Echocardiographic Parameters of Captive Western Lowland Gorillas (Gorilla gorilla gorilla)

Abstract

A total of 163 echocardiographic studies on western lowland gorillas (Gorilla gorilla gorilla) were submitted for evaluation; 140 from 99 animals were suitable for analysis. Of these, 81 studies (42 studies from 35 males ranging in age from 11-41+ yr and 39 studies from 31 females ranging in age from 11-41+ yr) are reported here. Three studies from 3 females and 56 studies from 30 males were excluded from this report due to cardiac abnormalities. Cardiac parameters measured were aortic root (Ao Rt) diameter and left atrial (L atrium) size. Left ventricular (LV) measurements included left ventricular internal diameter in systole (LVID(s)) and diastole (LVID(d)) as well as diastolic septal (IVS) and posterior wall thickness (LVPW). Values considered to be normal in females > 11 yr of age were: Ao Rt < 3.5 cm, L atrium < 4.0 cm, LVID(d) < 5.0 cm, IVS < 1.4 cm, LVPW < 1.4 cm, and ejection fraction (EF) > 60%. The data from male gorillas show a separation in animals based on three cardiac parameters: systolic function, LV cavity size, and LV wall thickness. Male gorillas > 11 yr of age fall into two groups; unaffected and affected. Unaffected animals are defined as those with no echocardiographic abnormalities and a consistent Ao Rt of < 4.0 cm, LVID(d) of < 6.0 cm, IVS and LVPW of <1.5 cm, and an EF of > 58%. The affected group consisted of male gorillas that exhibited changes in echocardiographic parameters representing the presence of cardiovascular disease. The results determined in this database, gathered from data collected from 1999-2009, suggest a sex-based difference between males and females with predominantly males demonstrating evidence of cardiac disease. The most striking finding seen in this study is that of progressive LV hypertrophy and depressed LV EF in affected adult male gorillas.

Comparative Pathology of Aging Great Apes

“…In gorillas, echocardiography revealed increasing left ventricular wall thickness from 1.6 cm in young adult males to >2.1 cm in males >31 yo, while left ventricular chamber size decreased. 180 In that study, female gorillas showed little difference in cardiac measurements with advancing age, with left ventricular wall thickness ranging from a minimum of 0.9 cm to a maximum of 1.4 cm. All of the males between 31 and 40 yo in the study were considered to have cardiomyopathy.…”

Commentary: is Alzheimer's disease uniquely human?

“…Clinical grade elevation of blood cholesterol is common in captive great apes on a wide range of diets (reviewed in Finch and Stanford, 2004, Table 3A). Although sudden death from heart failure is common in captive great apes, it may arise more frequently from fibrotic cardiomyopathy (Varki et al, 2009; Great Ape Heart Project, 2012) than from ischemic cardiovascular disease (Manning, 1943; Murphy et al, 2011). The relationship of various heart conditions to conditions of captivity is poorly understood.…”

Extraversion predicts longer survival in gorillas: an 18-year longitudinal study

“…Evidence consistent with this includes a study that showed an association between extraversion and higher rates of affiliation in a subsample of these gorillas [8]. Another possibility is that low extraversion could be linked to cardiovascular disease, which is the primary cause of mortality in captive gorillas [19].…”