RESUMO

In order to assess the usefulness of the Discrete Fourier Transform Model (DFT) to evaluate time-course drug effects on hypertensive patients studied with Ambulatory Blood Pressure Monitoring (ABPM) a number of experiments were carried out. A total of 10 mild to moderate hypertensive patients were evaluated under placebo and after 8 weeks of active treatment with Enalapril 20 mg per day using ABPM. Systolic and Diastolic blood pressure (SBP and DBP) were registered every 15 minutes during daytime and every 30 minutes at night. Pressure profiles of each patient were initially smoothed by hourly means. DFT was then applied to these profiles. The minimum number of harmonics necessary to generate a statistically significant fitting of the blood pressure profile, were obtained by residuals analysis (run test and analysis of variance of the mean sum of residual squares with each new harmonic incorporated to the model). A profile of the blood pressure differences (treatment-placebo) with the rough data of each patient was smoothed by hourly means. DFT was applied again on these substraction profiles. To estimate peak and trough drug effects for the blood pressure decrease function, maximum, minimum and inflexion points were calculated defining the following parameters: T peak: time from drug administration to maximum pressure decrease; T late response: time from drug administration to the inflexion point following the last minimum previous to the next dose; BP peak: the maximum blood pressure decrease amplitude; and the slope BP peak/T peak. The stability of the individual circadian rhythm was confirmed for both ABPM controls comparing times of maximum and minimum on the DFT smoothed profiles.(ABSTRACT TRUNCATED AT 250 WORDS)

Assuntos

RESUMO

Se estudiaron 10 pacientes con hipertensión arterial a moderada a quienes se efectuó un monitoreo ambulatorio (MAPA) luego de 30 dias de placebo, y otro al cabo de ocho semanas de tratamiento con una dosis fija de 20 mg de maleato de enalapril. La presión arterial sistólica (PAS) y diastólica (PAD) se registró cada 15 minutos de 07 a 22 hs, y cada 30 minutos de 22 a 07 hs. Los perfiles presores y los perfiles de las diferencias presoras droga-placebo individuales, fueron alisados por los promedios horarios. Luego se aplicó la Transformada de Fourier Discreta (TFD). Se determinó el menor número de armónicas que generan un ajuste estadisticamente significativo por análisis de residuos. En las curvas de diferencias presoras alisadas por TFD, se calcularon máximos, mínimos y puntos de inflexión para determinar: el tiempo de respuesta rápida (intervalo entre toma de la droga y máximo efecto), el tiempo de duración del efecto de la droga (intervalo entre toma de medicación y punto de inflexión, siguiente al último mínimo previo a una nueva dosis) y la pendidente de descenso rápido (cociente entre máximo descenso presor y tiempo de respusta rápida). Dependiendo del paciente, 3 a 5 armónicas en las curvas alisadas por TFD de PAS, PAD y de las diferencias droga-placebo, son suficientes para ajustar los promedios presores horarios. Se confirmó la estabilidad del ritmo circadiano en ambos monitoreos. El efectos se presentó a las 3 hrs (rango: 2 a 5) de toma de dosis; y la duración máxima media del efecto de la medicación fue de 17,6 hs para la PAS y de 18,5 hs para la PAD. Se concluye que las diferencias presoras tratamiento-placebo obtenidas a partir del MAPA y analizadas según el modelo de RFD permiten evaluar los intervalos de tiempo de protección presora asociados a un tratamiento antihipertensivo

