The role of thrombolytic therapy in patients with acute myocardial infarction presenting later than six hours after the onset of symptoms

Effect of Reperfusion Therapy on Cardiac Rupture After Myocardial Infarction in Japanese

BACKGROUND

Cardiac rupture after acute myocardial infarction (AMI) is unpredictable and almost always fatal, so the present study reviewed all the clinical characteristics of patients with cardiac rupture to determine if its occurrence can be predicted.

METHODS AND RESULTS

The clinical characteristics of 1,296 consecutive AMI patients from January 1992 to February 2002 were retrospectively evaluated using multi-logistic analysis. Cardiac rupture occurred in 45 patients (3.5%), comprising left ventricular free wall rupture (n=23), ventricular septal perforation (n=20) and papillary muscle rupture (n=2). Early-phase rupture (within 72 h after AMI onset) was associated with anterior infarction. Of the 45 patients who experienced ruptures, 24 (53.3%) survived to discharge; 21 (46.6%) of the 45 ruptures occurred after admission. Successful reperfusion therapy was performed within 24 h for 840 patients. The incidence of rupture was significantly lower for reperfused patients than for non-reperfused patients (0.6% vs 3.5%, respectively; p<0.01). Peak C-reactive protein concentration was a reliable predictor of late-phase rupture (p=0.01), but not of early-phase rupture.

CONCLUSIONS

Reperfusion therapy appears to aid in the prevention of cardiac rupture, especially late-phase rupture.

Determinants of left ventricular function two weeks and one year after an acute myocardial infarction

This study examines possible covariates of left ventricular function two weeks and sixteen months after an acute infarction. It was performed in a group of 312 patients randomized double blindly to recombinant tissue plasminogen activator (rt-PA) (n = 156) or placebo treatment and followed thereafter for at least one year. Two weeks after the infarction, enzymatic infarct size, infarct-related vessel, and number of diseased coronary arteries were significant determinants of the infarct-related regional wall motion (centerline method) (R2 = 0.25 to 0.60, P = 0.0001). Enzymatic infarct size, regional wall motion of both infarct-related and remote areas, reinfarction, and treatment allocation were significant independent correlates of ejection fraction (R2 = 0.76), end-diastolic volume (R2 = 0.20), and end-systolic volume (R2 = 0.69, P < 0.0001). Infarct-related coronary artery and predischarge end-systolic volume were significant independent covariates of ejection fraction at rest (R2 = 0.47) after sixteen months. Age, enzymatic infarct size, and predischarge end-diastolic volume were independent determinants of the maximal (R2 = 0.49, P < 0.0001) and peak exercise ejection fraction (R2 = 0.49, P < 0.0001).