DOCSLIB.ORG

The Usefulness of Vectorcardiography in the Early Diagnosis of Acute

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Usefulness of Vectorcardiography in the Early Diagnosis of Acute The usefulness of vectorcardiography Vectorcardiography in the early diagnosis of acute myocardial infarction: Preliminary report LEONARD MENNEN, D.O. Kansas City, Missouri This paper is a preliminary report technical problem in receiving laboratory re- of experience with a panoramic sults promptly, and valuable time may elapse before the seriousness of the patients condi- vectorcardiograph in confirming the tion is known. presence or absence of acute myocardial When such procedures give only equivocal infarction when the initial results, one searches for a more comprehensive electrocardiogram was equivocal. and sophisticated method of studying the vec- The theoretical basis for tors produced by the heart. vectorcardiography is discussed. Three This paper will relate preliminary experi- ence using a panoramic vectorcardiograph to cases are reported to illustrate the confirm the presence of acute myocardial in- usefulness of vectorcardiography. The farction when the initial electrocardiogram was depolarization changes that occur inconclusive. when myocardial activity is altered are pointed out. Vectorcardiography is Basis for vectorcardiography still in the embryonic stage and there Vectorcardiography is a theoretical advance- ment over the electrocardiogram for the follow- are technical difficulties and lack of ing reason : The electric field of the heart agreement on such factors as the exists in three-dimensional space and there- most efficacious lead system. In this fore must be expressed as such. One can predict study vectorcardiography has been a three-dimensional synthesis from the given found to be a useful tool in the electrocardiogram curves, but only within lim- evaluation of acute myocardial its, since precise vector synchronism cannot be attained. infarction. Its value in other instances A minimum of three physical leads will rep- of altered myocardial activity is under resent true X, Y, and Z electrical co-ordinates. continuing study. This is necessary for accurate measurements of the X, Y, and Z components of the dipole vector.2 To form the frontal plane vectorcardiogram, one lead representing the X co-ordinate is used The importance of early diagnosis of acute myocardial infarction has been stressed re- peatedly. Electrocardiography and laboratory _1_ studies have aided clinical determination of 1 altered myocardial activity. However, the H ---I--0- z-H---t- --- T electrocardiogram does not always substan- r tiate the diagnosis, and the laboratory studies, Frontal Sagittal Horizontal namely serum enzymes, are often elevated in Fig. 1. non-cardiac diseases. Frequently there is a 494/70 centripetal t R (vertex) i II (R loop) S i T .. ■ ---7 % .- . .. • Alba.-- .. , %..?I 4,- centrifugal I (Q loop) Fig. 2. Components of the vectorcardiographic loop. Fig. 4. Admission electrocardiogram of patient in Case 1. Fig. 3. Mobile panoramic vectorca/rdiograph used in study. ueiuieu uy analyzing ine imam 5 posiLion.- as the horizontal axis input, and a second lead The sagittal plane is formed by using the representing the Y axis is used as the vertical lead representing the Z component and the axis input to an oscilloscope. When this is lead representing the Y component as the two accomplished, the X input and the Y input act perpendicular signal inputs to the same cath- simultaneously upon the beam and cause the ode ray tube beam.2 beam to be displaced in an XY graphic pat- The horizontal plane projection of the dipole tern. At any one instant during the cardiac vector is obtained by utilizing a lead which cycle the XY axis of the dipole vector can be represents the X and Z components of the Journal AOA/vol. 66, January 1967 495/71 R R Frontal plane — Horizontal plane-- I A S A Horizontal plane Rt. sagittal plane A I Fig. 5. The vectorcardiogram of patient in Case I shows a disappearance of the Q loop in. the horizontal plane indicating a loss of the normal first septal vector. In the same plane (upper right and, for greater magnifica- tion, lower left) the centrifugal limb of the R loop has lost its normal configuration and is rotated backward, suggesting necrosis to the anterior and lateral regions of the free left ventricular wall. The J-point is also dis- placed. The sagittal plane demonstrates significant posterior displacement of the initial vectorial forces. In the frontal plane abnormal rotation is also noted. These findings were interpreted as representing an acute myo- cardial infarction involving the middle and lower portions of the interventricular septum, and the anterior and lateral regions of the free left ventricular wall. dipole vector as perpendicular signal inputs to rectangular systems and the modifications by the same cathode ray tube beam. In a similar Grishman and Frank. manner, the frontal (XY), sagittal (ZY), and Orthogonal lead systems differ from those horizontal (XZ) plane projections of the di- based on the equilateral triangle by having