Ventricular arrhythmias are associated with increased QT interval and QRS dispersion in patients with ST-elevation myocardial infarction.

INTRODUCTION AND OBJECTIVES: The electrocardiogram continues to be essential in the diagnosis of acute myocardial infarction, and a useful tool in arrhythmic risk stratification. We aimed to determine which electrocardiographic variables can successfully predict the occurrence of ventricular arrhythmias (VA) in patients following ST-segment elevation myocardial infarction (STEMI). METHODS: We performed an observational study including 667 patients with STEMI admitted to the University Hospital in Sancti Spíritus, Cuba. Demographic variables, cardiovascular risk factors, and clinical variables were recorded. Electrocardiographic variables included QT interval duration (measured and corrected) and QT dispersion, QRS duration and dispersion, JT interval duration and ST-segment elevation magnitude. We also determined left ventricular ejection fraction and glomerular filtration rate. A binary statistical regression model and a regression tree were used to determine the variables that successfully predicted VA. RESULTS: VA occurred in 92 (13.8%) patients, within the first 48 hours in 68 (73.9%) and after this period in 24 (26.1%) patients. The variables associated with VA were QT interval duration >529 ms and QT dispersion >66 ms, QRS dispersion >50 ms, and the presence of ST-segment elevation in six or more leads. CONCLUSIONS: The main predictor of VA occurring during the initial 48 hours was QT interval duration, while, after this period, it was QRS dispersion.

Increased QRS duration and dispersion are associated with mechanical dyssynchrony in patients with permanent right ventricular apical pacing.

BACKGROUND: Permanent right ventricular apical pacing may have negative effects on ventricular function and contribute to development of heart failure. We aimed to assess intra- and interventricular mechanical dyssynchrony in patients with permanent right ventricular apical pacing, and to establish electrocardiographic markers of dyssynchrony. METHODS: 84 patients (46:38 male:female) who required permanent pacing were studied. Pacing was done from right ventricular apex in all patients. We measured QRS duration and dispersion on standard 12-lead ECG. Intra- and interventricular mechanical dyssynchrony and left ventricular ejection fraction were assessed by transthoracic echocardiography. Patients were followed-up for 24 months.  Results: Six months after implantation, QRS duration increased from 128.02 ms to 132.40 ms, p≤0.05. At 24 months, QRS dispersion increased from 43.26 ms to 46.13 ms, p≤0.05. Intra- and interventricular dyssynchrony increased and left ventricular ejection fraction decreased during follow-up. A QRS dispersion of 47 ms predicted left ventricular dysfunction and long-term electromechanical dyssynchrony with a sensitivity of 80% and a specificity of 76%.  Conclusion: In patients with permanent right ventricular apical pacing there is an increased duration and dispersion of QRS related to dyssynchrony and decreased left ventricular ejection fraction. This study shows that QRS dispersion could be a better predictive variable than QRS duration for identifying left ventricular ejection fraction worsening in patients with permanent right ventricular apical pacing. The electrocardiogram is a simple tool for predicting systolic function worsening in these patients and can be used at the bedside for early diagnosis in the absence of clinical symptoms, allowing adjustments of medical treatment to prevent progression of heart failure and improve the patient's quality of life.

Prognostic Scale to Stratify Risk of Intrahospital Death in Patients with Acute Myocardial Infarction with ST-Segment Elevation.

INTRODUCTION The scales available to predict death and complica-tions after acute coronary syndrome include angiographic studies and serum biomarkers that are not within reach of services with limited resources. Such services need specifi c and sensitive instruments to evaluate risk using accessible resources and information. OBJECTIVE Develop a scale to estimate and stratify the risk of intra-hospital 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 fi nal study cohort included 667 patients, ex-cluding 102 due to branch blocks, atrial fi brillation, drugs that prolong the QT interval, low life expectancy or history of myocardial infarction. The demographic variables of age, sex, skin color, classic cardiovas-cular 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 fi ltration rate were included in the analysis. Patients were categorized according to the Killip-Kimball Classifi cation 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 dia-stolic blood pressure, left ventricular ejection fraction, and glomerular fi ltration rate were lower than those participants discharged alive. Rel-evant variables included in the scale were systolic blood pressure, Killip-Kimball class, cardiorespiratory arrest, glomerular fi ltration 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 strati-fi es risk of death during hospitalization for patients with ST-segment elevation myocardial infarction and has good metric properties for predictive ability and calibration. KEYWORDS ST-segment elevation myocardial infarction, mortality, risk assessment, Cuba.

Corrected QT-Interval Dispersion: An Electrocardiographic Tool to Predict Recurrence of Myocardial Infarction.

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 uncorrected 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. KEYWORDS ST-elevation myocardial infarction, myocardial infarction, electrocardiography, chronic disease, risk assessment, Cuba.

Cardiorenal syndrome as predictor of in-hospital mortality in ST-segment elevation myocardial infarction. / Síndrome cardiorrenal como predictor de mortalidad intrahospitalaria en el síndrome coronario agudo con elevación del segmento ST.

