Abstract 2084: Left Ventricular Hypertrophy Is Associated With Reversible Microvascular Dysfunction And Protection From Post-infarct Left Ventricular Remodeling
Background Whether the presence and amount of left ventricular (LV) hypertrophy influences the extent and temporal changes of microvascular damage and the incidence of LV remodeling after acute myocardial infarction (AMI) is currently unknown.
Methods Thirty-one patients (26 males, mean age 60 ± 9 yrs) presenting with their first ST-elevation AMI (22 anterior) were admitted to our Coronary Care Unit and were successfully treated by primary PCI within 6h from symptoms onset. Conventional 2D echo and myocardial contrast echo (MCE) were performed in all patients within 24 hours of coronary recanalization and at 3 months. LV mass (LVM) was calculated in accordance with the American Society Echocardiography criteria and indexed by Body Surface Area (LVMI), using normal limits from the Framingham Heart Study. LV end-diastolic (EDD) and end-systolic (ESD) diameters were measured. LV end-diastolic (EDV) and end-systolic (ESV) volumes were calculated from four-chamber and two-chamber view utilizing the modified Simpson biplane method. Delta EDV, ESV and EDD and ESD ((3 months - 24 hours)/24 hours)*100 were calculated. The length of perfusion defects at MCE was measured in 3 apical views, averaged and expressed as % of LV length.
Results Study population was divided in patients with (LVMI >116 g/m2 (men) or > 104/m2 (women)) and without LV hypertrophy (Group 1 and 2). Group 1 showed a significant reduction of length of perfusion defect (group 1 4.0±2.8 vs 1.5±2.4%, p<0.01; group 2 3.5±3.0 vs 2.8±3.8 %, p=ns). Only Group 2 patients showed a significant enlargement of EDV at 3 months (111±31 ml vs 126±39 ml, p<0.005). A significant linear relation between delta EDD and LVM was found (r 0.4, p<0.05).
Conclusions After AMI, patients with LV hypertrophy showed a significant improvement in microvascular flow within the first 3 months, associated with preserved LV volumes. Only post-AMI patients without LV hypertrophy demonstrated a significant LV enlargement. Thus, LV hypertrophy is associated with reversible microvascular dysfunction and appears to be a protective factor in the development of LV remodeling.