Heart Failure in Infants
Heart failure in infants is primarily caused by congenital heart defects (CHDs) with excessive pulmonary blood flow (left-to-right shunts). Unlike adults, clinical signs in infants are often subtle and related to feeding and growth.
1. Classic Clinical Presentation
- Feeding Difficulties: “Diaphoresis during feeding” (the most sensitive sign) and prolonged feeding times.
- Respiratory: Tachypnea, wheezing (often misdiagnosed as asthma), and grunting.
- Growth: Failure to thrive (FTT) due to high metabolic demand and poor intake.
- Systemic: Tachycardia (often > 160 bpm), gallop rhythm ($S_3$ or $S_4$), and hepatomegaly (a reliable sign of systemic venous congestion in infants).
2. Ross Classification (Modified for Infants)
| Class | Severity |
|---|---|
| Class I | Asymptomatic. |
| Class II | Mild tachypnea/sweating with feeding. |
| Class III | Marked tachypnea/sweating, prolonged feeding, FTT. |
| Class IV | Symptomatic at rest (tachypnea, retractions, grunting). |
3. Key Diagnostic Clues
- Hepatomegaly: Reflects right-sided venous congestion.
- Pulse Deficits: Always check femoral pulses (r/o Coarctation of the Aorta).
- CXR: Cardiomegaly (C/T ratio > 0.6 in infants) and increased pulmonary vascular markings.
NEET PG Hint: Remember that diaphoresis with feeding is the hallmark clinical indicator of heart failure in an infant. Do not look for peripheral edema (like in adults); infants often develop periorbital edema or generalized edema only in late stages. Always differentiate between cardiogenic and respiratory causes of tachypnea.