Marshall A. Wolf

Approaches to sudden death from coronary heart disease.

Sudden cardiac death (SCD) continues unabated. Coronary care units, while effective in lowering hospital mortality, cannot significantly reduce SCD which occurs primarily outside the hospital and accounts for the majority of deaths from coronary heart disease (CHD). In view of the frequent precipitous nature of SCD, only a program which identifies and protects the victim prior to the event can hope to be successful in preventing the majority of SCD. Since it is likely that SCD is due to an arrhythmia, drug prophylaxis might prove effective. In view of the toxicity of currently available agents, it is mandatory to preselect a population at highest risk before embarking on a drug trial. Ventricular premature beats (VPB) may identify subjects susceptible to SCD. Epidemiologic and physiologic information on VPB is reviewed, and proposals are made for studies designed to establish the usefulness of VPB as a risk factor for SCD.

A Trial of Two Strategies to Modify the Test-Ordering Behavior of Medical Residents

We studied two methods to reduce the ordering of laboratory and radiologic tests by medical residents in their first postgraduate year. Dividing the residents into three groups, we compared the effect of concurrent chart review and discussion in one group with the effect of a moderate financial incentive for limited ordering of tests in a second group. The third group of residents served as a concurrent control, and data on the testing patterns of residents at the same hospital during the year before the study provided a retrospective control.

An initiative in mentoring to promote residents' and faculty members' careers.

Internal medicine trainees and faculty recognize the value of effective mentoring to help meet the personal and professional needs of residents. However, the paradigm of the mentor–trainee relationship is seriously threatened by increased clinical, research, and administrative demands on both faculty and housestaff. Moreover, the current criteria for promotion in most teaching hospitals emphasize scholarship, rather than citizenship, so activities such as mentoring devolve to a lower priority. In 2000, the Department of Medicine at Brigham and Womens/ Faulkner Hospital initiated a program to improve the effectiveness of housestaff mentoring and recognize faculty contributions to resident career development. The authors report the feedback received from a survey of the 2002–03 medical housestaff (74% response rate) and describe their experiences with the initiation of this program. Over 90% of the housestaff respondents thought it important that the Department assigns an individual faculty mentor. In practice, time-consuming professional responsibilities made meetings difficult, but most pairs supplemented their interactions with e-mail. Discussions primarily focused on career advice and support. Housestaff thought mentors were helpful and available when needed. The department has established new metrics for recognizing faculty mentoring and now publicly rewards mentoring excellence. Of note, unassigned mentoring has increased since the initiation of this program. The authors conclude that the formal mentoring program has ensured that all trainees are provided with a mentor, which has facilitated faculty–housestaff interactions and increased recognition of faculty contributions to mentoring.

National Institutes of Health Consensus Development Conference: Lactose Intolerance and Health

National Institutes of Health (NIH) consensus and stateof-the-science statements are prepared by independent panels of health professionals and public representatives on the basis of 1) the results of a systematic literature review prepared under contract with the Agency for Healthcare Research and Quality; 2) presentations by investigators working in areas relevant to the conference questions during a 2-day public session; 3) questions and statements from conference attendees during open discussion periods that are part of the public session; and 4) closed deliberations by the panel during the remainder of the second day and morning of the third. This statement is an independent report of the panel and is not a policy statement of the National Institutes of Health or the U.S. government. The following statement is an abridged version of the panel’s report, which is available in full at http: //consensus.nih.gov/2010/lactosestatement.htm. Lactose intolerance is the syndrome of diarrhea, abdominal pain, flatulence, or bloating occurring after lactose ingestion. These symptoms, which are produced by malabsorption of lactose, a sugar found in milk and other dairy products, often cause afflicted individuals to avoid dairy products in their diets. Lactose malabsorption is caused by a decreased ability to digest lactose that is due to a deficiency in the levels of the enzyme lactase. Lactase breaks lactose down into 2 simpler sugars, glucose and galactose, which are readily absorbed into the bloodstream. This enzyme is produced by expression of the lactase‐phlorizin hydrolase gene in the cells lining the small intestine. All infants produce lactase and successfully digest lactose provided by human milk or by infant formulas. However, sometime after weaning, a genetically programmed decrease in lactase (lactase nonpersistence) occurs in most children worldwide. The symptoms of lactose intolerance result from bacterial fermentation of undigested lactose in the colon. Lactose malabsorption can be diagnosed by having individuals ingest a standard dose of lactose after fasting and measuring breath hydrogen; elevated breath hydrogen levels are caused by bacterial fermentation of undigested lactose in the colon. Other diagnostic tools include measuring lactase activity in an intestinal biopsy sample or genetic testing for the common polymorphism that is linked to lactase nonpersistence. The demonstration of lactose malabsorption does not necessarily indicate that an individual will have symptoms. Many variables determine whether a person who malabsorbs lactose develops symptoms, including the dose of lactose ingested, the residual intestinal lactase activity, the ingestion of food along with lactose, the ability of the colonic flora to ferment lactose, and individual sensitivity to the products of lactose fermentation.

Ventricular Ectopic Rhythms following Vagal Stimulation in Dogs with Acute Myocardial Infarction

Vagal stimulation inducing significant bradycardia did not precipitate ventricular fibrillation in any of 34 dogs subjected to ligation of the left anterior descending coronary artery. Vagal stimulation, however, did result in two distinct types of ventricular arrhythmias occurring at different times following coronary occlusion. Within 3 hours, couplets and salvos were provoked which were overdriven by pacing at slow rates. From 4.5 to 9 hours ventricular tachycardia resulted which was slower in rate than the intrinsic sinus rhythm and could be overdriven only by pacing at rates faster than the ectopic mechanism. The response to acetylcholine administration was similar to that of vagal stimulation. By pacing in the presence of complete heart block or by the use of beta-adrenergic blockade, bradycardia was shown to be the basis for the ventricular arrhythmias. Reentry is believed to be the mechanism for the ectopics provoked by bradycardia early after coronary acclusion, while enhanced Purkinje fiber automaticity may account for the late arrhythmias.