David Pickham

High prevalence of corrected QT interval prolongation in acutely ill patients is associated with mortality: Results of the QT in Practice (QTIP) Study*

Objective: To test the potential value of more frequent QT interval measurement in hospitalized patients. Design: We performed a prospective, observational study. Setting: All adult intensive care unit and progressive care unit beds of a university medical center. Patients: All patients admitted to one of six critical care units over a 2-month period were included in analyses. Interventions: All critical care beds (n = 154) were upgraded to a continuous QT monitoring system (Philips Healthcare). Measurements and Main Results: QT data were extracted from the bedside monitors for offline analysis. A corrected QT interval >500 msecs was considered prolonged. Episodes of QT prolongation were manually over-read. Electrocardiogram data (67,648 hrs, mean 65 hrs/patient) were obtained. QT prolongation was present in 24%. There were 16 cardiac arrests, with one resulting from Torsade de Pointes (6%). Predictors of QT prolongation were female sex, QT-prolonging drugs, hypokalemia, hypocalcemia, hyperglycemia, high creatinine, history of stroke, and hypothyroidism. Patients with QT prolongation had longer hospitalization (276 hrs vs. 132 hrs, p < .0005) and had three times the odds for all-cause in-hospital mortality compared to patients without QT prolongation (odds ratio 2.99 95% confidence interval 1.1–8.1). Conclusions: We find QT prolongation to be common (24%), with Torsade de Pointes representing 6% of in-hospital cardiac arrests. Predictors of QT prolongation in the acutely ill population are similar to those previously identified in ambulatory populations. Acutely ill patients with QT prolongation have longer lengths of hospitalization and nearly three times the odds for mortality then those without QT prolongation.

Comparison of three ECG criteria for athlete pre-participation screening

UNLABELLED Controversy regarding adding the ECG to the evaluation of young athletes centers on the implications of false positives. Several guidelines have been published with recommendations for criteria to distinguish between ECG manifestations of training and markers of risk for cardiovascular (CV) sudden death. With an athlete dataset negative of any CV related abnormalities on follow-up, we applied three athlete screening criteria to identify the one with the lowest rate of abnormal variants. METHODS High school, college, and professional athletes underwent 12L ECGs as part of routine physicals. All ECGs were recorded and processed using CardeaScreen (Seattle, WA). The European (2010), Stanford (2011), and Seattle criteria (2013) were applied. RESULTS From March 2011 to February 2013 1417 ECGs were collected. Mean age was 20±4years (14-35years), 36% female, 38.5% non-white (307 high school, 836 college and 284 professional). Rate of abnormal variants differed by criteria, predominately due to variation in interval thresholds for QT interval and QRS duration. There was a four-fold difference in abnormal variants between European and Seattle criteria (26% v 6%). CONCLUSION The Seattle criterion was the most conservative resulting in 78% fewer abnormal variants than the European criteria. Variation was most evident with thresholds for QT prolongation, short QT interval, and intraventricular conduction delay. Continued research is needed to further understand normal training related adaptations and to improve modern ECG screening criteria for athletes.

How many patients need QT interval monitoring in critical care units? Preliminary report of the QT in Practice study

UNLABELLED Recent Scientific Statement from the American Heart Association (AHA) recommends that hospital patients should receive QT interval monitoring if certain conditions are present: QT-prolonging drug administration or admission for drug overdose, electrolyte disturbances (K, Mg), and bradycardia. No studies have quantified the proportion of critical care patients that meet the AHAs indications for QT interval monitoring. This is a prospective study of 1039 critical care patients to determine the proportion of patients that meet the AHAs indications for QT interval monitoring. Secondary aim is to evaluate the predictive value of the AHAs indications in identifying patients who actually develop QT interval prolongation. METHODS Continuous QT interval monitoring software was installed in all monitored beds (n = 154) across 5 critical care units. This system uses outlier rejection and median filtering in all available leads to construct an root-mean-squared wave from which the QT measurement is made. Fridericia formula was used for heart rate correction. A QT interval greater than 500 milliseconds for 15 minutes or longer was considered prolonged for analyses. To minimize false positives all episodes of QT prolongation were manually over read. Clinical data was abstracted from the medical record. RESULTS Overall 69% of patients had 1 or more AHA indications for QT interval monitoring. More women (74%) had indications than men (64%, P = .001). One quarter (24%) had QT interval prolongation (>500 ms for ≥15 minutes). The odds for QT interval prolongation increased with the number of AHA indications present; 1 indication, odds ratio (OR) = 3.2 (2.1-5.0); 2 indications, OR = 7.3(4.6-11.7); and 3 or more indications OR = 9.2(4.8-17.4). Positive predictive value of the AHA indications for QT interval prolongation was 31.2%; negative predictive value was 91.3%. CONCLUSION Most critically ill patients (69%) have AHA indications for QT interval monitoring. One quarter of critically ill patients (24%) developed QT interval prolongation. The AHA indications for QT interval monitoring successfully captured the majority of critically ill patients developing QT interval prolongation.

