Author + information
- Samuel Wann, MD⁎ ()
- ↵⁎Chairman, Department of Cardiovascular Medicine, Wisconsin Heart Hospital, 10000 Bluemound Road, Milwaukee, Wisconsin 53226
I had just gotten home from rounds. While opening the Sunday newspaper, the phone rang. Dr. Clyde said, “Linda Bonobo was very lethargic and wouldn't get up for breakfast. Her breathing is labored and her edema is worse. We're taking her to the hospital now.”
Linda is a 51-year-old insulin-dependent diabetic, mother of 12, who presented a month ago with edema, ascites, lethargy, anorexia, and shortness of breath. Echocardiography showed anteroapical dyskinesis of the left ventricle, and ejection fraction 35%. She was treated with furosemide, lisinopril, metoprolol, and aspirin. Her appetite and level of physical activity improved. Her abdomen seemed less protuberant.
Linda has no prior history of heart disease. She has had insulin-dependent diabetes for 5 years. Her urine has recently been negative for glucose. Her low-density lipoprotein was 72 mg/dl, and her high-density lipoprotein was 142 mg/dl. No family history is available: Linda was born in the wild in the jungles of the Democratic Republic of Congo. Heart disease is a frequent cause of death in bonobos living in captivity. Being eaten by humans as “bush meat” is often the cause of death in wild bonobos. Bonobos are an endangered species.
I parked in the Heart Hospital lot and walked across the street to the Milwaukee Zoo. The Animal Health Center is just inside the gate. As I arrived, a technician was warming up the ultrasound machine just as Dr. Clyde and 3 assistants arrived by ambulance with Linda on a stretcher, anesthetized with ketamine. Bonobos are well known for their “human” characteristics, their communication skills and expressions of empathy, and their exuberant sexuality. They have been conditioned to voluntarily submit to some medical procedures. Although bonobos are phylogenetically Homo sapiens' closest relative, they are wild animals who will bite each other or their keepers. They must be placed under general anesthesia for extensive examinations or treatment. General anesthesia is risky and unpleasant for the bonobos and is only used when essential.
A quick ultrasound examination showed markedly reduced left ventricular function with anteroapical thinning and dyskinesis, ascites, and large bilateral pleural effusions. Blood pressure was 90/60 mm Hg. The electrocardiogram showed frequent premature ventricular complexes. Serum creatinine was 1.4 mg/dl. Serum potassium was slightly elevated. Enzymes were consistent with passive hepatic congestion.
Linda's overall condition seemed to improve slightly after thoracentesis of 250-ml straw-colored fluid, but her cardiovascular and respiratory function remained tenuous. Dr. Victoria Clyde, a zoo veterinarian who has worked with the bonobos for many years, convened a “family” conference with the head primate curator and several zookeepers. Many of the treatments available to humans, such as intensive nursing care, intravenous inotropic therapy or mechanical circulatory assist, myocardial revascularization, and heart transplantation are simply not feasible for bonobos. Issues of prognosis, quality of life, and the compassion of those caring for Linda Bonobo were similar.
As Linda was unable to return to living independently in the bonobo quarters, and there were no other reasonable options, she was euthanized. Post-mortem examination showed extensive coronary atherosclerosis and an extensive, old anteroapical myocardial infarction.
Linda Bonobo will be sorely missed by zoo staff and visitors, and especially by the 21 remaining members of the bonobo colony, where Linda served as a matriarch for 14 years.
- American College of Cardiology Foundation