Long term follow-up of aneurysmectomy for recurrent ventricular tachycardia or fibrillation.

The success of aneurysmectomy in abolishing recurrent ventricular tachycardia or ventricular fibrillation has not been clearly defined. Ten patients who underwent aneurysm resection to control ventricular arrhythmias were studied before and an average of 19 (4 to 42) months following operation. All patients had moderate to large aneurysms and four had asynergy in adjacent segments. Of four patients with significant stenosis in vessels not supplying the aneurysm, three had aortocoronary bypass grafts in addition to their resection. Ambulatory Holter monitoring and a graded exercise test were performed in all patients postoperatively. There was no operative mortality. Two patients who did not have associated revascularization procedures died suddenly 1.5 and 7 months postoperatively. Of the eight survivors, despite clinical improvement, the Holter ECG revealed runs of ventricular tachycardia in three patients and frequent multifocal ventricular extrasystoles in the other five patients. No correlation was found between recurrence of the ventricular arrhythmias and aneurysm size, contraction pattern of other myocardial segments, extent of coronary disease, or the presence of congestive heart failure. In conclusion, aneurysmectomy does not abolish ventricular tachyarrhythmias and probably should be reserved for patients who remain symptomatic despite an adequate medical trial. The persistence of complex arrhythmias following operation warrants a close follow-up in these patients.     

Tropical pyomyositis

A 22 year old male presented with symptoms of diffuse muscle pain and multiple abnormal laboratory findings that were eventually attributed to tropical myositis. Computed tomography scan was more reliable than ultrasound and served as a guide to needle aspiration and pathologic diagnosis.     

Detection thresholds to stimulation of ventrobasal complex in cats

Cats were trained to indicate, by bar pressing for food rewards, their detection of stimulation of the ventrobasal (VB) complex delivered through implanted bipolar electrodes. By varying stimulus intensity it was possible to determine thresholds for detection. Scaling stimulus intensity relative to the appearance of a minimal evoked potential allowed comparisons between animals and also comparisons with results obtained by stimulation of peripheral nerve. Animals could detect VB stimulation, but only at stimulus intensities consistently stronger than those required for minimal appearance of an evoked response in ipsilateral primary somatosensory cortex. Results of VB activation differed from cutaneous nerve effects in that VB detection thresholds were markedly influenced by stimulus frequency. They were lowest at frequencies above 30 Hz and increased greatly at lower frequencies. Discomfort or pain did not seem to result even from relatively high stimulus intensities. The results compare well with observations obtained from stimulation of VB in humans. The appearance of an evoked cortical response is not necessarily correlated with behavior. Under appropriate conditions, behavior can be elicited predictably with minimal electrocortical activity; under other conditions detection may be absent even when large numbers of cortical neurons are activated. We suggest that regions of the cerebral cortex receiving thalamocortical projections from VB may not be essential in the detection process.     

Immunoreactive beta-endorphin in the rat mammotropic transplantable tumor (MtT-F4).

Raised levels of what appeared to be beta-lipotropin (beta-LPH), beta-melanotropic hormone, and beta-endorphin were detected by radioimmunoassay in the plasma of rats bearing the mammotropic transplantable pituitary tumor MtT-F4. The immunoreactivity to anti-beta-endorphin in the assay was displayed by a substance with the molecular weight of beta-LPH, as determined by gel filtration. Isolated cells of MtT-F4 tumor incubated in vitro released immunoreactive beta-LPH and beta-endorphin, with the expected molecular weights, into the incubation medium. These results suggest that the pituitary transplantable rat tumor MtT-F4 secretes peptides structurally related to beta-LPH.