PubMed Health⌕ Search

Biomedical subjects

Barbara J Drew

Publications and source records attributed to Barbara J Drew.

At least 19 recordsLinked to original sources
PubMed2006

Phonocardiographic timing of third and fourth heart sounds during acute myocardial infarction.

A 47-year-old diabetic woman was referred for diagnostic coronary angiography as part of an evaluation before renal transplantation. During attempts to cannulate the left coronary artery, the patient developed severe dyspnea and new ST-segment elevations in the anterior leads. Left coronary angiography showed acute occlusion of the proximal left anterior descending (LAD) coronary artery. She then underwent emergent percutaneous intervention of the occluded vessel. Continuous electrocardiographic and phonocardiographic recordings were obtained during the procedure that documented the timing and appearance of ST-segment elevations and the onset of third and fourth heart sounds. In this report, the sequence of these events is discussed, and the literature is reviewed.

Coronary Disease↗
PubMed2006

Practice standards for ECG monitoring in hospital settings: executive summary and guide for implementation.

Current goals of hospital ECG monitoring are to diagnose cardiac arrhythmias, acute myocardial ischemia, and drug-induced prolonged QT interval. Recently, experts in the field of electrocardiology and cardiac monitoring convened to develop a practice standard for hospital ECG monitoring. This executive summary reviews key elements of the practice standard and answers questions that often arise when clinicians try to implement them.

Arrhythmias, Cardiac↗
PubMed2006

Pitfalls and artifacts in electrocardiography.

The standard 12-lead ECG is a common diagnostic test that provides a wealth of diagnostic information of value for clinical decision making. Its value, however, depends upon the accuracy of its recording. This article presents common errors in clinical electrocardiography including inaccurate lead placement, inappropriate serial comparisons using different lead sets, lead wire reversals, inappropriate filter settings, and excessively noisy signals. Practical information is provided to prevent errors and to improve the quality and utility of ECGs.

Artifacts↗
PubMed2006

Novel electrocardiogram configurations and transmission procedures in the prehospital setting: effect on ischemia and arrhythmia determination.

AIM: The aims of this report are to (1) describe a novel prehospital 12-lead electrocardiogram (ECG) configuration and transmission procedure used in the Synthesized Twelve-lead ST Monitoring and Real-time Tele-electrocardiography Study and to (2) report on the frequency of arrhythmias in field ECGs compared with the first hospital ECG. METHODS: The Synthesized Twelve-lead ST Monitoring and Real-time Tele-electrocardiography Study is a 5-year randomized clinical trial ending in 2008. All emergency vehicles responding to 911 calls in Santa Cruz County, Calif, have been equipped with portable monitor defibrillators with a special study software that (1) synthesizes a 12-lead ECG from 5 electrodes, (2) measures ST amplitudes in all 12 leads every 30 seconds, and (3) automatically transmits an ECG to the target emergency department if there is a change in ST amplitude of 200 microV in 1 lead or more or 100 microV in 2 contiguous leads or more lasting 2.5 minutes. An initial ECG is transmitted by paramedics, which activates the software. Subsequent transmissions of ST event ECGs occur automatically without paramedic decision making. RESULTS: Prehospital ECGs had a greater frequency of arrhythmias than the first hospital ECG in the group as a whole (n = 433; 33.3% vs 28.9%; P < or = .001), as well as the subgroup with acute coronary syndrome (n = 185; 30.3% vs 26.5%; P < or = .001). More tachyarrhythmias occurred in the field and slightly more bradyarrhythmias occurred at the time of the first hospital ECG. CONCLUSIONS: Prehospital continuous 12-lead ST-segment ischemia monitoring with computer-assisted automatic mobile telephone transmission of ST event ECGs to the target hospital is feasible. More arrhythmias occur in the prehospital phase than are evident on the first hospital ECG.

Adult↗
PubMed2005

Acute neurocardiogenic injury after subarachnoid hemorrhage.

