• Vol. 36 No. 12, 974–979
  • 15 December 2007

Trends in Mortality from Acute Myocardial Infarction in the Coronary Care Unit



Introduction: The treatment and outcome of acute myocardial infarction (AMI) has evolved greatly over the past few decades. We compared the mortality and complication rates of patients with AMI admitted to the Coronary Care Unit (CCU) in 2002 to previously reported data. Materials and Methods: All data for AMI patients admitted to National Heart Centre CCU in 2002 were collected through the Singapore Cardiac Data Bank, including demographics, in-hospital complications and mortality. These were compared to previous reports from the same institution in 1988, 1975 and 1967. Results: A total of 516 cases with AMI were identified. A higher proportion of patients were aged ≥70 years in 2002 (31.8%) compared to 1988 (25%), 1975 (11%) and 1967 (5.6%). Acute percutaneous transluminal coronary angioplasty (PTCA) was performed in 250 of 516 (48%) patients in 2002. The overall in-patient and age-standardised mortality was 14.7% and 10% respectively, compared to 20.6% and 17% respectively in 1988 (P = 0.06). For the 250 patients who underwent acute PTCA, overall mortality was 5.2% compared to 24% in those who did not (P <0.001). Common in-hospital complications included heart failure (38%), non-sustained ventricular tachycardia (8%), atrial fibrillation (8%) and complete heart block (6%). Age, heart failure, bundle branch block and sustained ventricular tachycardia were associated with higher mortality by univariate analysis. On multivariate analysis, older age, heart failure and the absence of percutaneous intervention were independently associated with higher mortality. Conclusion: In-hospital mortality for AMI patients admitted to the CCU declined from 1988 to 2002 despite a higher proportion of elderly patients. The introduction of new therapies including drugs and percutaneous intervention may have contributed to this decline.

Acute myocardial infarction (AMI) is a serious manifestation of coronary artery disease that is associated with high mortality from arrhythmias and heart failure. Its treatment has evolved over the decades. In the 1960s, coronary care units (CCUs) were developed to allow for close monitoring of AMI patients recognised to be at a higher risk of complications and death. Beginning in the late 1980s, and continuing in the 1990s, thrombolytic therapy was used for the treatment of AMI, and was shown to improve survival outcomes.1-3 During this period, aspirin, beta-blockers and angiotensin-converting enzyme inhibitors were also shown to reduce mortality and morbidity.2,4-6 In the 1990s, primary percutaneous transluminal coronary angioplasty (PTCA) for AMI was shown to be an effective alternative means of reperfusion, and is now increasingly practised in centres where experience is available.7 In our institution, primary PTCA was introduced in the early 1990s and is now the preferred method of reperfusion. Over the decades, several studies have reported a decline in early mortality after AMI.8-14

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