Limitations of Current AHA Guidelines and Proposal of New Guidelines for the Preparticipation Examination of Athletes.

Objective:To examine the prevalence of athletes who screen positive with the preparticipation examination guidelines from the American Heart Association, the AHA 12-elements, in combination with 3 screening electrocardiogram (ECG) criteria. Design:Observational cross-sectional study. Setting:Stanford University Sports Medicine Clinic. Participants:Total of 1596 participants, including 297 (167 male; mean age, 16.2 years) high school athletes, 1016 (541 male; mean age, 18.8 years) collegiate athletes, and 283 (mean age, 26.3 years) male professional athletes. Main Outcome Measures:Athletes were screened using the 8 personal and family history questions from the AHA 12-elements. Electrocardiograms were obtained for all participants and interpreted using Seattle criteria, Stanford criteria, and European Society of Cardiology (ESC) recommendations. Results:Approximately one-quarter of all athletes (23.8%) had at least 1 positive response to the AHA personal and family history elements. High school and college athletes had similar rates of having at least 1 positive response (25.9% vs 27.4%), whereas professional athletes had a significantly lower rate of having at least 1 positive response (8.8%, P < 0.05). Females reported more episodes of unexplained syncope (11.4% vs 7.5%, P = 0.017) and excessive exertional dyspnea with exercise (11.1% vs 6.1%, P = 0.001) than males. High school athletes had more positive responses to the family history elements when compared with college athletes (P < 0.05). The percentage of athletes who had an abnormal ECG varied between Seattle criteria (6.0%), Stanford criteria (8.8%), and ESC recommendations (26.8%). Conclusions:Many athletes screen positive under current screening recommendations, and ECG results vary widely by interpretation criteria. Clinical Relevance:In a patient population without any adverse cardiovascular events, the currently recommended AHA 12-elements have an unacceptably high rate of false positives. Newer screening guidelines are needed, with fewer false positives and evidence-based updates.

Hands-Free Image Capture, Data Tagging and Transfer Using Google Glass: A Pilot Study for Improved Wound Care Management

Chronic wounds, including pressure ulcers, compromise the health of 6.5 million Americans and pose an annual estimated burden of

Hyperglycemia is associated with corrected QT prolongation and mortality in acutely ill patients.

25 billion to the U.S. health care system. When treating chronic wounds, clinicians must use meticulous documentation to determine wound severity and to monitor healing progress over time. Yet, current wound documentation practices using digital photography are often cumbersome and labor intensive. The process of transferring photos into Electronic Medical Records (EMRs) requires many steps and can take several days. Newer smartphone and tablet-based solutions, such as Epic Haiku, have reduced EMR upload time. However, issues still exist involving patient positioning, image-capture technique, and patient identification. In this paper, we present the development and assessment of the SnapCap System for chronic wound photography. Through leveraging the sensor capabilities of Google Glass, SnapCap enables hands-free digital image capture, and the tagging and transfer of images to a patient’s EMR. In a pilot study with wound care nurses at Stanford Hospital (n=16), we (i) examined feature preferences for hands-free digital image capture and documentation, and (ii) compared SnapCap to the state of the art in digital wound care photography, the Epic Haiku application. We used the Wilcoxon Signed-ranks test to evaluate differences in mean ranks between preference options. Preferred hands-free navigation features include barcode scanning for patient identification, Z(15) = -3.873, p < 0.001, r = 0.71, and double-blinking to take photographs, Z(13) = -3.606, p < 0.001, r = 0.71. In the comparison between SnapCap and Epic Haiku, the SnapCap System was preferred for sterile image-capture technique, Z(16) = -3.873, p < 0.001, r = 0.68. Responses were divided with respect to image quality and overall ease of use. The study’s results have contributed to the future implementation of new features aimed at enhancing mobile hands-free digital photography for chronic wound care.

Clostridium difficile rates in asymptomatic and symptomatic hospitalized patients using nucleic acid testing