BACKGROUND: Left ventricular (LV) systolic dysfunction has been reported in humans with subarachnoid hemorrhage (SAH), and its underlying pathophysiology remains controversial. Possible mechanisms include myocardial ischemia versus excessive catecholamine release from sympathetic nerve terminals. METHODS AND RESULTS: For 38 months, echocardiography and myocardial scintigraphy with technetium sestamibi (MIBI) and meta-[(123)I]iodobenzylguanidine (MIBG) were performed on 42 patients admitted with SAH to assess myocardial perfusion and sympathetic innervation, respectively. A blinded observer interpreted the scintigraphic images. Cardiac troponin I (cTI) was measured to quantify the degree of myocyte necrosis. Blinded observers calculated the LV ejection fraction and graded each LV segment as normal (score=1), hypokinetic (score=2), or akinetic (score=3). A wall-motion score was calculated by averaging the sum of the 16 segments. All subjects with interpretable scans (N=41) had normal MIBI uptake. Twelve subjects had either global (n=9) or regional (n=3) absence of MIBG uptake. In comparison with patients with normal MIBG uptake, those with evidence of functional denervation were more likely to have LV regional wall-motion abnormalities (92% versus 52%, P=0.030) and cTI levels >1 microg/L (58% versus 21%, P=0.029). CONCLUSIONS: LV systolic dysfunction in humans with SAH is associated with normal myocardial perfusion and abnormal sympathetic innervation. These findings may be explained by excessive release of norepinephrine from myocardial sympathetic nerves, which could damage both myocytes and nerve terminals.

3-Iodobenzylguanidine↗
PubMed2005

Plasma B-type natriuretic peptide levels are associated with early cardiac dysfunction after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Serum B-type natriuretic peptide (BNP) is elevated after subarachnoid hemorrhage (SAH), as well as in the setting of congestive heart failure and myocardial infarction. The aim of this study was to prospectively quantify the relationship between BNP levels and cardiac outcomes after SAH. METHODS: Plasma was collected for BNP measurements as soon as possible after enrollment; a mean of 5+/-4 days after SAH symptom onset. On days 1, 3, and 6 after enrollment, troponin I (cTi) was measured and 2-dimensional echocardiography was performed. The following cardiac variables were collected and treated dichotomously: left ventricular ejection fraction (LVEF), regional wall motion abnormalities (RWMA), diastolic dysfunction, pulmonary edema, and cTi. RESULTS: There were 57 subjects. The median BNP level was 141 pg/mL (range, 0.8 to 3330 pg/mL). Higher mean BNP levels were present in those with RWMA (550 versus 261 pg/mL; P=0.012), diastolic dysfunction (360 versus 44; P=0.011), pulmonary edema (719 versus 204; P=0.016), elevated cTi (662 versus 240; P=0.004), and LVEF <50% (644 versus 281; P=0.015). CONCLUSIONS: Early after SAH, elevated BNP levels are associated with myocardial necrosis, pulmonary edema, and both systolic and diastolic dysfunction of the left ventricle. These findings support the hypothesis that the heart releases BNP into the systemic circulation early after SAH.

Aged↗
PubMed2005

Practical implementation of the guidelines for unstable angina/non-ST-segment elevation myocardial infarction in the emergency department: a scientific statement from the American Heart Association Council on Clinical Cardiology (Subcommittee on Acute Cardiac Care), Council on Cardiovascular Nursing, and Quality of Care and Outcomes Research Interdisciplinary Working Group, in Collaboration With the Society of Chest Pain Centers.

In the United States each year, >5.3 million patients present to emergency departments with chest discomfort and related symptoms. Ultimately, >1.4 million individuals are hospitalized for unstable angina and non-ST-segment elevation myocardial infarction. For emergency physicians and cardiologists alike, these patients represent an enormous challenge to accurately diagnose and appropriately treat. This update of the 2002 American College of Cardiology/American Heart Association Guidelines for the Management of Patients with Unstable Angina and Non-ST-Segment Elevation Myocardial Infarction (UA/NSTEMI) provides an evidence-based approach to the diagnosis and treatment of these patients in the emergency department, in-hospital, and after hospital discharge. Despite publication of the guidelines several years ago, many patients with UA/NSTEMI still do not receive guidelines-indicated therapy.

Angina Pectoris↗
PubMed2005

Practical implementation of the Guidelines for Unstable Angina/Non-ST-Segment Elevation Myocardial Infarction in the emergency department.

In the United States each year, >5.3 million patients present to emergency departments with chest discomfort and related symptoms. Ultimately, >1.4 million individuals are hospitalized for unstable angina and non-ST-segment elevation myocardial infarction. For emergency physicians and cardiologists alike, these patients represent an enormous challenge to accurately diagnose and appropriately treat. This update of the 2002 American College of Cardiology/American Heart Association Guidelines for the Management of Patients with Unstable Angina and Non-ST-Segment Elevation Myocardial Infarction (UA/NSTEMI) provides an evidence-based approach to the diagnosis and treatment of these patients in the emergency department, in-hospital, and after hospital discharge. Despite publication of the guidelines several years ago, many patients with UA/NSTEMI still do not receive guidelines-indicated therapy.

Angina, Unstable↗
PubMed2005

Designing prehospital ECG systems for acute coronary syndromes. Lessons learned from clinical trials involving 12-lead ST-segment monitoring.

