Sudden cardiovascular death following myocardial infarction: the importance of left ventricular systolic dysfunction and congestive heart failure.

Background: To study the prognostic information of congestive heart failure (CHF) and left ventricular systolic dysfunction regarding sudden and non-sudden cardiovascular death (SCD and non-SCD) in patients with acute myocardial infarction (MI), as this may indicate the potential benefit of implantable defibrillators.
Methods: Data from consecutive patients with acute MI screened in 1990-92 for the TRAndolapril Cardiac Evaluation (TRACE) study were entered into a registry. A total of 5502 patients were alive 30 days after the MI and were followed for up to 4 years with respect to cause of death. SCD was defined as cardiovascular death within 1 h of onset of symptoms. An echocardiography was performed 1-6 days after the admission and evaluated centrally using the wall motion index (WMI).
Results: Half of the patients had CHF and 17% of the patients had WMI < or =1.0 (corresponding to an ejection fraction < or =0.30). During follow-up 431 patients died from SCD and 606 from non-SCD. The risk ratios for SCD and non-SCD associated with WMI < or =1.0 were 3.17 and 2.95, transient CHF 2.01 and 1.46, and permanent CHF 3.71 and 4.42, respectively. No risk factor was a specific marker of SCD or non-SCD. The 3-year probability of SCD was 7.9% for patients with transient CHF, 13.3% for permanent CHF, and 15.5% for WMI < or =1.0.
Conclusions: CHF and low WMI identify a relevant proportion of patients with MI who are at high absolute risk of SCD. This study indicates the relevance of defibrillators in consecutive post-MI patients with left ventricular dysfunction or clinical signs of heart failure.