248 Comparative study of cardiac function between two populations in Latin America using the transthoracic echocardiogram: Atahualpa, Ecuador, and Mexico City, Mexico Estudio comparativo de la función cardíaca en dos poblaciones de América Latina mediante el ecocardiograma transtorácico: Atahualpa, Ecuador y Ciudad de México, México Juan M. García-Graullera 1 , Juan A. Nader-Kawachi 2 *, Liliana Crespo-Serge 1 , and Óscar H. del Brutto 3 1 Department of Echocardiography, Comprehensive Center for Diagnosis and Treatment; 2 Neurology and Neurosurgery Unit, Cerebrovascular Disease Clinic, Hospital Médica Sur, Mexico City, Mexico; 3 Medical School, Universidad Espíritu Santo, Samborondón, Ecuador RESEARCH ARTICLE Abstract Objective: The objective of the study was to compare morphological and functional differences of the heart in two Latin American populations with different ethnicity and living conditions. Methods: Using transthoracic echocardiogram, we obtained data on 206 individuals: 103 from Atahualpa, Ecuador (living at sea level, mean age: 75 ± 4.2 years, 53 women) and 103 inhabitants from Mexico City (living at 2,300 m above sea level, mean age: 75 ± 4.2 years, 52 women). Results: Significant differences between Atahualpa and Mexico were: Heart rate 66 versus 80 x’, left ventricular diastolic diameter 40.8 versus 42.7, septum thickness 9.8 versus 11.6, posterior wall 10.2 versus 11.8, stroke volume cc 53.0 versus 46.6, left atrial volume 25. 8 versus 33.6, systolic pressure of the pulmonary artery 27.1 versus 42.0, cardiac output 3.1 versus 4.8, E/Ea ratio 6.4 versus 9.2, and mitral area 3.4 versus 3.0. Comparison of diastolic function between Atahualpa and Mexico was: Type 0; 2 versus 1, Type 1; 96 versus 81, Type 2; 5 versus 20, and Type 3; 0 versus 1. Conclusions: Echocardiographic character- istics that identify adaptive changes of the heart in Atahualpa are coincident with people living at sea level and with good physical activity, and Mexico City, with inhabitants living at high altitudes and exposed to environmental pollution. The sys- tolic function of the left ventricle was similar in both populations, indicating that adaptive changes allow the heart to be effec- tive in different circumstances of the ecosystem. Key words: Transesophageal echocardiogram. Pulmonary hypertension. Hypoxemia. Latin America. High altitude. Environ- mental pollution. Resumen Objetivo: Comprobar las diferencias morfológicas y funcionales del corazón en dos poblaciones latinoamericanas con distintas características raciales y condiciones de vida. Métodos: Mediante el ecocardiograma transtorácico se obtuvieron datos de 206 personas: 103 del poblado de Atahualpa, Ecuador (nivel del mar, edad x 75 ± 4.2 años, 53 mujeres) y 103 habitantes de la Ciudad de México (altitud de 2,300 m, edad x 75 ± 4.2 años, 52 mujeres). Resultados: Las diferencias significativas Correspondence: *Juan A. Nader-Kawachi E-mail: juan.nader.k@gmail.com Available online: 04-12-2020 Arch Cardiol Mex (Eng). 2020;90(3):248-257 www.archivoscardiologia.com Date of reception: 08-10-2019 Date of acceptance: 16-01-2020 DOI: 10.24875/ACME.M20000127 2604-7063 / © 2020 Instituto Nacional de Cardiología Ignacio Chávez. Published by Permanyer. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).