BACKGROUND: Clinical trials in prehospital electrocardiography have focused primarily on ST elevation myocardial infarction (STEMI). The aims of this study were to determine, in patients presenting to the emergency department with acute coronary syndrome (ACS), the (1) relative frequency of various ACS types and (2) sensitivity of conventional ST-T criteria for diagnosing ischemia in non-STEMI or unstable angina. METHODS: A secondary analysis was conducted using data from prospective trials involving 12-lead ST monitoring. RESULTS: Of 968 patients with ACS, 120 (12%) were STEMI, 289 (30%) were non-STEMI, and 559 (58%) were unstable angina. Conventional electrocardiogram (ECG) criteria were insensitive (sensitivity, 20%) for detecting ischemia in patients with non-STEMI or unstable angina. There was no ischemia on the initial ECG in 85 patients who had subsequent events with ST monitoring. CONCLUSION: Non-STEMI and unstable angina are the most prevalent types of ACS. The initial ECG is insensitive for detecting ischemia in this population. Transient myocardial ischemia detected with ST monitoring commonly occurs in patients without ischemia on the initial ECG. ST monitoring should be considered in designing prehospital ECG systems.

Acute Disease↗
PubMed2004

Practice standards for electrocardiographic monitoring in hospital settings: an American Heart Association scientific statement from the Councils on Cardiovascular Nursing, Clinical Cardiology, and Cardiovascular Disease in the Young: endorsed by the International Society of Computerized Electrocardiology and the American Association of Critical-Care Nurses.

The goals of electrocardiographic (ECG) monitoring in hospital settings have expanded from simple heart rate and basic rhythm determination to the diagnosis of complex arrhythmias, myocardial ischemia, and prolonged QT interval. Whereas computerized arrhythmia analysis is automatic in cardiac monitoring systems, computerized ST-segment ischemia analysis is available only in newer-generation monitors, and computerized QT-interval monitoring is currently unavailable. Even in hospitals with ST-monitoring capability, ischemia monitoring is vastly underutilized by healthcare professionals. Moreover, because no computerized analysis is available for QT monitoring, healthcare professionals must determine when it is appropriate to manually measure QT intervals (eg, when a patient is started on a potentially proarrhythmic drug). The purpose of the present review is to provide 'best practices' for hospital ECG monitoring. Randomized clinical trials in this area are almost nonexistent; therefore, expert opinions are based upon clinical experience and related research in the field of electrocardiography. This consensus document encompasses all areas of hospital cardiac monitoring in both children and adults. The emphasis is on information clinicians need to know to monitor patients safely and effectively. Recommendations are made with regard to indications, timeframes, and strategies to improve the diagnostic accuracy of cardiac arrhythmia, ischemia, and QT-interval monitoring. Currently available ECG lead systems are described, and recommendations related to staffing, training, and methods to improve quality are provided.

Arrhythmias, Cardiac↗
PubMed2004

Pre-hospital synthesized 12-lead ECG ischemia monitoring with trans-telephonic transmission in acute coronary syndromes: pilot study results of the ST SMART trial.

INTRODUCTION: The aim of the ST SMART trial is to determine whether prehospital ST monitoring with telephone transmission to the target hospital will improve hospital time to treatment in acute coronary syndromes. The present analysis reports results of the feasibility pilot study. METHODS: All patients calling 911 for chest pain in Santa Cruz County California were monitored with a synthesized 12-lead ECG. Prehospital ECGs were printed for clinical use in the experimental group; control group patient care used only ECGs recorded after hospital arrival. RESULTS: Five patients with non-ST elevation myocardial infarction or unstable angina had normal ECGs upon hospital arrival but evidence of ischemia in their prehospital ECGs. Three patients with ST elevation myocardial infarction were treated with primary percutaneous coronary intervention, with "door to balloon" times of 47 and 65 minutes in 2 experimental group patients and 148 minutes in the one control group patient. CONCLUSION: Prehospital ST monitoring appears feasible. Its potential to improve hospital time to diagnosis and treatment in acute coronary syndromes, and the clinical benefits of such improvement will be studied in the larger, ongoing ST SMART trial.

Aged↗
PubMed2003

Factors to consider when analyzing 12-lead electrocardiograms for evidence of acute myocardial ischemia.

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.

Acute Disease↗
PubMed2003

Frequency and outcomes of transient myocardial ischemia in critically ill adults admitted for noncardiac conditions.

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 (R2 = 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.

APACHE↗
PubMed2002

Comparison of a new reduced lead set ECG with the standard ECG for diagnosing cardiac arrhythmias and myocardial ischemia.