pole vector may be obtained throughout the their lead electrodes formed perpendicular to cardiac cycle2 (Fig. 1). one another.3 Proper magnification of the loops is of the We have found the Frank and Grishman utmost importance so that every component systems to be the most convenient technically. may be adequately studied. Our vectorcardio- We are still experimenting with other lead graph gives magnification from 50 millivolts systems and are particularly interested in the per centimeter to 1 millivolt per centimeter, "balanced bipolar system" used by Lamb, and related to the oscilloscope input sensitivity. the McFee and Parungao system. Lambs sys- Many lead reference systems have been tem has a major advantage of obtaining large, devised to measure X, Y, and Z components. clear signals because of its high signal-to-noise Basically there are two types. One type of ratio. It also measures the vectors representing system is based on the Einthoven equilateral the atria more accurately than other available triangle and includes those devised by Milo- systems. The McFee and Parungao system vanovich, Jouve, Vastesaeger, and the "equi- supposedly has the advantage of eliminating lateral tetrahedron" system suggested by Wil- the inaccuracy or error in the location of an- son. The other consists of orthogonal lead terior and lateral thoracic electrodes. systems. These include Duchosal and Sulzers The components of the vectorcardiographic 496/72 ei I , i. ,,. Arl -agnAmeas ItitiligliallAtIfilli Mini Elwell 1111E,r5ItTgif Itegilial 4,.4.16,fa,,,Agt SPPRITHIP illkel$Mitall IMiklutlilltelll L,!lli,diffftitliON: WPM MX Nil Min ::, A 44, Ittifilallffinni Nei n Cate i AVM . 11,f,NutfmimitiN fflgill 111111tEglik , *atilbill. ,grimaggikrufArtvf RI Malin .rfftern ttIlliMilla AlE04414111P4111 Aolfiklhiellith:1410::Tairr ION ,01010e4M;firtilt41011/11 11814114411141111114.ALIR MR SOMBIJAREUtegt 4910E44-J111111111111011Mt 4 30110341111111fifilt,IMElk • ,41:04NeleSEIt red? filligliing TIP TM 1.10tgA. lPlinliiMP 1414 lite,,t 1P.,4, 4 ., • loop are the QRS, T, and P loops (Fig. 2, left). 3r,110P llitill4PlItO ' Ora; tio$ The Q loop (Fig. 2) corresponds to the re- gs sultant vectors produced by the activation of - 41044.,,r,§1MMICIO ' Yft00:1:4:MiritifAii the middle and lower third of the interven- 40441441! tricular septum belonging predominantly to the left septal, inferior, and right anterior * •.. septal masses. The R loop (Fig. 2) represents #4: .foiiiNgage imatmainon, the resultant vectors produced by the activa- NinfitittWillittkint tion of the free left ventricular wall. It con- raw la'cfAKIANKTOnef4f1 ormarmwhi sists of two segments : A—The initial or cen- ink famidifla trifugal limb (Fig. 2, left) is produced by the activation in the apical segment. This includes the anterior and lateral surfaces at the middle and lower regions. B—The final or centripetal segment corresponds to activations at the mid- -Avow.AA4 dle and upper thirds of the posterior, high somatim lateral, and posterolateral regions. At the 7.7.a junction of the initial and final portions of the f1004,60PIO5PE2ZOI irrOrliite QRS loop a vertex is noted (Fig. 2, left). This la P. is due to the activation in the lateral free left T.41: ventricular wall at its thickest region.4 The S loop (Fig. 2) is actually a portion of the centripetal segment of the QRS loop. It represents the activation within the basal por- tions of the heart. This includes the high pos- terior portions of the left ventricular wall, high portions of the right septal mass, and the free right ventricular wal1.4 The P loop (Fig. 2, left) reflects the activa- tion of the atria, and the T loop (Fig. 2, left) depicts the repolarization of the ventricles.4 In order to use the vectorcardiograph as a useful clinical instrument, one must under- stand the vectorcardiographic changes which occur when myocardial activity is altered. In 0 sY: . 444,4 this preliminary report, discussion will be sontomarf limited to the depolarization changes noted in 41,101110NOR an acute myocardial infarction. The repolari- zation abnormalities reflected by the T loop are not specific for myocardial infarction and therefore will not be mentioned. Necrotic tissue does not produce an action Fig. 6. Serial electrocardiograms of patient in Case 1. Journal AOA/vol. 66, January 1967 497/73 /RLL ,10.f“ R /AO y 1 \ ...a Frontal plane — 3 ‘/ I P Roc R Avg /4— 36 Horizontal plane A Fig. 7. Admission electrocardiogram of patient in Case 2. S current and therefore contributes little to the configuration of the vectorcardiograph loop.4 It is this absence of vectorial forces at the site P of necrosis that is responsible for the changes in the magnitude and configuration of normal loop morphology. Materials and methods Rt. sa6ittal plane A fully mobile panoramic vectorcardiograph was used (Fig. 3). This instrument not only Fig. 8. The vectorcardiogram of patient in Case 2 records the standard frontal, horizontal, and demonstrates an abnormally oriented Q loop, most sagittal planes, but any azimuth and elevation noticeable in the right sagittal plane where it is pro- longed upward and anteriorly.
