Gunther-Harrington C T, Ontiveros E S, Hodge T E, Visser L C, Stern J A
Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA.
Veterinary Medical Center, University of California, San Diego, CA.
J Vet Intern Med. 2016 May;30(3):733-40. doi: 10.1111/jvim.13931. Epub 2016 Mar 10.
Echocardiographic assessment of diastolic function is challenging in cats, partially because of transmitral flow pattern fusion associated with high heart rates. With heart rate (HR) reduction, transmitral flow waveforms separate, allowing identification of diastolic dysfunction. Timolol, an ophthalmic, nonselective beta-blocker used in glaucoma is safe and transiently decreases HR in clinical trials.
Administration of timolol ophthalmic solution decreases HR and facilitates echocardiographic assessment of diastolic function in cats without inducing clinically relevant adverse effects.
Twenty-five apparently healthy cats.
Electrocardiograms and echocardiograms including transmitral flow patterns were evaluated before and 20 minutes after ocular administration of 1 drop of timolol 0.5% solution. Twenty cats underwent treatment with timolol, and 5 different cats served as untreated controls to evaluate the effects of acclimation to the hospital environment on HR.
Acclimation to the hospital had no effect on HR in control cats. After timolol administration, a significant median HR reduction of 25 bpm was observed (P < .0001). Timolol had no effect on E/A ratio in cats without E/A fusion (7/20, P = .44). Of the 13 cats with E and A waves that were fused before timolol application, separation of these waves was identified in 8 cats (62%) after timolol treatment. No bradyarrhythmias were noted after timolol administration, but 2 cats had first-degree atrioventricular block. Timolol resulted in resolution of dynamic outflow tract obstruction in 6 of 6 cats.
Ocular administration of timolol safely decreases HR in cats and could facilitate assessment of diastolic function.
猫的舒张功能超声心动图评估具有挑战性，部分原因是与高心率相关的二尖瓣血流模式融合。随着心率（HR）降低，二尖瓣血流波形分离，从而能够识别舒张功能障碍。噻吗洛尔是一种用于青光眼治疗的眼科非选择性β受体阻滞剂，在临床试验中安全且能短暂降低心率。
局部应用噻吗洛尔滴眼液可降低猫的心率，并有助于在不引起临床相关不良反应的情况下进行舒张功能的超声心动图评估。
25只看似健康的猫。
在眼部滴入1滴0.5%噻吗洛尔溶液前及用药后20分钟，评估心电图和包括二尖瓣血流模式的超声心动图。20只猫接受噻吗洛尔治疗，另外5只不同的猫作为未治疗的对照，以评估适应医院环境对心率的影响。
对照猫适应医院环境对心率无影响。给予噻吗洛尔后，观察到心率显著中位数降低25次/分钟（P < .0001）。噻吗洛尔对E/A比值未融合的猫的E/A比值无影响（7/20，P = .44）。在应用噻吗洛尔前E波和A波融合的13只猫中，治疗后8只猫（62%）的这些波分离。给予噻吗洛尔后未观察到缓慢性心律失常，但有2只猫出现一度房室传导阻滞堵塞。噻吗洛尔使6只猫中的6只动态流出道梗阻得到缓解。
眼部应用噻吗洛尔可安全降低猫的心率，并有助于舒张功能的评估。
