Chronic hypertension with subsequent congestive heart failure in a westernlowland gorilla (Gorilla gorilla gorilla)

Chronic severe subclinical systemic hypertension was diagnosed in a 28-yr-o ld male western lowland gorilla (Gorilla gorilla gorilla). Thoracic radiogr aphy, electrocardiography, and echocardiography revealed an enlarged heart with a hypertrophied left ventricle, mitral regurgitation, and a persistent left bundle branch black. Enalapril, later combined with nifedipine, was o f some value in reducing the hypertension, with partial reversal of cardiac enlargement and resolution of the bundle branch block. Two years after ini tiation of treatment, the gorilla developed lethargy and dyspnea. The diagn osis of heart failure was confirmed under anesthesia; the gorilla did not r ecover and was euthanized. Postmortem examination confirmed congestive hear t failure with chronic, fibrosing cardiomyopathy similar to that in other g orillas.