RESUMEN
Three patients with isolated disease of the left anterior descending coronary received a minimally invasive direct coronary artery bypass operation. All were discharged from the hospital in 2 days and are doing well. This is an exciting new procedure which combines the long-term benefits of bypass using the mammary artery with a shortened hospital stay and a rapid postoperative recovery.
Asunto(s)
Puente de Arteria Coronaria/métodos , Enfermedad Coronaria/cirugía , Enfermedad Coronaria/complicaciones , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio/etiologíaRESUMEN
Milrinone improves function in failing adult hearts, but it has not been examined in the immature myocardium. The purpose of this study was to characterize the effects of milrinone, a phosphodiesterase inhibitor, on immature hearts, and compare these to dobutamine, a commonly used catecholamine inotrope. One hundred isolated working neonatal rabbit hearts were used. Hearts were made ischemic (37 degrees C) for 1 hour and reperfused for 0, 10, 40, or 70 minutes. In separate groups, infusion of milrinone (1.0 microg/mL) or dobutamine (0.1 microg/mL) was begun after reperfusion for 10 or 40 minutes. High energy phosphates, total nondiffusable nucleotides, cyclic adenosine monophosphate (cAMP), and the percent recovery of cardiac output were determined. Cardiac output returned to normal, and adenosine triphosphate (ATP) and total nondiffusable nucleotide levels did not decline when dobutamine or milrinone were begun after 10 minutes of reperfusion. In hearts receiving inotropes after 40 minutes of reperfusion, when high energy phosphates were low, ATP increased, and total nondiffusable nucleotide repletion was observed. Cardiac output did not improve when inotropes were begun after 40 minutes. cAMP was higher in milrinone hearts compared to dobutamine, but there was no simple relation between cAMP and ventricular function. Inotropes may increase purine salvage pathway activity. Deriving maximum benefit from inotropes may depend on beginning infusions early, before the appearance of irreversible changes.
Asunto(s)
Cardiotónicos/farmacología , Corazón/efectos de los fármacos , Isquemia Miocárdica/fisiopatología , Inhibidores de Fosfodiesterasa/farmacología , Piridonas/farmacología , Adenosina Trifosfato/metabolismo , Animales , Animales Recién Nacidos , Gasto Cardíaco/efectos de los fármacos , AMP Cíclico/metabolismo , Dobutamina/farmacología , Milrinona , Isquemia Miocárdica/metabolismo , Reperfusión Miocárdica , Miocardio/metabolismo , Nucleótidos/metabolismo , Purinas/metabolismo , Conejos , Factores de Tiempo , Función Ventricular/efectos de los fármacosRESUMEN
Milrinone improves function in failing adult hearts. This study examined its effect on immature myocardium. Using an isolated working neonatal rabbit heart preparation, we measured myocardial function, high-energy compounds, and cyclic adenosine monophosphate. Hearts were subjected to 1 hour of normothermic ischemia, 10 minutes of reperfusion with Ringer's solution, and 30 minutes of reperfusion with either unaltered Ringer's, Ringer's with dobutamine (0.1 microgram/mL), or Ringer's with milrinone (1 microgram/mL). These hearts were compared with each other, with a control group continuously perfused for 70 minutes, and with a group of hearts that were made ischemic and reperfused for only 10 minutes. There was a progressive decline in adenosine triphosphate levels measured in hearts from the groups receiving 10 and 40 minutes of reperfusion with unaltered perfusate, and cardiac output fell to 82% +/- 4% of preischemic control in the latter group. When either dobutamine or milrinone was added to the reperfusion solution, postischemic myocardial function was restored completely, and the loss of adenosine triphosphate with reperfusion was halted. Cyclic adenosine monophosphate level was highest in ischemic/40-minute reperfused hearts, and there was no measurable increase in cyclic adenosine monophosphate level in the group of hearts receiving milrinone. The mechanism of preservation of high-energy stores with inotropic agents is not known but may involve potentiation of mitochondrial oxidative phosphorylation.(ABSTRACT TRUNCATED AT 250 WORDS)