Load more

Recommended publications
  • Left Ventricular Wall Findings in Non-Electrocardiography-Gated CE-CT After ECPR Might Be Useful for Diagnosis and Prognostic Prediction
    Sugiyama et al. Critical Care (2019) 23:357 https://doi.org/10.1186/s13054-019-2624-1 RESEARCH Open Access Left ventricular wall findings in non- electrocardiography-gated contrast- enhanced computed tomography after extracorporeal cardiopulmonary resuscitation Kazuhiro Sugiyama1* , Masamichi Takahashi2, Kazuki Miyazaki1, Takuto Ishida1, Mioko Kobayashi1 and Yuichi Hamabe1 Abstract Background: Few studies have reported left ventricular wall findings in contrast-enhanced computed tomography (CE-CT) after extracorporeal cardiopulmonary resuscitation (ECPR). This study examined left ventricular wall CE-CT findings after ECPR and evaluated the association between these findings and the results of coronary angiography and prognosis. Methods: We evaluated out-of-hospital cardiac arrest patients who were treated with ECPR and subsequently underwent both non-electrocardiography-gated CE-CT and coronary angiography at our center between January 2011 and April 2018. Left ventricular wall CE-CT findings were classified as follows: (1) homogeneously enhanced (HE; the left ventricular wall was homogeneously enhanced), (2) segmental defect (SD; the left ventricular wall was not segmentally enhanced according to the coronary artery territory), (3) total defect (TD; the entire left ventricular wall was not enhanced), and (4) others. Successful weaning from extracorporeal membrane oxygenation, survival to hospital discharge, and predictive ability of significant stenosis on coronary angiography were compared among patients with HE, SD, and TD patterns. Results: A total of 74 patients (median age, 59 years) were eligible, 50 (68%) of whom had initial shockable rhythm. Twenty-three (31%) patients survived to hospital discharge. HE, SD, TD, and other patterns were observed in 19, 33, 11, and 11 patients, respectively. The rates of successful weaning from extracorporeal membrane oxygenation (84% vs.
    [Show full text]
  • Good Quality Care Increases Hospital Profits Under Prospective Payment by David C
    Good quality care increases hospital profits under prospective payment by David C. Hsia and Cathaleen A. Ahern This study shows that, contrary to popular belief, the overlooked because ofthis skimping. After deduction prospective payment system discourages skimping on for the cost ofthe omitted services and probability of medically indicated care. The quality ofcare on a negative diagnostic tests, good quality care would have nationally representative sample ofMedicare discharges increased hospital profits a significant 7.9 percent. As underwentjudgmental review using implicit criteria. the specificity ofdiagnosis and intensity oftreatment The reviewing physicians identified hospitalizations that increase, the DRG payment rises faster than the cost of omitted medically indicated services and diagnoses providing medically indicated services. Background Classification ofDiseases 9th Revision, Clinical Modification (ICD-9-CM) numeric codes (Public Since October 1, 1983, Medicare has used a Health Service and Health Care Financing prospective payment system (PPS) to pay hospitals for Administration, 1980). The fiscal intermediary groups inpatient care, as required by the Social Security the ICD-9-CM codes to the proper DRG, converts the Amendments of 1983. Each discharge's diagnoses and corresponding relative weight to a dollar amount (with procedures "group" it to one of 477 diagnosis-related certain minor adjustments for hospital-specific factors), groups (DRGs). The Health Care Financing and pays the hospital (Averill et al., 1986). Administration (HCFA) pays the hospital a fixed Omission of medically indicated procedures could amount representing the average cost for that DRG's cause diagnostic uncertainty and may therefore produce discharges (Code ofFederal Regulations, 1988). The vague ICD-9-CM codes (e.g., the classic weak, tired, hospital retains surpluses from discharges that cost it and dizzy).
