MI References ============= Goldbourt et al. Early administration of nifedipine in suspected acute MI. Arch Intern Med 1993 Feb 8:153(3):345-53.] The SPRINT II study from Israel. Patients with acute MI were randomized to nifedipine 60 mg/d or placebo as soon as possible after admission. Of note are the exclusionary criteria which included a *need* for Ca channel blockers as judged by the patient's attending physician. Presumably some of these patients were on Ca channel blockers for treatment of HTN. The study was stopped because of excess mortality noted in the nifedipine group (6.3% vs 4.3%) in the first 6 days of hospitalization. This did *not* reach the level of statistical significance, however (p=0.1). Over six months all of the excess mortality could be attrributed to this early mortality. After that the mortality rates were 11.8% with nifedipine and 10.6% without (NS). Of note is the fact that 8/42 deaths in the nifedipine group had received dopamine/dobutamine before randomization as opposed to only 1/27 given placebo. Thus it appears that sicker patients had been randomized to the nifedipine limb. Thus the conclusion that Ca channel blockers are contraindicated in acute MI does not follow because 1) patient requiring these drugs for treatment (say of HTN) were specifically excluded 2) the results did not reach statistical significance and 3) the group treated with nifedipine had a much greater percentage of patients requiring inotropic support *before* randomization. In fact the authors merely concluded that "Early routine administration of nifedipine in acute MI, *other than to patients in whom it may be specifically indicated (e.g., those with Printzmetals varient angina or severe hypertension*) may be hazardous and seems to be contraindidcated" [emphasis mine]. In spite of all of the above I am not advocating the use of nifedipine in acute MI. Theoretical disadvantages include the precipitation of tachycardia. I think that better drugs are available for the treatment of hypertension in this setting, specifically NTG. --H. Louzon MD Wasserberger J, Ordog GJ, Lau JC, Gilston M, Herman LS Intravenous prochlorperazine for the rapid control of nausea and vomiting in acute myocardial infarction: a clinical observation. Am J Emerg Med 1987 Mar;5(2):153-6 Sixteen patients with acute myocardial infarctions who were either vomiting or nauseated were given an intravenous injection of prochlorperazine. All patients obtained relief with exception of one patient who was in acute renal failure. No patient developed symptomatic hypotension. Intravenous prochlorperazine in the dose of 2.5 mg is a rapid, effective, and safe method to relieve vomiting and nausea in patients who have sustained an acute myocardial infarction. Lee TH, Short LW, Brand DA, et al. Patients with acute chest pain who leave emergency departments against medical advice: prevalence, clinical characteristics, and natural history J Gen Intern Med 1988; 3:21-4 The study group identified 107 patients who left against advice from the emergency departments of three university and four community hospitals after presenting for evaluation of acute chest pain. In comparison with other emergency department patients with acute chest pain, patients who left against advice had findings that suggested they were at higher risk for myocardial infarction than patients for whom admission was not recommended but at lower risk than patients who consented to be admitted. Specific follow-up plans were made at the time of evaluation for 45 patients (42%). Survival data were obtained at 48-72 hours for 104 patients (97%) and at one month for 101 patients (94%). Fourteen patients (12%) were hospitalized within three days of their original emergency department visits, and three patients had documented acute myocardial infarctions. The only death within one month was that of a patient who died suddenly out-of-hospital later on the day of his emergency department visit. The authors conclude that patients who left against medical advice had presentations and prognoses that were in between those of patients for whom admission was not recommended and those of patients who consented to be admitted. Lee TH, Rouan GW, Weisberg MC, et al. Sensitivity of routine clinical criteria for diagnosing myocardial infarction within 24 hours of hospitalization Ann Intern Med 1987; 106:181-6 Myocardial infarction was diagnosed in 431 (30%) of 1460 patients with acute chest pain who had serial enzyme testing after admission to intensive or intermediate care units at three teaching and three community hospitals. The diagnosis was made within 12 hours of admission in 331 (77%) patients and within 24 hours in 415 (96%). Of the 16 patients with myocardial infarction who did not have enzyme abnormalities within 24 hours, 9 (56%) had recurrent ischemic pain during this 24-hour period. Of 451 patients who had neither enzyme abnormalities nor recurrent ischemic pain in the first 24 hours, only 7 (2%) ultimately met diagnostic criteria for myocardial infarction. These findings were prospectively validated in an independent testing set of 275 patients with myocardial infarction, 271 (99%) of whom either met diagnostic criteria for myocardial infarction or had recurrent ischemic pain within 24 hours of admission. These data suggest that 24 hours is nearly always a sufficient period to exclude myocardial infarction in patients without recurrent chest pain. Lee TH, Cook EF, Weisberg M, et al. Acute chest pain in the emergency room. Identification and examination of low-risk patients Arch Intern Med 1985; 145:65-9 Clinical and laboratory data from 596 patients who came to an emergency room complaining of chest pain indicated that no single variable could identify low-risk patients as well as a normal ECG. A combination of three variables--sharp or stabbing pain, no history of angina or myocardial infarction, and pain with pleuritic or positional components or pain that was reproduced by palpation of the chest wall--defined a very-low-risk group in which ECGs did not add accuracy to the evaluation and were potentially misleading; however, only 48 patients (8%) fell into this category. Standard cardiac enzyme levels were of almost no use as an emergency room indicator of myocardial infarction. These findings emphasize the difficulty of identifying patients at low risk for myocardial infarction or unstable angina in the emergency room without consideration of many factors from the history, the physical examination, and the ECG. Diamond TH, Smith R, Goldman AP, et al. The dilemma of the creatine kinase cardiospecific iso-enzyme (CK-MB) in marathon runners S Afr Med J 1983; 63:37-41 Serum creatine kinase iso-enzyme (CK-MB) levels were measured in 51 marathon runners before and after a 50 km marathon event. Ninety-five per cent of the runners were found to have pathologically elevated values, i.e. CK-MB concentrations were elevated to the range normally considered indicative of myocardial necrosis. Results indicate that a rise in the CK-MB level is common after marathon running. We therefore believe that cardiac enzymes are an unreliable indicator of myocardial infarction in patients who experience chest pain following strenuous muscular exercise.