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Biomedical subjects

Mary G Adams

Publications and source records attributed to Mary G Adams.

12 recordsLinked to original sources
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

Inverted P waves.

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Diagnosis, Differential↗
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↗
PubMedDate not supplied

Transient myocardial ischemia is an independent predictor of adverse in-hospital outcomes in patients with acute coronary syndromes treated in the telemetry unit.

OBJECTIVE: The purpose of this study was to determine whether transient myocardial ischemia (TMI) is predictive of adverse in-hospital outcomes among patients admitted to a telemetry unit with acute coronary syndrome (ACS). DESIGN AND SETTING: The study was designed as a prospective clinical trial in a telemetry unit of a large, urban, university medical center. SAMPLE: The sample was comprised of adult patients admitted to the telemetry unit for treatment of acute myocardial infarction, unstable angina, or coronary artery disease warranting cardiac catheterization or percutaneous coronary intervention. METHODS: Continuous 12-lead electrocardiographic (ECG) ST-segment monitoring was initiated in patients admitted to the telemetry unit. TMI was defined as a change in ST amplitude of > or = 100 microV (elevation or depression) in > or = 1 ECG lead lasting > or = 60 seconds, comparing a baseline 12-lead ECG with an event ECG. Frequencies, measurements of central tendency, t test, chi(2) test, and logistic regression analysis were used for data analysis. A P value of <.05 was adopted as the critical value to determine statistical significance. RESULTS: In 237 telemetry unit patients, 39 patients (17%) had ischemia. Overall, 46% of the patients with ischemia had in-hospital complications compared with 10% of the group without ischemia (P <.001). After controlling for other predictors of adverse outcomes (eg, age, gender, Norris prognostic indicator), patients with TMI were 8.5 times more likely to have in-hospital complications (95% CI, 3.71 to 19.71). CONCLUSION: TMI is an independent predictor of in-hospital complications among patients with ACS treated in the telemetry unit setting. Continuous 12-lead ECG ST-segment monitoring provides prognostic information for risk stratification of patients admitted to the hospital for treatment of ACS.

Adult↗