1 Er Articulo

A Simplified Clinical Electrocardiogram Score for the Prediction of Cardiovascular Mortality
Swee Yaw Tan, M.D.,∗,† Gannon W Sungar, B.A.,‡ Jonathan Myers, PH.D.,∗ Marcus Sandri, B.Sc.,∗ Victor Froelicher, M.D.∗
Palo Alto Veterans Affairs Health Care System, Cardiology, 3801 Miranda Avenue, Cardiology Section 111-C, VA Palo Alto Health Care System, Palo Alto, CA 94304, USA; ∗ Stanford UniversitySchool of Medicine, Cardiovascular Medicine, 300 Pasteur Drive, Stanford, CA 94305, USA; † National Heart Centre Singapore, Cardiovascular Rehabilitation & Preventative Cardiology, 17 Third Hospital Avenue, 168752, Singapore; ‡ Stanford University Human Performance Lab, 341 Galvez St, Stanford, CA 94305, USA

Address for correspondence: Victor Froelicher, M.D. 3801 Miranda Avenue, CardiologySection 111-C VA Palo Alto Health Care System Palo Alto, CA94304 vicmd@pacbell.net

Background: Electrocardiogram (ECG) scores have been demonstrated to predict CV mortality but they are rarely utilized clinically. Objective: Develop a simple score consisting of adding classical ECG abnormalities to make the ECG a more convenient prognostic tool. Methods: Resting ECGs of 29,320 outpatient maleveterans from the Palo Alto Veteran Affairs Healthcare System (PAVHS) collected between 1987 and 2000 were computer analyzed with an average follow-up of 7.5 y. Twelve classic ECG abnormalities were chosen on the basis of prevalence and corresponding relative risks, including left and right bundle branch block, diagnostic Q waves, intraventricular conduction defect, atrial fibrillation, left atrialabnormality, left and right axis deviation, left and right ventricular hypertrophy, ST depression, and abnormal QTc interval. A simple score derived from the summation of these criteria was then entered into an age and heart rate adjusted Cox analysis. Results: There was a progressive increase in risk of death as the number of ECG abnormalities increased. The relative risks for 1, 2, 3, 4, and 5 ECGabnormalities were 1.8 (CI 1.6–2.0), 2.4 (CI 2.2–2.7), 3.6 (CI 3.2–4.1), 4.5 (CI 3.8–5.4), and 6.0 (CI 4.7–7.8) respectively (p110 ms where RBBB and LBBB are not present • Presence of Q wave (QW): Q waves greater than 100 mV in chest leads with Q duration >30 ms in anterior septal leads, and greater than 75 mv in the inferior leads with Q duration of 35 ms. • ST depression (STD): ST junctiondepressed by 100 mV (1mm) • Atrial fibrillation (AF): R-R interval variability with lack of discernible P wave. • Left atrial abnormality (LAA): P amplitude of less than −200 mV in lead V1 or V2 • Left axis deviation (LAD): QRS axis −30 to −89 degrees • Right axis deviation (RAD): QRS axis +90 to +289 degrees • Prolonged QTc interval (PQT): Corrected QT duration of more than 450 ms
Outcomes

Theprimary outcome variable was CV mortality. The California Death Index (from the California Department of Health Services) and the Social Security Death Index (national) were used to ascertain the vital status of each patient as of December 31, 2002. The California Death Index provided cause of death which was confirmed by reviewing the VA Clinical Database.
Statistical Analysis

Our ECG score is aderivation of 12 variables, selected by their prevalence in our population and their association with CV mortality. Each abnormality was given 1 point and the score for a particular ECG was determined by summing the number of abnormalities on the ECG with a maximal possible score of 12. Below is a list of the ECG abnormalities and how the GE MUSE system classifies them. • Left ventricularhypertrophy by Romhilt–Estes criteria (LVH): Amplitude of QRS (Limb lead R or S >than 2 mm, R or S in V1, V2, V5, V6 greater than 30 mm), STT strain pattern, LAA, left axis deviation (LAD), QRS duration >0.09, intrinsicoid QRS deflection of >0.05 second in V5 or V6 . • Right ventricular hypertrophy (RVH): R or R’ >500 mv in lead V1, QRS axis >90 degrees, QRS amplitude negative in lead V5 and V6 • Right...