In a few patients, 12-lead electrocardiograms (ECGs) derived from reduced-lead-set configurations do not match the standard ECG. Constructing an ECG from a reduced number of standard leads should minimize this problem because some of the resultant 12 leads would always include "true" standard leads. The purpose of this study was to compare the ability of a new reduced-lead-set 12-lead ECG ("interpolated" ECG) with the standard ECG to diagnose cardiac arrhythmias and acute myocardial ischemia. The interpolated ECG uses six standard electrode sites (limb leads plus V(1) and V(5)), from which the remaining four precordial leads (V(2), V(3), V(4), and V(6)) are constructed. Standard and interpolated ECGs were compared using data from 2 prospective clinical trials involving 649 patients evaluated for 1) chest pain in the emergency department (ischemia group, n = 509) or 2) tachycardias in the cardiac electrophysiology laboratory (arrhythmia group, n = 140). Diagnoses were identical between standard and interpolated ECGs for bundle branch and fascicular blocks, left atrial enlargement, right ventricular hypertrophy, prior inferior myocardial infarction (MI), and the distinction of ventricular tachycardia from supraventricular tachycardia with aberrant conduction. There was 99% agreement for prior anterior MI (kappa, .935, P =.000). The percent agreement for acute myocardial ischemia on the initial ECG recorded in chest-pain patients in the emergency department was 99.2% (kappa, .978, P =.000). Of the 120 patients who had ST events with continuous standard 12-lead ECG monitoring, 116 (97%) also had criteria for transient ischemia with the interpolated ECG (ie, DeltaST >or= 100 microV in >or=1 lead(s) lasting >or=1 minute(s). The interpolated 12-lead ECG is comparable to the standard ECG for diagnosing multiple cardiac abnormalities, including wide-QRS-complex tachycardias and acute myocardial ischemia. The advantages of this ECG method are that the standard electrode sites are familiar to clinicians and that eight of the 12 leads are "true" standard leads. Hence, QRS-axis and morphology criteria for diagnosing wide-QRS-complex tachycardia and bundle branch and fascicular blocks are preserved.

Aged↗
PubMed2002

Efficacy of 2 strategies to detect body position ST-segment changes during continuous 12-lead electrocardiographic monitoring.

Body positional change is the most frequent cause of false positive ST-segment monitor alarms. This study evaluates 2 strategies to distinguish ST events due to positional change from those due to transient myocardial ischemia: 1) A biosensor device to indicate body position with tick marks on the electrocardiogram (ECG) tracing, and 2) An initially recorded ECG "template" in four positions (supine, right, left, and upright) for subsequent comparison with ST alarm ECGs. A purposive sample of 96 patients on a cardiac telemetry unit was recruited to have both strategies implemented and evaluated. The biosensor correctly identified all 4 body positions in the 96 patients. A subgroup of 30 patients were continuously monitored and 9 (30%) had at least 1 ST event due to body position change, for a total of 25 false positive events. Of the 25 positional events detected by the biosensor, the ECG template method detected 18 (73%). The biosensor method is superior to the ECG template method for detecting positional ST events. However, a limitation of both strategies is that they require clinicians to be skilled in integrating such positional information to reach a correct diagnosis.

Biosensing Techniques↗
PubMed2002

Electrocardiographic repolarization abnormalities in subarachnoid hemorrhage.

Electrocardiographic abnormalities, particularly in those waveforms representing ventricular repolarization, have been reported in subarachnoid hemorrhage. This study reports abnormalities on the initial electrocardiogram in 100 patients with SAH. Overall, one or more repolarization abnormalities occurred in 41% of patients. Analysis revealed prolonged QTc interval >460 ms in 16%, ST segment elevation in 9%, ST depression in 3%, T wave inversion in 7%, and U wave >or=100 microV in 15%. Electrocardiographic criteria for left ventricular hypertrophy were met in 14%, and 43% of those patients had no history of hypertension. Serum cardiac troponin I was elevated in 21%, and was significantly associated with QTc interval >460 ms (P <.001). Controlling for gender, those with QTc interval >460 ms were 5.5 times more likely to have elevated serum cardiac troponin I. It is concluded that repolarization abnormalities are present in a high proportion of patients with SAH. Some SAH patients also have left ventricular hypertrophy voltage unrelated to hypertension or coronary artery disease. Prolonged QTc interval after SAH is significantly related to myocardial injury, but unrelated to mortality, and there is no association between ST-T wave abnormalities and either myocardial injury or mortality.

Adult↗
PubMed2002

Association of transient myocardial ischemia with adverse in-hospital outcomes for angina patients treated in a telemetry unit or a coronary care unit.

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 microV 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.

Aged↗