    [Show full text]
  • Using Vectorcardiography in Cardiac Resynchronization Therapy
    Using Vectorcardiography In Cardiac Resynchronization Therapy By L.Lindeboom BMTE 10.19 Report Internship Catharina Hospital Eindhoven Eindhoven University of Technology Supervisors Dr. Ir. M. van ‘t Veer Dr. B.M. van Gelder Dr. Ir. M.C.M. Rutten Prof. Dr. N.H.J. Pijls 1 Abstract (English) The conductive system of the heart may be affected by a heart disease due to direct damage of the Purkinje bundle branches or by a changed geometry in a dilated heart. As a result the electrical activation impulse will no longer travel across the preferred pathway and a loss of ventricular synchrony, prolonged ventricular depolarization and a corresponding drop in the cardiac output is observed. During cardiac resynchronization therapy (CRT) a biventricular pacemaker is implanted, which is used to resynchronise the contraction between different parts of the myocardium. Optimize pacing lead placement and CRT device programming, is important to maximize the benefit for the selected patients. The use of vectorcardiography (VCG) for CRT optimization is investigated. In current clinical practice a 12-lead electrocardiogram (ECG) is used to measure the electric cardiac activity of a patient. Each cell in the heart can be represented as an electrical dipole with differing direction during a heartbeat. A collection of all cellular dipoles will result in a single dipole, the cardiac electrical vector. Spatial visualization of the intrinsically three- dimensional phenomena, using VCG, might allow for an improved interpretation of the electric cardiac activity as compared to the one dimensional projections of a scalar ECG. The VCG loops of one healthy subject and two subjects with a left bundle branch block (LBBB) and two subjects with a right bundle branch block (RBBB) are qualitatively described.
    [Show full text]
  • Sparse-Input Detection Algorithm with Applications in Electrocardiography and Ballistocardiography
    Sparse-input Detection Algorithm with Applications in Electrocardiography and Ballistocardiography ;1 ;1 2 1 1 F. Wadehn∗ , L. Bruderer∗ , D. Waltisberg , T. Keresztfalvi and H.-A. Loeliger 1 Signal and Information Processing Laboratory, ETH Zurich, Gloriastrasse 35, Zurich, Switzerland 2 Institut fuer Elektronik, ETH Zurich, Gloriastrasse 35, Zurich, Switzerland Keywords: Ballistocardiography, Heart Rate Estimation, Hypothesis Test, Factor Graphs, System identification, State- space Models, Maximum likelihood, Maximum a posteriori. Abstract: Sparse-input learning, especially of inputs with some form of periodicity, is of major importance in bio- signal processing, including electrocardiography and ballistocardiography. Ballistocardiography (BCG), the measurement of forces on the body, exerted by heart contraction and subsequent blood ejection, allows non- invasive and non-obstructive monitoring of several key biomarkers such as the respiration rate, the heart rate and the cardiac output. In the following we present an efficient online multi-channel algorithm for estimating single heart beat positions and their approximate strength using a statistical hypothesis test. The algorithm was validated with 10 minutes long ballistocardiographic recordings of 12 healthy subjects, comparing it to synchronized surface ECG measurements. The achieved mean error rate for the heart beat detection excluding movement artifacts was 4:7%. 1 INTRODUCTION Early signal-processing methods for BCG signals (Watanabe et al., 2005; Mack et al., 2009) concerned Cardiovascular diseases are among the leading causes estimation of heart rates averaged over a few sec- of death and severe health impairments both in high- onds using frequency-based methods. These meth- income countries with an aging population, as well ods do not provide beat-to-beat resolution or infor- as in developing countries, which are increasingly mation on irregular arrhythmias.
