Gorilla Cardiac Care
It wasn't your typical day for two of our clinicians May 9. Joan Olson, lead cardiac ultrasonographer and Walker Thomas, perioperative cardiac sonographer, travelled to Omaha's Henry Doorly Zoo & Aquarium to perform an echocardiogram on one of the zoo's gorillas. Out of eight gorillas, five males, whose ages range from 16 to 20 years old, have been diagnosed with heart disease and are currently being monitored by cardiologist Thomas Porter, MD. Since December 2013, Dr. Porter and Olson have been performing echocardiograms on the gorillas. "An echocardiogram is an ultrasound exam with a special probe that gets pictures of the heart at a frame rate that allows analysis of the heart's pumping ability and valve function. It also measures the size of the heart chambers and walls," explains Dr. Porter. "It's exactly the same type of test we perform on human patients." During the exam, the gorilla, Mosuba, who does not have heart disease, was awake. Trainers coaxed him to sit in a certain spot, by using crunchy vegetables and an oatmeal mixture. The gorilla raised his arms and rested his hands on the fencing in front of them. Gel was placed on a probe, which was then placed on the gorilla's chest by the trainer, under the direction of Olson. "The trickiest part is scanning and capturing the images simultaneously on the ultrasound cart," describes Olson. "When we scan a human heart, the patient is lying down and rolled up onto their left side. But, with the gorillas, they're squatting in an upright position. We have to capture all the images extremely quickly." After the images were captured, the pair assessed the heart's left and right ventricular function, along with any valve problems. "What we see is reduced contractility of the heart muscle, which means the overall pumping ability of the heart is poor," explains Dr. Porter. "Heart disease is very common and a common cause of death among gorillas. It could be due to a virus, high blood pressure or a sedentary lifestyle." Once a gorilla has been diagnosed with heart disease, they are placed on medication and monitored for behavior, appetite, activity and weight. "The diet is monitored for all our gorillas, regardless of health status," says Julie Napier, DVM, a senior veterinarian at the zoo. The echocardiogram results are also entered into a national gorilla cardiac database called The Great Ape Heart Project, which tries to understand heart disease in gorillas. "There are several papers coming out that indicate this is a problem in the wild population as well," says Dr. Napier. "But, right now, there isn't enough information to indicate how widespread it is in the wild." "It's an honor to help these gorillas with the heart scans," says Olson. "It's a surreal experience to look them in the eye and gain their trust. They all have a different personality -- just like humans."