The relationship between the electrocardiogram (ECG) and cardiac structure in chimpanzees (Pan troglodytes)

Abstract

Objective – to examine potential relationship(s) between electrocardiographic characteristics and measures of cardiac structure in chimpanzees (Pan troglodytes). Animals – 341 chimpanzees, 175 males and 166 females. Procedures – During routine health examinations, 341 chimpanzees from five sanctuaries and two zoological collections underwent a 12-lead electrocardiogram (ECG) and transthoracic echocardiogram assessment. Relationships between multiple ECG characteristics and echocardiographic measures, of atrial areas, left ventricular internal cavity dimension and wall thicknesses were first explored using correlational analysis, then multiple linear regression analyses were used to create hierarchical models to predict cardiac structure from the ECG. Results – Significant correlations between ECG characteristics and echocardiographic measures of cardiac morphology were observed (r2 range: -0.231 – 0.310). P wave duration and amplitude in lead II had the strongest correlations to atrial areas. Sokolow-Lyon criteria, QRS duration, R wave in V6 and II demonstrated the strongest correlations with mean left ventricular wall thickness, while the Sokolow-Lyon criteria, QRS duration, S wave in V2 and V1 had the strongest correlations with the internal dimension of the left ventricle. Despite these significant correlations the predictive models generated only accounted for 17,7,11,8% of the variance in right and left atrial areas, left ventricular (LV) wall thicknesses and LV internal dimension, respectively. Conclusions and Clinical Relevance – This study has shown significant relationships exist between the ECG and cardiac morphology in chimpanzees. Further work is required to examine whether the prediction models generated can be modified to improve their clinical utility.