[Observation on left ventricular remodeling in acute myocardial infarction]

After an acute myocardial infarction (AMI), there will be regional dilation and global remodeling of the infarcted left ventricle. This study was aimed to observe the features of the ventricular remodeling after AMI.

Based on the time of onset of the symptoms, 37 patients (pts) with AMI were divided into 4 groups. The time of onset of AMI for group 1 (16 pts), group 2 (7 pts), group 3 (11 pts) and group 4 (3 pts) was < or = 3 hours (hrs), > 3 hrs - < or = 6 hrs, > 6 hrs - < or = 12 hrs and > 12 hrs respectively. The size of the left ventricle in all the patients were analysed with resting myocardial gated SPECT (GSPECT). Tc-99m MIBI was infused at admission and data of GSPECT were collected 2 hours later following the infusion. End-diastolic volume (EDV), end-systolic volume (ESV) and LVEF were shown by the system. Stroke volume (SV) was then calculated.

EDV for group 1 to 4 was (98.5 +/- 31.9) ml, (99.4 +/- 55.6) ml, (128.1 +/- 55.1) ml and (140.0 +/- 25.3) ml, respectively. ESV for group 1 to 4 was (57.0 +/- 30.9) ml, (55.1 +/- 40.3) ml, (77.4 +/- 39.8) ml and (81.3 +/- 26.0) ml, respectively. SV for group 1 to 4 was (57.0 +/- 30.9) ml, (55.1 +/- 40.3) ml, (77.4 +/- 39.8) ml and (81.3 +/- 26.0) ml, respectively. LVEF for group 1 to 4 was (44.6 +/- 13.1) ml, (49.7 +/- 13.1) ml, (42.8 +/- 13.5) ml, and (42.7 +/- 8.6) ml, respectively. In pts with anterior infarction, EDV, ESV and SV after 6 hrs of the onset of AMI were greater than those in pts with in 6 hrs of the onset. It was the same in pts with inferior infarction.

It is suggested that the left ventricular size increased in 3 hrs after AMI. Following the initial dilation of left ventricle, EDV, ESV and SV did not change significantly with in 6 hrs, but then increased gradually after 6 hrs from the onset of the symptoms. The early and significant dilation of left ventricle after AMI may be one of the risk factors of severe cardiac events.