ABSTRACT
Introducción: El efecto de prostanoides inhalatorios sobre la función auricular derecha (AD) en hipertensión arterial idiopática (HAP) no ha sido estudiado. Objetivo: Evaluar cambios agudos en la función AD y función diastólica del ventrículo derecho en pacientes con HAP post uso de Iloprost inhalatorio. Métodos: Se incluyeron pacientes con HAP sin uso previo de prostanoides. Se realizó un ecocardiograma transtorácico basal y 30 min posterior a la inhalación de iloprost. Se midió dimensión AD, relación E/e' y strain de la AD por speckle tracking, registrando la onda negativa de contracción auricular (SaAD) y la onda positiva de la fase de reservorio (SsAD). Se midió el tiempo de inicio de la fase de reservorio AD durante el sístole ventricular. Resultados: Se estudiaron 16 pacientes (15 mujeres), con edad promedio 44 ± 7,8 años. Post Iloprost disminuyó el volumen AD (basal: 140ml, post Iloprost: 109 ml; p 0,008) y las presiones de llenado (E/e’ basal: 13, post Iloprost: 9,8; p 0,028). No se registraron diferencias en el SaAD (basal: -8,4%, post Iloprost: -8,5%; p 0,834). El SsAD fue mayor post Iloprost (basal: 8,6%, post Iloprost: 11,7%; p 0,002) iniciándose antes durante el sístole ventricular (basal: 445ms, post Iloprost: 368ms; p 0,001). Conclusión: Con Iloprost inhalatorio en pacientes con HAP se observa una reducción aguda en el tamaño de la AD y en las presiones de llenado del VD. La deformación durante la fase de reservorio de la AD aumenta y se inicia significativamente antes. Esto sugiere que el Iloprost podría mejorar en forma aguda el trabajo mecánico de la AD en paciente con HAP.
Background: The effects of inhaled prostanoids on right atrial (RA) function in patients with Pulmonary Arterial Hypertension (PAH) have not been studied. We evaluated acute changes in RA function and right ventricular diastolic function after inhaled iloprost. Methods: We included PAH patients without prior prostanoid treatment. A surface echocardiogram was performed at baseline and 30 minutes after iloprost inhalation. Measurements included RA dimensions, right E/e’ ratio and RA strain by speckle tracking, registering a RA contraction wave (RASa) and RA reservoir wave (RASs). RA time to peak of deformation during the reservoir phase was also measured. Results: We included 16 patients (15 females, aged 44±7.8 years. Post iloprost there was a reduction in RA volume (baseline: 140ml, post iloprost: 109ml; p 0.008) and right ventricular filling pressure (baseline E/e’: 13, post iloprost: 9.8; p 0.028). There was no difference in the magnitude of the RASa wave (baseline: -8.4%, post iloprost: -8.5%; p 0.834). The RASs wave was larger post iloprost (baseline: 8.6%, post iloprost: 11.7%; p 0.002), and began earlier (baseline RA time to peak of deformation during reservoir phase: 445ms, post iloprost: 368ms; p 0.001). Conclusion: Inhaled iloprost acutely reduces RA size and right ventricular filling pressure in patients with HAP It also significantly increases the magnitude of RA systolic deformation as well as making it occur earlier in RA filling phase. This suggests that iloprost might improve RA mechanical performance.
Subject(s)
Humans , Male , Female , Adolescent , Adult , Middle Aged , Atrial Function, Right/drug effects , Iloprost/administration & dosage , Hypertension, Pulmonary/drug therapy , Vasodilator Agents/administration & dosage , Administration, Inhalation , Echocardiography , Cross-Sectional Studies , Arterial Pressure/drug effects , Hypertension, Pulmonary/physiopathologyABSTRACT
The present study deals with the chronotropic effects of Sildenafil citrate [Viagra] on right atrial contracctility of mammalian isolated heart muscle. Effects of Sildenafil citrate on rat isolated heart in-vitro using right atrial samples, in comparison with nor-adrenaline, revealed that Sildenafil at 10[-7] M and above produced dose related increases in contractility. The maximum observed increase at 10[-4] M represented a 126% +/- 31% increase above control amplitude. Nor-adrenaline produced similar dose-related increases in contractility and was appoximately three times more potent than Sildenafil citrate. Dimaprit also produced similar responses to the Sildenafil but was less potent. These results indicated that rat responds to Sildenafil citrate, which increases contracility and enhances atrial automaticity, with sensitivity comparable to that for nor-adrenaline. The selective antagonism of the Sildenafil contractility response by cimetidine indicated that this response is mediated via histamine H [2]-receptors and not H [1] noradrenergic beta receptors. The involvement of histamine H [2]- receptors is confirmed by the similarity of the response to dimaprit. The production of spontaneous contractions by dimaprit further suggests that Sildenafil citrate-induced enhancement of atrial automaticity is mediated via modified histamine H [2]-receptors
Subject(s)
Animals, Laboratory , Atrial Function, Right/drug effects , Rats , Heart Atria/drug effects , Myocardial Contraction/drug effectsABSTRACT
Estudar o efeito cronotrópico negativo de nitrendipina, nifedipina e verapamil no átrio direito isolado de ratos normotensos e com hipertensäo renovascular. A hipertensäo foi produzida pela implantaçäo de anel de prata na artéria renal esquerda e nefrectomia direita. Os animais foram estudados 15 dias após a cirurgia, quando a PA média (medida diretamente, no animal acordado, através de cânula intravascular) do grupo hipertenso (154 ñ 4 mm Hg) era maior que a do grupo controle (109 ñ 2 mmHg). A freqüência atrial "in vitro" foi determinada a partir dos registros das contraçöes isométricas. Atrios diferentes foram usados para se obter as curvas dose-resposta (0,01 micronM - 100 micronM) de cada droga. A freqüência atrial "in vitro" foi idêntica nos normotensos (243 ñ 7 bpm) e hipertensos (245 ñ 5 bpm). A sensibilidade às drogas testadas também foi a mesma, em ambos os grupos. A concentraçäo de droga necessária para reduzir 50% da freqüência sinusal foi cerca de 2 micronM para o verapamil, 4 micronM para a nitrendipina e 20 micronM para a nifedipina. A hipertensäo näo altera a sensibilidade do marca-passo sinusal aos bloqueadores de canal de cálcio. O efeito cronotrópico negativo da nitrendipina é intermediário entre o do verapamil e o da nifedipina