Heart Rate Variability Measured Early in Patients with Evolving Acute Coronary Syndrome and 1-year Outcomes of Rehospitalization and Mortality

Objective: This study sought to examine the prognostic value of heart rate variability (HRV) measurement initiated immediately after emergency department presentation for patients with acute coronary syndrome (ACS). Background: Altered HRV has been associated with adverse outcomes in heart disease, but the value of HRV measured during the earliest phases of ACS related to risk of 1-year rehospitalization and death has not been established. Methods: Twenty-four-hour Holter recordings of 279 patients with ACS were initiated within 45 minutes of emergency department arrival; recordings with �18 hours of sinus rhythm were selected for HRV analysis (number [N] �193). Time domain, frequency domain, and nonlinear HRV were examined. Survival analysis was performed. Results: During the 1-year follow-up, 94 patients were event-free, 82 were readmitted, and 17 died. HRV was altered in relation to outcomes. Predictors of rehospitalization included increased normalized high frequency power, decreased normalized low frequency power, and decreased low/high frequency ratio. Normalized high frequency �42 ms2 predicted rehospitalization while controlling for clinical variables (hazard ratio [HR] �2.3; 95% confidence interval [CI] �1.4–3.8, P�0.001). Variables significantly associated with death included natural logs of total power and ultra low frequency power. A model with ultra low frequency power �8 ms2 ( HR �3.8; 95% CI �1.5–10.1; P�0.007) and troponin �0.3 ng/mL (HR �4.0; 95% CI �1.3–12.1; P�0.016) revealed that each contributed independently in predicting mortality. Nonlinear HRV variables were significant predictors of both outcomes. Conclusion: HRV measured close to the ACS onset may assist in risk stratification. HRV cut-points may provide additional, incremental prognostic information to established assessment guidelines, and may be worthy of additional study

Prevalence and Prognostic Significance of Long QT Interval among Patients with Chest Pain: Selecting an Optimum QT Rate Correction Formula

Background: Little is known about the prevalence and prognostic significance of long QT interval among patients with chest pain during the acute phase of suspected cardiovascular injury. Objectives: Our aim was to investigate the prevalence and prognostic significance of long QT interval among patients presenting to the emergency department (ED) with chest pain using an optimum QT rate correction formula. Methods: We performed secondary analysis on data obtained from the IMMEDIATE AIM trial (N, 145). Data included 24-hour 12-lead Holter electrocardiographic recordings that were stored for offline computer analysis. The QT interval was measured automatically and rate corrected using seven QTc formulas including subject specific correction. The formula with the closer to zero absolute mean QTc/RR correlation was considered the most accurate. Results: Linear and logarithmic subject specific QT rate correction outperformed other QTc formulas and resulted in the closest to zero absolute mean QTc/RR correlations (mean ± SD: 0.003 ± 0.002 and 0.017 ± 0.016, respectively). These two formulas produced adequate correction in 100% of study participants. Other formulas (Bazett’s, Fridericia’s, Framingham\u27s, and study specific) resulted in inadequate correction in 47.6 to 95.2% of study participants. Using the optimum QTc formula, linear subject specific, the prevalence of long QTc interval was 14.5%. The QTc interval did not predict mortality or hospital admission at short and long term follow-up. Only the QT/RR slope predicted mortality at 7 year follow-up (odds ratio, 2.01; 95% CI, 1.02–3.96; p \u3c 0.05). Conclusions: Adequate QT rate correction can only be performed using subject specific correction. Long QT interval is not uncommon among patients presenting to the ED with chest pain

Heart Rate Variability Measurement and Clinical Depression in Acute Coronary Syndrome Patients: Narrative Review of Recent Literature

Aim: We aimed to explore links between heart rate variability (HRV) and clinical depression in patients with acute coronary syndrome (ACS), through a review of recent clinical research literature. Background: Patients with ACS are at risk for both cardiac autonomic dysfunction and clinical depression. Both conditions can negatively impact the ability to recover from an acute physiological insult, such as unstable angina or myocardial infarction, increasing the risk for adverse cardiovascular outcomes. HRV is recognized as a reflection of autonomic function. Methods: A narrative review was undertaken to evaluate state-of-the-art clinical research, using the PubMed database, January 2013. The search terms “heart rate variability” and “depression” were used in conjunction with “acute coronary syndrome”, “unstable angina”, or “myocardial infarction” to find clinical studies published within the past 10 years related to HRV and clinical depression, in patients with an ACS episode. Studies were included if HRV measurement and depression screening were undertaken during an ACS hospitalization or within 2 months of hospital discharge. Results: Nine clinical studies met the inclusion criteria. The studies’ results indicate that there may be a relationship between abnormal HRV and clinical depression when assessed early after an ACS event, offering the possibility that these risk factors play a modest role in patient outcomes. Conclusion: While a definitive conclusion about the relevance of HRV and clinical depression measurement in ACS patients would be premature, the literature suggests that these measures may provide additional information in risk assessment. Potential avenues for further research are proposed

Concrete services usage on child placement stability: Propensity score matched effects

