Antemortem screening for left ventricular hypertrophy in rhesus macaques (Macaca mulatta)

Concentric left ventricular hypertrophy (LVH) is a hallmark finding in hypertrophic cardiomyopathy that leads to diastolic dysfunction and variable cardiac consequences as severe as congestive heart failure and sudden cardiac death. LVH was diagnosed postmortem in a large colony of rhesus macaques (Macaca mulatta), but methods to screen and diagnose LVH in living animals are desired. We hypothesized that targeted echocardiography of macaques with a familial association of LVH would yield antemortem LVH diagnoses. We also hypothesized that cardiac biomarker levels would be higher in sudden-death LVH or occult LVH than controls and that cardiac troponin I (cTnI) levels would be higher in macaques housed outdoors than indoors. Sera were assayed for cardiac biomarkers (cTnI, C-reactive protein, creatinine kinase-MB, creatine phosphokinase, and LDH), in conjunction with echocardiography, after diagnosis by postmortem exam or from animals with different levels of exercise due to indoor compared with outdoor housing. None of the investigated biomarkers were associated with LVH. cTnI levels were significantly higher in serum collected from outdoor than indoor macaques. In addition, LVH was diagnosed in 29.4% of subjects with a familial association of LVH. These findings suggest that exercise may increase cTnI levels in rhesus macaques and that targeted echocardiography of rhesus macaques with a familial association of LVH was the most useful variable examined for disease surveillance.