The effect of L-arginine and citrulline on endothelial function in patients in heart failure with preserved ejection fraction

Background: To evaluate the effect of the amino acids L-arginine and citrulline on endothelial function in patients in stable diastolic and right heart failure using photoplethysmography. Methods: Thirty patients from the Heart Failure Clinic of the Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán" underwent photoplethysmography using the hyperemia technique. Index finger flow was assessed at baseline and after ischemia every 30 s by maximum amplitude time (MAT), total time of the curve (TT) and the index of the two (MAT/TT < 30 = normal) before and after the administration of L-arginine (8 g/day in two doses, n = 15) or citrulline (3 g/day in one dose, n = 15) for 60 days in addition to optimal pharmacological treatment. Results: There were no statistically significant differences between the two groups at baseline. After the intervention, the MAT/TT index of all patients normalized in each evaluation period with statistically significant differences. Basal L-arginine group = 38.75 &#177; 11.52, final 23.32 &#177; 6.08, p = 0.007 and basal citrulline group = 41.4 &#177; 13.47, final 23.65 &#177; 6.74, p = 0.007 at 60&#8211;90 s. Post-ischemia: basal L-arginine 36.60 &#177; 11.51, final 18.81 &#177; 15.13, p = 0.004 and basal citrulline = 49.51 &#177; 15.17, final 27.13 &#177; 7.87, p = 0.003. Conclusions: The administration of L-arginine and citrulline has a beneficial effect on endothelial function as shown by the normalized MAT/TT index. It probably improves systemic and pulmonary hemodynamics, which could help in the treatment of diastolic heart failure. (Cardiol J 2010; 17, 5: 464-470

Improvement of ventricular function in systolic heart failure patients with oral L-citrulline supplementation

Background: The utility of L-arginine and L-citrulline in treatment of arterial hypertension by increasing vascular oxide nitric availability has been demonstrated. Photoplethysmography, a simple and low-cost optical technique, makes it possible to assess vascular function and to detect changes in blood flow, pulse and swelling of the microvascular tissular space. The aim of the study was to evaluate the effect of L-citrulline supplementation on functional class, ejection fraction and peripheral blood flow in patients with systolic heart failure. Methods: Thirty-five stable outpatients attending the Heart Failure Clinic at the INCMNSZ underwent clinical evaluation, radioisotopic ventriculography and photoplethysmography before and at the end of 4 months. They were randomized into two groups: experimental group, with oral L-citrulline supplementation (3 g/day, n = 20) and control group, without supplementation (n = 15). Results: In the experimental group the left ventricular ejection fraction (LVEF) increased 20.3% at rest and 12.7% with stress, as well as the right ventricular ejection fraction at rest of 15.10% and 14.88% with stress. In addition, functional class improved in 35%, and the maximum amplitude time/total time (MAT/TT) index decreased 23.1%. These changes were statistically significant compared with the control group. Conclusions: Citrulline supplementation significantly improved the LVEF, the endothelial function (MAT/TT index) and functional class. Citrulline can be an important co-adjuvant in the treatment of stable and stable systolic heart failure patients

Monitor de señales de electrocardiografía y frecuencia cardiaca mediante un teléfono móvil con el protocolo de comunicación Bluetooth

Objetivo: Desarrollar un equipo de monitoreo de señales de electrocardiografía (ECG) y frecuencia cardiaca (FC) portátil, comunicado con un teléfono móvil mediante el protocolo de comunicación Bluetooth (BT), para su visualización en pantalla. Métodos: Se diseñó un sistema de monitoreo que en su sección electrónica realiza la adquisición de la señal de ECG, así como su amplificación, filtrado, conversión analógica a digital y transmisión por BT del ECG y la FC. Se desarrollaron dos programas para el sistema. El primero calcula la FC a través de la identificación del QRS, y envía las señales del ECG y FC al teléfono móvil. El segundo es una aplicación que permite adquirirlas y visualizarlas en la pantalla del móvil. Resultados: Se desarrolló un sistema electrónico portátil alimentado por una batería de 9 volts, de amplificación y ancho de banda que cumplen con los estándares internacionales, para monitoreo de ECG. La identificación del complejo QRS se realizó con el algoritmo de la segunda derivada, mientras que los programas realizados permiten enviar y recibir la información del ECG y la FC a través de BT, para visualizarlos en la pantalla del móvil. El monitoreo es factible hasta 15 m de distancia. Se probó en distintos móviles de Nokia®, Sony Ericsson® y Samsung®. Conclusiones: Este sistema muestra una alternativa de monitoreo móvil, con un teléfono por medio de BT y la programación en Java 2 Micro Edition (J2ME). Permite registrar el trazo del ECG y la FC, y puede implementarse en diferentes móviles

