The American journal of cardiology
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Hypertrophic cardiomyopathy (HC) is characterized by impaired diastolic function, and left ventricular (LV) outflow tract obstruction in about one-fourth of patients. Verapamil improves diastolic properties, but may have dangerous adverse effects. This study investigates the effects of diltiazem on hemodynamics and LV function in 16 patients with HC who were studied with cardiac catheterization and simultaneous radionuclide angiography. ⋯ LV outflow tract gradient does not increase despite systemic vasodilation. In some patients, however, a marked increase in obstruction and a potentially harmful elevation in pulmonary artery wedge pressure do occur. Passive diastolic function is not affected.
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Clinical evaluation of the antiplatelet glycoprotein (GP) IIb/IIIa receptor antagonists has now extended over nearly a decade. The largest experience to date with this new class of agents has been in the prevention and management of complications of percutaneous coronary intervention. Four trials involving 3 different agents in the setting of coronary intervention are discussed: the Evaluation of c7E3 in Preventing Ischemic Complications (EPIC) and the Evaluation of PTCA to Improve Long-term Outcome by c7E3 GPIIB/IIIA Receptor Blockade (EPILOG) trials of the antibody fragment abciximab (ReoPro); the Integrilin to Minimize Platelet Aggregation and Prevent Coronary Thrombosis II (IMPACT II) trial evaluating the peptide Intergrilin; and the Randomized Efficacy Study of Tirofiban for Outcomes and Restenosis (RESTORE) trial studying the nonpeptide mimetic tirofiban (Aggrastat). ⋯ Bleeding risks can be minimized by minor changes in standard patient care algorithms. Dosing strategies and treatment duration still need to be refined, especially for the competitive antagonists. The role of these agents as adjuncts in stenting and rotational atherectomy and as adjunctive therapy in other disease settings requires further study.
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Dobutamine stress ventriculography is a safe test that appears to separate groups of patients with and without significant coronary artery stenoses. In this study, all 7 patients with significant coronary artery stenoses who reached a heart rate > or = 110 beats/min had a positive stress test, whereas 9 of 10 control patients had a negative stress test.