Cardiac structure and function characterized across age groups and between sexes in healthy wild-born captive chimpanzees (Pan troglodytes) living in sanctuaries

Abstract

OBJECTIVETo comprehensively characterize cardiac structure and function, from infancy to adulthood, in male and female wild-born captive chimpanzees (Pan troglodytes) living in sanctuaries. ANIMALS 290 wild-born captive chimpanzees. PROCEDURESPhysical and echocardiographic examinations were performed on anesthetized chimpanzees in 3 sanctuaries in Africa between October 2013 and May 2017. Results were evaluated across age groups and between sexes, and potential differences were assessed with multiple 1-way independent Kruskal-Wallis tests. RESULTSResults indicated that left ventricular diastolic and systolic function declined at a younger age in males than in females. Although differences in right ventricular diastolic function were not identified among age groups, right ventricular systolic function was lower in adult chimpanzees (> 12 years old), compared with subadult (8 to 12 years old) and juvenile (5 to 7 years old) chimpanzees. In addition, male subadult and adult chimpanzees had larger cardiac wall dimensions and chamber volumes than did their female counterparts. CONCLUSIONS AND CLINICAL RELEVANCEResults of the present study provided useful reference intervals for cardiac structure and function in captive chimpanzees categorized on the basis of age and sex; however, further research is warranted to examine isolated and combined impacts of blood pressure, age, body weight, and anesthetic agents on cardiac structure and function in chimpanzees.

Evaluation of relationships between results of electrocardiography and echocardiography in 341 chimpanzees (Pan troglodytes)

“…All health assessments were conducted at the housing facilities and by experienced veterinarians as previously described. 22,23 Briefly, once a chimpanzee was anesthetized and unresponsive to external stimuli, the animal was weighed, then transported to an assessment area, where a full health assessment was completed. Each health assessment included a thorough physical examination, blood sampling, morphometric measurements, and cardiac assessment with 12-lead ECG and transthoracic echocardiography.…”

“…Echocardiography-After undergoing ECG, chimpanzees were positioned in left lateral recumbency for comprehensive transthoracic echocardiography, which was completed with a commercially available ultrasound machine d and probes e,f as previously described 23 and in line with human guidelines. 25,[45][46][47] To minimize measurement variability inherent with composite echocardiographic measures and to not make any assumptions regarding cardiac geometry in chimpanzees, we chose to use measures of areas and dimensions, instead of measures of volume or mass.…”

“…Although most (314/341 [92.1%]) chimpanzees did not have overt cardiac remodeling, echocardiography revealed abnormal cardiac morphology, including suspected LVH (n = 15), dilated LV (6), and dilated atria (9). Of note, 1 chimpanzee had extreme LVH (MLVWT, 1.62 cm; reference range, 0.55 to 1.1 cm 23 ) on echocardiography and an SLV25 of 5.5 mV (reference range, 1.7 to 5.8 mV 24 ).…”

“…Compared with humans, it appears that the atrial contribution to ventricular filling is relatively modest in chimpanzees. 23 As such, the atria might function more as a conduit rather than an active pump, and so the atrial myocardial mass and resulting P-wave amplitudes could be smaller in chimpanzees.…”

Reply to Jensen and Wang: Chimpanzees under pressure—Selection of a left ventricular structural and functional phenotype

“…Specifically, the highly trabeculated LV apex and absence of apical rotation that was observed in almost all animals in our original study (2) was confirmed in this larger cohort. Basic echocardiographic parameters from this cohort have been published (4), and data on trabeculations and rotational mechanics will follow in due course. Confirmation of marked apical trabeculation in chimpanzees across the full age spectrum, including those anesthetized with and without medetomidine, strongly supports the hypothesis that this phenotype represents a defining structural characteristic of the derived chimpanzee heart.…”