RESUMEN
BACKGROUND: This investigation was designed to identify clinical variables associated with recovery of normal ventricular function in patients with dilated cardiomyopathy treated with medical therapy. Recovery of normal ventricular function with medical treatment of patients with dilated cardiomyopathy is observed with increasing frequency. However, the clinical variables associated with such dramatic improvement of ventricular performance are poorly defined. METHODS: Fifty-three patients with dilated cardiomyopathy and reduced ejection fractions who achieved an increase in ejection fraction to > or = 40% with medical therapy were identified during follow-up in a dedicated heart failure clinic. A cohort of patients frequency-matched on baseline ejection fraction who did not recover ventricular systolic function to this magnitude constituted the control group. Clinical variables characterizing the 2 groups were compared by univariable analysis. Variables that significantly differed between the 2 groups were entered in a stepwise logistic regression analysis to identify factors independently associated with recovery of ejection fraction to > or = 40%. RESULTS: In the final logistic regression model, QRS duration, sex, etiology of cardiomyopathy, diabetes, and systolic blood pressure were significantly associated with improvement of ejection fraction to > or = 40%. CONCLUSIONS: Five clinical variables that are independently associated with improvement of left ventricular ejection fraction to normal or near-normal values with medical therapy alone were identified by this modeling process. These variables may be used to discriminate between patients in whom ventricular function will normalize with medical therapy alone and those who will require more aggressive pharmacologic or device therapy.
Asunto(s)
Cardiomiopatía Dilatada/diagnóstico , Cardiomiopatía Dilatada/tratamiento farmacológico , Cardiotónicos/uso terapéutico , Volumen Sistólico/fisiología , Función Ventricular Izquierda/fisiología , Adulto , Factores de Edad , Análisis de Varianza , Cardiomiopatía Dilatada/mortalidad , Estudios de Casos y Controles , Estudios de Cohortes , Femenino , Pruebas de Función Cardíaca , Hemodinámica , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Pronóstico , Curva ROC , Recuperación de la Función , Medición de Riesgo , Índice de Severidad de la Enfermedad , Factores Sexuales , Tasa de Supervivencia , Resultado del TratamientoRESUMEN
BACKGROUND: The purpose of this study was to compare the effects of immediate-release (IR) metoprolol and extended-release (XL) metoprolol on measures of heart rate variability in chronic systolic heart failure patients. METHODS AND RESULTS: Thirteen metoprolol-treated heart failure patients were randomized to a 2-way crossover study of equal daily doses of metoprolol IR and metoprolol XL, each administered for 3 weeks. After each 3-week interval, patients underwent 24-hour Holter and ambulatory blood pressure monitoring. Over the entire 24-hour period, the ratio of high to total variability (normalized measure of parasympathetic activity) was significantly greater (P < .05), the ratio of low to total variability (normalized measure of sympathetic activity) was significantly lower (P < .05), and the ratio of high to low variability (index of parasympathetic to sympathetic balance) was greater (P < .08) for metoprolol XL compared with metoprolol IR. Over the entire 24-hour period, both systolic and diastolic blood pressure were significantly lower for metoprolol XL compared with metoprolol IR (P < .0001, and .0005, respectively). CONCLUSION: These data suggest that with twice daily dosing, metoprolol IR is inferior to metoprolol XL in its effects on heart rate variability, autonomic balance, and blood pressure in patients with heart failure.
