Clinical management of a western lowland gorilla (Gorilla gorilla gorilla) with a cardiac resynchronization therapy device.

A 24-yr-old, male western lowland gorilla (Gorilla gorilla gorilla) was diagnosed with congestive heart failure using transesophageal and transthoracic echocardiology. New York Heart Association (NYHA) Class III was assigned to the severity of the condition. Over 16 mo, this progressed to NYHA Class IV despite increasing medical therapy. Repeated evaluations suggested that implantation of a cardiac resynchronization therapy device with a defibrillator (CRT-D) could benefit this animal based on clinical signs and underlying evidence of dyssynchrony and suspected fibrotic myocardial disease. Surgical implantation of leads into the right atrium, right ventricle, and left ventricle was accomplished. The CRT-D device was placed under the thoracic pectoral muscles during an initial surgical procedure. Improvement in the gorilla's clinical condition after implantation of the CRT-D device was immediate and dramatic. Subsequent scanning of the device was accomplished through operant conditioning. The data from these device interrogations included stored and real-time cardiac data, which were used to minimize recognized environmental stressors and change device settings. Over 4 yr, case management was critical to successful device use in treatment of the clinical disease. This involved medications, training for device interrogation, exercise to increase activity and improve body condition, and phlebotomy attempts. Dietary management was necessary to manipulate caloric and sodium intake and encourage medication compliance. Cardiac resynchronization therapy device implantation, although requiring specialized equipment and surgical skill, appears to be a viable option for treatment of fibrosing cardiomyopathy with systolic dysfunction in gorillas refractory to medical management. In addition to treatment, this device provides cardiovascular data at rest that could allow for early diagnosis and treatment of gorillas with this and other cardiac conditions in the future. This describes the comprehensive medical, husbandry, and training techniques necessary to successfully manage this intense clinical case in conjunction with intracardiac device therapy.

Surgical implantation of a cardiac resynchronization therapy device in a western lowland gorilla (Gorilla gorilla gorilla) with fibrosing cardiomyopathy.

A 24-yr-old, male western lowland gorilla (Gorilla gorilla gorilla) was diagnosed in March of 2003 with congestive heart failure (CHF). Transesophageal and transthoracic echocardiography demonstrated global left and right ventricular hypokinesia with a left ventricular ejection fraction of 0.20. At the time of diagnosis, the animal exhibited symptoms and signs of CHF with minimal exertion (New York Heart Association class III). Over a 16-mo period, the severity of CHF progressed to class IV (resting signs and symptoms) despite angiotensin-converting enzyme inhibition, beta-blockers, and diuretics. Because of intractable CHF and a QRS duration that was markedly prolonged compared with the normal range for this species, a cardiac resynchronization therapy (CRT) device was implanted using implantation techniques based on human surgical procedures. Placement of the right ventricular, right atrial, and left ventricular leads and pulse generator were accomplished in 5.5 hr. Telemetry of the device postoperatively via wand or remote radio frequency has allowed for noninvasive programming and interrogation. The clinical improvement in CHF with this therapy was immediate and dramatic for this animal. Six months after CRT device implantation, the device leads became dislodged during an altercation with another gorilla, with the rapid development of CHF upon cessation of biventricular pacing. A second procedure to replace the leads returned the gorilla to his previous level of activity. In 2007, the pulse generator was electively replaced for battery depletion with a device capable of remote radiofrequency programming and interrogation. CRT implantation, although requiring specialized equipment and surgical skill, appears to be a viable option for treatment of dilated cardiomyopathy in gorillas.