My program of research focuses on expanding information obtained from electrocardiographic (ECG) recordings to improve clinical decision-making and patient outcomes in hospital and pre-hospital settings. I helped develop a monitoring strategy, “reduced lead set” technology, a method to derive a multi-lead electrocardiogram from a reduced number of electrodes. I was invited to present my research in reduced lead set technology at the Einthoven Foundation’s Celebration of 100 years of the Electrocardiogram in the Netherlands in 2002. Einthoven won a Nobel Prize for inventing the ECG machine in 1902, and this celebration acknowledged scientists who had made important and lasting contributions to the field.
Results of studies from my research laboratory (ECG Monitoring Research Lab in the School of Nursing) have informed the development of ST-segment (ischemia) monitoring algorithms for cardiac monitors. We discovered causes of false ischemia monitoring alarms, such as changes in a patient’s body position, which can alter waveforms and mimic the electrocardiographic changes of myocardial ischemia. Our publications provided evidence for the importance of ischemia monitoring in patients presenting to the emergency room with chest pain or treated in hospital units for acute coronary syndromes. A series of studies from my laboratory have shown that transient ischemia following treatment for acute coronary syndromes is: (1) usually missed with routine “arrhythmia” monitoring leads, (2) associated with poor hospital outcomes and, (3) most often (80%) clinically silent (asymptomatic). In addition, we were the first to publish that automated ST segment ischemia monitoring provided prognostic information above and beyond the initial standard 12-lead ECG in patients with acute coronary syndrome.
Realizing that the under-utilization of ischemia monitoring by clinicians in emergency rooms and hospital units was due to a lack of clarity about how to perform it, I organized an international group of experts to develop a practice guideline. The resultant report was entitled, Multi-lead ST-segment monitoring in patients with acute coronary syndromes: A consensus statement for healthcare professionals, published in 1999. This guideline has influenced clinical practice internationally.
Recent studies have focused on ECG monitoring in emergency rooms and pre-hospital settings. I helped design computer software for an ambulance device capable of monitoring patients for ischemia using reduced lead set technology and automatically transmitting abnormal ECGs by cell phone to the destination hospital. Results from our study show that this pre-hospital monitoring strategy increases paramedic utilization of pre-hospital ECG, reduces time from 911call to first ECG, and reduces hospital time to treatment for acute coronary syndrome.
I have also worked recently on another goal of hospital ECG monitoring: QT interval monitoring. By monitoring QT intervals in patients who are started on potentially pro-arrhythmic drugs, it may be possible to prevent the complication of torsade de pointes, a cause of sudden cardiac death in hospital settings. I advised engineers to design an automated QT interval measurement strategy that was approved by the U.S. Food and Drug Administration in 2008. After implementing the QT monitoring system in the 5 critical care units at Stanford Hospitals & Clinics, we found that a high proportion (24%) of patients had dangerous QT interval prolongation episodes and that they were 3 times more likely to have in-hospital death. I believe this upgrade to cardiac monitors will save nursing time by eliminating the need for manual measurements and provide more frequent, reliable, and accurate measurement of the QT interval and may prevent cardiac arrests in hospital settings.
In collaboration with a professor at Yale School of Nursing, we have been funded by NHLBI for a 5-yr, multi-center randomized clinical trial to implement the American Heart Association Practice Standards for ECG Monitoring in Hospital Settings and to determine whether it will improve nurse monitoring behaviors, quality of care, and patient outcomes. We developed interactive educational computer modules recommending the best practices for arrhythmia, ischemia, and QT interval monitoring for use in the study.
Currently, I am conducting a pilot study in post-heart-transplant patients to determine whether an increase in the QT interval measured with a home ECG device and transmitted to my research laboratory is an early biomarker for acute cardiac allograft rejection. If this noninvasive biomarker proves sensitive for the detection of acute rejection, then I will submit a proposal for a randomized clinical trial comparing it with routine invasive endomyocardial biopsies.