Effects of 0.5% Timolol Maleate Ophthalmic Solution on Heart Rate and Selected Echocardiographic Indices in Apparently Healthy Cats

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Background: 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. Hypothesis: Administration of timolol ophthalmic solution decreases HR and facilitates echocardiographic assessment of diastolic function in cats without inducing clinically relevant adverse effects. Animals: Twenty-five apparently healthy cats. Methods: 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. Results: 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. Conclusions and clinical importance: Ocular administration of timolol safely decreases HR in cats and could facilitate assessment of diastolic function.

Original languageEnglish (US)
Pages (from-to)733-740
Number of pages8
JournalJournal of Veterinary Internal Medicine
Volume30
Issue number3
DOIs
StatePublished - May 1 2016

Fingerprint

maleates
Timolol
Ophthalmic Solutions
heart rate
Cats
Heart Rate
eyes
cats
Ophthalmic Administration
Acclimatization
acclimation
beta-adrenergic antagonists
glaucoma
Atrioventricular Block
electrocardiography
Bradycardia
Glaucoma
clinical trials
Electrocardiography

Keywords

  • Cardiomyopathy
  • Doppler
  • Echocardiography
  • Feline

ASJC Scopus subject areas

  • veterinary(all)

Cite this

@article{272b80b1b25548f6b860f9b9741a01e8,
title = "Effects of 0.5{\%} Timolol Maleate Ophthalmic Solution on Heart Rate and Selected Echocardiographic Indices in Apparently Healthy Cats",
abstract = "Background: 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. Hypothesis: Administration of timolol ophthalmic solution decreases HR and facilitates echocardiographic assessment of diastolic function in cats without inducing clinically relevant adverse effects. Animals: Twenty-five apparently healthy cats. Methods: 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. Results: 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. Conclusions and clinical importance: Ocular administration of timolol safely decreases HR in cats and could facilitate assessment of diastolic function.",
keywords = "Cardiomyopathy, Doppler, Echocardiography, Feline",
author = "Gunther-Harrington, {C. T.} and Ontiveros, {E. S.} and Hodge, {T. E.} and Visser, {L. C.} and Stern, {J. A.}",
year = "2016",
month = "5",
day = "1",
doi = "10.1111/jvim.13931",
language = "English (US)",
volume = "30",
pages = "733--740",
journal = "Journal of Veterinary Internal Medicine",
issn = "0891-6640",
publisher = "Wiley-Blackwell",
number = "3",

}

TY - JOUR

T1 - Effects of 0.5% Timolol Maleate Ophthalmic Solution on Heart Rate and Selected Echocardiographic Indices in Apparently Healthy Cats

AU - Gunther-Harrington, C. T.

AU - Ontiveros, E. S.

AU - Hodge, T. E.

AU - Visser, L. C.

AU - Stern, J. A.

PY - 2016/5/1

Y1 - 2016/5/1

N2 - Background: 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. Hypothesis: Administration of timolol ophthalmic solution decreases HR and facilitates echocardiographic assessment of diastolic function in cats without inducing clinically relevant adverse effects. Animals: Twenty-five apparently healthy cats. Methods: 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. Results: 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. Conclusions and clinical importance: Ocular administration of timolol safely decreases HR in cats and could facilitate assessment of diastolic function.

AB - Background: 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. Hypothesis: Administration of timolol ophthalmic solution decreases HR and facilitates echocardiographic assessment of diastolic function in cats without inducing clinically relevant adverse effects. Animals: Twenty-five apparently healthy cats. Methods: 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. Results: 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. Conclusions and clinical importance: Ocular administration of timolol safely decreases HR in cats and could facilitate assessment of diastolic function.

KW - Cardiomyopathy

KW - Doppler

KW - Echocardiography

KW - Feline

UR - http://www.scopus.com/inward/record.url?scp=84960510791&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84960510791&partnerID=8YFLogxK

U2 - 10.1111/jvim.13931

DO - 10.1111/jvim.13931

M3 - Article

C2 - 26969017

AN - SCOPUS:84960510791

VL - 30

SP - 733

EP - 740

JO - Journal of Veterinary Internal Medicine

JF - Journal of Veterinary Internal Medicine

SN - 0891-6640

IS - 3

ER -