Combined minimally invasive pulmonary vein isolation, left atrial appendage excision and cardiac resynchronization therapy for heart failure: case report

A 76-year-old male with ischemic cardiomyopathy presented with heart failure symptoms in the absence of angina. Several hospitalizations were required due to heart failure exacerbation and paroxysmal atrial fibrillation. Electrocardiography and tissue synchronization imaging confirmed ventricular dyssynchrony, requiring biventricular pacing. After a failed attempt of percutaneous placement of the left ventricular lead, a novel minimally invasive approach was indicated. It consisted of left ventricular epicardial lead placement, microwave pulmonary vein isolation, and left atrial appendage excision through bilateral minithoracotomies. The postoperative recovery was unremarkable, with reestablishment of the ventricular synchrony and regular rhythm.     

Treatment of nontoxic megacolon by colonoscopy

The indications for colonoscopy in a recent consecutive series of 232 examinations were analyzed. Of these examinations, 30 (13%) were performed for nontoxic megacolon. Nontoxic megacolon is defined as severe dilatation of a segment or the entire colon unaccompanied by signs or symptoms of colon toxicity. Mechanical factors (volvulus, anastomosis, diverticulosis, carcinoma) were responsible for the nontoxic megacolon in 13 of these patients. Nontoxic megacolon was classified as secondary to acute pseudoobstruction (Ogilvie's syndrome, pancolonic megacolon, acute myxedema ileus) in 17 patients. All patients were being evaluated for possible exploratory celiotomy to prevent perforation of the colon because of the massive colonic distention. Colonoscopic examination was performed at the bedside or in the intensive care unit for 11 of 30 patients. No bowel preparation was used. Evacuation of air and fecal material was more efficiently accomplished by use of an external suction device attached to the biopsy part of the endoscope. For 12 of the 13 patients who had a mechanical basis for their nontoxic megacolon the colon was successfully decompressed. All 17 patients with acute pseudoobstruction were successfully treated. There were no iatrogenic perforations. Possible emergency operation was avoided for all patients except one who had a cecal volvulus. Colonoscopy should be considered as the initial treatment for nontoxic megacolon prior to surgical intervention.     

Effect of errors in reangulation on planar and tomographic thallium-201 washout profile curves

Cardiac phantom studies were performed with and without a defect present to test the hypothesis that myocardial 201TI quantitative circumferential washout profile curves calculated from planar and rotating slant hole (RSH) collimator tomographic images are equally affected by errors in axial repositioning. Simulated stress images were acquired with the long axis of the phantom perpendicular to the camera surface and redistribution images were acquired to represent 50% 201TI washout with axial repositioning errors relative to the stress position ranging from 0 to 20 degrees in 5 degrees increments. There was a decrease in the 201TI washout profile curves compared to that expected (50%) in the wall tilted away from the camera surface, and a reciprocal increase in the 201TI washout profile curves in the wall tilted towards the camera surface for both imaging techniques whether a lesion was present or not. This effect became more pronounced as the error in axial repositioning was increased for both the planar (p less than 0.001) and the RSH tomographic (p less than 0.001) techniques. However, the deviation of the 201TI washout profile curves from that expected (50%) was greater for the planar imaging technique with or without a lesion (p less than 0.05 to 0.001). Thus, we conclude that 201TI quantitative circumferential washout profile curves calculated using this tomographic imaging technique are less affected by errors in axial repositioning than those calculated using an equivalent projection by standard planar imaging methods. These data emphasize the importance which must be placed on the repositioning of patients to obtain valid 201TI washout profile curves for the detection and localization of coronary artery disease.     

Alterations in N-methyl-D-aspartate receptor sensitivity and magnesium blockade occur early in development in the R6/2 mouse model of Huntington's disease

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder that affects primarily the striatum and cerebral cortex. A search for the factors that increase the vulnerability of striatal neurons will lead to a better understanding of the pathological cascades of this disease. A current hypothesis for neurodegeneration of striatal medium-sized spiny neurons in HD is an alteration in N-methyl-D-aspartate (NMDA) receptor function. In the present study we examined electrophysiological properties of NMDA receptors in the R6/2 transgenic mouse model. These animals express exon 1 of the human HD gene and present an overt behavioral phenotype at about 5 weeks of age. Whole-cell voltage clamp recordings from acutely dissociated striatal neurons were obtained from three different age groups of transgenic mice (15, 21, and 40 days old) and their littermate controls (WT). In transgenic animals, two groups of neurons were found with respect to NMDA and Mg2+ sensitivity. One group of R6/2 cells displayed responses similar to those of WT, whereas the other showed increased responses to NMDA and decreased Mg2+ sensitivity. These cells were encountered in all age groups. The abnormal sensitivity to NMDA and Mg2+ indicates that NMDA receptor alterations occur very early in development and suggest the presence of constitutively abnormal NMDA receptors. These alterations may contribute to an enhancement of NMDA responses at hyperpolarized membrane potentials that may be a key factor in striatal neuronal dysfunction.