Asunto(s)
Altitud , Presión Sanguínea/fisiología , Frecuencia Cardíaca/fisiología , Hipertensión/fisiopatología , Esfuerzo Físico/fisiología , Adulto , Anciano , Diástole/fisiología , Electrocardiografía , Ejercicio Físico/fisiología , Prueba de Esfuerzo , Humanos , Masculino , Persona de Mediana Edad , Sístole/fisiologíaRESUMEN
The aim of conservative management of mitral regurgitation caused by floppy mitral valve is to restore a valvular function which closely resembles that of normal physiology. Fifty-eight patients affected by floppy mitral valve underwent surgical procedures for severe mitral regurgitation due to chordal elongation and/or rupture. Of these, 28 presented posterior mitral prolapse corrected by quadrangular excision of the prolapsed part and posterior anuloplasty achieved by apposition of a polytetrafluoroethylene conduit. The remaining 30 patients presented anterior or bilateral prolapse corrected by transposition of chordae from the posterior leaflet to the anterior cusp together together with anuloplasty. A complete echo-Doppler study was performed preoperatively, 10 days after the operation and every 6 months thereafter. Mean follow-up was 16.1 +/- 6.3 months. Preoperatively, 44 patients presented severe mitral regurgitation and 14 had moderate regurgitation (quantified by means of pulsed Doppler). All patients showed severe enlargement of the left cavities (LVDD 67.1 +/- 8.6 mm, left atrium 53.4 +/- 10.9 mm) with normal mitral area (6.08 +/- 2.14 sqcm, Doppler measurement). Following surgery we found a significant reduction in: 1) the degree of mitral regurgitation (29 patients had no regurgitation; 20 had mild protosystolic mitral regurgitation (29 patients had no regurgitation; 20 had mild protosystolic mitral regurgition, confirmed by color-M-mode; moderate or severe regurgitation was found in 6 cases); 2) the left ventricle and left atrium dimensions (LVDD 53.4 +/- 5.2 mm, p less than 0.01; left atrium 43.8 +/- 11.1 mm, p less than 0.01). Color flow imaging provided information about the recovery of a normal valvular function.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Ecocardiografía Doppler , Insuficiencia de la Válvula Mitral/diagnóstico por imagen , Insuficiencia de la Válvula Mitral/cirugía , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Insuficiencia de la Válvula Mitral/etiología , Prolapso de la Válvula Mitral/complicaciones , Cuidados Posoperatorios , Cuidados PreoperatoriosRESUMEN
By analysis of spectral components of heart rate variability, sympathovagal interaction was assessed in patients after acute myocardial infarction (AMI). At 2 weeks after AMI (n = 70), the low-frequency component was significantly greater (69 +/- 2 vs 53 +/- 3 normalized units [NU], p less than 0.05) and the high-frequency component was significantly smaller (17 +/- 1 vs 35 +/- 3 NU) than in 26 age-matched control subjects. This difference was likely to reflect an alteration of sympathovagal regulatory outflows with a predominance of sympathetic activity. At 6 (n = 33) and 12 (n = 29) months after AMI, a progressive decrease in the low- (62 +/- 2 and 54 +/- 3 NU) and an increase in the high-frequency (23 +/- 2 and 30 +/- 2 NU) spectral components was observed, which suggested a normalization of sympathovagal interaction. An increase in sympathetic efferent activity induced by tilt did not further modify the low-frequency spectral component (78 +/- 3 vs 74 +/- 3 NU) in a subgroup of 24 patients at 2 weeks after AMI. Instead, 1 year after AMI, this maneuver was accompanied by an increase in the low-frequency component (77 +/- 3 vs 53 +/- 3 NU, p less than 0.05) of a magnitude similar to the one observed in control subjects (78 +/- 3 vs 53 +/- 3 NU). These data indicate that the sympathetic predominance that is detectable 2 weeks after AMI is followed by recovery of vagal tone and a normalization of sympathovagal interaction, not only during resting conditions, but also in response to a sympathetic stimulus.