INTRODUCTION: Cardiorenal syndrome includes numerous conditions affecting the heart and kidney, and is a strong predictor of cardiovascular mortality. METHOD: An analysis was performed on 157 consecutive patients admitted to the Coronary Care Unit of the Camilo Cienfuegos Hospital due to an ST-segment elevation myocardial infarction and heart failure, from January 2013 to December 2016. An analysis was made of the presence of cardiorenal syndrome and its relationship with epidemiological, clinical, and analytical variables, as well as complementary explorations. The relationship between cardiorenal syndrome and in-hospital mortality was assessed using binary logistical regression. RESULTS: A total of 52 (33.1%) patients had a cardiorenal syndrome. The haemoglobin level was lower in the group of patients with cardiorenal syndrome (117.2 ± 15.3 vs. 123.3 ± 15.1, P = .019), and in left ventricular ejection fraction (34.8 ± 8 vs. 43.2 ± 10.8). A positive correlation was found between the Killip class and the increase in serum creatinine after 48 h. The serum creatinine was associated with left ventricular ejection fraction (r = 0.166; P = .038). The multivariate analysis showed that cardiorenal syndrome was an independent predictor of in-hospital mortality when adjusted for a history of ischaemic heart disease, diabetes mellitus status, atrial fibrillation, ventricular arrhythmias, left ventricular ejection fraction, age and systolic blood pressure. CONCLUSIONS: The presence of cardiorenal syndrome has an influence on the prognosis of patients who suffer a cardiorenal syndrome. Its detection could be useful in the risk stratification.

El índice tobillo-brazo como predictor de enfermedad coronaria multivaso en pacientes con síndrome coronario agudo y enfermedad arterial periférica / The Ankle-brachial Index as a Predictor of Multivess el Coronary Disease in Patients with Acute Coronary Syndrome and Peripheral Arterial Disease

RESUMEN Fundamento: la coexistencia de la enfermedad arterial periférica y el síndrome coronario agudo se asocia con peor pronóstico. El índice tobillo-brazo ha demostrado ser un marcador de ateroesclerosis multisitios. Objetivo: determinar la relación entre el índice tobillo-brazo y la enfermedad arterial coronaria multivasos. Método: se realizó un estudio observacional analítico que incluyó a todos los pacientes egresados de la unidad de cuidados coronarios del Hospital Provincial Universitario Camilo Cienfuegos Gorriarán, de la provincia Sancti Spíritus, en el período comprendido entre el primero de marzo de 2011 al 30 de febrero de 2018, con diagnóstico de síndrome coronario agudo, con y sin elevación del segmento ST. Se recogieron datos clínicos, de índice tobillo-brazo, ecocardiográficos y de angiografía coronaria y se determinó la implicación pronóstica del índice en la enfermedad multivaso a través de un árbol de clasificación con las variables incluidas en el modelo de regresión logística binaria. Resultados: la enfermedad multivaso se presentó en 85,2 % pacientes, de ellos eran hombres el 81,9 %, el 85,9 % de ellos con enfermedad multivaso, la edad media fue de 59,1 años, el 52,3 % presentó SCACEST con enfermedad multivaso el 78,8 %. Los factores de riesgo más frecuentes fueron: el hábito de fumar (86,8 %), la dislipidemia (85,8 %) y la hipertensión arterial (84,8 %) en el grupo con enfermedad multivaso e ITB=0,9 (DE=0,3). Recibieron tratamiento con clopidogrel (86,1 %), ácido acetilsalicílico (86,3 %), IECA o ARA II (85,8 %), estatinas (73,2 %), betabloqueantes (87,5 %) y nitratos (86,3 %). En la angiografía, el 85,2 % presentó una enfermedad coronaria severa. Las dos variables predictoras fueron: el SCASEST y el ITB≤0,9 que mostraron un elevado valor predictivo positivo en el pronóstico de enfermedad arterial coronaria multivaso. Conclusiones: el índice tobillo-brazo<0,9 mostró una capacidad predictiva para la enfermedad multivaso que se incrementa si se asocia a la diabetes mellitus y el hábito de fumar.

ABSTRACT Background: the coexistence of peripheral arterial disease and acute coronary syndrome is associated with a worse prognosis. The ankle-brachial index has been shown to be a marker of multisite atherosclerosis. Objective: to determine the relationship between the ankle-brachial index and coronary artery disease. Method: an analytical observational study was carried out that included all the patients discharged from the coronary care unit of the Camilo Cienfuegos Gorriarán Provincial University Hospital, of the Sancti Spíritus province, in the period from March 1, 2011 to February 30 of 2018, with a diagnosis of acute coronary syndrome, with and without ST segment elevation. Clinical data, ankle-brachial index, echocardiography and coronary angiography were collected and the prognostic implication of the index in disease was determined through a classification tree with the variables included in the binary logistic regression model. Results: multivessel disease occurred in 85.2 % patients, 81.9 % of them were men, 85.9 % of them with multivessel disease, the mean age was 59.1 years, 52.3 % presented STEACS with multivessel disease 78.8 %. The most frequent risk factors were: smoking (86.8 %), dyslipidemia (85.8 %) and arterial hypertension (84.8 %) in the group with multivessel disease and ABI = 0.9 (SD = 0.3). They received treatment with clopidogrel (86.1 %), acetylsalicylic acid (86.3 %), ACEI or ARB (85.8 %), statins (73.2 %), beta-blockers (87.5 %) and nitrates (86, 3 %). On angiography, 85.2 % had severe coronary disease. The two-predictor variables were: NSTEACS and ABI≤0.9, which showed a high positive predictive value in the prognosis of multivessel coronary artery disease. Conclusions: ankle-brachial index <0.9 showed a predictive capacity for multivessel disease that increases if it is associated with diabetes mellitus and smoking.

Dispersión del intervalo QT corregido como predictor de arritmias ventriculares en el infarto agudo del miocardio / Dispersion of the corrected QT interval as a predictor of ventricular arrhythmias in 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.

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.