Varios

Spectral Analysis of Arterial System Resonance

2026-05-20T05:00:12Z

Spectral Analysis of Arterial System Resonance Clara, Fernando Mario; Alfie, José; Blanco, Gustavo; Casarini, Alfredo Introduction: The Windkessel model simulates the radial pulse wave. When the aortic valve closes, instead of a pressure decrease during diastole, there is an initial increase due to a resonant response. The aim of this study was to explain this phenomenon based on the spectral analysis, and determine how it is affected by aging. Methods: The Fourier spectrum of resting pressure wave was analysed in a healthy set of 49 young individuals (26.9±7.3 years) and 51 adults (53.4±10.3 years). To explain the results, the Windkessel was considered a low-pass filter composed by distal compliance Cd, aortic inertance L, and peripheral resistance Rp. Results: The spectrum obtained showed a maximum amplitude between 3 and 4 Hz, evidencing resonant behavior in that frequency range. Linear regression of diastolic pressure increases revealed that it depends mainly on the amplitude of the 3rd harmonic of the spectrum (p<0.001), for normal heart rate values. Conclusions: The arterial system resonates at a frequency close to 3.5 Hz, generating the oscillation responsible for the diastolic pressure increase. The resonance frequency remains constant with age, however, the oscillation amplitude, related to small distal artery compliance and endothelial dysfunction, decreases by more than 50%. The resonant configuration of the arterial system results from an evolutionary development that allows diastolic pressure to be increased for approximately 300 ms, using the energy stored during systole. Spectral analysis allows the assessment of aging of the arterial system, and could be useful in evaluating the effects of cardiometabolic diseases on small arteries.

Radial Pulse Wave Analysis in Young Male Elite Athletes

2026-05-20T05:00:13Z

Radial Pulse Wave Analysis in Young Male Elite Athletes Clara, Fernando Mario; Alfie, José; Blanco, Gustavo; Resina, Cecilia; Meschino, Gustavo Javier; Fita, Mariana Background: Indicators obtained from the analysis of the radial pulse wave allow an indirect evaluation of the interaction between cardiac ejection and arterial walls. Objectives: To analyze the characteristics of the arterial pulse in young elite athletes through a cross-sectional observational study. Methods: We evaluated the radial pulse wave in 35 high performance young male athletes, who practice various sports, comparing them with 36 healthy men of similar ages, using the applanation tonometry technique. We computed conventional indicators of central increase in central pressure and aortic propagation velocity, and added two new indicators: the slope of the increase in radial pressure and the amplitude of the oscillatory component during diastole. Results: In relation to controls, athletes exhibited lower heart rate (61.6 ± 9.1 vs. 71.4 ± 10.6 bpm, p < 0.001), lower pulse wave velocity (7.0 ± 1.0 vs. 7.5 ± 0.8 m/s, p < 0.001), lower diastolic blood pressure (67.6 ± 8.2 vs. 78.5 ± 7.3 mmHg, p < 0.001) and higher brachial pulse pressure (53.6 ± 8.3 vs. 46.7 ± 7.1 mmHg, p < 0.001). The systolic slope (0.70 ± 0.15 vs. 0.59 ± 0.13 mmHg/ms, p < 0.001) and the amplitude of diastolic oscillation (25.7 ± 6.4 vs. 18.4 ± 4.7%, p < 0.001) were significantly higher in athletes than in controls. Conclusion: Young athlete presented low aortic velocity, but significantly higher systolic slope and diastolic oscillation amplitude than controls. The steeper systolic slope and the lower diastolic blood pressure could underlie a higher stroke volume and a lower peripheral resistance respectively. The greater diastolic oscillation could be the consequence of the eccentric remodeling and increased compliance of the distal arteries, in response to intense training. We propose new pulse wave parameters obtained from the analysis of the radial waveform for the assessment of the cardiovascular adaptation to intense training. HIGHLIGHTS •• Pulse wave contour of athletes is characterized by a steeper pressure slope and greater diastolic oscillation. •• In contrast, traditional tonometric indicators did not differ significantly between athletes and controls. •• The cardiovascular adaptation to high performance training could be evaluated by pulse wave analysis.

