Nadas' Criteria for Clinical Diagnosis of Heart Disease
Definition and Application
- Nadas' criteria provide a systematic clinical approach utilized for the assessment and diagnosis of congenital heart disease.
- For a positive clinical diagnosis of heart disease, the patient must present with either one major criterion or two minor criteria.
- Clinicians must recognize that these criteria are of limited use in the newborn population, as clinical signs of heart disease in neonates are frequently subtle or masked.
Diagnostic Criteria
| Category | Clinical Findings |
|---|---|
| Major Criteria | Systolic murmur of grade III or greater intensity; Diastolic murmur; Central cyanosis; Congestive cardiac failure. |
| Minor Criteria | Systolic murmur of grade I or II intensity; Abnormal second heart sound; Abnormal electrocardiogram (ECG); Abnormal chest X-ray; Abnormal blood pressure. |
Clinical Nuances and Investigation Findings
- Systolic Murmurs (
Grade III): A pansystolic murmur is always abnormal regardless of its intensity, typically representing lesions such as a ventricular septal defect (VSD), mitral regurgitation, or tricuspid regurgitation. - Diastolic Murmurs: The presence of a diastolic murmur on auscultation almost always indicates organic heart disease.
- Central Cyanosis: This major criterion suggests unoxygenated blood is entering the systemic circulation (right-to-left shunt) or that blood is not getting fully oxygenated in the lungs. Oxygen saturations of 95% or lower while breathing room air are considered abnormal.
- Congestive Cardiac Failure: While a major criterion for heart disease, pediatricians evaluating neonates and infants must first exclude extracardiac causes of failure, such as anemia and hypoglycemia.
- Minor Systolic Murmurs (Grade I or II): Soft, less than grade III murmurs by themselves do not exclude the presence of underlying heart disease.
- Abnormal Second Heart Sound: Auscultatory abnormalities of the second heart sound always indicate the presence of heart disease.
- Abnormal Electrocardiogram (ECG): Serves as a minor criterion; however, voltage criteria alone for ventricular hypertrophy are not strictly diagnostic of heart disease, as QRS complexes can be altered by chest wall thickness, electrode position, or blood viscosity.
- Abnormal Chest X-ray: Cardiomegaly observed on a good inspiratory film suggests heart disease, but care must be taken in infants under two years of age, where a normal thymus shadow might mimic an enlarged heart.