cardiovascular disorders
Acute Myocardial Infarction (MI)
Prognosis for Acute MI
Risk should be estimated via formal clinical risk scores (eg, Thrombosis in Myocardial Infarction [TIMI]) or a combination of the following high-risk features: Recurrent angina/ischemia at rest or during low-level activity Heart failure Worsening mitral regurgitation High-risk stress test result (test stopped in ≤ 5 minutes due to symptoms, marked ECG abnormalities, hypotension, or complex ventricular arrhythmias) Hemodynamic instability Sustained ventricular tachycardia Diabetes mellitus PCI within past 6 months Prior coronary artery bypass grafting (CABG) LV ejection fraction < 0.40 Overall mortality rate prior to the modern era of treatment with fibrinolytics and PCI was about 30%, with 25 to 30% of these patients dying before reaching the hospital (typically due to Ventricular Fibrillation (VF) ). In-hospital mortality rate is about 10% (typically due to cardiogenic shock) but varies significantly with severity of left ventricular failure (see table For patients receiving reperfusion (fibrinolysis or PCI), in-hospital mortality is 5 to 6%, versus 15% for patients eligible for reperfusion who do not receive reperfusion therapy. In centers with established primary PCI programs, in-hospital mortality is reported to be < 5%. 50% of LV mass. Five clinical characteristics predict 90% of the mortality in patients who present with STEMI (see table Mortality Risk at 30 Days in STEMI and Older age (31% of total mortality) Lower systolic blood pressure (24%) Killip class>1 (15%) Faster heart rate (12%) Anterior infarct location (6%) Mortality rates tend to be higher in women and in patients with diabetes. Mortality rate of patients who survive initial hospitalization is 8 to 10% in the year after acute myocardial infarction. Most fatalities occur in the first 3 to 4 months. Persistent ventricular arrhythmia, heart failure, poor ventricular function, and recurrent ischemia indicate high risk. Many authorities recommend stress ECG before hospital discharge or within 6 weeks. Good exercise performance without ECG abnormalities is associated with a favorable prognosis; further evaluation is usually not required. Poor exercise performance is associated with a poor prognosis. Cardiac performance after recovery depends largely on how much functioning myocardium survives the acute attack. Acute damage adds to scars from previous infarcts. When>50% of left ventricular mass is damaged, prolonged survival is unusual. 