Alteraciones en la distensibilidad arterial de pacientes dislipidémicos

2026-05-20T05:00:08Z

Alteraciones en la distensibilidad arterial de pacientes dislipidémicos Fernando Mario, Clara; Pablo, Corral; Gustavo Hector, Blanco; Adriana Graciela, Scandurra; Gustavo Javier, Meschino Introducción: Se estudió la alteración en la distensibilidad de las paredes arteriales producidas por la dislipidemia dependiente de c-LDL a lo largo de las distintas décadas de la vida, utilizando el análisis de onda de pulso radial. Métodos: Se efectuó el registro de onda de pulso en la arteria radial mediante un transductor de movimiento apoyado sobre la zona de palpación, sobre un conjunto de 100 varones dislipidémicos sin otros factores de riesgo, de edades comprendidas entre la 3.a y la 6.a décadas de la vida. Se calculó en cada caso el índice de aumentación. También se identificó en los registros la onda reflejada y se definió un coeficiente de velocidad como el cociente entre la talla del individuo y el tiempo transcurrido entre el máximo de la onda sistólica y el instante de llegada de dicha onda. Los resultados se compararon con los de un conjunto de 161 voluntarios sanos. Resultados: Se halló que los dislipidémicos presentaron valores del índice de aumentación similares a los controles hasta la 4.a década, aumentando a partir de entonces, con diferencias significativas a partir de la 6.a década. No se hallaron diferencias significativas en el índice de velocidad en ninguna de las edades estudiadas. Conclusiones: Se concluye que las alteraciones producidas por la dislipidemia requieren décadas para manifestarse, y comienzan afectando al mecanismo de vasodilatación de las arterias distales con mayor proporción de músculo liso, sin alterar las arterias de conducción proximales con mayor contenido de elastina.; Abstract: Introduction: We studied the alteration on the distensibility of the arterial walls caused by dyslipidemia LDLc dependent, along the decades of life, by means of a study of the radial artery pulse wave. Methods: We made an analysis of the radial artery pulse wave records acquired by means a movement displacement sensor, placed on radial palpation area. We recruited 100 dyslipidemic men without other cardiovascular risk factors, between the 3rd and the 6th decade. We identified the reflected wave in the records and we computed the augmentation index in order to quantify its amplitude and position. This index is useful to assess the endothelial dysfunction. Besides, we defined a velocity coefficient as the ratio between the size of the individuals and the delay time between the peak of the systolic wave and the arrival of the reflected wave. Results were compared against those obtained in a group of 161 healthy volunteers. Results: We found that dyslipidemic patients presented augmentation index values similar to controls until the fourth decade, increasing thereafter with significant differences only in the 6th decade. No significant differences were found in the velocity index in any of the ages studied. Conclusions: We conclude that alterations produced by dyslipidemia take decades to manifest, and they begin affecting the mechanism of vasodilation of distal arteries with highest proportion of smooth muscle, without altering the proximal conduit arteries with more elastin content.

Evaluación de hipertensos en base a registros de variación de diámetro arterial radial

2026-05-08T05:00:13Z

Evaluación de hipertensos en base a registros de variación de diámetro arterial radial Clara, Fernando Mario; Casarini, Alfredo; Scandurra, Adriana Gabriela; Meschino, Gustavo Javier; Introzzi, Aníbal R. Se utilizó la técnica de análisis del registro incruento de las variaciones de diámetro de arteria radial para evaluar el deterioro arterial y el riesgo cardiovascular en pacientes hipertensos. El transductor utilizado consistió en un sensor de movimiento apoyado sobre la zona de palpación del pulso radial. Se efectuó la determinación del índice de aumentación radial, un parámetro que cuantifica la magnitud de las reflexiones de la onda de presión en la región aórtica, sobre un conjunto de 47 hipertensos, y se lo comparó con otro estudio similar efectuado sobre 81 normotensos sanos. Estos últimos presentaron menores valores de dicho índice, pero al avanzar la edad los valores de ambos grupos tendieron a coincidir. Esto fue confirmado al comparar morfológicamente los registros de ambos grupos, hallándose que los registros de ancianos normotensos sanos e hipertensos de edades similares resultaron visiblemente parecidos. Se halló también que determinados hipertensos jóvenes presentaron ciertas características morfológicas similares a las de normotensos de la misma edad, indicando que aún conservaban las características elásticas propias de su grupo etario. Los resultados fueron similares a los logrados sobre registros de presión arterial radial obtenidos mediante tonometría de aplanación, utilizándose una tecnología disponible en nuestro medio y de menor costo.; ABSTRACT: Evaluation of hypertensive patients by radial arterial diameter variation recording. A blood less analysis technique of the diameter variation signal at radial artery was used to evaluate the arterial disease and the cardiovascular risk in hypertensive patients. A movement transducer was used to record the wrist pulse. A radial augmentation index was proposed to quantify the magnitude of the pressure wave reflec- tions in the aortic region. The experiment was carried out with a group of 47 hypertensive men and compared with a similar study performed on 81 normotensive healthy men. The last ones presented smaller values of this index, but as age progresses, values of both groups come closer among them. This was confirmed by morpho- logical comparison of both groups. Similar behavior was found in signals coming from healthy normotensive and hypertensive old men with similar age. Furthermore, some of the hypertensive youth presented similar morpho- logical characteristics to normotensive of the same age. That indicates they still conserved the elastic behavior characteristic of its age group. These results, using available technology of smaller cost, were well-matched to those achieved by pressure signals at radial artery obtained by means of applanation tonometry.