    [Show full text]
  • Mcfee and Parungao Orthogonal Lead Vectorcardiography in Normal Dogs C
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1-1-1972 McFee and Parungao orthogonal lead vectorcardiography in normal dogs C. B. Chastain Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Recommended Citation Chastain, C. B., "McFee and Parungao orthogonal lead vectorcardiography in normal dogs" (1972). Retrospective Theses and Dissertations. 17945. https://lib.dr.iastate.edu/rtd/17945 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. McFee and Parungao orthogonal lead vectorcardiography in normal dogs by Claud Blankenhorn Chastain A Thesis Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of MASTER OF SCIENCE Major: Veterinary Clinical Sci ences Appr oved: Signatures have been redacted for privacy Iowa State University Ame s, Iowa 1972 ~ 1?C&R3 - ~­ l - I . ii ~r:,1 V J/- ;/; ~ (; . 5 .:< TABLE OF CONTENTS Page INTRODUCTION AND OBJECTIVES 1 LITERATURE EVALUATION 3 Evolution of Vectorcardiology 3 Comparison of Lead Systems 9 Normal Human Vectorcardiograms 10 Clinical Application 13 Vectorcardiography in the Canine 15 MATERIALS AND METHODS 19 Selection of Subjects and Recording Method 19 Storage and Reproduction of the QRS Loop 21 Evaluation of the QRS Loop 24 RESULTS 26 Magnitude and Orientation of Vectors 26 Statistical Analysis 28 DISCUSSION 29 SUMMARY AND CONCLUSIONS 36 LITERATURE CITED 39 ACKNOWLEDGMENTS 51 APPENDIX 52 1 INTRODUCTION AND OBJECTIVES I Vectorcardiography is a measurement of the direction, magnitude and orientation of the mean instantaneous voltage distributions of the heart.
    [Show full text]
  • Acute Coronary Syndrome
    Technology Assessment Systematic Review of ECG-based Signal Analysis Technologies for Evaluating Patients With Acute Coronary Syndrome Technology Assessment Program Prepared for: Agency for Healthcare Research and Quality October 2011 540 Gaither Road Rockville, Maryland 20850 Systematic Review of ECG-based Signal Analysis Technologies for Evaluating Patients With Acute Coronary Syndrome Technology Assessment Report Project ID: CRDD0311 October 2011 Duke Evidence-based Practice Center Remy R. Coeytaux, M.D., Ph.D. Philip J. Leisy, B.S. Galen S. Wagner, M.D. Amanda J. McBroom, Ph.D. Cynthia L. Green, Ph.D. Liz Wing, M.A. R. Julian Irvine, M.C.M. Gillian D. Sanders, Ph.D. DRAFT – Not for citation or dissemination This draft technology assessment is distributed solely for the purpose of peer review and/or discussion at the MedCAC meeting. It has not been otherwise disseminated by AHRQ. It does not represent and should not be construed to represent an AHRQ determination or policy. This report is based on research conducted by the Duke Evidence-based Practice Center under contract to the Agency for Healthcare Research and Quality (AHRQ), Rockville, MD (Contract No. HHSA 290-2007-10066 I). The findings and conclusions in this document are those of the authors, who are responsible for its contents. The findings and conclusions do not necessarily represent the views of AHRQ. Therefore, no statement in this report should be construed as an official position of the Agency for Healthcare Research and Quality or of the U.S. Department of Health and Human Services. None of the investigators has any affiliations or financial involvement related to the material presented in this report.
