Activity of the renin-angiotensin-aldosterone and sympathetic nervous system and their relation to hemodynamic and clinical abnormalities in infants with left-to-right shunts

We studied neurohormonal, clinical and invasively measured hemodynamic data of 47 infants with left-to-right shunts and varying degrees of congestive failure. When referred to a clinical heart failure score, plasma renin activities (r=0.71) and norepinephrine levels (r=0.43) are significantly increased. Arterial hypotension seems to be the hemodynamic trigger of renin release (r=-0.72), but not decreased systemic cardiac index (r=-0.43), the magnitude of the left-to-right shunt (r=0.33) or a reduced ejection fraction (r=0.12). These data indicate neurohormonal activation in infants with left-to-right shunts with preserved myocardial function is similar to the activation in adults with heart failure secondary to myocardial pump failure. These findings have to be considered for optimal medical treatment of these infants with angiotensin-converting enzyme inhibitors or beta-blockers.