In the Literature: HM-Related Research You Need to Know

Setting: University hospital in the U.S.

Synopsis: From 1994 to 2009, 401 consecutive patients undergoing evaluation for acute coronary syndrome with LBBB on initial ECG were included in the analysis. Of these patients, 64% had new (37%) or presumably new (27%) LBBB. Twenty-nine percent were diagnosed with MI, but there was no difference in frequency or size of MI between the new, presumably new, or chronic LBBB groups.

Concordant ST-T changes were an independent predictor of MI (OR 17, 95% CI 3.4-81, P<0.001) and mortality (OR 4.3, 95% CI 1.3-15, P<0.001), although this finding was present in only about 11% of the patient group.

Bottom line: Left bundle branch block is not a predictor of MI, although concordant ST-T changes were an independent predictor of MI and mortality.

Citation: Kontos MC, Aziz HA, Chau VQ, et al. Outcomes in patients with chronicity of left bundle-branch block with possible acute myocardial infarction. Am Heart J. 2011;161(4):698-704.

Acute Beta-Blocker Therapy for MI Increased Risk of Shock

Clinical question: How does acute beta-blocker therapy in myocardial infarction (MI) impact outcome?

Background: Long-term treatment with beta-blockers after myocardial infarction (MI) reduces mortality. However, data regarding outcome after acute use of beta-blockers in the first 24 hours of MI is conflicting. Updated ACA/AHA guidelines for STEMI and NSTEMI recommend caution when using beta-blockers in the first 24 hours, particularly in patients at risk for shock.

Study design: Observational registry study.

Setting: Two hundred ninety-one U.S hospitals.

Synopsis: More than 34,600 patients diagnosed with STEMI and NSTEMI from January 2007 to June 2008 were identified from a national QI MI registry. Patients were stratified by guideline-stated risk factors for shock; age >70, HR >110, and systolic BP <120 were associated with increased risk of composite outcome of shock or death.

At least one high-risk factor was present in 63% of the NSTEMI patients and 45% of STEMI patients; however, >90% of these patients received acute beta-blocker therapy. Nearly half (49%) of the NSTEMI patients received beta-blockers in the ED and 62% of the STEMI patients received beta-blockers before PCI.

In a multivariable model, NSTEMI patients receiving beta-blocker therapy in the ED were more likely to develop cardiogenic shock (OR 1.54, 95% CI 1.26-1.88, P<.001), as were STEMI patients receiving beta-blocker therapy prior to PCI (1.40, 95% CI 1.10-1.79, P=.006).

Bottom line: Caution should be exercised when using beta-blocker therapy during acute MI, particularly in the ED or prior to primary PCI.

Citation: Kontos MC, Diercks DB, Ho MP, Wang TY, Chen AY, Roe MT. Treatment and outcomes in patients with myocardial infarction treated with acute beta-blocker therapy: results from the American College of Cardiology’s NCDR. Am Heart J. 2011;161(5):864-870.

CLINICAL SHORTS

NO MORTALITY BENEFIT FROM MEDICAL TREATMENT FOR HEART FAILURE WITH PRESERVED EJECTION FRACTION

Meta-analysis evaluating 53,878 patients from 18 randomized trials and 12 observational trials revealed that pharmacotherapy of heart failure with preserved ejection fraction improved exercise tolerance but not mortality.

Citation: Holland DJ, Khumbani DJ, Ahmed SH, Marwick TH. Effects of treatment on exercise tolerance, cardiac function, and mortality in heart failure with preserved ejection fraction. JACC. 2011;57(16):1676-1686.

AMBULATORY PHYSICIAN ACCEPTANCE OF PRIVATE COVERAGE DECREASED MORE THAN MEDICARE

Analysis of 2005 to 2008 national survey data from 4,632 non-hospital-based ambulatory physicians showed a small decline in Medicare acceptance (95.5% to 93%) and a larger, unexpected decline in noncapitated private insurance acceptance (97.3% to 89.9%).

Citation: Bishop TJ, Federman AD, Keyhani S. Declines in physician acceptance of Medicare and private coverage. Arch Intern Med. 2011;121(12):1117-1119.

ADVERSE EVENTS HIGHER FOR PATIENTS WITH HEART DISEASE AND CHRONIC NSAID USE

Post-hoc analysis of a large study enrolling patients with hypertension and coronary artery disease identified a significant increase in cardiovascular mortality among self-reported chronic NSAID users.

Citation: Bavry AA, Khaliq A, Gong Y, Handberg EM, Cooper-Dehoff RM, Pepine CJ. Harmful effects of NSAIDs among patients with hypertension and coronary artery disease. Am J Med. 2011;124(7):614-620.

LOW-SERUM TOTAL CHOLESTEROL LEVEL ASSOCIATED WITH INCREASED ISCHEMIC STROKE MORTALITY IN THE JAPANESE POPULATION

Prospective cohort study involving 16,461 Japanese patients showed that low total cholesterol level (<160 mg/dl) was associated with increased ischemic stroke mortality rate, although the subtypes of ischemic stroke were unknown.

Citation: Tsuji H. Low serum cholesterol level and increased ischemic stroke mortality. Arch Intern Med. 2011;171(12):1121-1123.

INCREASING RATE OF VENA CAVA FILTER PLACEMENT HIGHEST FOR PROPHYLACTIC PLACEMENT

Observational study evaluating 270,000 inpatient records showed that vena cava filter placement for DVT only or PE increased linearly over time, while prophylactic placement increased threefold from 2001 to 2006, suggesting progressive liberalization of use.

Citation: Stein, PD, Matta, F, Hull, RD. Increasing use of vena cava filters for prevention of pulmonary embolism. Am J Med. 2011;124(7):655-661.

LOCAL HOSPITALIZATION FOR ACUTE MI DECREASED AFTER COMMUNITY SMOKING BAN

Observational study showed a 27% decrease in local hospitalization for acute MI after enactment of a smoking ordinance, although there was no significant reduction when compared with the surrounding region.

Citation: Bruintjes G, Bartleson B, Hurst P, et al. Reduction in acute myocardial infarction hospitalization after implementation of a smoking ordinance. Am J Med. 2011;124(7):647-654.