Abstract INTRODUCTION The scales available to predict death and complications after acute coronary syndrome include angiographic studies and serum biomarkers that are not within reach of services with limited resources. Such services need specific and sensitive instruments to evaluate risk using accessible resources and information. OBJECTIVE Develop a scale to estimate and stratify the risk of intrahospital death in patients with acute ST-segment elevation myocardial infarction. METHODS An analytical observational study was conducted in a universe of 769 patients with acute ST-segment elevation myocardial infarction who were admitted consecutively to the Camilo Cienfuegos Provincial Hospital in Sancti Spíritus Province, Cuba, from January 2013 to March 2018. The final study cohort included 667 patients, excluding 102 due to branch blocks, atrial fibrillation, drugs that prolong the QT interval, low life expectancy or history of myocardial infarction. The demographic variables of age, sex, skin color, classic cardiovascular risk factors, blood pressure, heart rate, blood glucose level, in addition to duration and dispersion of the QT interval with and without correction, left ventricular ejection fraction, and glomerular filtration rate were included in the analysis. Patients were categorized according to the Killip-Kimball Classification for degree of heart failure. A risk scale was constructed, the predictive ability of which was evaluated using the detectability index associated with an receiver-operator curve. RESULTS Seventy-seven patients died (11.5%). Mean blood glucose levels were higher among the deceased, while their systolic and diastolic blood pressure, left ventricular ejection fraction, and glomerular filtration rate were lower than those participants discharged alive. Relevant variables included in the scale were systolic blood pressure, Killip-Kimball class, cardiorespiratory arrest, glomerular filtration rate, corrected QT interval dispersion, left ventricular ejection fraction, and blood glucose levels. The variable with the best predictive ability was cardiorespiratory arrest, followed by a blood glucose level higher than 11.1 mmol/L. The scale demonstrated a great predictive ability with a detectability index of 0.92. CONCLUSIONS The numeric scale we designed estimates and stratifies risk of death during hospitalization for patients with ST-segment elevation myocardial infarction and has good metric properties for predictive ability and calibration.

ABSTRACT INTRODUCTION Many clinical settings lack the necessary resources to complete angiographic studies, which are commonly used to predict complications and death following acute coronary syndrome. Corrected QT-interval dispersion can be useful for assessing risk of myocardial infarction recurrence. OBJECTIVE Evaluate the relationship between corrected QT-interval dispersion and recurrence of myocardial infarction in patients with ST- segment elevation. METHODS We conducted a prospective observational study of 522 patients with ST-segment elevation myocardial infarction admitted consecutively to the Camilo Cienfuegos General Provincial Hospital in Sancti Spiritus, Cuba, from January 2014 through June 2017. Of these, 476 were studied and 46 were excluded because they had other disorders. Demographic variables and classic cardiovascular risk factors were included. Blood pressure, heart rate, blood glucose, and corrected and un- corrected QT-interval duration and dispersion were measured. Patients were categorized according to the Killip-Kimball classification. Association between dispersion of the corrected QT-interval and recurrence of infarction was analyzed using a binary logistic regression model, a regression tree and receiver operator characteristic curves. RESULTS Patients with recurrent infarction (56; 11.8%) had higher average initial blood glucose values than those who did not have recurrence; the opposite occurred for systolic and diastolic blood pressure and for left ventricular ejection fraction. Dispersion of the corrected QT-interval was a good predictor of infarction recurrence according to a multivariate analysis (OR = 3.09; 95% CI = 1.105–8.641; p = 0.032). Cardiac arrest is the variable that best predicts recurrence. No recurrence of infarction occurred in 97% of patients without cardiac arrest, left ventricular ejection fraction >45% and corrected QT- interval dispersion <80 ms. CONCLUSIONS Risk of infarction recurrence is low in patients without cardiac arrest, with left ventricular ejection fraction >45% and with dispersion of corrected QT-interval <80 ms. Patients with corrected QT-interval dispersion ≥80 ms have greater risk of recurrence of infarction, which suggests that this variable could be used for stratification of risk following ST-segment elevation myocardial infarction.

ABSTRACT Background: Dispersion of the QT interval is an electrocardiographic marker that can be useful in the stratification of arrhythmic risk in patients with acute myocardial infarction. Objective: To describe the influence of corrected QT interval dispersion in association with other risk factors as predictors of ventricular arrhythmias in acute myocardial infarction with ST-segment elevation. Methodology: 209 patients who entered consecutively with diagnosis of acute myocardial infarction with elevation of the ST segment from January 2013 to June 2014 at Camilo Cienfuegos General Provincial Hospital of Sancti Spíritus were studied prospectively. Clinical, electrocardiographic and echocardiographic laboratory data were collected; the prognostic implication of the corrected QT interval dispersion in the appearance of ventricular arrhythmias through binary logistic regression and operator-receiver curves was determined. Results: Ventricular arrhythmias occurred in 39 (18.7%) patients. The dispersion of the corrected QT showed an adequate discrimination capacity in the prediction of any serious ventricular arrhythmic episode (c = 0.768, p = 0.0001). In the multivariate analysis, QT dispersion was an independent predictor of ventricular arrhythmias (OR = 7.075, 95% CI = 1.6-32.9, p = 0.009). Conclusions: The probability of presenting ventricular arrhythmias during acute myocardial infarction is greater when the dispersion of the QT interval is increased, so it is suggested that it should be a variable to be evaluated in the prognostic stratification of acute myocardial infarction.

