Increased left ventricular mass index (LVMI) is associated with a greater incidence of acute myocardial infarction (AMI), but there are no data regarding its impact on infarct size.

The objective of this study was to determine whether LVMI impacts on infarct size.

We analyzed consecutive patients with a first ST-elevation AMI and successful reperfusion of the culprit artery who underwent an echocardiographic assessment of LVMI and regional wall motion score index (RWMSI) <72 hours post AMI.

Of the 165 patients (76.4% men) with a mean age of 61.0 ± 13.9 years, 53.9% had anterior wall involvement and 59.3% had increased LVMI. There were no significant differences in baseline characteristics between patients with and without increased LVMI, except for a greater prevalence of hypertension among patients with increased LVMI (44.0% vs 22.4%, P < .001). The distributions of anterior wall AMI location and culprit artery involvement were similar between the groups. Patients with increased LVMI were more likely to present with single-vessel coronary artery disease (P = .04) and heart failure upon presentation (P = .03). There was no significant difference between patients with and without increased LVMI in peak creatine kinase (2106.8 ± 1642.7 vs 2551.2 ± 2357.4 U/L, P = .16) or RWMSI (1.62 ± 0.44 vs 1.61 ± 0.38, P = .91). In addition, no correlation was observed between LVMI as a continuous variable and RWMSI (r = 0.11, P = .18) or peak creatine kinase values (r = 0.02, P = .81).

Among patients with a first ST-elevation AMI and successful reperfusion, antecedent increased LVMI was fairly common and did not impact on infarct size.