Current status of the Maze procedure for the treatment of atrial fibrillation.

Since the first patient underwent the Maze procedure on September 25, 1987, 346 patients have undergone this operation for the treatment of atrial fibrillation. The procedure was designed as an open-heart operation performed through a median sternotomy. It underwent 2 major modifications relatively early in the series, evolving into the so-called Maze-III procedure, which has been used exclusively since April 16, 1992. Since that time, the Maze-III procedure has been adapted to allow it to be done by minimally invasive techniques. In addition, we recently performed the entire procedure in 2 patients without the use of cardiopulmonary bypass. The operative mortality rate has remained at 2% to 3%. This includes patients undergoing concomitant high-risk cardiac surgical procedures and all re-do cases. The overall success rate in curing atrial fibrillation has been 99%. The procedure itself has been shown to cause no permanent damage to the sinus node. The left atrium has been documented to function long-term postoperatively in 93% of patients and the right atrium functions in 99% of patients. The Maze-III procedure remains the surgical procedure of choice for the treatment of medically refractory atrial fibrillation.

The Maze-III procedure combined with valve surgery.

Previous studies have suggested that the Maze procedure is not as effective in controlling atrial fibrillation when the arrhythmia is associated with significant valvular heart disease. In this study, we evaluate our own results in 83 patients who underwent 96 valve procedures in combination with the Maze-III procedure. Our results indicate that the Maze-III procedure is just as safe and effective in controlling atrial fibrillation associated with valvular heart disease as it is in controlling atrial fibrillation not associated with valvular heart disease.

Observations on the perioperative management of patients undergoing the Maze procedure.

In addition to the usual measures that constitute optimal perioperative care after cardiac surgery, the Maze procedure demands several other measures because of certain complications that are unique to this particular operation. These complications include preoperative conditions such as amiodarone therapy, thromboembolism, diastolic dysfunction of the left ventricle, and associated valvular heart disease, as well as intraoperative differences that include multiple atriotomies and excision of both atrial appendages. The most common postoperative complications are atrial arrhythmias, excessive fluid retention, and pulmonary complications. In this article, we outline our own approach to the perioperative care of patients undergoing the Maze procedure.

17-Beta estradiol regulation of myocardial glutathione and its role in protection against myocardial stunning in dogs.

We studied the effect of 2-week treatment with estradiol 17beta on myocardial glutathione concentration in dogs and isolated perfused rat heart subjected to brief coronary ischemia and reperfusion. Estradiol protected against ischemia/reperfusion-induced myocardial systolic shortening and malonylaldehyde production and increased myocardial glutathione concentration and glucose-6-phosphate dehydrogenase enzyme activity. Reduction of myocardial glutathione with buthionine sulfoximine to levels seen in the absence of estrogen reversed the protective effect of estradiol against myocardial dysfunction and lipid peroxidation associated with ischemia/reperfusion. These results suggest that the antioxidant effect of estradiol in ischemia/reperfusion may be mediated by regulation of myocardial glutathione metabolism.

The economic and clinical efficiency of point-of-care testing for critically ill patients: a decision-analysis model.

Our study objective was to assess economic and clinical outcomes of use of a point-of-care (POC) blood analysis device for postoperative coronary artery bypass graft (CABG) patients. A decision analytic model was developed for patients with high expected use of blood analysis, high potential benefit from rapid turn around time of results, a large annual volume of patients, and substantial expense associated with surgery. Published literature and clinical experts provided incidence, outcome, and cost estimates associated with four clinical scenarios potentially influenced by POC testing (ventricular arrhythmias, cardiac arrest, severe postoperative bleeding, and iatrogenic anemia). We found that changes in clinical outcomes were predominantly dependent on comparative turn around time or CABG patient volume. The positive clinical impact of using POC testing was consistently associated with a positive economic impact. POC blood gas analysis may be associated with decreased incidence of adverse clinical events or earlier detection of such events, resulting in significant cost savings. This study also supports previous findings that the costs of STAT blood analysis are more personnel-related than equipment-related.

Norepinephrine throughout the spinal cord of the cat: I. Normal quantitative laminar and segmental distribution.

Norepinephrine (NE) concentrations were measured by radioenzymatic assay in microdissected individual laminae of each segment of the cat spinal cord. Norepinephrine was detected in all areas of the spinal gray matter and showed more than a 7-fold difference in concentration between the laminae with the highest and lowest NE. The cervical, thoracic, and lumbosacral spinal regions showed significant interlaminar differences in NE. Intersegmental changes in NE were seen within single laminae of the thoracic and lumbosacral spinal cord, but not in the cervical spinal cord. A significant rostral to caudal, increasing regional gradient of NE was observed from the cervical to lumbosacral spinal cord in laminae I-III, V, VI, VII, and IX. In the intermediolateral cell column (IML), epinephrine concentrations were 2 to 5% of NE. Neither neurotransmitter showed a significant intersegmental variation in the IML. These data should prove useful in further defining the precise role of NE in specific regions of the spinal cord that mediate sensory, motor, autonomic, or propriospinal functions.