Clinical aspects of silent myocardial ischemia in patients with angina and other forms of coronary heart disease.
Silent myocardial ischemia is defined as objective evidence of myocardial ischemia occurring in the absence of symptoms in a patient who has either coronary artery disease or spasm. The largest number of patients with silent myocardial ischemia identified to date are those with effort angina, in whom silent episodes are at least three to four times as frequent as painful episodes. Since episodes of silent myocardial ischemia are not alarming to the patient and are likely to escape detection, their clinical importance must reside in their association with morbid events of ischemic heart disease. In fact, silent myocardial ischemia can result in silent myocardial infarction, sudden death, or other events. The detection of these episodes has the potential to provide clinicians with a more complete understanding of all the ischemic processes occurring in patients with angina or other forms of coronary disease. Silent myocardial ischemia can be detected by a variety of methods. Transient ischemic-type electrocardiographic abnormalities that occur without symptoms and that have been recorded during exercise testing or by means of ambulatory, coronary care unit, or telemetry monitoring may be used to document silent myocardial ischemia. Reversible left ventricular wall motion abnormalities without symptoms, observed at rest or during exercise radionuclide angiography, 2-D echocardiography, or contrast angiography, may also be used to document silent myocardial ischemia. However, only ambulatory electrocardiographic monitoring provides long-term evaluation that documents repeated episodes of silent myocardial ischemia outside of the laboratory. Controlled studies, directed specifically at preventing silent myocardial ischemia and/or its consequences in patients with angina, are limited. It has been determined, however, that both hourly administration of sublingual nitroglycerin and intravenous administration of isosorbide dinitrate are effective. Other studies examining the effects of beta blockers (propranolol, atenolol, and labetalol) in the treatment of angina have shown that their use also results in a reduced frequency of silent episodes, but that a large number of episodes persist. It has been observed that verapamil alone and nifedipine, either alone or in combination with a beta blocker, appear to significantly decrease silent myocardial ischemia in patients with angina. A major limitation of these studies is that treatment was not specifically titrated to reduce or eliminate silent myocardial ischemia.(ABSTRACT TRUNCATED AT 400 WORDS)
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D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000787:Angina Pectoris / Q000175:diagnosis / Q000503:physiopathology*; D002121:Calcium Channel Blockers / Q000627:therapeutic use; D002986:Clinical Trials as Topic; D003327:Coronary Disease / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology*; D004311:Double-Blind Method; D004452:Echocardiography; D004562:Electrocardiography; D005080:Exercise Test; D006801:Humans; D008297:Male; D005996:Nitroglycerin / Q000627:therapeutic use; D011379:Prognosis; D011897:Random Allocation; D012306:Risk; D014055:Tomography, Emission-Computed
D000319:Adrenergic beta-Antagonists; D002121:Calcium Channel Blockers; D005996:Nitroglycerin