Reliability of electromechanical dissociation in the diagnosis of left ventricular free wall rupture in acute myocardial infarction.

The reliability of electromechanical dissociation (EMD) in diagnosing acute left ventricular free wall rupture (LVFWR) was assessed in 479 consecutive patients with acute myocardial infarction (AMI). EMD was the mechanism of death in 193 patients, 140 without heart failure (group A, 74%), and 53 with heart failure (group B, 26%). Autopsies performed on 121 patients with EMD showed LVFWR in 81 (95%) of 85 from group A and in 7 (17%) of 36 from group B. Of the 106 patients without EMD (group C) autopsied, 5 (4.7%) had LVFWR. Excluding the eight patients with associated septal rupture, LVFWR occurred in 79 (95.2%) of 83 patients from group A, 4 (12.1%) of 33 from group B, and 2 (1.9%) of 103 from group C. Predictive accuracy of EMD for LVFWR in group A was 95% but only 17% in group B. Moreover, in 13 consecutive cases with a first AMI without heart failure and EMD, emergency surgery demonstrated LVFWR in all. Thus EMD has a highly predictive accuracy in diagnosing LVFWR in patients with a first AMI without overt heart failure.