Background Acute allograft rejection appears to be associated with increases in QT/QTc intervals. Objectives To determine the relationship between acute allograft rejection and electrocardiogram changes in patients undergoing an orthotopic heart transplant. Methods The study population comprised 220 adult patients undergoing heart transplant and enrolled in the NEW HEART study. Electrocardiograms obtained within 72 hours of endomyocardial biopsy were analyzed; electrocardiograms obtained fewer than 10 days after transplant surgery were excluded. Repeated-measures analysis was performed with statistical models including effects for rejection severity (mild and moderate/severe) and time trends independent of rejection status. Results The 151 male and 69 female transplant recipients (mean age [SD], 54 [13] years) had 969 biopsy/electrocardiogram pairs: 677 with no rejection, 280 with mild rejection, and 12 with moderate/severe rejection. Moderate to severe organ rejection was associated with significant increases in QRS duration ( P < .001), QT ( P = .009), QTc ( P = .003), and PR interval ( P = .03), as well as increased odds of right bundle block branch ( P = .002) and fascicular block ( P = .009) occurring. Conclusions Moderate to severe acute allograft rejection was associated with electrocardiographic changes after transplant surgery. Studies are needed to assess the value of computerized electrocardiogram measurement algorithms for detecting acute allograft rejection.

Background Many medications commonly used in hospitals can cause prolonged corrected QT interval (QTc), putting patients at risk for torsade de pointes (TdP), a potentially fatal arrhythmia. However, documentation of QTc for hospitalized patients receiving QT-prolonging medications is often not consistent with American Heart Association standards. Objective To examine effects of education and computerized documentation enhancements on QTc documentation. Methods A quasi-experimental multisite study among 4011 cardiac-monitored patients receiving QTc-prolonging medications within a 10-hospital health care system was conducted to compare QTc documentation before (n=1517), 3 months after (n = 1301), and 4 to 6 months after (n = 1193) an intervention. The intervention included (1) online education for 3232 nurses, (2) electronic notifications to alert nurses when a patient received at least 2 doses of a QT-prolonging medication, and (3) computerized calculation of QTc in electronic health records after nurses had documented heart rate and QT interval. Results QTc documentation for inpatients receiving QTc-prolonging drugs increased significantly from baseline (17.3%) to 3 months after the intervention (58.2%; P < .001) within the 10 hospitals and had increased further 4 to 6 months after the intervention (62.1%, P = .75). Patients at larger hospitals were significantly more likely to have their QTc documented (46.4%) than were patients at smaller hospitals (26.2%; P < .001). Conclusion A 3-step system-wide intervention was associated with an increase in QTc documentation for patients at risk for drug-induced TdP, and improvements persisted over time. Further study is needed to assess whether increased QTc documentation decreases occurrence of drug-induced TdP. ( American Journal of Critical Care . 2015;24:e6–e15)

Background A collaboration led by the American Heart Association recently released the scientific statement “Prevention of Torsade de Pointes in Hospital Settings.” Patients receiving proarrhythmic drugs, who have electrolyte disturbances, or who have bradyarrhythmias require QT-interval monitoring. Prior studies have demonstrated that physicians have a poor level of proficiency at calculating QT intervals. The ability of nurses at calculating QT intervals remains untested. Objectives To evaluate nurses’ knowledge and ability to perform QT/QTc interval monitoring. Methods At a single institution, 47 QT-education classes were provided to 480 eligible nurses who regularly perform cardiac monitoring. All nurses completed a researcher-developed knowledge test at baseline and after the QT-related education intervention. Results Overall 379 nurses participated (mean age 39 [SD, 10] years), 71% had more than 5 years’ nursing experience. Total test scores increased after intervention (46% vs 77%, P < .001). Education significantly improved marking of the QT/RR intervals (QT: 65% vs 91%, RR: 83% vs 90%, P = .001 and P = .02) and measurement of the QT/RR intervals (QT: 47% vs 84%, RR: 35% vs 71% P = .001 and P = .001). Calculation of the QTc interval also increased significantly (6% vs 52%, P < .001). Conclusions Our study results demonstrate that nurses’ baseline ability to perform QT interval monitoring is extremely poor. An unacceptable amount of error persists after an educational intervention. Accurate computer-assisted methods are needed to reduce the error associated with manual QT-interval monitoring.

Background The American Heart Association 2004 practice standards for electrocardiographic monitoring in hospitals recommend that nurses record an atrial electrogram whenever tachycardia of unknown origin develops in a patient after cardiac surgery. An atrial electrogram can be recorded from atrial epicardial pacemaker wires left in place following surgery. Because surgical practices have changed in recent years (earlier extubation and mobilization, shorter stays), it is unclear whether epicardial wires are still readily available to record an atrial electrogram. Objective To determine current practices in recording atrial electrograms. Methods A convenience sample of nurses subscribing to the American Association of Critical-Care Nurses electronic newsletter was surveyed. Results The sample comprised 247 nurses who worked in an intensive or progressive care unit in which patients were treated after cardiac surgery. Respondents were from 41 states and 139 cities. Nearly 90% of respondents had more than 5 years’ nursing experience; 75% had more than 5 years’ experience caring for patients after cardiac surgery. Although 92.1% of respondents reported that atrial epicardial pacing wires were left in place after cardiac surgery, only 10.2% recorded atrial electrograms often, and more than 30% had never recorded one. Analysis of written comments indicated that atrial electrograms are rarely used. Among nurses who had recorded an atrial electrogram, recordings were made about equally with a standard 12-lead electrocardiography machine and a bedside cardiac monitor. Conclusions Although atrial epicardial pacemaker wires are often available for recording atrial electrograms, few nurses use apical epicardial wires for atrial electrograms to analyze arrhythmias.

