Ivabradine in a Neonate With Severe Hypertrophic Cardiomyopathy.

BACKGROUND

Hypertrophic cardiomyopathy (HCM) affects approximately 20% of patients with Noonan syndrome and contributes significantly to mortality, particularly in neonates with severe HCM and left ventricular outflow tract obstruction, where controlling heart rate (HR) and maintaining systemic vascular resistance can be challenging.

CASE SUMMARY: A full-term neonate with an Raf-1 proto-oncogene, serine/threonine kinase mutation and severe HCM developed diastolic heart failure requiring high-dose esmolol for rate control and phenylephrine for systemic vascular resistance support. After inadequate HR response and associated vasodilation due to esmolol, off-label ivabradine was started at 20 days of life, achieving HR control within 48 hours and allowing weaning of vasoactive agents and respiratory support.

DISCUSSION: Standard therapies-β-blockers, nondihydropyridine calcium channel blockers, and sodium-channel blockers-can worsen left ventricular outflow tract obstruction. Ivabradine selectively inhibits the I(f) current via hyperpolarization-activated cyclic nucleotide-gated channel 4 in sinoatrial tissue, providing HR reduction without compromising contractility or hemodynamics.

TAKE-HOME MESSAGE: Ivabradine provides durable HR control without negative inotropy or hypotension, supporting its use in symptomatic pediatric HCM.