    [Show full text]
  • 2Nd Quarter 2001 Medicare Part a Bulletin
    In This Issue... From the Intermediary Medical Director Medical Review Progressive Corrective Action ......................................................................... 3 General Information Medical Review Process Revision to Medical Record Requests ................................................ 5 General Coverage New CLIA Waived Tests ............................................................................................................. 8 Outpatient Hospital Services Correction to the Outpatient Services Fee Schedule ................................................................. 9 Skilled Nursing Facility Services Fee Schedule and Consolidated Billing for Skilled Nursing Facility (SNF) Services ............. 12 Fraud and Abuse Justice Recovers Record $1.5 Billion in Fraud Payments - Highest Ever for One Year Period ........................................................................................... 20 Bulletin Medical Policies Use of the American Medical Association’s (AMA’s) Current Procedural Terminology (CPT) Codes on Contractors’ Web Sites ................................................................................. 21 Outpatient Prospective Payment System January 2001 Update: Coding Information for Hospital Outpatient Prospective Payment System (OPPS) ......................................................................................................................... 93 he Medicare A Bulletin Providers Will Be Asked to Register Tshould be shared with all to Receive Medicare Bulletins and health care
    [Show full text]
  • Electrocardiography: a Technologist's Guide to Interpretation
    CONTINUING EDUCATION Electrocardiography: A Technologist’s Guide to Interpretation Colin Tso, MBBS, PhD, FRACP, FCSANZ1,2, Geoffrey M. Currie, BPharm, MMedRadSc(NucMed), MAppMngt(Hlth), MBA, PhD, CNMT1,3, David Gilmore, ABD, CNMT, RT(R)(N)3,4, and Hosen Kiat, MBBS, FRACP, FACP, FACC, FCCP, FCSANZ, FASNC, DDU1,2,3,5 1Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia; 2Cardiac Health Institute, Sydney, New South Wales, Australia; 3Faculty of Science, Charles Sturt University, Wagga Wagga, New South Wales, Australia; 4Faculty of Medical Imaging, Regis College, Boston, Massachusetts; and 5Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia CE credit: For CE credit, you can access the test for this article, as well as additional JNMT CE tests, online at https://www.snmmilearningcenter.org. Complete the test online no later than December 2018. Your online test will be scored immediately. You may make 3 attempts to pass the test and must answer 80% of the questions correctly to receive 1.0 CEH (Continuing Education Hour) credit. SNMMI members will have their CEH credit added to their VOICE transcript automatically; nonmembers will be able to print out a CE certificate upon successfully completing the test. The online test is free to SNMMI members; nonmembers must pay $15.00 by credit card when logging onto the website to take the test. foundation for understanding the science of electrocardiog- The nuclear medicine technologist works with electrocardio- raphy and its interpretation. graphy when performing cardiac stress testing and gated cardiac imaging and when monitoring critical patients.
    [Show full text]
  • Early Or Delayed Cardioversion in Recent-Onset Atrial Fibrillation
    The new england journal of medicine Original Article Early or Delayed Cardioversion in Recent-Onset Atrial Fibrillation N.A.H.A. Pluymaekers, E.A.M.P. Dudink, J.G.L.M. Luermans, J.G. Meeder, T. Lenderink, J. Widdershoven, J.J.J. Bucx, M. Rienstra, O. Kamp, J.M. Van Opstal, M. Alings, A. Oomen, C.J. Kirchhof, V.F. Van Dijk, H. Ramanna, A. Liem, L.R. Dekker, B.A.B. Essers, J.G.P. Tijssen, I.C. Van Gelder, and H.J.G.M. Crijns, for the RACE 7 ACWAS Investigators*​​ ABSTRACT BACKGROUND Patients with recent-onset atrial fibrillation commonly undergo immediate restora- The authors’ full names, academic degrees, tion of sinus rhythm by pharmacologic or electrical cardioversion. However, whether and affiliations are listed in the Appen- dix. Address reprint requests to Dr. Crijns immediate restoration of sinus rhythm is necessary is not known, since atrial fibril- at the Department of Cardiology, Maas- lation often terminates spontaneously. tricht University Medical Center, P. Debye- laan 25, 6229 HX Maastricht, the Nether- METHODS lands, or at hjgm . crijns@ mumc . nl. In a multicenter, randomized, open-label, noninferiority trial, we randomly assigned *A complete list of investigators in the patients with hemodynamically stable, recent-onset (<36 hours), symptomatic atrial RACE 7 ACWAS trial is provided in the fibrillation in the emergency department to be treated with a wait-and-see approach Supplementary Appendix, available at (delayed-cardioversion group) or early cardioversion. The wait-and-see approach in- NEJM.org. volved initial treatment with rate-control medication only and delayed cardioversion Drs.
    [Show full text]
  • Guide to Exercise Electrocardiogram
    Guide to the Exercise Electrocardiogram (The Treadmill Stress Test) An exercise stress test is performed to evaluate heart rate, heart rhythm, blood pressure and electrocardiographic (ECG) responses to progressive exercise. You do not need to be an athlete or to be trained to have this test for evaluation of your cardiovascular system, but you do need to be able to walk without support. The exercise ECG is used to evaluate the adequacy of blood supply to the heart during exercise that may be symptomatic or asymptomatic and to assess the extent of limitation of blood supply to the heart in people with known coronary artery disease. The test is also used to quantify effort capacity, to evaluate the effect of medications on symptoms and effort tolerance, to assess general health and prognosis, and to evaluate the heart rate and blood pressure responses to exercise before surgical procedures and before entry into programs of cardiac rehabilitation. Imaging of the heart with echocardiography or with radionuclide agents is not performed during basic exercise ECG unless prearranged by the referring physician. Pre-Registration and Testing Location Please call 2 days before the date your test is scheduled to confirm your appointment. At this time we can also answer questions you may have. Please have your referring physician complete the order form. Plan to arrive 20 minutes before the scheduled time of your test. Bring your hospital and insurance cards with you. Go directly to the test location. NewYork-Presbyterian Hospital/Weill Cornell Medical Center 212-746-4670 Exercise ECG Laboratory Starr Pavilion 520 East 70th Street, east of York Avenue New York, NY 10021 Take the Starr elevators to the 4th floor, follow the signs to room K-425.