• Background Critically ill adults admitted for noncardiac conditions are at risk for acute myocardial ischemia. • Objectives To detect myocardial ischemia and injury in patients admitted for noncardiac conditions and to examine the relationship of myocardial ischemia, injury, and acuity to cardiac events. • Methods Transient myocardial ischemia, acuity, elevations in serum troponin I, and in-hospital cardiac events were examined in 76 consecutive patients. Transient myocardial ischemia, determined by using continuous electrocardiography, was defined as a 1-mm (0.1-mV) change in ST level from baseline to event in 1 or more leads lasting 1 or more minutes. Acuity was determined by scores on Acute Physiology and Chronic Health Evaluation II. • Results A total of 37 ischemic events were detected in 8 patients (10.5%); 32 (86%) were ST-segment depressions, and 35 (96%) were silent. Twelve patients (15.8%) had elevated levels of troponin I. Transient myocardial ischemia, elevated troponin I levels, and advanced age were significant predictors of cardiac complications (R 2 = 0.387, F = 15.2, P < .001). Acuity correlated only modestly with increased length of stay in the intensive care unit (r = 0.26, P = .02) and elevated troponin I levels (r = 0.25, P = .03). Patients with transient myocardial ischemia had significantly higher rates of elevations in troponin I (P < .001) and cardiac events (P < .001) than did patients without. • Conclusions Transient myocardial ischemia and advanced age are predictors of cardiac events and may indicate patients at risk for cardiac events.

An important factor to consider when using findings on electrocardiograms for clinical decision making is that the waveforms are influenced by normal physiological and technical factors as well as by pathophysiological factors. Traditionally, the focus of bedside monitoring is detection of arrhythmia. However, continuous ST-segment monitoring for the detection of myocardial ischemia is now readily available. Many factors affect electrocardiographic waveforms and may interfere with diagnosis of myocardial ischemia based on electrocardiographic findings. Accordingly, a principal leadership role for clinical nurse specialists and nurse practitioners is to become knowledgeable about interpretation of 12-lead electrocardiograms and to share this knowledge with staff nurses who care for patients with acute coronary syndromes. The factors that alter electrocardiographic findings are reviewed, and the alterations that interfere with electrocardiogram-based diagnosis of myocardial ischemia are discussed.

• Background Little is known about the frequency or consequences of transient myocardial ischemia in patients admitted to a telemetry unit for treatment of angina. • Objectives To compare the rate of transient myocardial ischemia in a group of patients with angina treated in a telemetry unit with the rate in a similar group treated in a coronary care unit and to determine if transient myocardial ischemia is associated with adverse in-hospital outcomes. • Methods Continuous 12-lead electrocardiography was used to monitor changes in the ST segment in 186 patients in the coronary care unit (1994–1996) and 186 patients in the telemetry unit (1997–2000). Transient myocardial ischemia was defined as a change from baseline of 100 μV or more in the ST segment in 1 or more leads lasting 60 seconds or longer. • Results The rate of transient myocardial ischemia was 15% for patients in the telemetry unit and 19% for patients in the coronary care unit. Regardless of hospital unit, patients with transient myocardial ischemia were more likely than those without this complication to experience death or acute myocardial infarction after hospital admission. Most patients did not experience signs or symptoms during transient myocardial ischemia: 71% of patients in the telemetry unit versus 58% of patients in the coronary care unit (P = .28). • Conclusions Transient myocardial ischemia is common among patients with angina treated in a telemetry unit. ST-segment monitoring may be useful for detecting patients with ischemia who may benefit from more aggressive therapies aimed at abolishing ongoing ischemia.

The electrocardiogram continues to be the gold standard for the diagnosis of cardiac arrhythmias and acute myocardial ischemia. The treatment of arrhythmias in critical care units has become less aggressive during the past decade because research indicates that antiarrhythmic agents can be proarrhythmic, causing malignant ventricular arrhythmias such as torsade de pointes. However, during the same period, the treatment of acute myocardial ischemia has become more aggressive, with the goal of preventing or interrupting myocardial infarction by using new antithrombotic and antiplatelet agents and percutaneous coronary interventions. For this reason, critical care nurses should learn how to use ST-segment monitoring to detect acute ischemia, which is often asymptomatic, in patients with acute coronary syndromes. Because the electrocardiographic lead must be facing the localized ischemic zone of the heart to depict the telltale signs of ST-segment deviation, the challenge is to find ways to monitor patients continuously for ischemia without using an excessive number of electrodes and lead wires. The current trend is to use reduced lead set configurations in which 5 or 6 electrodes, placed at convenient places on the chest, are used to construct a full 12-lead electrocardiogram. Nurse scientists at the University of California, San Francisco, School of Nursing are at the forefront in developing and assessing the diagnostic accuracy of these reduced lead set electrocardiograms.

In 1902, a Dutch physiologist, Willem Einthoven, invented the first ECG machine and recorded limb leads I, II, and III in a human, for which he was awarded the Nobel Prize in Medicine. In the ensuing 100 years, an explosion of knowledge in the field of electrocardiography has sparked technological advances, including pacemakers, defibrillation, invasive cardiac electrophysiology testing, implantable cardioverter defibrillators, radio-frequency ablation, trans-telephonic transmission of ECG signals, and much more.