Use of the 12 Lead EKG in Distinguishing Concentric LV Remodeling from Normal LV Geometry

Abstract

Introduction: The EKG is a simple inexpensive tool to screen for the presence of increased LV mass in patients with hypertension. Studies have shown that in addition to increased LV mass, patients with concentric remodeling (CR, as defined by increased relative wall thickness (RWT) and normal LV mass) also have an increase in adverse cardiovascular events. It remains unclear whether or not the 12 lead EKG criteria used for identifying increased LV mass can similarly differentiate these patients from those with normal LV geometry. Hypothesis: We hypothesized that the 12 lead EKG in CR has a significantly increased frequency of increased voltage, ST depressions, T wave inversions and left atrial enlargement in comparison to normal geometry. Methods: We reviewed data from 640 consecutive hypertensive patients with a normal LV ejection fraction, no ischemic heart disease, no prior infarction (as evidenced by a q wave on EKG), no atrial fibrillation and no valvular dysfunction. CR was based upon a RWT >/= 45% (RWT = (2 X posterior wall thickness)/(LV internal diameter during diastole)) and normal LV mass indexed for body surface area (males < 125 gm/m2; females < 110 gm/m2). Increased voltage was determined using the modified Cornell criteria. ST depression > 0.1 mV and T wave inversions of any degree were considered present if found in any lead except aVR, and V1 to V3. Left atrial enlargement was present if the p wave inversion in lead V1 > 1mm in length and >1mV in amplitude. Results: There were 217/640 patients (34%) with echocardiographic evidence of CR and 173/640 patients (28%) that were normal. For CR, 13% had increased voltage criteria, 10% had ST depressions, 28% had T wave inversions and 36% had left atrial enlargement. For normals, there were 0% that had increased voltage criteria, 0% with ST depression, 17% with T wave inversions and 23% with left atrial enlargement. (CR vs normal p < 0.01 for every criteria). Conclusion: Despite the previous association of increased LV mass with specific 12 lead EKG criteria, patients with CR are also identified by these EKG patterns. Additional studies are necessary, to distinguish further, appropriate criteria that can separate CR from both normal geometry and increased LV mass.