RESUMEN Fundamento: La dispersión del intervalo QT es un marcador electrocardiográfico que puede resultar útil en la estratificación de riesgo arrítmicos en pacientes con infarto agudo del miocardio. Objetivo: Describir la influencia de la dispersión del intervalo QT corregido en asociación a otros factores de riesgo como predictores de arritmias ventriculares en el infarto agudo del miocardio con elevación del segmento ST. Metodología: Se estudiaron de menera prospectiva 209 pacientes que ingresaron de forma consecutiva con diagnóstico de infarto agudo de miocardio con elevación del segmento ST de enero de 2013 a junio de 2014 en el Hospital Provincial General Camilo Cienfuegos de Sancti Spíritus. Se recogieron datos clínicos, de laboratorio electrocardiográficos y ecocardiográficos; se determinó la implicación pronóstica de la dispersión del intervalo QT corregido en la aparición de arritmias ventriculares a través de la regresión logística binaria y las curvas de operador-receptor. Resultados: Las arritmias ventriculares se presentaron en 39 (18.7 %) pacientes. La dispersión del QT corregido mostró una adecuada capacidad de discriminación en la predicción de cualquier episodio arrítmico ventricular grave (c=0.768, p=0.0001). En el análisis multivariado la dispersión del QT resultó un predictor independiente de arritmias ventriculares (OR= 7.075; IC 95%= 1.6- 32.9; p=0.009). Conclusiones: La probabilidad de presentar arritmias ventriculares durante el infarto agudo del miocardio es mayor cuando se incrementan la dispersión del intervalo QT, por lo que se sugiere debe ser una variable a evaluar en la estratificación pronostica del infarto agudo del miocardio.

Foundation: atrial fibrillation is the most common arrhythmia in the general population and complicates 2 to 22 % of myocardial infarctions. Objective: to determine the prognostic implications of de novo atrial fibrillation in hospital mortality in patients with myocardial infarction with ST-segment elevation. Method: an observational, retrospective study was performed of 326 patients with myocardial infarction and ST-elevation admitted to the Camilo Cienfuegos Provincial University Hospital from January 1, 2013 to June 30, 2015. The studied variables were: age, sex, factors of coronary risk, history of ischemic heart disease, presence of atrial fibrillation, myocardial dysfunction, cardiogenic shock, number of thrombolyzed patients, success of thrombolysis, glycemia values, uric acid, creatinine, cholesterol, triacylglycerides, leukocytes and hemoglobin. For the statistical significance of the variables under study, the chi-squared test was used if they were qualitative and the student’s t test for quantitative ones. A multivariate analysis was also performed to determine the independence of atrial fibrillation as a prognostic factor. Results: the variables associated with in-hospital mortality were: diabetes mellitus, history of ischemic heart disease, age over 75 years, ejection fraction less than 30 %, glomerular filtration rate less than 60 ml/min, Killip class Kimbal III-IV and de novo atrial fibrillation. Atrial fibrillation was found to have a statistically significant association with in-hospital mortality. Conclusions: de novo atrial fibrillation was an independent predictor of intra-hospital mortality in patients with myocardial infarction with ST-segment elevation.

Fundamento: la fibrilación auricular es la arritmia más frecuente en la población general y complica del 2 al 22 % de los infartos miocárdicos. Objetivo: determinar la implicación pronóstica de la fibrilación auricular de novo en mortalidad hospitalaria de los pacientes con infarto miocárdico con elevación del segmento ST. Método: se realizó un estudio observacional, retrospectivo de 326 pacientes con infarto miocárdico con elevación del ST ingresados en el Hospital Provincial Universitario Camilo Cienfuegos del 1 de enero de 2013 al 30 de junio de 2015. Las variables estudiadas fueron: edad, sexo, factores de riesgo coronario, antecedentes de cardiopatía isquémica, presencia de fibrilación auricular, disfunción miocárdica, choque cardiogénico, número de pacientes trombolizados, éxito de la trombolisis, valores de glucemia, ácido úrico, creatinina, colesterol, triacilglicéridos leucocitos y hemoglobina. Para la significación estadística de las variables en estudio se empleó la prueba ji cuadrado si fueron cualitativas y la t de student para las cuantitativas. Se realizó además un análisis multivariado para determinar la independencia de la fibrilación auricular como factor pronóstico. Resultados: las variables asociadas a la mortalidad intrahospitalaria fueron: la diabetes mellitus, el antecedente de cardiopatía isquémica, la edad mayor de 75 años, la fracción de eyección menor del 30 %, el filtrado glomerular menor de 60 ml/min, la clase Killip Kimbal III-IV y la fibrilación auricular de novo. La fibrilación auricular resultó tener asociación estadística significativa con la mortalidad intrahospitalaria. Conclusiones: la fibrilación auricular de novo resultó ser un predictor independiente de mortalidad intrahopitalaria en pacientes con infarto miocárdico con elevación del segmento ST.