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152. Effectiveness of Prehospital Wireless Transmission of Electrocardiograms to a Cardiologist Via Hand-Held Device for Patients With Acute Myocardial Infarction (from the Timely Intervention in Myocardial Emergency, NorthEast Experience [TIME-NE])

Author

Adams, George L., Campbell, Paul T., Adams, John M., Strauss, David G., Wall, Karen, Patterson, Janet, Shuping, Kathy B., Maynard, Charles, Young, Dwayne, Corey, Craig, Thompson, Alan, Lee, Benjamin A., and Wagner, Galen S.

Published
2006
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162. Validation of cardiologists' decisions to initiate reperfusion therapy for acute myocardial infarction with electrocardiograms viewed on liquid crystal displays of cellular telephones

Author

Leibrandt, Paul N., Bell, Samuel J., Savona, Michael R., Pettis, Karlton S., Selvester, Ronald H., Maynard, Charles, Warner, Robert, and Wagner, Galen S.

Subjects
Telemedicine -- Research, Heart attack -- Care and treatment, Thrombolytic therapy -- Innovations, Cardiologists -- Practice, Health
Published
2000

163. Negative T waves shortly after ST-elevation acute myocardial infarction are a powerful marker for improved survival rate

Author

Sgarbossa, Elena B., Meyer, Peter M., Pinski, Sergio L., Pavlovic-Surjancev, Biljana, Barbagelata, Alejandro, Goodman, Shaun G., Lum, Andrea S., Underwood, Donald A., Gates, Kathy B., Califf, Robert M., Topol, Eric J., and Wagner, Galen S.

Subjects
Heart attack -- Prognosis, Cardiac patients -- Patient outcomes, Diastole (Cardiac cycle) -- Physiological aspects, Heart -- Electric properties, Health
Published
2000

169. The electromechanical substrate for response to cardiac resynchronization therapy in patients with right bundle branch block

Author

Brett D. Atwater, Niels Risum, Galen S. Wagner, and Joseph Kisslo

Subjects
Male, medicine.medical_specialty, medicine.medical_treatment, Bundle-Branch Block, Cardiac resynchronization therapy, Pilot Projects, 030204 cardiovascular system & hematology, Ventricular Function, Left, Cardiac Resynchronization Therapy, 03 medical and health sciences, 0302 clinical medicine, Internal medicine, Humans, Medicine, Single-Blind Method, In patient, Prospective Studies, cardiovascular diseases, 030212 general & internal medicine, Aged, Lv function, Cross-Over Studies, Ejection fraction, business.industry, Double crossover, General Medicine, Right bundle branch block, equipment and supplies, medicine.disease, Biomechanical Phenomena, Electrophysiological Phenomena, Heart failure, Cardiology, Left axis deviation, Cardiology and Cardiovascular Medicine, business
Abstract

Background Some patients with RBBB may respond to cardiac resynchronization therapy (CRT). However, little is known regarding the electromechanical substrate for CRT and whether this is the optimal pacing strategy. Methods This was a pilot prospective double crossover randomized controlled clinical study comparing ventricular back up pacing (VVI-40), RV fusion pacing (DDD-40, RV only), and biventricular (BIV) pacing (DDD-40 BIV) in nine patients with RBBB and depressed EF. The study compared the frequency of dyssynchrony on baseline echocardiogram in patients with RBBB (n = 4), RBBB + anterior MI (RBBB with left axis deviation + left ventricular (LV) anterior wall thinning, n = 3), and RBBB + LAFB (RBBB with left axis deviation without LV anterior wall thinning n = 2). Echocardiographic assessment of LV dyssynchrony, LV size, and LV function was repeated after 6 months in each pacing mode. Results Patients with RBBB + LAFB demonstrated baseline echocardiographic dyssynchrony between the LV anterior and inferior wall. Both DDD-40 RV-only pacing and DDD-40 BIV pacing resulted in improved LV function and clinical status compared to VVI-40 back up pacing. Patients with RBBB alone and RBBB with anterior MI had no baseline dyssynchrony and CRT using either RV only or BIV pacing resulted in LV dilation, worsened left ventricular ejection fraction and worsened clinical status compared to VVI-40 back up pacing. Conclusion Patients with RBBB, left axis deviation, and no prior anterior MI may have LV dyssynchrony between the anterior and inferior walls that is correctable with CRT.