Assuntos

RESUMO

In order to assess the usefulness of the Discrete Fourier Transform Model (DFT) to evaluate time-course drug effects on hypertensive patients studied with Ambulatory Blood Pressure Monitoring (ABPM) a number of experiments were carried out. A total of 10 mild to moderate hypertensive patients were evaluated under placebo and after 8 weeks of active treatment with Enalapril 20 mg per day using ABPM. Systolic and Diastolic blood pressure (SBP and DBP) were registered every 15 minutes during daytime and every 30 minutes at night. Pressure profiles of each patient were initially smoothed by hourly means. DFT was then applied to these profiles. The minimum number of harmonics necessary to generate a statistically significant fitting of the blood pressure profile, were obtained by residuals analysis (run test and analysis of variance of the mean sum of residual squares with each new harmonic incorporated to the model). A profile of the blood pressure differences (treatment-placebo) with the rough data of each patient was smoothed by hourly means. DFT was applied again on these substraction profiles. To estimate peak and trough drug effects for the blood pressure decrease function, maximum, minimum and inflexion points were calculated defining the following parameters: T peak: time from drug administration to maximum pressure decrease; T late response: time from drug administration to the inflexion point following the last minimum previous to the next dose; BP peak: the maximum blood pressure decrease amplitude; and the slope BP peak/T peak. The stability of the individual circadian rhythm was confirmed for both ABPM controls comparing times of maximum and minimum on the DFT smoothed profiles.(ABSTRACT TRUNCATED AT 250 WORDS)

RESUMO

Se estudiaron 10 pacientes con hipertensión arterial a moderada a quienes se efectuó un monitoreo ambulatorio (MAPA) luego de 30 dias de placebo, y otro al cabo de ocho semanas de tratamiento con una dosis fija de 20 mg de maleato de enalapril. La presión arterial sistólica (PAS) y diastólica (PAD) se registró cada 15 minutos de 07 a 22 hs, y cada 30 minutos de 22 a 07 hs. Los perfiles presores y los perfiles de las diferencias presoras droga-placebo individuales, fueron alisados por los promedios horarios. Luego se aplicó la Transformada de Fourier Discreta (TFD). Se determinó el menor número de armónicas que generan un ajuste estadisticamente significativo por análisis de residuos. En las curvas de diferencias presoras alisadas por TFD, se calcularon máximos, mínimos y puntos de inflexión para determinar: el tiempo de respuesta rápida (intervalo entre toma de la droga y máximo efecto), el tiempo de duración del efecto de la droga (intervalo entre toma de medicación y punto de inflexión, siguiente al último mínimo previo a una nueva dosis) y la pendidente de descenso rápido (cociente entre máximo descenso presor y tiempo de respusta rápida). Dependiendo del paciente, 3 a 5 armónicas en las curvas alisadas por TFD de PAS, PAD y de las diferencias droga-placebo, son suficientes para ajustar los promedios presores horarios. Se confirmó la estabilidad del ritmo circadiano en ambos monitoreos. El efectos se presentó a las 3 hrs (rango: 2 a 5) de toma de dosis; y la duración máxima media del efecto de la medicación fue de 17,6 hs para la PAS y de 18,5 hs para la PAD. Se concluye que las diferencias presoras tratamiento-placebo obtenidas a partir del MAPA y analizadas según el modelo de RFD permiten evaluar los intervalos de tiempo de protección presora asociados a un tratamiento antihipertensivo (AU)

Assuntos

RESUMO

In order to evaluate left ventricular diastolic function by means of Doppler echocardiography in borderline and established hypertension, identified by office and ABPM, compared with normotensives, 54 subjects: 15 normotensives, 11 borderlines and 28 nontreated mild to moderate essential hypertensives were studied. Age and weight were similar among groups. Established hypertensives showed higher left ventricular mass index (p < 0.05), peak velocity of late left ventricular filling (peak A; p < 0.01), ratio peak A/peak velocity of early ventricular filling, peak E (p < 0.01), velocity time integral of systolic atrial volume (p < 0.001), deceleration half time of peak early diastolic inflow velocity (p < 0.05), left ventricular isovolumic relaxation period (IRP; p < 0.01) than normotensives and lower Doppler indexes of early diastolic left ventricular filling (p < 0.01), peak filling rat normalized to mitral stroke volume (PFRn; p < 0.01) than normotensives. Although borderline hypertensives showed intermediate LVM and Doppler indexes between hypertensives and normotensives only IRP (p < 0.05) and PFRn (p < 0.05) were significant different to normotensives. In conclusion, established hypertension leads to abnormalities in left ventricular diastolic function which can be detected by Doppler echocardiography. In borderline hypertension, the left ventricular diastolic abnormalities are predominantly related to the active process of early diastole. Therefore, these indexes may be early markers of left ventricular dysfunction in hypertension.(Au)

