Three-dimensional echocardiographic assessment of left atrial size and function and the normal range of asynchrony in healthy individuals.

Left atrial size and function are very important prognostic factors. Our aim was to evaluate left atrial size, function and mechanical synchrony using three-dimensional echocardiography in order to establish normal reference values. The study involved 63 healthy individuals enrolled at two hospitals. All underwent two-dimensional and three-dimensional echocardiography. Mechanical asynchrony was assessed by determining the standard deviation of the time each left atrial segment took to reach the minimum volume during atrial systole, normalized by the RR interval. The mean value for this normalized standard deviation was 15.4+/-10.9. In conclusion, it is possible to analyze left atrial asynchrony, size and function using three-dimensional echocardiography.

Adaptación morfológica del corazón a la hipertensión arterial esencial: fisiopatología e implicaciones terapéuticas / Morphologic adaptation of the heart to high blood pressure: pathophysiology and therapeutic implications

El diseño experimental de los estudios prospectivos sobre el tratamiento de la hipertensión arterial esencial, ha ignorado un aspecto fundamental de la fisiopatología del paciente hipertenso: Los pacientes hipertensos no son homogéneos, en lo que respecta a los mecanismos responsables del aumento de la presión arterial. La adptación cardiovascular a la hipertensión arterial es anatómica y funcionalmente heterogénea. Investigaciones clínicas recientes indican que, esta heterogeneidad, puede ser minimizada con el uso de la eco-cardiografía. El análisis de los perfiles hemodinámicos y neurohormonales de los pacientes hipertensos permite distinguir la presencia de denominadores comunes: La hipertrofia ventricular concéntrica y la hipertrofia ventricular excéntrica representan los extremos opuestos de adaptación del corazón a la hipertensión arterial. El primero se caracteriza por tener una forma geométrica elíptica, con un perfil hemodinámico de gasto cardíaco normal y resistencias vasculares periféricas elevadas. Los niveles plasmáticos de renina y de los péptidos natriuréticos están elevados.

The experimental design of clinical studies, on the pharmacological treatment of essencial hypertension, has ignored a fundamental issue: Hypertensive patiens are not a homogenous population. The adaptation of the cardiovascular system to hypertension is structurally and funtionally heterogeneous. Recent clinical investigations suggest that this heterogeneity can be minimized by echocardiography. Thus, when the hemodynamic and neurohormonal profiles of untreated hypertensive patients are considered, in the particular context of the cardiac morphologic adaptation to high blood pressure, distinct common denominator emerge. Concentric Hypertrophy is characterized by an elliptic left ventricle, normal stroke volume and high peripheral vascular resistance. Its predominant neurohormonal profile includes elevated plasma renin and natriuretic peptide levels. Conversely, most patients with eccentric hypertrophy have a spheric left ventricle, increased stroke volume and low peripheral vascular resistance. Its corresponding neurohormonal profile shows low serum renin and anhanced sympathetic nervous activity. The therapeutic response, to angiotensin II antagonists and to beta-adrenergic blockers, of these two geometric patterns is also different. Concentric hypertrophy is substantially reversed by angiotensin II blockers, where as, eccentric hypertrophy is refractory to both, angiotensin II blockerds and atenol. These facts raise a relevant question: Should ventricular geometry be considered when deciding which antihypertensive drug is to be prescribed?.

Patterns of left ventricular hypertrophy in essential hypertension: should echocardiography guide the pharmacological treatment?

The experimental design of clinical studies, on the pharmacological treatment of essential hypertension, has ignored a fundamental issue: Hypertensive patients are not a homogenous population. The adaptation of the cardiovascular system to hypertension is structurally and functionally heterogeneous. Recent clinical investigations suggest that this heterogeneity can be minimized by echocardiography. Thus, when the hemodynamic and neurohormonal profiles of untreated hypertensive patients are considered, in the particular context of the cardiac morphologic adaptation to high blood pressure, distinct common denominators emerge. Concentric and eccentric hypertrophy, the two most common patterns of ventricular hypertrophy, are at the extremes of the geometric spectrum. Concentric hypertrophy is characterized by an elliptic left ventricle, normal stroke volume and high peripheral vascular resistance. Its predominant neurohormonal profile includes elevated plasma renin and natriuretic peptide levels. Conversely, most patients with eccentric hypertrophy have a spheric left ventricle, increased stroke volume and low peripheral vascular resistance. Its corresponding neurohormonal profile shows low serum renin and enhanced sympathetic nervous activity. The therapeutic response, to angiotensin II antagonists and to beta-adrenergic blockers, of these two geometric patterns is also different. Concentric hypertrophy is substantially reversed by losartan, whereas, eccentric hypertrophy is refractory to both, losartan and atenolol. These facts raise a relevant question: Should ventricular geometry be considered when deciding which antihypertensive drug is to be prescribed?

Inter-atrial conduction time shortens after blood pressure control in hypertensive patients with left ventricular hypertrophy.

UNLABELLED: Assuming that blood pressure control could induce a shortening of the inter-atrial conduction time and prevent atrial fibrillation occurrence, we studied the inter-atrial conduction time in hypertensive patients with left ventricular hypertrophy. METHODS: Sixty-eight (26 male) 58.34+/-8.08-year-old patient participated in the study. All were in sinus rhythm and had abnormal blood pressure (163+/-18/95+/-9 mm Hg). Their cardiac mass index was increased (151+/-43 g/m(2) SC) and their left atrial dimension was normal (3.67+/-0.54 cm). The inter-atrial conduction time was measured in the echocardiogram from the beginning of the electrocardiographic P wave to the beginning of the A wave in the mitral Doppler signal and was corrected for heart rate. Heart rhythm disturbances were monitored clinically and by means of a Holter. Most patients were treated with angiotensin antagonists. RESULTS: It was found that arterial blood pressure decreased significantly after treatment and that the P-A interval was significantly reduced (71.4+/-14.5 vs. 63.9+/-11.5 ms). During the follow-up, no patient complained of arrhythmia symptoms or exhibited atrial fibrillation in the Holter recording. CONCLUSION: In this selected group of patients with hypertensive heart disease (left ventricular hypertrophy), an effective blood pressure control was accompanied by a significant decrease in the inter-atrial conduction time. It is possible that these effects prevent atrial fibrillation.

El balance autonómico cardíaco es normal en pacientes chagásicos agudos / The balance normal autonomic in sharp chagasic in patients

Evaluar la utilidad del ECG de señales promediadas y de variabilidad de la frecuencia cardíaca en el estudio de pacientes chagásicos agudos. 21 pacientes con síndrome febril prolongado, parasitemia positiva para trypanosoma cruzi y evidencias de miocarditis en la biopsia miocárdica, fueron estudiados con ECG de reposo, Holter de 24 horas, ecocardiograma, ECG de señales promediadas y análisis de variabilidad de frecuencia cardíaca, en un lapso máximo de 2 meses pos-tratamiento. Se identificaron potenciales tardíos en 6 pacientes, sin el hallazgo concomitante de arritmia ventricular compleja. No hubo diferencias en los resultados del análisis de variabilidad de la frecuencia cardíaca entre sujetos controles sanos y pacientes chagásicos agudos. En el análisis de correlación múltiple se encontró que el índice cardiotorácico estuvo correlacionado en forma independiente con la presencia de potenciales tardíos y con alteraciones individuales de los componentes simpático y parasimpático del análisis especial de la variabilidad de la frecuencia cardíaca. La presencia de potenciales tardíos está relacionada con la presencia de daño miocárdico (índice cardiotorácico) en los pacientes chagásicos agudos. No se demostraron alteraciones del balance autonómico en estos pacientes