Ivabradine significantly reduced heart rate and left ventricular contractile function, and increased left ventricular end-diastolic pressure in anesthetized cats with hypertrophic cardiomyopathy.
Does ivabradine reduce heart rate and improve left ventricular function in anesthetized cats with hypertrophic cardiomyopathy?
In anesthetized cats with HCM, ivabradine successfully reduced heart rate and blunted catecholamine-induced tachycardia, but also increased left ventricular end-diastolic pressure and impaired relaxation.
OBJECTIVE: To evaluate the effects of the pacemaker funny current (I(f)) inhibitor ivabradine on heart rate (HR), left ventricular (LV) systolic and diastolic function, and left atrial performance in healthy cats and cats with hypertrophic cardiomyopathy (HCM). ANIMALS: 6 healthy cats and 6 cats with subclinical HCM. PROCEDURES: Anesthetized cats underwent cardiac catheterization and were studied over a range of hemodynamic states induced by treatment with esmolol (200 to 400 μg/kg/min, IV), esmolol and dobutamine (5 μg/kg/min, IV), ivabradine (0.3 mg/kg, IV), and ivabradine and dobutamine. Left ventricular systolic and diastolic function, cardiac output, and left atrial function were studied via catheter-based methods and echocardiography. RESULTS: Treatment with ivabradine resulted in a significant reduction of HR, rate-pressure product, and LV contractile function and a significant increase in LV end-diastolic pressure, LV end-diastolic wall stress, and LV relaxation time constant (tau) in cats with HCM. Concurrent administration of ivabradine and dobutamine resulted in a significant increase of LV contractility and lusitropy, with blunted chronotropic effects of the catecholamine. Left atrial performance was not significantly altered by ivabradine in cats with HCM. Regression analysis revealed an association between maximum rate of LV pressure rise and tau in cats with HCM. CONCLUSIONS AND CLINICAL RELEVANCE: Ivabradine had significant effects on several cardiovascular variables in anesthetized cats with HCM. Studies in awake cats with HCM are needed to clinically validate these findings.
Riesen et al. (Thu,) conducted a other in Hypertrophic cardiomyopathy (n=12). Ivabradine was evaluated on Heart rate, left ventricular systolic and diastolic function, and left atrial performance. Ivabradine significantly reduced heart rate and left ventricular contractile function, and increased left ventricular end-diastolic pressure in anesthetized cats with hypertrophic cardiomyopathy.