Assuntos

RESUMO

In order to evaluate left ventricular diastolic function by means of Doppler echocardiography in borderline and established hypertension, identified by office and ABPM, compared with normotensives, 54 subjects: 15 normotensives, 11 borderlines and 28 nontreated mild to moderate essential hypertensives were studied. Age and weight were similar among groups. Established hypertensives showed higher left ventricular mass index (p < 0.05), peak velocity of late left ventricular filling (peak A; p < 0.01), ratio peak A/peak velocity of early ventricular filling, peak E (p < 0.01), velocity time integral of systolic atrial volume (p < 0.001), deceleration half time of peak early diastolic inflow velocity (p < 0.05), left ventricular isovolumic relaxation period (IRP; p < 0.01) than normotensives and lower Doppler indexes of early diastolic left ventricular filling (p < 0.01), peak filling rat normalized to mitral stroke volume (PFRn; p < 0.01) than normotensives. Although borderline hypertensives showed intermediate LVM and Doppler indexes between hypertensives and normotensives only IRP (p < 0.05) and PFRn (p < 0.05) were significant different to normotensives. In conclusion, established hypertension leads to abnormalities in left ventricular diastolic function which can be detected by Doppler echocardiography. In borderline hypertension, the left ventricular diastolic abnormalities are predominantly related to the active process of early diastole. Therefore, these indexes may be early markers of left ventricular dysfunction in hypertension.

Assuntos

RESUMO

In order to evaluate left ventricular diastolic function by means of Doppler echocardiography in borderline and established hypertension, identified by office and ABPM, compared with normotensives, 54 subjects: 15 normotensives, 11 borderlines and 28 nontreated mild to moderate essential hypertensives were studied. Age and weight were similar among groups. Established hypertensives showed higher left ventricular mass index (p < 0.05), peak velocity of late left ventricular filling (peak A; p < 0.01), ratio peak A/peak velocity of early ventricular filling, peak E (p < 0.01), velocity time integral of systolic atrial volume (p < 0.001), deceleration half time of peak early diastolic inflow velocity (p < 0.05), left ventricular isovolumic relaxation period (IRP; p < 0.01) than normotensives and lower Doppler indexes of early diastolic left ventricular filling (p < 0.01), peak filling rat normalized to mitral stroke volume (PFRn; p < 0.01) than normotensives. Although borderline hypertensives showed intermediate LVM and Doppler indexes between hypertensives and normotensives only IRP (p < 0.05) and PFRn (p < 0.05) were significant different to normotensives. In conclusion, established hypertension leads to abnormalities in left ventricular diastolic function which can be detected by Doppler echocardiography. In borderline hypertension, the left ventricular diastolic abnormalities are predominantly related to the active process of early diastole. Therefore, these indexes may be early markers of left ventricular dysfunction in hypertension.