Background:The QT interval on an electrocardiogram represents ventricular repolarization time. Increased length of this interval, known as corrected QT (QTc) prolongation, can be a precursor to torsade de pointes, a potentially life-threatening ventricular dysrhythmia. An association exists between blood glucose and QTc interval in ambulatory populations. Because both hyperglycemia and QTc prolongation are common in critically ill patients, we sought to examine the relationship between blood glucose, QTc interval prolongation, and all-cause mortality in critically ill patients. Methods:We studied adult patients admitted to cardiac monitoring units. Blood glucose and other clinical variables were abstracted from the medical record. Corrected QT measurements were automatically derived from continuous bedside cardiac monitoring systems. Results:Twenty-five percent (233/940) of the patients had QTc prolongation, and 53% had elevated blood glucose (>140 mg/dL) during hospitalization. Adjusted odds for QTc prolongation were 2.1 (95% confidence interval, 1.5–3.1) for moderately elevated blood glucose (140–180 mg/dL) and 3.7 (95% confidence interval, 2.5–5.4) for severely elevated blood glucose (>180 mg/dL). Mortality rate was highest (16%) in patients experiencing both severely elevated blood glucose (>180 mg/dL) and QTc interval prolongation. Conclusions:Hyperglycemia is linked with QTc prolongation, and both are associated with increased odds of mortality in critically ill patients. Further studies are needed to extrapolate the relationship between glucose and ventricular repolarization, as well as appropriate glucose control parameters and QTc interval monitoring in critical care units.

Electrocardiographic abnormalities in the first year after heart transplantation.

BACKGROUND The Clostridium difficile rate in symptomatic patients represents both those with C. difficile infection (CDI) and those with colonization. To predict the extent of CDI overdiagnosis, we compared the asymptomatic colonization rate to the symptomatic positivity rate in hospitalized patients using nucleic acid testing. METHODS Between July 2014 and April 2015, formed stool samples were collected from asymptomatic patients after admission to 3 hospital wards at the Stanford Hospital. Stool samples from symptomatic patients with suspected CDI in the same wards were collected for testing per provider order. The GeneXpert C. difficile tcdB polymerase chain reaction (PCR) assay (Cepheid, Sunnyvale, CA, USA) was performed on all stool samples and PCR cycle threshold was used as a measure of genomic equivalents. Chart review was performed to obtain clinical history and medication exposure. RESULTS We found an asymptomatic C. difficile carriage rate of 11.8% (43/365) (95% confidence interval [CI], 8.5-15.1%) and a positivity rate in symptomatic patients of 15.4% (54/351) (95% CI, 11.6-19.2%; P=0.19). The median PCR cycle thresholds was not significantly different between asymptomatic carriers and symptomatic positives (29.5 versus 27.3; P=0.07). Among asymptomatic patients, 11.6% (5/43) of carriers and 8.4% (27/322; P=0.56) of noncarriers subsequently became symptomatic CDI suspects within the same hospitalization. Single and multivariate analysis did not identify any demographic or clinical factors as being significantly associated with C. difficile carriage. CONCLUSIONS Asymptomatic C. difficile carriage rate was similar to symptomatic positivity rate. This suggests the majority of PCR-positive results in symptomatic patients are likely due to C. difficile colonization. Disease-specific biomarkers are needed to accurately diagnose patients with C. difficile disease.

Time dependent history improves QT interval estimation in atrial fibrillation.

STUDY AIM Describe ECG abnormalities in the first year following transplant surgery. METHODS Analysis of 12-lead ECGs from heart transplant subjects enrolled in an ongoing multicenter clinical trial. RESULTS 585 ECGs from 98 subjects showed few with abnormal cardiac rhythm (99% of ECGs were sinus rhythm/tachycardia). A majority of subjects (69%) had either right intraventricular conduction delay (56%) or right bundle branch block (13%). A second prevalent ECG abnormality was atrial enlargement (64% of subjects) that was more commonly left atrial (55%) than right (30%). CONCLUSIONS Right intraventricular conduction delay or right bundle branch block is prevalent in heart transplant recipients in the first year following transplant surgery. Whether this abnormality is related to acute allograph rejection or endomyocardial biopsy procedures is the subject of the ongoing clinical trial. Atrial enlargement ECG criteria (especially, left atrial) are also common and are likely due to transplant surgery with subsequent atrial remodeling.

Lean Manufacturing Improves Emergency Department Throughput and Patient Satisfaction.

PURPOSE It is not recommended to perform QTc estimation in patients with atrial fibrillation (AF). We evaluated multiple QT interval correction formulas, including a novel time-dependent history approach, in an effort to identify the best method for correcting the QT interval in patients with AF. The ideal correction results in independence between the QTc estimate and HR. METHODS Per-beat characteristics were derived using SuperECG (Mortara Instrument). Offline beat-to-beat QTc interval estimates were constructed using standard formulae and averaged (2-10) groups constructed. RESULTS Seventy-one patients were included, age 67 ± 10 years, 69% men. Mean-mean QTc intervals varied by correction (range 394-459 ms). Averaging resulted in the same mean-mean QTc estimate, but significantly reduced variability by up to 55%. Time-dependent RR interval history reduced variability the most (Δ 80%), increased QT/RR dynamics (m=.03 vs .17), and was independent with HR (m = 0.0008). CONCLUSIONS Our data suggests that QTc interval estimation in patients with AF can be performed reliably using time-dependent history (RRc) outperforming other correction methods.