Normal percentile curves for left atrial size in healthy children and adolescents.

BACKGROUND: Despite the clinical utility of echocardiography to measure left atrial (LA) structure and function, there are scarcities of data about the percentiles of LA diameter (LAD ), LA volume (LAVOL ), and LA volume indexed by body surface area (LAVOL/BSA ) from prospective population-based studies in healthy children and adolescents from the Southern Cone of Latin America. METHODS: Echocardiographic studies were obtained in 1095 healthy subjects nonexposed to cardiovascular risk factors (5-24 years). Age- and sex-specific reference values of LAD , LAVOL , and LAVOL/BSA were generated using parametric regression based on fractional polynomials. RESULTS: After covariate analysis (ie, adjusting by age, body surface area), specific sex-specific percentiles were evidenced as necessaries. Age- and sex-specific 1st, 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, 97.5th, and 99th percentile and curves were reported. Our percentiles showed high concordance and complementarity with what was previously reported for the population of North American, European, and Asiatic Populations. CONCLUSIONS: In children and adolescents, the interpretation of the LA size requires sex-related percentiles. This study provides the largest Argentinean database concerning percentile curves of LAD , LAVOL , and LAVOL/BSA obtained in healthy children and adolescents. These data are valuable in that they provide values with which data of populations of children, adolescents, and young adults can be compared.

Functional ß2-adrenoceptors in rat left atria: effect of foot-shock stress.

Altered sensitivity to the chronotropic effect of catecholamines and a reduction in the ß1/ß2-adrenoceptor ratio have previously been reported in right atria of stressed rats, human failing heart, and aging. In this report, we investigated whether left atrial inotropism was affected by foot-shock stress. Male rats were submitted to 3 foot-shock sessions and the left atrial inotropic response, adenylyl cyclase activity, and ß-adrenoceptor expression were investigated. Left atria of stressed rats were supersensitive to isoprenaline when compared with control rats and this effect was abolished by ICI118,551, a selective ß2-receptor antagonist. Schild plot slopes for the antagonism between CGP20712A (a selective ß1-receptor antagonist) and isoprenaline differed from unity in atria of stressed but not control rats. Atrial sensitivity to norepinephrine, as well as basal and forskolin- or isoprenaline-stimulated adenylyl cyclase activities were not altered by stress. The effect of isoprenaline on adenylyl cyclase stimulation was partially blocked by ICI118,551 in atrial membranes of stressed rats. These findings indicate that foot-shock stress equally affects inotropism and chronotropism and that ß2-adrenoceptor upregulation contributes to the enhanced inotropic response to isoprenaline.

Remodelado auricular adverso en atletas de alto rendimiento: Estudio de deformación auricular con speckle tracking 2D / Adverse left atrial remodeling in highly trained athletes: an echocardiography study using 2D speckle tracking

Background: Highly trained athletes are at increased risk of atrial fibrillation (AF) and flutter. Atrial dilatation and dysfunction might be the underlying substrate for the increased risk. The aim of the present study was to relate atrial size and deformation in a selected group of highly trained athletes and patients with paroxysmal atrial fibrillation (PAF). Methods: 20 professional male hand-ball players, 18 patients with PAF and 20 healthy age-matched, non-sportive males were compared. All subjects underwent a transthoracic echocardiogram with evaluation of left atrial (LA) dimensions. Left atrial strain (LASa) and strain rate (LASRa) derived from speckle tracking were used to evaluate LA deformation post atrial contraction. Results: LA volumes were significantly larger in athletes and PAF patients compared to controls (36 + 1.7 ml/m2; 36 ± 2.3 ml/m2 and 24 + 1 ml/m2, respectively, p < 0.01;). LASa and LASRa during active atrial contraction were decreased in PAF patients compared to athletes and controls (-10.6 ± 0.2 %; -12.2 ± 0.4 % and -14.5 ± 0.5 %, p < 0.01 for LASa and -1.2 ± 0.08 sec-1; -1.5 ± 0.12 sec-1; -1.7 ± 0.13 sec-1, p= 0.04 for LASRa respectively). Athletes with LA volume > 40 ml/m2 (n=7) showed reduced LASa compared to athletes with LA volume < 40 mL/m2 (-10.3 ± 0.4% versus -13.0 ± 0.5%, p < 0.01). PAF patients had LASa values similar to those of subjects with normal LA volume. Conclusion: Athletes with increased LA volume exhibit lower strain parameters compared to subjects with PAF. It is postulated that measurement of LA strain may be used to predict development of AF in highly trained athletes.

Introducción: Atletas de alto rendimiento tienen un riesgo aumentado de desarrollar fibrilacion auricular (FA) y flutter. La dilatación y disfunción auricular podrían ser el sustrato subyacente para este incremento en el riesgo. El objetivo fue analizar y relacionar el tamaño y deformación auricular en un grupo seleccionado de atletas y en pacientes con FA paroxística. Métodos: Se incluyeron 20 jugadores de balón-mano profesionales y 20 controles sedentarios, pareados por edad y sexo, junto a 18 pacientes con FA paroxística. En todos los sujetos se realizó un estudio ecocardiográfico bidimensional con evaluación de las dimensiones y de la deformación (post contracción auricular) por strain (Sa) y strain rate (SRa) de la aurícula izquierda (AI). Resultados: El volumen AI fue significativamente mayor en atletas y pacientes con FA respecto de los controles (36 + 1,7 ml/m2; 36 ± 2,3 ml/m2 y 24 + 1 ml/m2, p < 0,01; respectivamente). El SaAI y SRaAI durante la contracción auricular estaban disminuidos en los pacientes con FA paroxística respecto de atletas y controles (-10,6 ± 0,2 %; -12,2 ± 0,4 % y -14,5 ± 0,5 %, p < 0,01 para SaAI y -1,2 ± 0,08 sec-1; -1,5 ± 0,12 sec-1; -1,7 ± 0,13 sec-1, p= 0,04 para SRaAI, respectivamente). Los atletas con un volumen AI > 40 ml/m2 (n=7) mostraron valores reducidos de SaAI comparados con atletas con un volumen AI < 40 mL/m2 (-10,3 ± 0,4% versus -13,0 ± 0,5%, p < 0,01) y éstos fueron similares a los pacientes con FA (-10,3 ± 0,4% versus -10,6 ± 0,2%, p= 0,6). Conclusiones: Una proporción de atletas con dilatación AI presentan evidencia de disfunción contráctil de la AI, caracterizado por valores de strain disminuidos que son similares a los de pacientes con FA paroxística. Esto podría corresponder a un sustrato para el desarrollo posterior de arritmias auriculares en estos atletas.