[Early cardiovascular changes in young people with normal and normal-high blood pressure]. / Alteraciones cardiovasculares precoces en jóvenes con presión arterial normal y normal alta.

INTRODUCTION: Increased cardiac mass, as well as reduced arterial distensibility, are well recognised independent cardiovascular risk factors. OBJECTIVE: The aim of this study was to determine the existence of early structural and/or functional alterations of the left ventricle (LV) and the aortic root in young people with optimal (O), normal (N) or normal-high (HN) blood pressure (BP). MATERIAL AND METHODS: BP was recorded, and LV mass (LVM), LV function, and aortic distensibility (AD) were evaluated by echocardiogram in medical students. RESULTS: The study included 754 students (271 males; 20.47±1.35 years old). According to their BP, 54% were classified as O, 32% N, and 14% HN. LVM index was higher in N (30.9±0.44g/m(2.7)), and HN (31.26±0.73g/m(2.7)) than O (28.39±0.29g/m(2.7), P<.01). Corrected mean ventricular shortening was similar between O (99.8±0.8%) and N (99.2±1.1%, ns), but smaller in HN (95.4±1.9%, P<.05). The e'/a' ratio used to evaluate LV diastolic function, was higher in O (2.18±0.03) compared to HN (2.03±0.06, P<.03). AD was lower in HN (1.41±0.05mmHg/cm(3)/m(2)) compared to N (1.22±0.02mmHg/cm(3)/m(2), P<.01) and O (1.14±0.01mmHg/cm(3)/m(2), P<.01). CONCLUSIONS: Those young individuals with an N and HN BP showed an increased LVM index with decreased LV function and AD; evidence that would probably allow us to early identify non-hypertensive subjects with an increased cardiovascular risk.

Bilateral atrial function after chemical cardioversion of atrial fibrillation with amiodarone: an echo-Doppler study.

Cardioversion of atrial fibrillation transiently increases the risk of embolism presumably by decreased atrial mechanical function. It has been suggested that a component of early dysfunction relates to the mode of cardioversion. Amiodarone is one of the drugs used to restore sinus rhythm in patients with atrial fibrillation. However, the effect of this drug on left and right atrial mechanical function after conversion to sinus rhythm is not well known. Thirty-one patients (group AF) cardioverted from atrial fibrillation with intravenous amiodarone (average dose 1 gm/day) were prospectively studied to examine the effect of this drug on recovery of left and right atrial mechanical function. These patients were compared with 17 consecutive individuals without evidence of cardiac disease who became our control group (group C). Transmitral flow velocities and echocardiographic parameters were recorded within 24 hours after cardioversion and on the seventh day in group AF and one time in group C. Left and right atrial ejection force to evaluate atrial mechanical function was defined as 0.5 x 1.06 x mitral (m) or tricuspid (t) orifice area x (m or t peak A velocity)2. If this value in group AF was more than the mean minus 1 standard deviation of control group data, atrial ejection function after cardioversion was considered normal. The two groups were similar with respect to age, sex, arterial blood pressure, heart rate, left ventricular diameters, and left ventricular ejection fraction. Left and right atrial size was higher in group AF (left: group AF, 18.1 +/- 3.9 cm2; group C, 11.3 +/- 2.5 cm2, p < 0.01; right: group AF, 14.9 +/- 3.2 cm2; group C, 11.6 +/- 2.3, p < 0.01). Measurements of right and left atrial ejection force measured within 24 hours and on day 7 in group AF were similar to that in group C (left: group C, 11.9 +/- 5.3 kdyne; AF group, 24 hours, 19.4 +/- 15.5 kdyne [NS]; AF group, day 7, 14.7 +/- 13.6 kdyne [NS]; right: group C, 3.6 +/- 1.99 kdyne; AF group, 24 hours, 4.3 +/- 3.3 kdyne [NS]; AF group, day 7, 3.5 +/- 2.9 kdyne [NS]). Therefore almost all patients undergoing cardioversion for atrial fibrillation with amiodarone recovered bilateral atrial mechanical function within 24 hours after cardioversion (26 of 31-84%-left atrial ejection force; 28 of 31-93.5%-right atrial ejection force), with normal left atrial function in 97% of patients and normal right atrial function in 100% of patients on day 7 after conversion to sinus rhythm. These findings may have significant implications on postcardioversion anticoagulation strategies.

Study of the left ventricular function in pregnancy-induced hypertension.

