Temporal evolution in the management of acute ST elevation myocardial infarction: the seven-year GUSTO experience from canada and the united states. The North American GUSTO-I and GUSTO-III investigators.

BACKGROUND: Temporal changes in baseline characteristics, treatment and clinical outcomes of patients presenting with acute ST elevation myocardial infarction in Canada and the United States have not been examined comprehensively over time. OBJECTIVES: To evaluate baseline characteristics, process of care and clinical outcomes. Also, to explore whether earlier process-of-care differences between Canada and the United States had changed and, if so, whether they influenced clinical outcomes. PATIENTS AND METHODS: A total of 13, 888 American and 3011 Canadian patients enrolled in 184 American and 38 Canadian hospitals that participated in both the Global Utilization of Streptokinase and Tissue Plasminogen Activator (alteplase) for Occluded Coronary Arteries (GUSTO-I) trial (1990 to 1993) and the Global Utilization of Strategies to Open Occluded Coronary Arteries (GUSTO-III) trial (1995 to 1997) were studied. Logistic regression was used to identify significant prognostic factors, to assess illness severity at hospital presentation and to classify trends between Canada and the United States. RESULTS: In both countries, illness severity on admission increased, door-to-needle time for thrombolysis was reduced, intensive care unit stay was shortened and hospital stay decreased from GUSTO-I to GUSTO-III. Whereas the administration of oral nitrates, calcium blockers and beta-blockers at discharge converged over time between countries, the disparity in the use of angiography and revascularization widened; the rise in American revascularization rate was most evident in patients without in-hospital ischemia. The 30-day and one-year mortality rates were comparable and declined nonsignificantly in both countries. CONCLUSIONS: Despite increased illness severity and varying medication and procedure rates, there was no increase over time in 30-day or one-year mortality; this remained comparable between countries throughout the seven-year observation period.

Serial myoglobin quantitation in the early assessment of myocardial damage: a clinical study.

OBJECTIVES: (a) To evaluate serial serum myoglobin pattern as an early marker of myocardial damage and compare it to conventional enzyme markers, and (b) to test the hypothesis that a patient admitted within 6 h of the onset of chest pain who has normal myoglobin concentrations that do not increase significantly in the first 2 h has not suffered a myocardial infarction (MI). DESIGN AND METHODS: A clinical study was conducted including 98 patients (62 males, 36 females) who presented to our Emergency Department with a diagnosis of possible MI. Patients with chest discomfort were selected to participate in the trial if their ECG was equivocal, their diagnosis was not obvious, and their treatment in hospital was to be the same as a MI patient until proven otherwise. Myoglobin measurements were made on admission and at 1 and 2 h thereafter. Quantitative myoglobin assays were performed by fluorometric enzyme immunoassay (STRATUS). Traditional cardiac enzymes were also measured. RESULTS: The myoglobin assay had good precision with CVs less than 10%. The sensitivity and specificity for MI of the myoglobin assay were 0.77 and 1.00 at 1 h and 0.93 and 1.00 at 2 h, respectively. Of positive diagnoses, 90% were clear 1 h after admission. Serial myoglobin assays provided better predictive efficiency (0.96) than baseline ECG (0.70) or CK-MB (0.62) in the admission assessment of possible MI patients. CONCLUSIONS: Negative myoglobin serial assays can be used effectively to rule out MI. Positive myoglobin serial assays help in the early diagnosis of MI in uncomplicated patients.

Intermittent intravenous amrinone infusion: a potentially cost effective mode of treatment of patients with refractory heart failure.

OBJECTIVE: To describe the experience of 41 New York Heart Association (NYHA) class III and IV heart failure patients treated with intermittent intravenous amrinone infusions in addition to conventional therapy. BACKGROUND: Congestive heart failure is a condition often requiring repeated admission to hospital. Accordingly, a treatment modality which can reduce the number of admissions is desirable and potentially cost-effective. DESIGN: Retrospective analysis of data from hospital and office charts. SETTING: Community hospital with 640 active beds. INTERVENTION: The initial amrinone infusion was administered in the hospital under electrocardiographic monitoring; subsequent infusions were given in an out-patient unit. A bolus injection of 0.75 mg/kg followed by an infusion of 5 to 10 micrograms/kg/min for 8 to 12 h was administered every two to six weeks as clinically indicated. RESULTS: Results are reported for the first 51 months. Sixty-six per cent of the patients improved their NYHA class, 34% remained unchanged or deteriorated. Survival paralleled that of other studies involving similar patients not receiving nonglycoside positive inotropes. The number of days spent in the hospital in the six months after starting on amrinone compared with the six months before treatment was reduced to 50% (P < 0.05), and the number of hospital admissions in the six months after starting amrinone compared with the six months before decreased to 56% (P < 0.05). CONCLUSIONS: Intermittent intravenous amrinone infusions can be given in an out-patient setting in patients with NYHA class III to IV heart failure. This program is cost-effective, reducing hospital admissions and in-patient hospital days.