Ventriculo-arterial coupling in children with Still's murmur

Area of Science:

• Pediatric Cardiology
• Cardiovascular Physiology
• Echocardiography

Background:

• Still's murmur is the most frequent innocent heart murmur in children, often attributed to blood flow but lacking a definitive explanation.
• Understanding the underlying mechanisms of Still's murmur is crucial for accurate diagnosis and parental reassurance.

Purpose of the Study:

• To investigate the hemodynamic ventriculo-arterial interaction in children with and without Still's murmur.
• To assess the proportional anatomical dimensions of the left ventricle and aortic root in relation to cardiac function.

Main Methods:

• A case-control study involving healthy children with (n=43) and without (n=42) Still's murmur.
• Application of the ventriculo-arterial coupling (VAC) model, utilizing M-mode echocardiography to derive parameters like effective arterial elastance (EA) and left ventricular contractility (ELV).
• Analysis included VAC ratio (EA/ELV), ejection fraction (EF), stroke volume (SV), blood pressure (BP), heart rate (HR), and cardiac dimensions.

Main Results:

• Children with Still's murmur exhibited a significantly lower VAC ratio (EA/ELV) compared to controls (P < 0.005).
• Higher ejection fraction (EF%) and greater stroke volume (SV) per kg bodyweight were observed in children with Still's murmur (P < 0.005, P < 0.05).
• No significant differences were found in blood pressure, heart rate, or aortic root and left ventricular dimensions between the groups.

Conclusions:

• Still's murmur in healthy children appears to be associated with subtle alterations in ventriculo-arterial coupling.
• The findings suggest a 'lively interplay' between the heart and aorta as the likely cause of this common innocent murmur.
• This understanding can help reassure parents about the benign nature of Still's murmur.