Current cardiology reports
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Life-long therapy is necessary for patients with symptomatic long QT syndrome to prevent arrhythmic death. The merits and limitations of the different therapeutic modalities are discussed. beta-blockers remain the mainstay of therapy, but this medication may not be sufficient for cardiac arrest survivors and for those with the LQT3 genotype. "Genotype-specific" therapy, like potassium-channel openers for patients with inadequate potassium outflow (LQT1 and LQT2 genotypes) or sodium-channel blockers for patients with excessive sodium inflow (LQT3), significantly shortens the QT interval, but the effects of these drugs on arrhythmia prevention is less well established. ⋯ More important is to recognize that device programming for preventing tachyarrhythmias in patients with long QT differs from the standard pacemaker programming. Finally, implantable defibrillators with dual-chamber pacing capability are indicated for patients at high risk for arrhythmic death, including all cardiac arrest survivors.
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Observational studies have shown an inverse relationship between consumption of fruits and vegetables high in beta-carotene, vitamins C and E, and ischemic heart disease (IHD) and stroke. In large observational studies, beta- carotene reduced the risk of IHD events in men, particularly in smokers. In contrast, four large randomized trials did not reveal a reduction in cardiovascular events with beta-carotene use, and may, in fact, increase IHD and total mortality in male smokers. ⋯ However, a meta-analysis of the four randomized trials done in Europe and America involving a total of 51,000 participants allocated to vitamin E or placebo for 1.4 to 6 years, did not demonstrate a reduction in cardiovascular and IHD mortality and nonfatal myocardial infarction. Currently, there are no data to support the use of these vitamins to reduce the risk of cardiovascular events. Trials are in progress to determine whether a longer duration of administration of vitamin E or the association of vitamin E with cofactors may reduce cardiovascular events.
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New surgical techniques for the treatment of the isolated lesion of the left anterior descending coronary artery (LAD) include off-pump surgery, minimal access to the heart, and endoscopic or computer enhanced coronary artery bypass surgery. The term minimally invasive direct coronary artery bypass surgery (MIDCAB) is related to a left-side minithoracotomy, the harvest of the left internal mammary artery (IMA) under direct vision, and an anastomosis performed between IMA and LAD under direct vision, using the technique of mechanical local immobilization by a special device. ⋯ Mid-term results after 6 months have shown a patency rate between 94% and 97%, and more than 90% of the patients are without any angina symptoms. Due to this promising results MIDCAB is an alternative treatment for high-grade LAD lesions.
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The thienopyridine class of antiplatelet drugs includes ticlopidine and clopidogrel, drugs that are used increasingly to prevent ischemic events in and out of the cardiac catheterization laboratory. Formerly, the only oral antiplatelet drug available for these purposes was aspirin, which has been studied randomized placebo-controlled trials in which 70,000 patients have been enrolled. ⋯ Both ticlopidine and clopidogrel have been compared with aspirin in randomized controlled trials and both are approximately 10% more effective than aspirin. Recently, ticlopidine and clopidogrel have been compared with one another; clopidogrel appears to be at least as efficacious as ticlopidine, but with few fewer side effects.
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More than 200,000 people have been enrolled into clinical trials examining different reperfusion strategies for patients with acute myocardial infarction. Each year approximately 1 million people in the United States experience acute myocardial infarction. ⋯ These agents are often divided into "fibrin-specific" and "non-fibrin-specific" drugs. New thrombolytic agents designed to address several of the shortcomings of existing thrombolytics are in various stages of clinical development.