Clinical and investigative medicine. Médecine clinique et experimentale
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Review
Mexiletine/quinidine combination therapy: electrophysiologic correlates of anti-arrhythmic efficacy.
This article reviews the data which support the use of selected drug combinations to enhance anti-arrhythmic activity. Specifically, we have focused on the mexiletine-quinidine interaction and the relation between anti-arrhythmic efficacy and electrophysiologic effects. In an initial clinical study, we found that combination therapy with mexiletine-quinidine produced enhanced efficacy in suppressing spontaneous ventricular tachycardia with fewer side-effects than high dose monotherapy. ⋯ To assess the contribution of prolongation of action potential duration by quinidine to the combined effect we compared the anti-arrhythmic and electrophysiologic effects of the stereoisomers quinidine and quinine given alone and in combination with mexiletine. These experimental data confirm that the property of prolongation of action potential duration by quinidine is essential to the interaction. When comparing quinidine and quinine it is apparent that prolongation of refractoriness in the peri-infarct zone is essential for anti-arrhythmic activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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Physicians and surgeons have long recognized that septic illness may be accompanied by abnormal brain functions; however, no systematic, comprehensive study has been done to define the clinical and laboratory features of the syndrome of sepsis-associated encephalopathy. We undertook such a prospective study in a tertiary care hospital and found that of 69 patients with fever and microbial cultures, 32 had marked brain dysfunction, 17 showed mild encephalopathy, and 20 were clinically nonencephalopathic. Severe cases showed obtundation and paratonic rigidity while milder cases showed confusion, inappropriate behavior, inattention, disorientation, and writing errors. ⋯ Pathogenetic mechanisms are discussed. The brain dysfunction should be regarded as potentially reversible, even in severely encephalopathic cases. Prompt control of the infection is the most important measure in controlling the encephalopathy and in preventing the increased mortality found with severely encephalopathic patients.
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Complete reorganization of the Quebec health and social services system, as envisaged by a new bill to be studied by the provincial government, is of major importance for the future of academic medicine since it includes all aspects of the training of health care professionals. While the bill aims to stimulate fundamental and applied research to the highest standards of academic medicine, its clearly stated spending limitations are a major concern to academic physicians. With the proposed centralization of all health care institutions, the role of medical schools and universities will be significantly diminished. ⋯ Programs oriented toward personnel support and the development of research centres and institutes should continue to be fostered. The future of academic medicine, particularly in its clinical components, is closely linked to the health care system. Academic physicians must become involved in the strategic planning of health care delivery since the development of academic medicine will otherwise not flourish.
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Comparative Study
Power spectrum of heart rate variability: a non-invasive test of integrated neurocardiac function.
Under steady state conditions, frequency specific oscillations in the heart rate record reflect beat-to-beat autonomic control of sinus node activity. Using an autoregressive model, samples (2.5 min) of continuous ECG records were analyzed in 36 healthy young adults during supine rest (45 min), orthostatic stress and controlled respiration. In the supine state, constancy of heart rate was achieved (mean HR 62.8 bt/min +/- 4.88 SD). ⋯ There was a maximum increase in the low frequency (0.1 Hz) peak power of 40 (bt/min)2. Hz-1 at a controlled breathing frequency of 0.25 Hz in the standing compared to supine position. The data show that reproducibility of the power spectrum heart rate variability is best achieved at controlled but physiologic respiratory rates and, preferably, in the upright position.
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Comparative Study Historical Article
The impact of the National Institutes of Health on the development of Canadian biomedical research.