Left ventricular (LV) morphological and functional characteristics in 9 women suffering from pregnancy-induced hypertension (PIH) were studied by means of echocardiograms. In order to distinguish which changes depended on the pressure values and which were the result of pregnancy, 10 nonpregnant control women with no heart disease and 10 normal pregnant women (NP) were studied and the results of each of the groups compared. To evaluate the structure, left ventricular systodiastolic diameters and wall thickness were measured. The only statistically significant difference was in the diastolic diameters between the PIH (4.7 +/- 0.3 cm) and the control group (4.4 +/- 0.2 cm) p less than 0.01. Left ventricular mass was significantly increased (p less than 0.01) in the PIH patients (185 +/- 53.1 g) compared to the NP patients (161 +/- 29.6 g) and the control group (125 +/- 17.4 g). No statistically significant differences were found in the radius thickness ratio in the three groups. The systolic function assessed by the shortening percentage was significantly lower (p less than 0.05) in the control group (32.8 +/- 4.4%) and in the NP patients (37.8 +/- 5.2%) than in the PIH group (39 +/- 6.5%). Afterload assessed by isovolumic period stress was significantly greater (p less than 0.01) in the PIH patients (157 +/- 10.6 dyne/cm2) compared with the NP group (118.9 +/- 7.01 dyne/cm2). There were no significant differences between the first group and the control group (134.09 +/- 8.7 dyne/cm2). As evidence of the diastolic function, analysis was made, on the one hand, of diastolic isovolumic period length (DIP).(ABSTRACT TRUNCATED AT 250 WORDS)

[Characteristics of the isovolumic relaxation period in dilated cardiomyopathy]. / Características del periódo de relajación isovolúmica en la miocardiopatía dilatada.

The duration of isovolumic relaxation (IR) was used in order to analyze several aspects of diastolic function in patients with dilated cardiomyopathy (DC). This period as measured from the aortic closure sound (A2 on phonocardiogram) to the opening of the mitral valve (on echocardiogram) was determined in 14 patients with DC and compared with findings in 10 normal volunteers (N). Heart rate (HR) and blood pressure (BP) were similar in both groups. The duration of IR was significantly increased in DC (72 ms +/- 6.3 ns) compared with N (41.6 ms +/- 2.8 ns; p less than 0.01). These data suggest that the prolongation in IR may result from alterations in ventricular relaxation.

[Left ventricular structure and function in young male students of La Plata University with stage I hypertension]. / Estructura y función del ventrículo izquierdo en jóvenes estudiantes varones de la Universidad Nacional de La Plata con hipertensión arterial en estadío I.

From an homogeneous population of 219 male medical students of La Plata University (20.9 +/- 1.6 years) who underwent a blood pressure screening, 34 were selected for measurements of left ventricular structure and function. Considering the JNC-V classification, samples from two groups were selected for comparisons: Optimal blood pressure (OBP) (21 males, 20.33 +/- 1.8 years) and Hypertensives stage I (H) (13 males, 20.85 +/- .66 years). The H showed values of body mass index (BMI) and heart rate (HR) higher than OBP (BMI OBP: 22.5 +/- 0.38 kg/m2, H: 24.26 +/- 0.84 kg/m2 -p < 0.04; HR OBP: 69.9 +/- 1.53 lat/min-H 80.5 +/- 3.58 lat/min -p < 0.03). Although the H were not reaching values of left ventricular mass index (LVMI) or septal (S) and posterior wall thickness to be considered hypertrophics, they were exceeding the OBP group (LVMI OBP: 89.6 +/- 3.33 g/m2, H: 124.5 +/- 6 g/m2 -p < 0.01; S OBP: 8.7 +/- 0.17 mm, H: 11.5 +/- 0.04 mm; P OBP: 7.9 +/- 0.18 mm, H: 10 +/- 0.13 mm -p < 0.01). Cardiac index (CI) was increased in H (OBP: 3.3 +/- 0.14 l/min/m2, H: 4.8 +/- 0.36 l/min/m2 -p < 0.01) supporting the existence of a hyperkinetic circulatory phase. OBP showed total peripheral resistance (TPR) higher than H group (OBP: 17 +/- 0.8 mmHg/l.min.m2, H: 13 +/- 1 mmHg/l.min.m2 -p < 0.008). Left ventricular (LV) systolic function indexes were not different in the two groups analyzed. The pattern of left ventricular late filling was however different between the two groups. The area of late diastolic flow (Area A) was lower in OBP (OBP: 2.64 +/- 0.09 cm2, H: 3.78 +/- 0.95 cm2 -p < 0.01) independently of HR value (adjusted mean OBP: 2.9 +/- 0.09 cm2, H: 3.52 +/- 0.95 cm2 -p < 0.01). The early filling fraction (EFF) was also detecting a significant shift to more prominent late diastolic filling in H (OBP 0.72 +/- 0.06%, H: 0.64 +/- 0.01% -p < 0.01) independently of HR values (adjusted mean PAO: 0.71 +/- 0.96%, H: 0.65 +/- 0.01% -p < 0.01). Healthy young males with hypertension stage I have similar LV systolic function, increased CI, LVMI, LV wall thickness, decreased TPR and evidence of impaired LV filling with shift of the pattern of filling to a late flow.

