Acute effect of Ivabradine, a novel I-f current inhibitor, on dynamic obstruction of the left ventricular outflow tract in cats with preclinical hypertrophic cardiomyopathy

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This randomized, double-blind, active-control single-dose study addresses the hypothesis that ivabradine does reduce dynamic obstruction of the left ventricular outflow tract in cats with Hypertrophic cardiomyopathy (HCM).


Hypertrophic cardiomyopathy (HCM) is the most common heart disease in cats predisposing cats to the development of congestive heart failure (CHF), thromboembolic disease, and sudden death. Intolerance to episodes of fast heart rate induced by stress seems to be one of the most important trigger events leading to decompensation in previously stable cats with HCM. Control of heart rate is an important treatment strategy in asymptomatic cats with HCM. Currently, atenolol (a beta blocker) and diltiazem (a calcium channel inhibitor) are used to treat preclinical HCM. However, both drugs may induce adverse events including weakness, fainting, inappetence, cough, and weight loss. Ivabradine is a novel agent that selectively lowers heart rate, is clinically well tolerated in cats, and might become a new treatment option in cats with HCM. While the effects of Ivabradine on heart rate and cardiac function have been studied in cats, its effect on obstruction of the left ventricular outflow tract (a commonly seen pathologic phenomenon in cats with HCM) is unknown. We hypothesized that Ivabradine will have favorable effects on outflow tract obstruction in cats with HCM (reduction or complete elimination).

Inclusion criteria

  • Cats with asymptomatic, stable HCM that are currently not on any treatment

Study Design

Your cat will undergo a general exam which includes a physical examination, a noninvasive blood pressure measurement, and a cardiac ultrasound study. Once completed, Ivabradine or active control will be administered, and the diagnostic procedures will be repeated.

Client Compensation

  • The study will pay for the drug administered, either Ivabradine or Atenolol
  • The study covers the blood pressure measurement, and a down grade of the cardiac ultrasound study from a regular level-III to an adjusted level-I.
  • The total incentive for participating in the study will be $220.

Client Cost

  • The client will be responsible for the exam and chart fees ($125) along with a level-I echocardiogram ($140)
  • If needed, the client will cover any costs related to additional procedures or drugs.


Dr. Karsten Schober, DVM, PhD (Cardiologist) at 614.292.3551, ext. 48676 or E-mail: schober [dot] 4 [at] osu [dot] edu, or Dr. Keith Blass (blass [dot] 9 [at] osu [dot] edu) for further information.