Background: Experiencing poverty and financial difficulties are significant barriers to outcomes of permanency and placement stability. This is particularly true for children who are in out of home placements. The provision of concrete services is intended to meet concrete needs of families to address this barrier. However, little is known about how concrete services meet the needs of families in need of these services or if the use of concrete services is a viable treatment for children who are in out of home placements. Methods: The present study examined differences between those who received and those who did not receive concrete services on factors of stability, child and caregiver traumatic stress, number of placements, and current out of home placement. Regression analysis examined the association between amount of concrete service spending and permanency. Then to test concrete services as an intervention for children in a current out of home placement, we used propensity score matching to match participants on characteristics that predicted whether they would receive concrete services. We then ran a hierarchical regression to test the treatment condition of concrete services with children who are in a current out of home placement. Results: Participants who received concrete services were at a much higher level of need with significantly higher levels of traumatic stress and number of placements and lower levels of placement stability. The amount of money spent on concrete services was associated with increases in placement stability. And, children in a current out of home placement had an increase in placement stability when they received concrete services. Conclusions: The present study is the first to evidence concrete service as a treatment for placement stability for children in current out of home placements. Spending on concrete services in addition to child welfare services improves a child's current placement stability. This is an important finding with implications for improving child welfare services' approach to those in their care with financial burdens

Integrating monitor alarms with laboratory test results to enhance patient deterioration prediction

AbstractPatient monitors in modern hospitals have become ubiquitous but they generate an excessive number of false alarms causing alarm fatigue. Our previous work showed that combinations of frequently co-occurring monitor alarms, called SuperAlarm patterns, were capable of predicting in-hospital code blue events at a lower alarm frequency. In the present study, we extend the conceptual domain of a SuperAlarm to incorporate laboratory test results along with monitor alarms so as to build an integrated data set to mine SuperAlarm patterns. We propose two approaches to integrate monitor alarms with laboratory test results and use a maximal frequent itemsets mining algorithm to find SuperAlarm patterns. Under an acceptable false positive rate FPRmax, optimal parameters including the minimum support threshold and the length of time window for the algorithm to find the combinations of monitor alarms and laboratory test results are determined based on a 10-fold cross-validation set. SuperAlarm candidates are generated under these optimal parameters. The final SuperAlarm patterns are obtained by further removing the candidates with false positive rate>FPRmax. The performance of SuperAlarm patterns are assessed using an independent test data set. First, we calculate the sensitivity with respect to prediction window and the sensitivity with respect to lead time. Second, we calculate the false SuperAlarm ratio (ratio of the hourly number of SuperAlarm triggers for control patients to that of the monitor alarms, or that of regular monitor alarms plus laboratory test results if the SuperAlarm patterns contain laboratory test results) and the work-up to detection ratio, WDR (ratio of the number of patients triggering any SuperAlarm patterns to that of code blue patients triggering any SuperAlarm patterns). The experiment results demonstrate that when varying FPRmax between 0.02 and 0.15, the SuperAlarm patterns composed of monitor alarms along with the last two laboratory test results are triggered at least once for [56.7–93.3%] of code blue patients within an 1-h prediction window before code blue events and for [43.3–90.0%] of code blue patients at least 1-h ahead of code blue events. However, the hourly number of these SuperAlarm patterns occurring in control patients is only [2.0–14.8%] of that of regular monitor alarms with WDR varying between 2.1 and 6.5 in a 12-h window. For a given FPRmax threshold, the SuperAlarm set generated from the integrated data set has higher sensitivity and lower WDR than the SuperAlarm set generated from the regular monitor alarm data set. In addition, the McNemar’s test also shows that the performance of the SuperAlarm set from the integrated data set is significantly different from that of the SuperAlarm set from the regular monitor alarm data set. We therefore conclude that the SuperAlarm patterns generated from the integrated data set are better at predicting code blue events

Feasibility and Compliance with Daily Home ECG Monitoring of the QT Interval in Heart Transplant Recipients

Background: Recent evidence suggests that acute allograft rejection after heart transplantation causes an increased QT interval on electrocardiogram (ECG). The aims of this pilot study were to (1) determine whether heart transplant recipients could achieve compliance in transmitting a 30-second ECG every day for 1 month using a simple ECG device and their home telephone, (2) evaluate the ease of device use and acceptability by transplant recipients, and (3) evaluate the quality of transmitted ECG tracings for QT-interval measurement. Methods: A convenience sample of adult heart transplant recipients were recruited and trained to use the device (HeartOne, Aerotel Medical Systems, Holon, Israel). Lead II was used with electrodes that were easy to slip on and off (expandable metal wrist watch-type electrode for right wrist and C-shaped band electrode for left ankle). Patients used a toll-free number with automated voice prompts to guide their ECG transmission to the core laboratory for analysis. Results: Thirty-one subjects (72% were male; mean age of 52 ± 17 years; 37% were nonwhite) achieved an ECG transmission compliance of 73.4% (daily) and 100% (weekly). When asked, how difficult do you think it was to record and transmit your ECG by phone, 90% of subjects replied “somewhat easy” or “extremely easy.” Of the total 644 ECGs that were transmitted by subjects, 569 (89%) were acceptable quality for QT-interval measurement. The mean QTc was 448 ± 44 ms (440 ± 41 ms for male subjects and 471 ± 45 ms for female subjects). Eleven subjects (35%) had an extremity tremor, and 19 subjects (55%) had ≥ 1+ left leg edema. Neither of these conditions interfered with ECG measurements. Conclusion: Transplant recipients are compliant with recording and transmitting daily and weekly ECGs

Normal prehospital electrocardiography is linked to long-term survival in patients presenting to the emergency department with symptoms of acute coronary syndrome

We studied 735 patients who activated “911” for chest pain and/or anginal equivalent symptoms and received 12-lead ECG monitoring with specialized ischemia monitoring software in the ambulance. Prehospital electrocardiograms (PH ECG) were analyzed to determine the proportion of patients who present with completely normal PH ECG findings (absence of ischemia/infarction, arrhythmia, or any other abnormality) and to compare outcomes amongst patients with and without any PH ECG abnormality