INTRODUCTION Heart failure, primarily in the elderly, is a growing epidemic in today's world. It leads to high rates of disability and mortality, as well as significant health care expenditures, making it important to assess possible predictors of adverse cardiac events. In Cuba, heart failure mortality is 19.1/100,000 population. OBJECTIVES Assess the value of stress-rest protocol gated-SPECT for identifying patients with symptomatic heart failure likely to suffer adverse cardiac events. METHODS A study was conducted of 52 patients (mean age 59 years, SD 9; 62% women) with functional capacity II/III (New York Heart Association scale) and left ventricular ejection fraction <40%. Patients were divided into two groups based on coronary heart disease diagnosis: those with coronary heart disease (41), labeled ischemic; and those without (11), labeled nonischemic. All underwent gated SPECT myocardial perfusion scintigraphy with technetium-99m-labeled methoxyisobutyl isonitrile, using a two-day stress–rest protocol, including evaluation of intraventricular synchrony by phase analysis. Patients were followed over 36 months for adverse cardiac effects. RESULTS No significant differences were observed between the two groups during the stress test with regard to exercise time, metabolic equivalents or percentage of maximal heart rate during maximal stress. Summed stress, rest and difference scores, however, were significantly different between the ischemic and nonischemic groups: 16.82 (SD 6.37) vs. 7.54 (SD 5.8), p <0.001; 14.43 (SD 6.28) vs. 6.45 (SD 3.77), p = 0.001; and 2.39 (SD 4.89) vs. 1.09 (SD 3.7), p = 0.034. No differences were found in ventricular function, although stress-minus-rest left ventricular ejection fraction was slightly lower in patients with ischemic heart disease (−1.29, SD 5.8) than in patients without ischemic heart disease (1.27, SD 4.31). Dyssynchrony was greater in patients with ischemic heart disease than in those without, primarily during stress (p <0.01). The only variable that showed a possible association with the occurrence of adverse events was <5 metabolic equivalents on the stress test (p = 0.03), while resting phase SD showed only a tendency toward association (p = 0.05). CONCLUSIONS Information on myocardial perfusion, functional capacity and intraventricular synchrony obtained from stress-rest gated SPECT may help identify patients with symptomatic heart failure who are likely to develop adverse cardiac events, enabling better management of higher-risk cases and improved allocation of resources.

Objetive: To present the height- and sex-specific reference intervals for the urinary excretion of creatinine in cuban subjects with ages between 19-58 years. Background: The standards advanced by Bistrian (1985) for anglosaxon subjects have been traditionally used for the construction of the Index of Creatinine Excretion (ICE). This practice could lead to diagnostic errors in the case of ICE calculation for non-anglosaxon populations differing in dietetic behaviour and body composition. Methods: Values of urinary excretion of Creatinine measured in 103 men and 112 women with ages between 19 and 58 years, and preserved nutritional wellbeing (weight within the interquartile range for height; 18.5 ≤ body mass index ≤ 30.0 kg/m²) and renal function (serum Creatinine ≤ 132 µmol/l) were drawn retrospectively from the databases of the Section of Urinalysis, Service of Clinical Laboratory, "Hermanos Ameijeiras" Hospital (La Habana, Cuba). For each sex, the regression line urinary- Excrecion-of-Creatinine = c + d · height, where c, d: parameters dependent on the subject’s height, were constructed. The predicted values of the urinary excretion of Creatinine for the cuban subjects were derived from the 100 (1-α)% prediction intervals (Pl) of the regression line. Results: The urinary excretion of Creatinine for a 170 cm-height, 66.5 kg-weight, cuban male with age between 19-58 years, was 1216.19 mg/24 hours (95% Pl: 821.02-1611.36 mg/24 hours). The urinary excretion of Creatinine for a 160 cm-height, 59.7kKg-weight, cuban female with age between 19-58 years, was 852.00 mg/24 hours (95% Pl: 420.15-1283.84 mg/24 hours). After taking into account the subject’s weight, the urinary excretion of Creatinine for the cuban subjects was lower than that of their anglosaxon counterparts. There was not correlation between the age of the subject and the urinary excretion of Creatinine. Conclusions: We recommend the use of the values of the urinary excretion of Creatinine tabulated in this article in the conduction of studies of body composition and nutritional assessment.

Objetivo: Presentar los intervalos de referencia, específicos para la talla y el sexo, de la excreción urinaria de creatinina para sujetos cubanos con edades entre 19-58 años. Trasfondo teórico: Los estándares propuestos por Bistrian (1985) para sujetos anglosajones sanos se han usado tradicionalmente para la construcción del índice de excreción de creatinina (IEC). Esta práctica puede conducir a errores diagnósticos en el caso del cálculo del IEC en otras poblaciones con diferentes composición corporal y hábitos dietéticos. Métodos: Se obtuvieron los valores de excreción urinaria de creatinina de 103 hombres y 112 mujeres con edades entre 19 y 58 años, y estado nutricional (peso dentro del rango intercuartil para la talla; 18,5 ≤ índice de masa corporal ≤ 30,0 kg/m²) y función renal (creatinina sérica ≤ 132 µmol/l) conservados, después del análisis retrospectivo de las bases de datos de la Sección de Orina del Servicio de Laboratorio Clínico del Hospital Clínico-Quirúrgico "Hermanos Ameijeiras" (La Habana, Cuba). En cada sexo, se construyeron las rectas de regresión excreción urinaria de creatinina = c + d · talla, con c, d: parámetros dependientes de la talla del sujeto. Los valores predichos de excreción urinaria de creatinina para los sujetos cubanos, específicos para el sexo, se derivaron de los intervalos de predicción (IP) al 100 (1-α) asociados a la recta de regresión. Resultados: La excreción urinaria de creatinina en un hombre cubano con una edad entre 19 y 58 años, talla de 170 cm y peso de 66,5 kg fue de 1.216,19 mg/24 horas (IP 95%: 821,02-1.611,36 mg/24 horas). La excreción urinaria de creatinina en una mujer cubana con una edad entre 19 y 58 años, talla de 160 cm y peso de 59,7 kg fue de 852,00 mg/24 horas (IP 95%: 420,15-1.283,84 mg/24 horas). Cuando se corrigió para el peso del sujeto, la excreción urinaria de creatinina de los sujetos cubanos fue menor que la observada en sujetos anglosajones que compartían las mismas propiedades biológicas. No se comprobó correlación entre la edad del sujeto y la excreción urinaria de creatinina. Conclusiones: Se recomienda emplear los valores de la excreción urinaria de creatinina obtenidos localmente y tabulados en este artículo para la realización de estudios de composición corporal y evaluación nutricional.