Abstract
There have been few reports concerning the influences of cardiac hypertrophy on the clinical features and prognosis of acute myocardial infarction (AMI) . Therefore, the left ventricular myocardial mass index (LVMI) was calculated using echocardiogram obtained on the first hospital day in 202 patients with initial AMI (148 males and 54 females with a mean age of 66.3 years) . The patients were divided into Groups A and B with high (LVMI: M≥130, F≥120) and low (LVMI: M<130, F<120) myocardial masses, respectively, consisting of 110 and 92 patients, and the hemodynamics, echocardiographic findings, clinical features and prognosis in the acute and chronic stages were compared. Group A was further divided into an improved group in which the myocardial mass was decreased on the 28th hospital day compared to the 1st day (Group A1), and an unimproved group distinguished by myocardial mass remained unchanged or increased (Group A2) . The mean duration of follow-up was 4.7 years. The appearance rate of left ventricular wall thinning increased with time in both groups but the incidence was higher and the appearance after onset was also earlier in Group A. Regarding the prognosis, the incidences of congestive heart failure (CHF) and cardiac events (CE) in the acute stage and CHF, angina pectoris (AP) and CE in the chronic stage were significantly higher in Group A. With respect to the odds ratios of coronary risk factors, such as hypertension, diabetes, smoking, hyperlipidemia, obesity, and myocardial mass in the acute stage of CHF. AP and CE, the myocardial mass ratios in CHF and CE were 2.77 and 2.07, respectively, showing significant differences. As for the chronic stage, the odds ratios of myocardial mass in CHF, AP and CE were 3.51, 3.30 and 4.29, respectively, showing significant differences. On comparison of groups AI and A2, the appearance rate of left ventricular wall thinning increased with time, and the thinning was noted more frequently and earlier in Group A2. Regarding the prognosis, the incidences of CHF and CE were significantly higher in Group A2 in the acute stage. Based on the above findings, when cardiac hypertrophy is complicated by AMI, the prognosis is significantly poor in both the acute and chronic stages. Aggressive treatment to minimize the infarct area, to inhibit cardiac remodeling and to reduce the myocardial mass should be initiated from the onset of MI.