Published
2017
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171. New Feldspar Lead Isotope and Trace Element Evidence from the Sudbury Igneous Complex Indicate a Complex Origin of Associated Ni-Cu-PGE Mineralization Involving Underlying Country Rocks

Author

C. Michael Lesher, Galen S. McNamara, and Balz S. Kamber

Subjects
010504 meteorology & atmospheric sciences, Lithology, Continental crust, Trace element, Geochemistry, Geology, Platinum group, 010502 geochemistry & geophysics, Feldspar, 01 natural sciences, Igneous rock, Geophysics, Geochemistry and Petrology, visual_art, Breccia, visual_art.visual_art_medium, Economic Geology, Norite, 0105 earth and related environmental sciences
Abstract

The Sudbury Igneous Complex is the preserved remnant of a 1.85 Ga impact-induced crustal melt sheet that eventually crystallized into a coherent magmatic stratigraphy. At its base, the complex hosts world-class Ni-Cu- platinum group element (PGE) sulfide mineralization, distributed around the basin. Previous studies have shown strong Pb and Sr isotope contrasts between the North and South ranges of the Sudbury Igneous Complex. This study presents an extensive dataset of Pb isotopes and trace elements of hand-picked feldspars and sulfides from the complex, Ni-Cu-PGE mineralization, and underlying country rocks that reveals the finer details of isotopic decoupling between the North and South ranges. In terms of mean Pb isotope compositions, the new data confirm the previously established picture that North Range Main Mass rocks and associated Ni-Cu-PGE sulfide deposits are more juvenile than South Range Main Mass and associated mineralization, but there are several findings that point to a more complex evolution, with considerable implications for the source of sulfide in the Sudbury Igneous Complex. First, North Range sulfide ores and Main Mass silicates are more radiogenic than local footwall rocks. When expressed as per mil deviation in Pb-207/Pb-204 from a model contemporaneous mantle isochron (Delta Pb-207/Pb-204), the North Range Main Mass ores range from + 130 to + 421 and North Range ores range from + 160 to + 518 (primarily + 160 to + 260). This indicates that the Huronian Supergroup cover constituted a significant target rock type also in the North Range of the Sudbury Igneous Complex. Second, there is significant variability in the Pb isotope compositions between Ni-Cu-PGE sulfide deposits in both the North and South ranges and systematic differences between the average silicate compositions and sulfide compositions of Ni-Cu-PGE deposits. In the South Range Main Mass rocks, the Delta Pb-207/Pb-204 values range from + 360 to + 494, and associated ores range from + 150 to + 481 (primarily + 400 to + 480). Third, North Range mafic norite is much less radiogenic than North Range Main Mass, indicating that it may be contaminated by or derived from less radiogenic Ni-Cu-PGE-bearing mafic-ultramafic rocks. Finally, the Pb isotope variations between Sudbury Igneous Complex ores are corroborated by similar systematic variations in rare earth element patterns likely inherited by assimilation of local footwall rocks. Importantly, the considerable variations in the Pb isotope compositions of the ores between different deposits and the intermediate compositions between overlying Main Mass and footwall rocks suggest that the sulfides originally equilibrated with Main Mass, but acquired significant amounts of Pb (and therefore likely S and other metals) from local footwall rocks, most likely during thermomechanical erosion of the footwall rocks by dense molten sulfides. Potential S and metal sources are the Nipissing gabbros and the East Bull Lake intrusions, both of which are mineralized and whose Pb isotope compositions help to explain the variability in Sudbury Igneous Complex Ni-Cu-PGE sulfide ores. Small-scale lateral variations in Pb isotopes previously identified in the South Range of the Sudbury Igneous Complex are also present in the North Range. This indicates that the laterally extensive (200-km wide x 2.5-km thick) superheated Sudbury Igneous Complex melt sheet developed multiple chemically and isotopically isolated convection cells that continued to assimilate isotopically distinctive footwall rocks after impact. Lateral variations are much greater at lower levels in the magmatic stratigraphy than in the upper part of the stratigraphy. This resulted from a combination of three factors: (1) the overall depletion in Pb of the proto-Sudbury Igneous Complex (likely due to volatile element loss upon impact) made it more susceptible to contamination in this element than in more refractory elements; (2) assimilation of heterogeneous footwall into the base vs. incorporation of more homogeneous fallback breccias into the roof of the Sudbury Igneous Complex; and (3) possible hydrothermal roof alteration. Lead isotopes and trace element data for samples of the footwall collected and analyzed as part of this study used in tandem with data from previous work confirm that the Sudbury Igneous Complex can be reproduced by mixing the currently exposed target lithologies and indicate that no mantle or lower crustal component is required.

