Abstract 9256: Improving the Sensitivity for Left Ventricular Hypertrophy in Obese Patients by Normalizing Electrocardiographic Criteria to Body Mass Index

Abstract

Introduction: The electrocardiogram (ECG) has low sensitivity for the diagnosis of LVH in obese patients. We hypothesized that adjusting the voltage on ECG to body mass index (BMI) would increase the sensitivity in this population.

Methods: From our institutional database we identified patients over age 35 who underwent ECG and transthoracic echocardiography within 6 months. Those with prolonged QRS duration, paced rhythm and significant acute cardiopulmonary disease were excluded. Three ECG criteria for LVH- Sokolow, Cornell and Romhilt-Estes- were compared to echocardiographically derived left ventricular mass index using the Devereux formula. LVH was defined as 134g/m² for men and 110 g/m² for women. We then performed an adjustment of individuals' summed ECG voltage for each criterion by normalizing to a BMI of 25 with the formula: Adjusted voltage = ECG voltage*BMI/25.

Results: Of 476 patients studied (255 male, 221 female, mean age 62.5) 36.8% were obese (BMI≥30), and 41.7% had LVH based on echocardiogram (34.1% in the non-obese and 41.7% in the obese group). The sensitivity of all ECG criteria was lower in the obese population. The sensitivity for identifying LVH by Sokolow was 37.7 % vs. 25.0 %, by Cornell 47.7% vs. 41.1 and by Romhilt-Estes 54.6% vs. 37.5% for non-obese and obese patients, respectively (p>0.05). Adjusted Sokolow augmented the sensitivity substantially in from 40.9% to 81.8% (p<0.001) in men and from 14.7% to 38.2% (p=0.001) in women, respectively. Similarly, the adjusted Cornell criterion increased the sensitivity from 40.9% to 86.4% in men (p<0.001) and 41.2% to 73.5% in women (p=<0.001). Adjusted Romhilt-Estes did not show statistically different results. Overall accuracy was not significantly reduced with the adjusted ECG criteria.

Conclusion: Normalizing Cornell and Sokolow criteria to the BMI significantly improves the sensitivity of ECG to identify LVH in obese patients.