Sensitivity of the Morris index in the assessment of left atrial volume and area measured by echocardiography in patients with chronic hypertension, Caaguazú, 2025

Abstract

Introduction: Chronic hypertension is a key risk factor for cardiac structural remodeling, including left atrial (LA) dilation. The Morris index is an easily accessible electrocardiographic criterion for detecting LA hypertrophy, but its sensitivity compared to gold-standard echocardiographic methods requires evaluation.

Objective: To evaluate the sensitivity of the Morris index compared to the assessment of LA volume and area measured by echocardiography in patients with long-standing hypertension at a private clinic in the city of Caaguazú in 2025.

Methodology: An observational, analytical, and cross-sectional study was conducted. Forty-two patients diagnosed with chronic hypertension were included; they underwent an electrocardiogram to calculate the Morris index and a transthoracic echocardiogram to measure LA area and volume. Statistical associations were analyzed, and sensitivity, specificity, and predictive values were calculated.

Results: In the 42 patients studied, the mean age was 62 years and the prevalence of LA dilation was 88.10%. The Morris index was positive in 78.57% of cases. A statistically significant association was found between a positive Morris index and LA dilation (p=0.001). The diagnostic test demonstrated a sensitivity of 86.5%, a specificity of 80.0%, a positive predictive value of 97.0%, and a negative predictive value of 44.4%.

Conclusion: The Morris index exhibits high sensitivity and excellent positive predictive value for detecting LA dilation in the studied cohort of patients with chronic hypertension. Multicenter studies with a larger number of patients are required to validate its utility as a screening tool in the Paraguayan population.