Published
2017
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184. Prognostic significance of the initial electrocardiogram in patients with acute myocardial infarction

Author

Hathaway, William R., Peterson, Eric D., Wagner, Galen S., Granger, Christopher B., Zabel, K. Michael, Pieper, Karen S., Clark, Kathryn Andersen, Woodlief, Lynn H., and Califf, Robert M.

Subjects
Electrocardiogram -- Analysis, Heart attack -- Prognosis, Cardiac patients -- Patient outcomes
Abstract

Several findings on the electrocardiogram (ECG) may help doctors predict which heart attack patients are at highest risk of death and may consequently need intensive monitoring. An ECG measures the electrical activity of the heart. Researchers analyzed data on 41,021 heart attack patients treated at 1,081 hospitals in 15 countries. Specific ECG findings predicted 30-day mortality, including abnormalities in the ST segment, the duration of the QRS segment, heart rate and evidence of a previous heart attack., Context. -- Early risk stratification of patients with myocardial infarction is critical to determine optimum treatment strategies and enhance outcomes, but knowledge of the prognostic importance of the initial electrocardiogram (ECG) is limited. Objective. -- To assess the independent value of the initial ECG for short-term risk stratification after acute myocardial infarction. Design. -- Retrospective analysis of the Global Utilization of Streptokinase and t-PA (alteplase) for Occluded Coronary Arteries (GUSTO-I) clinical trial database. Setting. -- A total of 1081 hospitals in 15 countries. Patients. -- From the 41 021 patients enrolled in the overall study, we selected those who presented within 6 hours of chest pain onset with ST-segment elevation and no confounding factors (paced rhythms, ventricular rhythms, or left bundle-branch block) on the ECG performed before thrombolysis was administered (n=34 166). Main Outcome Measure. -- Ability of initial ECG to predict all-cause mortality at 30 days. Results. -- Most ECG variables were associated with 30-day mortality in a univariable analysis. In a multivariable analysis combining the initial ECG variables and clinical predictors of mortality, the sum of the absolute ST-segment deviation (both ST elevation and ST depression: odds ratio [OR], 1.53; 95% confidence interval [CI], 1.38-1.69), ECG, heart rate (OR, 1.49; 95% CI, 1.41-1.59), QRS duration (for anterior infarct: OR, 1.55; 95% CI, 1.43-1.68), and ECG evidence of prior infarction (for new inferior infarct: OR, 2.47; 95% CI, 2.02-3.00) were the strongest ECG predictors of mortality. A nomogram based on the multivariable model produced excellent discrimination of 30-day mortality (C-index, 0.830). Conclusions. -- In patients presenting with myocardial infarction accompanied by ST-segment elevation, components of the initial ECG help predict 30-day mortality. This information should be valuable in early risk stratification, when the opportunity to reduce mortality is greatest, and may help in assessing outcomes adjusted for patient risk. JAMA. 1998;279:387-391

Published
1998

190. Comparison of teaching the basic electrocardiographic concept of frontal plane QRS axis using the classical versus the orderly electrocardiogram limb lead displays

Author

Pahlma, Ulrika S., O'Brien, Jeanne E., Pettersson, Jonas, Pahlm, Olle, White, Thomas, Maynard, Charles, and Wagner, Galen S.

