A study of hospital discharge data conducted by researchers at the University of Colorado Health Sciences Center (Denver, Colorado) shows that the number of acute myocardial infarctions (MIs) in the U.S. may be overestimated by a considerable margin. The study, published in the May issue of the journal Medical Care, found that 10% to 15% of heart attack patients may be counted twice due to being transferred to specialty facilities. And the rate may be twice that in rural areas. The double counting of heart attack patients has another aspect, according to the researchers: a greater percentage of people who have heart attacks die from them than previously reported.

The study's lead author, Jack Westfall, MD, associate professor of family medicine at CU Health Sciences Center, said study data "indicates that double counting patients has resulted in a significant overestimation in the incidence rate for hospitalization for acute heart attacks," and that when the data is corrected, "we find a much lower incidence rate and a higher in-hospital mortality rate." The study noted that patients who are transferred from one facility to another, and therefore counted twice, are typically in a more acute state, further introducing a bias into heart attack outcome studies.

The report said that recent studies of hospitalization for heart disease report inconsistent findings – "some report a decrease, while others an increase or little change over the last 30 years." Westfall noted, "We think this study will help explain some of the inconsistent findings published on the incidence of hospitalization for this condition, especially in rural regions, where the likelihood that a patient will be transferred to an urban center for care is much higher."

Westfall and his colleagues estimate that there are about 100,000 to 200,000 fewer heart attacks each year in the U.S. than previously reported. The study, which was supported by grants from the Robert Wood Johnson Foundation and the Colorado Heart Consortium, analyzed hospital discharge data from Arizona, Colorado, Illinois, Kansas, Michigan, Nebraska, New Jersey and Pennsylvania for 1995-1997.

Carpentier technique works well

In a study of long-term clinical results – really long-term – a French surgeon reported during last month's meeting of the American Association for Thoracic Surgery in San Diego, California, that patients who underwent surgery to repair their mitral heart valves continued to experience excellent clinical results as long as three decades after their procedure. In his presentation, "Mitral Valve Repair with Carpentier's Techniques: The Third Decade," Sylvain Chauvaud, MD, of Hopital Europeen Georges Pompidou, presented results of annuloplasty associated with correction of valve prolapse or leaflet restriction. Those surgical techniques for repairing diseased or damaged mitral heart valves were developed by pioneering cardiovascular surgeon Alain Carpentier and used on more than 430 patients who underwent annuloplasty procedures between 1970 and 1984.

Patients in Chauvaud's study were classified as having one of three possible sources of valvular disease or disorder – including rheumatic fever or subacute bacterial endocarditis – and those who had experienced degenerative heart valve disease. The various conditions had impacted patients' mitral valves, which control blood flow between the heart's left atrium and left ventricle. Rheumatic patients comprised 63% of the total, those with degenerative valve disease 34%, and SBE patients the remaining 3%. Follow-up was completed in 96% of patients in the study group, with a mean post-operative time of 18 years.

Some 92% of the patients in the study had received a Carpentier-Edwards Classic annuloplasty ring, developed by Carpentier and Edwards Lifesciences (Irvine, California).

Trial backs amiodarone over lidocaine

Researchers at St. Michael's Hospital and the University of Toronto (both Toronto, Ontario) have reported trial results that have implications for improving the chances of heart attack victims. The ALIVE (Amiodarone vs. Lidocaine In pre-hospital Ventricular fibrillation Evaluation) trial studied the effectiveness of lidocaine vs. amiodarone. The trial followed 348 randomized patients who had suffered cardiac arrest and who had one of the two drugs administered in a blinded fashion by Toronto Emergency Medical System paramedics. The study found that more than 50% more patients survived to be admitted to the hospital when they received amiodarone compared to those who received the traditional treatment of lidocaine. This was the first such study comparing commonly-used anti-arrhythmic drugs.

Dr. Paul Dorian, cardiologist and director of the arrhythmia service at St. Michael's and professor at the University of Toronto, presented the results at the May meeting of the North American Society of Pacing and Electrophysiology. Dorian said that the results of ALIVE "mean that we can now tell ambulance personnel and emergency departments that amiodarone appears to be the most effective drug, based on the evidence that we have to date."

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