Cardiovascular variability in Mexican patients with Parkinson's disease

Cardiovascular variability (CVV) has been evaluated in patients with Parkinson's disease (PD) in other countries and exhibit ethnic differences. Objective We investigated heart rate variability (HRV) and blood pressure variability (BPV) in Mexican patients with PD. Method We further compared HRV and BPV between this group and young healthy controls (YHC) in order to estimate, for the first time in our country, the magnitude of the difference. Twenty patients were examined. Time- and frequency-domain CVV parameters were studied during supine rest (SR), active standing (AS) and controlled breathing. These measurements were compared to those of 20 YHC. Results In the three conditions tested, our study showed a decrease in almost all HRV parameters in PD patients; on the contrary, decreased BPV parameters were found less frequently and only during SR and AS. Conclusion Our results indicate that HRV is impaired in PD. Some BPV parameters are also diminished

Respiratory and non respiratory oscillations of the skin blood flow: A window to the junction of the sympathetic fibers to the skin blood vessels

Objective of the study: The skin blood flow (SBF) has been known to oscillate in frequency and amplitude. The nature and type of these oscillations have remained obscure. We studied the oscillations of the SBF in frequency and amplitude with non invasive techniques during normal breathing at rest and compared it to the oscillations during rhythmic paced breathing at 6 cycles per minute. Subjects and methods: Thirty healthy subjects were studied under normothermic conditions. The following variables were recorded: 1) EKG signal; 2) SBF signal given by an infrared photoplethysmograph; 3) respiratory movements (RM). A correlation of the frequency of the respiration, the SBF and the EKG was made. The variability of the amplitudes of the SBF, RR intervals and pulse intervals was analyzed in the time domain and with spectral analysis using Fourier analysis. Results: We found no clear respiratory modulation of the amplitude of the SBF during natural breathing at rest. With default breathing there was a low frequency oscillations (LF 0.04 to 0.15 Hz) modulation of the amplitude of the SBF that was non respiratory in nature. During rhythmic breathing at 0.1 Hz there was a strong modulation at LF of the SBF with a typical waxing and waning appearance, decreasing in amplitude during the tachycardia period and increasing in amplitude during the bradycardia period. Conclusions: Under normothermic conditions there is a consistent variability of the frequency and amplitude of the SBF with normal and rhythmic breathing. While breathing at rest the modulation of SBF amplitude was clearly seen at LF and non respiratory related. With rhythmic breathing there is a strong modulation of amplitude and frequency at the respiratory frequency

Correlation between Angiotensin Serum Levels and Very-Low-Frequency Spectral Power of Heart Rate Variability during Hemodialysis

Cardiovascular regulatory mechanisms that fail to compensate for ultrafiltration and cause hypovolemia during hemodialysis (HD) are not completely understood. This includes the interaction between the autonomic nervous system and the biochemistry that regulates blood pressure and modulates cardiac activity and vascular tone in response to hypovolemia in patients treated with HD. The objective was to evaluate the association of spectral indices of heart rate variability (HRV) with serum levels of angiotensin II, angiotensin 1&ndash;7, nitric oxide and total antioxidant capacity during HD. Electrocardiographic records were obtained from 20 patients during HD (3 h), from which HRV data and spectral power data in the very-low-frequency (VLF), low-frequency (LF) and high-frequency (HF) bands were generated. Three blood samples per patient were collected during HD (0.0, 1.5, 3.0 h) to determine the levels of biomarkers involved in the pressor response during HD. Angiotensin II had a positive correlation with VLF (r = 0.390) and with LF/HF (r = 0.359) and a negative correlation with LF (r = &minus;0.262) and HF (r = &minus;0.383). There were no significant correlations between HRV and the other biomarkers. These results suggest that during HD, VLF could reflect the serum levels of angiotensin II, which may be associated with the autonomic response to HD

Effect of Ivabradine on Endothelial Function in Diastolic and Right Heart Failure Patients

Background. Ivabradine is an If ion current inhibitor that has proved to reduce mortality in patients with systolic heart failure by slowing heart rate without decreasing myocardial contractility. Photoplethysmography is a simple, low-cost optical technique that can evaluate vascular function and detect changes in blood flow, pulse, and swelling of tissular microvascular space. Objective. To evaluate the effect of ivabradine on endothelial function by photoplethysmography in diastolic and right heart failure patients. Methodology. 15 patients were included (mean age of 78.1 ± 9.2 years) with optimally treated diastolic and right heart failure. They underwent photoplethysmography before and after induced ischemia to evaluate the wave blood flow on the finger, using the maximum amplitude time/total time (MAT/TT) index. Two measurements were made before and after oral Ivabradine (mean 12.5 mg a day during 6 months of followup). Results. In the study group, the MAT/TT index was 29.1 ± 2.2 versus 24.3 ± 3.2 () in basal recording and 30.4 ± 2.1 versus 23.3 ± 2.9 (), before versus after ischemia and before versus after Ivabradine intervention, respectively. Conclusions. Ivabradine administration improves endothelial function (shear stress) in diastolic and right heart failure patients