[Use of ergometry for evaluating left ventricular function in chronic aortic insufficiency]. / Utilidad de la ergometría para valorar la función ventricular izquierda en la insuficiencia aórtica crónica.

Fourteen patients with chronic aortic regurgitation (AR) underwent radionuclide angiography at rest and during supine exercise with ergometric controls. Ten subjects without evidence of heart disease were taken as controls. The behavior of heart rate, ST segment and R wave amplitude were analyzed at peak exercise in relationship with ejection fraction (EF) changes. Abnormal EF, (defined by an increase less than 10%, no change or decrease respect EF control), was present in 9 of 14 patients. Five of 14 patients had normal EF response to exercise defined by an increase of 10% or more than control value. Sensitivity and specificity of heart rate changes at exercise (abnormal: less than 10 beats to MET) to identify abnormal EF were 10% and 100%, respectively. The analysis of ST segment alterations at peak exercise (abnormal more than 2 mm ST depression) to the same objective showed 33% of sensitivity and 80% of specificity. Changes in R wave amplitude (abnormal: increase, no change or decrease less than 22% R wave amplitude at control) at peak exercise had 100% sensitivity and 80% of specificity to identify abnormal EF. Our results suggest that exercise test could be useful to analyze the response to left ventricular function during stress in patients with AR. Changes in R. wave amplitude at peak exercise appeared the best parameter.

[Effects of acute hypercapnia upon the myocardium: contractility, coronary resistance, oxygen consumption and potassium balance (author's transl)]. / Effectos de la hipercapnia aguda sobre el miocardio: contractilidad, resistencia coronaria, consumo de O2 y balance de K.

In the isolated perfused dog heart, at constant coronary blood flow and heart rate, we studied the effect of altering CO2 in the gas mixture from 5 to 15% on contractility, coronary resistance, myocardial O2 consumption and K balance. Contractility, assessed by the developed force, and its derivative through a strain-gauge arch sewed to the left ventricle decreased to 54 +/- 7% (p less than 0.01) and 59 +/- 6% (p less than 0.01), respectively from control values. Coronary resistance decreased to 79 +/- 3% of control ( less than 0.01). The negative inotropic effect of hypercapnia was accompanied by a decrease in myocardial O2 consumption to 68 +/- 11% (p less than 0.01) of control value and a net uptake of K by the heart. The possibility of an exchange of H+ by K+ is suggested as a possible mechanism involved in the negative inotropic effect of hypercapnia.

The pulse in patients with atrial fibrillation: its irregularity and inequality.

In 32 patients with atrial fibrillation the distributions of the R-R intervals and the carotid pulse records were analyzed in an attempt to define and quantify 'irregularity' and 'inequality' of the pulse and its relationship to the mean ventricular rate. Using our definition or irregularity and inequality of the pulse (the percentage scatter around the mean) we arrived at the conclusion that: (1) the same degree of irregularity is maintained with different mean ventricular rates in the range studied by us (digitalis administration had no significant effect on this irregularity (2) the 'inequality' between beats decreases at slower ventricular rates: (3) a relationship with the postextrasystolic potentiation is suggested.

Caracteristicas del periodo de relajacion isovolumica en la miocardiopatia dilatada / Characteristics of the isovolumic relaxation period in dilated cardiomyopathy

A los efectos de analizar algunso aspectos de la función diastólica en la miocardiopatía dilatada (Md) utilizamos la duración del período de relajación isovolúmico (PRI) obtenido por métodos no invasivos en un grupo de pacientes con dicha patología. Se examinaron un total de 24 pacientes, 10 de los cuales configuraron el grupo control (C) y 14 el portador de Md; la duración del PRI se midió desde el comienzo de las vibraciones rápidas del segundo ruido aórtico obtenida por fonocardiograma y hasta el momento de separación de ambas valvas de la mitral analizada por ecocardiograma. Dado que la duración del PRI no sólo depende del estado de la relajación también analizamos otros parámetros como la frecuencia cardíaca y la presión arterial. La cavidad ventricular izquierda estaba significativamente aumentada en los pacientes con Md y la función sistólica estaba severamente deprimida. La frecuencia cardíaca resultó similar en los dos grupos. La presión arterial tampoco resultó diferente. El PRI resultó prolongado significativamente en los pacientes con Md. Los datos analizados permiten concluir que la prolongación del PRI encontrada en los pacientes con Md puede estar vinculada a alteraciones en la relajación miocárdica