Frequency of rupture of the left ventricular free wall or ventricular septum among necropsy cases of fatal acute myocardial infarction since introduction of coronary care units.

Review of 18 published reports before the widespread use of cardiac care units disclosed that the frequency of rupture of the left ventricular free wall or ventricular septum among necropsy cases of acute myocardial infarction (AMI) ranged from 4 to 24% (mean 8%) (619 of 7,905 cases). The frequency of rupture of the left ventricular free wall or ventricular septum among necropsy patients with fatal AMI studied in this laboratory since 1968 was analyzed. Of 648 such patients, 204 (31%) had rupture of the left ventricular free wall or ventricular septum. Rupture occurred in 171 (40%) of 431 patients without healed myocardial infarcts (grossly visible left ventricular scars), and in 29 (13%) of 217 patients with a healed myocardial infarct (p less than 0.01). Thus, the frequency of rupture of the left ventricular free wall or ventricular septum during AMI appears to have increased substantially since the widespread use of coronary care units. Also, the frequency of rupture is nearly 3 times greater in those in whom rupture occurred during the first AMI compared to those with a previous infarct that healed.