Subjects
Health
Abstract

Byline: Ulrika S. Pahlma, Jeanne E. O'Brien, Jonas Pettersson, Olle Pahlm, Thomas White, Charles Maynard, Galen S. Wagner Abstract: This study compares the effectiveness of teaching the calculation of frontal plane QRS axis with the use of the classical versus the orderly electrocardiographic limb lead display. Eighty-three students from two environments were randomized into two groups and were taught to determine frontal plane axis with one of the methods. The accuracy and time to determine the axis were tested on 10 electrocardiograms. In the United States the group using the classical display achieved 4.2 ([+ or -]2.7) correct answers, whereas those using the orderly method achieved 6.8 ([+ or -]3.0) (p = 0.0006). The classical group used 9.2 ([+ or -]2.8) minutes to complete the test, whereas the orderly group needed 7.2 ([+ or -]2.0) minutes (p = 0.015). The results achieved in Sweden were similar. The use of the orderly electrocardiographic limb lead display results in greater diagnostic accuracy in less time than the classical display when determining the frontal plane QRS axis. (Am Heart J 1997;134:1014-8.) Author Affiliation: Durham, N.C.; Lund, Sweden; and Seattle, Wash Article History: Received 7 October 1996; Accepted 13 June 1997 Article Note: (footnote) [star] From the aDepartment of Medicine/Cardiology, Duke University Medical Center, Durham, N.C., the bDepartment of Clinical Physiology, Lund University, Lund, Sweden, and the cDepartment of Health Services Research, University of Washington, Seattle, Wash., [star][star] Ulrika Pahlm was supported as a Medical Student Research Fellow of the American Heart Association., a Reprint requests: Galen S. Wagner, MD, Department of Medicine/Cardiology, Duke University Medical Center, Box 3636, Durham, NC 27710., aa 4/1/86029

Published
1997

195. Cardiac troponin T levels for risk stratification in acute myocardial ischemia

Author

Ohman, E. Magnus, Armstrong, Paul W., Christenson, Robert H., Granger, Christopher B., Katus, Hugo A., Hamm, Christian W., O'Hanesian, Mary Ann, Wagner, Galen S., Kleiman, Neal S., Harrell, Frank E., Jr., Califf, Robert M., and Topol, Eric J.

Subjects
Carrier proteins -- Measurement, Coronary heart disease -- Prognosis, Cardiac patients -- Patient outcomes, Muscle proteins -- Physiological aspects
Abstract

Troponin T concentrations may predict further risk in patients with acute myocardial ischemia, the lack of oxygen supply to the heart. Troponin T is a binding protein involved in regulating heart cell functions. One-month mortality rates were three times higher among the 289 patients with initially elevated troponin T levels, measured within hours of hospitalization, than those of patients with average troponin T concentrations. Serum creatine kinase MB levels and electrocardiographic results alone were less pronounced risk markers unless used in combination with troponin T measurements.

Published
1996

196. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block

Author

Sgarbossa, Elena B., Pinski, Sergio L., Barbagelata, Alejandro, Underwood, Donald A., Gates, Kathy B., Topol, Eric J., Califf, Robert M., and Wagner, Galen S.

Subjects
Heart attack -- Diagnosis, Electrocardiogram, Heart block -- Diagnosis, Heart ventricle, Left -- Physiological aspects
Abstract

Analysis of one portion of electrocardiograms, the ST segment, may help identify heart attacks in patients with left bundle-branch block (LBBB), an abnormal conduction of the heart impulse between ventricles. The presence of LBBB may hide indications of a heart attack, preventing diagnosis and treatment. Researchers developed distinct electrocardiographic criteria using the data of 131 patients with LBBB, chest pain, and confirmed heart attacks. The control group consisted of 131 patients without chest pain who had stable heart disease and LBBB. The most dependable sign of a heart attack was any degree of wave abnormality in the ST segment of at least 1 millimeter. On the other hand, changes in the QRS segment of the electrocardiogram were unexpectedly not useful markers of heart attacks.

Published
1996

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