Assuntos

RESUMO

In order to evaluate left ventricular diastolic function by means of Doppler echocardiography in borderline and established hypertension, identified by office and ABPM, compared with normotensives, 54 subjects: 15 normotensives, 11 borderlines and 28 nontreated mild to moderate essential hypertensives were studied. Age and weight were similar among groups. Established hypertensives showed higher left ventricular mass index (p < 0.05), peak velocity of late left ventricular filling (peak A; p < 0.01), ratio peak A/peak velocity of early ventricular filling, peak E (p < 0.01), velocity time integral of systolic atrial volume (p < 0.001), deceleration half time of peak early diastolic inflow velocity (p < 0.05), left ventricular isovolumic relaxation period (IRP; p < 0.01) than normotensives and lower Doppler indexes of early diastolic left ventricular filling (p < 0.01), peak filling rat normalized to mitral stroke volume (PFRn; p < 0.01) than normotensives. Although borderline hypertensives showed intermediate LVM and Doppler indexes between hypertensives and normotensives only IRP (p < 0.05) and PFRn (p < 0.05) were significant different to normotensives. In conclusion, established hypertension leads to abnormalities in left ventricular diastolic function which can be detected by Doppler echocardiography. In borderline hypertension, the left ventricular diastolic abnormalities are predominantly related to the active process of early diastole. Therefore, these indexes may be early markers of left ventricular dysfunction in hypertension.

RESUMO

In order to assess their ventricular function at rest and during exercise, 42 essential hypertensives (164 +/- 2/98.7 +/- 2 mmHg) and 12 normotensives (131.7 +/- 4/81.2 +/- 1 mmHg) were studied. Ejection fraction (EF), peak filling rate (PFR) and peak ejection rate (PER) were measured by means of gated radionuclide ventriculography. At rest, no differences in EF, PFR and PER between hypertensives and normotensives were found. During exercise, hypertensives showed lower PFR (5.3 +/- 0.2 EDV/s) and EF (67.7 +/- 1%) than normotensives (PFR 7 +/- 0.5 EDV/s, p < 0.005 and EF 79.4 +/- 2%, p < 0.001). Likewise, hypertensive showed a lower increase from rest to exercise in PFR and in EF than normotensives p < 0.001. In addition, hypertensives showed a great individual variability in EF response to exercise, where 23 patients increased EF more than 5% and 19 patients failed to increase it during stress. Moreover, the last group of patients had higher systolic blood pressure (SBP) both at rest and during exercise than patients who increased EF, p < 0.01. In addition, there was a significantly negative correlation between resting SBP and the variation of Ef (r = 0.47 y: 163.1-0.79X, p < 0.01). Left ventricular mass (LVM) was similar in the two groups of hypertensives. On the other hand, there were no differences in any of the variables analyzed between the hypertensives with LV hypertrophy and those with normal LVM. These findings suggest that abnormalities in both systolic and diastolic LV during exercise may be found in hypertensive patients even before myocardial hypertrophy can be detected

Assuntos

RESUMO

In order to assess their ventricular function at rest and during exercise, 42 essential hypertensives (164 +/- 2/98.7 +/- 2 mmHg) and 12 normotensives (131.7 +/- 4/81.2 +/- 1 mmHg) were studied. Ejection fraction (EF), peak filling rate (PFR) and peak ejection rate (PER) were measured by means of gated radionuclide ventriculography. At rest, no differences in EF, PFR and PER between hypertensives and normotensives were found. During exercise, hypertensives showed lower PFR (5.3 +/- 0.2 EDV/s) and EF (67.7 +/- 1%) than normotensives (PFR 7 +/- 0.5 EDV/s, p < 0.005 and EF 79.4 +/- 2%, p < 0.001). Likewise, hypertensive showed a lower increase from rest to exercise in PFR and in EF than normotensives p < 0.001. In addition, hypertensives showed a great individual variability in EF response to exercise, where 23 patients increased EF more than 5% and 19 patients failed to increase it during stress. Moreover, the last group of patients had higher systolic blood pressure (SBP) both at rest and during exercise than patients who increased EF, p < 0.01. In addition, there was a significantly negative correlation between resting SBP and the variation of Ef (r = 0.47 y: 163.1-0.79X, p < 0.01). Left ventricular mass (LVM) was similar in the two groups of hypertensives. On the other hand, there were no differences in any of the variables analyzed between the hypertensives with LV hypertrophy and those with normal LVM. These findings suggest that abnormalities in both systolic and diastolic LV during exercise may be found in hypertensive patients even before myocardial hypertrophy can be detected (Au)

Assuntos