (vital sign) monitors have expanded considerably. Current bedside monitors now include sophisticated ECG software designed to identify myocardial ischemia (ie, ST-segment monitoring), QT-interval prolongation, and a myriad of other cardiac arrhythmia types. Physiologic monitoring has had similar advances from noninvasive assessment of core vital signs (blood pressure, respiratory rate, oxygen saturation) to invasive monitoring including arterial blood pressure, temperature, central venous pressure, intracranial pressure, carbon dioxide, and many others. The benefit of these monitoring devices is that continuous and real-time information is displayed and can be configured to alarm to alert nurses to a change in a patient's condition. I think it is fair to say that critical and high-acuity care nurses see these devices as having a positive impact in patient care. However, this enthusiasm has been somewhat dampened in the past decade by research highlighting the shortcomings and unanticipated consequences of these devices, namely alarm and alert fatigue. In this article, which is associated with the American Association of Critical-Care Nurses' Distinguished Research Lecture, I describe my 36-year journey from a clinical nurse to nurse scientist and the trajectory of my program of research focused primarily on ECG and physiologic monitoring. Specifically, I discuss the good, the not so good, and the untapped potential of these monitoring systems in clinical care. I also describe my experiences with community-based research in patients with acute coronary syndrome and/or heart failure.

Meta-Analysis of Dynamic Electrocardiography in the Diagnosis of Myocardial Ischemic Attack of Coronary Heart Disease

Background and Aims

Patients with coronary artery disease (CHD) are prone to early myocardial ischemia; early diagnosis of myocardial ischemia is of great significance in judging disease progression and guiding clinical intervention. However, reports on the accuracy of dynamic electrocardiogram (ECG) in the diagnosis of myocardial ischemia in patients with CHD are inconsistent. The purpose of the current meta-analysis was to analyze the efficacy of ECG in the diagnosis of myocardial ischemia attack in CHD.

Methods

Chinese database (Wanfang, VIP, and CNKI) and English database (PubMed, Web of Science, Embase, SinoMed, and Cochrane Library) were searched. A study on the collection of dynamic ECG in the diagnosis of myocardial ischemic attack of coronary heart disease to extract data and calculate sensitivity (Sen), specificity (Spe), positive likelihood ratio (+LR), negative likelihood ratio (- LR), and diagnostic odds ratio (DOR). Draw summary receiver operating characteristic curves (SROC), and calculate area under curve (AUC). Stata 15 software was used for meta-analysis.

Results

Twenty-seven literatures were included in this study. Meta-analysis results showed that Sen = 0.78 (95% CI: 0.73~0.82), Spe = 0.76 (95% CI: 0.68~0.82), +LR = 2.79 (95% CI: 2.17~3.59), −LR = 0.33 (95% CI: 0.27~0.40), AUC = 0.84 (95% CI: 0.80~0.87), and DOR = 9.66 (95% CI: 6.13~15.21). Subgroup analysis showed that the sensitivity of 12-lead ECG was higher than that of 3-lead ECG. The sensitivity and specificity of ST segment and QTc interphase changes were higher than those of ST segment changes alone (P < 0.05).

Conclusion

Dynamic ECG has high application value in the diagnosis of myocardial ischemia attack of coronary heart disease. But it is difficult to achieve a satisfactory level of use alone. ST segment combined with QTc interval observation can improve the diagnostic accuracy. Synchronous observation of ST segment and QTc interval can improve the diagnostic efficiency.

Predictive Value of Serial ECGs in Patients with Suspected Myocardial Infarction

The electrocardiogram (ECG) is an important diagnostic tool for patients with suspected acute myocardial infarction (AMI). Current guidelines recommend serial ECGs in case of persisting symptoms. We aimed to analyze the predictive value of ischemic ECG-signs in patients with suspected AMI. Patients presenting to the emergency department with suspected AMI were included. All patients with ST-elevation AMI were excluded from analyses. Patients received 12-lead-ECG and high-sensitive Troponin T (hs-TnT)-measurement at admission and after 3 h. Four groups were defined: no ischemic signs in either ECG; new ischemic signs in the second ECG; resolved ischemic signs in the second ECG; and persistent ischemic signs in both ECGs. Patients were followed for 2 years to assess the composite endpoint of all-cause-mortality, AMI, and coronary revascularization. Using a 30-day landmark analysis, a Cox regression with ischemic signs as the variable of interest, adjusted by cardiovascular risk factors, was calculated. Of 1675 patients, 1321 showed no ischemic signs, in 25 new-, in 92 resolved- and in 237 patients, persistent ischemic signs were documented. Patients with persistent ischemic signs had significantly worse outcomes, compared to those without. Compared to no ischemic signs, adjusted hazard ratios for the combined endpoint were 0.81 (95% CI 0.20, 3.31; p-value = 0.77) for new-, 0.59 (95% CI 0.26, 1.34; p-value = 0.21) for resolved-, and 1.47 (95% CI 1.102, 2.13; p-value = 0.041) for persistent ischemic signs. In patients with suspected AMI, persistent ischemic ECG-signs are predictive of a higher rate of all-cause-mortality, AMI, and revascularization.