Mitral regurgitation is a valvular heart lesion that is difficult to diagnose accurately; thus, it is difficult to determine the appropriate timing for surgical correction. With increasing use of reparative techniques, including local resection of valve pathology and placement of an annuloplasty ring, and the realization that chronic atrial fibrillation leads to decreased long-term survival, the timing of surgery has changed. In addition, serial noninvasive studies have indicated that despite the absence of symptoms, patients may progress to a myopathic condition if the regurgitation progresses over a long period and surgery is not performed when signs of left ventricular dysfunction are evident. Preservation of the papillary muscle is also extremely important for late postoperative function in patients with mitral regurgitation, and reparative surgery that preserves both anterior and posterior papillary muscle complexes and continuity with the anulus appears to satisfy this assumption. Worldwide experience is reviewed and I present conclusions related to the appropriate indications for mitral valve repair or replacement in patients with mitral regurgitation.

Positron emission tomography permits examination of the chemistry of the brain in living human beings. Until recently, positron emission tomography had been considered a research tool, but it is rapidly moving into clinical practice. This report describes the uses and applications of positron emission tomography in examinations of patients with strokes, epilepsy, malignancies, dementias, and schizophrenia and in basic studies of synaptic neurotransmission.

Concern with weight control should begin sufficiently early in life to reduce the risk of developing obesity. The complex etiology of obesity is, in part, responsible for the difficulty physicians encounter in treating this condition. Prevention is the "treatment" of choice. Early identification of individuals genetically at risk can be helpful in targeting those most likely to gain excess weight. Numerous dietary regimens have been devised in an attempt to achieve progressive weight loss in obese individuals. Since the ultimate goal of a weight-reduction program is to lose weight and maintain the loss, a nutritionally balanced, low-energy diet that is applicable to the patient's life-style is most appropriate. Increasing energy expenditure through physical activity, in addition to decreasing energy intake, generally improves results in the management of obesity. Major changes in eating and exercise behaviors are necessary to ensure long-term weight control. Diet, exercise, and behavior modification are interdependent and mutually supportive. A comprehensive weight-reduction program that incorporates all three components is more likely to lead to long-term weight control.

The effects of prophylactic lidocaine hydrochloride on early ventricular fibrillation and death in patients with suspected acute myocardial infarction were investigated in an overview of 14 randomized trials. During follow-up intervals of one to four hours in the trials of intramuscular lidocaine infusion (6961 patients) and 24 to 48 hours in the trials of intravenous lidocaine injection (2194 patients), a total of 103 cases of ventricular fibrillation and 137 deaths were recorded. Overall, allocation to lidocaine was associated with a reduction in the odds of ventricular fibrillation of about one third, with a 95% confidence interval that ranged from a 3% to a 56% reduction. There was no evidence of any beneficial effect on early mortality; indeed, the odds of early death were about one third greater among patients allocated lidocaine, though this difference was not statistically significant (95% confidence interval, 2% reduction to 95% increase). Because of the small numbers of reported events, the short follow-up periods, and the unavailability of data for some specific causes of death, even an overview of all the trial results does not provide good evidence as to whether prophylactic lidocaine is likely to be helpful or harmful. To answer this question reliably, future trials will need to involve large numbers of patients and prolonged follow-up.

Before assessment can begin we must decide how quality is to be defined and that depends on whether one assesses only the performance of practitioners or also the contributions of patients and of the health care system; on how broadly health and responsibility for health are defined; on whether the maximally effective or optimally effective care is sought; and on whether individual or social preferences define the optimum. We also need detailed information about the causal linkages among the structural attributes of the settings in which care occurs, the processes of care, and the outcomes of care. Specifying the components or outcomes of care to be sampled, formulating the appropriate criteria and standards, and obtaining the necessary information are the steps that follow. Though we know much about assessing quality, much remains to be known.

This case study of the public policy implications of introducing a new technology in radiology, namely, low-osmolar contrast media (LOCM), raises the issues of whether and how to place appropriate limits on new technologies. Although these contrast media represent small episodic costs, they may add up to an aggregate expenditure of nearly $1 billion per year if used for all contrast injections. As a result, this technology raises a number of important medical, economic, legal, and public policy questions. Our cost-effectiveness analysis and an analysis of the medical evidence suggest that LOCM should be limited to high-risk patients. We discuss in this article how the legal system might respond to such limitations, and we consider various public policy options for adopting restrictions on use. We conclude that the medical profession should take the lead in developing protocols for appropriate assessment, reimbursement, and use of LOCM.

The Council on Long Range Planning and Development of the American Medical Association has identified trends in the environment of medicine and the implications of these trends for specific medical specialties. This report considers the evolution of family practice as a specialty and its role in the future of health care delivery. As a specialty established less than 20 years ago, family practice has successfully surmounted several obstacles to achieve recognition within the medical community and among the public. However, the Council has identified new challenges and opportunities facing this specialty. In particular, the areas of graduate medical education, reimbursement, professional liability, and several health-related societal and ethical issues will pose challenges for and place constraints on family physicians. Family practice will encounter a number of opportunities in the evolving environment of medicine, due in part to demographic trends in the population and the growth in managed care. The Council concludes that, despite the challenges, the increasing demand for the services of family physicians has positive implications for the future of this specialty.

This report discusses some of the inherent limitations of cancer studies in animals and humans and presents a qualitative carcinogen risk assessment of a number of pesticides based on the judgment of national and international authorities who have reviewed the available experimental and epidemiologic evidence. A large number of pesticidal compounds have shown evidence of genotoxicity or carcinogenicity in animal and in vitro screening tests, but no pesticides--except arsenic and vinyl chloride (once used as an aerosol propellant)-definitely have been proved to be carcinogenic in man. Resolution 94 (1-86), which was referred to the Board of Trustees, calls for the American Medical Association, through its scientific journals and publications, to alert physicians to the potential hazards of agricultural pesticides, to provide physicians with advice on such hazards for their patients, and to urge that these substances be appropriately labeled. This report addresses the potential carcinogenicity of pesticides by review of the available literature.

Within medicine there is growing uneasiness and debate about changes in medical care delivery. Much of this concern centers on the evolution of organizations and the role of physicians. The emergence of multi-institutional organizations, the rise of investor-owned health care corporations, and the expansion of group medical practice illustrate the increasing organizational influence in medicine. Added to these trends are new financial incentives confronting both physicians and organizations so that the environment increasingly favors conflict. This article reviews the primary strategies for resolving physician-organization conflicts, including cooperation between physicians and organizations, having physician representatives in governance and management, restructuring incentives, and restructuring organizations. Although these strategies have various merits, we suggest that every physician has a personal responsibility to become more involved in organization and management issues. Physicians can play an important role in guiding the evolution of medicine.