    [Show full text]
  • (VCG) Parameters for Analyzing Repolarization Variability in ECG Signals
    Biomed. Eng.-Biomed. Tech. 2016; 61(1): 3–17 Review Muhammad A. Hasan* and Derek Abbott A review of beat-to-beat vectorcardiographic (VCG) parameters for analyzing repolarization variability in ECG signals Abstract: Elevated ventricular repolarization lability is Introduction believed to be linked to the risk of ventricular tachycardia/ ventricular fibrillation. However, ventricular repolariza- The biological signals are generated within the human tion is a complex electrical phenomenon, and abnor- body through different physiological processes. These malities in ventricular repolarization are not completely signals are usually acquired in their raw form, and there- understood. To evaluate repolarization lability, vector- fore, it is required to carry out signal processing and cardiography (VCG) is an alternative approach where the analysis to reveal pertinent details. In the case of an electrocardiographic (ECG) signal can be considered as electrocardiographic (ECG) signal, the signal contains possessing both magnitude and direction. Recent research amplitude information without orientation of the heart has shown that VCG is advantageous over ECG signal vector direction. In clinical practice, the QT interval is analysis for identification of repolarization abnormality. measured as the duration of onset of Q wave and the One of the key reasons is that the VCG approach does not offset of T wave in the heart’s ECG electrical cycle, which rely on exact identification of the T-wave offset, which represents the global electrical repolarization of the ven- improves the reproducibility of the VCG technique. How- tricles. Note that QT-interval variability analysis from a ever, beat-to-beat variability in VCG is an emerging area single ECG beat demonstrates the static picture of repo- for the investigation of repolarization abnormality though larization abnormalities, but the beat-to-beat QT inter- not yet fully realized.
    [Show full text]
  • Echocardiography to Supplement Stress Electrocardiography in Emergency Department Chest Pain Patients
    Original research Echocardiography to Supplement Stress Electrocardiography in Emergency Department Chest Pain Patients Mark I. Langdorf, MD, MHPE* * University of California, Irvine, Department of Emergency Medicine, Irvine, CA Eric Wei, MD† † University of Michigan, Ann Arbor, MI Ali Ghobadi, MD* Scott E. Rudkin, MD, MBA* Shahram Lotfipour, MD, MPH* Supervising Section Editor: David E. Slattery, MD Submission history: Submitted July 18, 2009; Revision Received February 21, 2010; Accepted March 24, 2010 Reprints available through open access at http://escholarship.org/uc/uciem_westjem Introduction: Chest pain (CP) patients in the Emergency Department (ED) present a diagnostic dilemma, with a low prevalence of coronary disease but grave consequences with misdiagnosis. A common diagnostic strategy involves ED cardiac monitoring while excluding myocardial necrosis, followed by stress testing. We sought to describe the use of stress echocardiography (echo) at our institution, to identify cardiac pathology compared with stress electrocardiography (ECG) alone. Methods: Retrospective cohort study of 57 urban ED Chest Pain Unit (CPU) patients from 2002- 2005 with stress testing suggesting ischemia. Our main descriptive outcome was proportion and type of discordant findings between stress ECG testing and stress echo.The secondary outcome was whether stress echo results appeared to change management. Results: Thirty-four of 57 patients [59.7%, 95% confidence interval (CI) 46.9-72.4%] had stress echo results discordant with stress ECG results. The most common discordance was an abnormal stress ECG with a normal stress echo (n=17/57, 29.8%, CI 17.9-41.7%), followed by normal stress ECG but with reversible regional wall-motion abnormality on stress echo (n = 10/57, 17.5%, CI 7.7- 27.4%).
    [Show full text]