Related Experiment Videos
[Neonatal electrocardiographic manifestations of congenital hypothyroidism. Correlation with echocardiographic data]
Insights
Congenital hypothyroidism in infants primarily causes low-amplitude left ventricular potentials on ECG, not significant conduction delays. Echocardiography confirmed no pericardial effusion, ruling it out as a cause of these ECG findings.
Area of Science:
- Pediatric Cardiology
- Neonatal Endocrinology
- Clinical Electrophysiology
Context:
- Congenital hypothyroidism (CH) is a common neonatal endocrine disorder.
- Early diagnosis and treatment are crucial to prevent developmental delays.
- Electrocardiogram (ECG) and echocardiography are non-invasive tools for assessing cardiac function in infants.
Purpose:
- To investigate the specific electrocardiographic (ECG) characteristics of congenital hypothyroidism in neonates.
- To correlate ECG findings with the severity of hypothyroidism.
- To determine the role of echocardiography in evaluating cardiac structural changes, specifically pericardial effusion, in hypothyroid infants.
Summary:
- Twelve infants with CH (average age 5.4 weeks) underwent comprehensive ECG and echocardiogram evaluations.
- ECG analysis focused on heart rate, intervals, wave amplitudes, and ventricular activation times.
- Echocardiography assessed pericardial effusion, ventricular wall thickness, and dimensions.
- Key findings include low amplitude of left ventricular potentials as the primary ECG abnormality in neonatal CH, with less evident conduction time increases.
- The severity of hypothyroidism correlated with specific ECG parameters like R+S wave sum in V2, T wave amplitude in V6, and QRS duration in V3R.
- Pericardial effusion was absent in all cases, excluding it as a cause of left ventricular microvoltage.
Impact:
- Establishes characteristic ECG patterns for neonatal hypothyroidism, aiding in diagnosis.
- Highlights that left ventricular microvoltage in CH is not attributable to pericardial effusion.
- Provides insights into the cardiac manifestations of CH, informing clinical management and follow-up.
Abstract:
Twelve infants, average age 5, 4 weeks (range 3 to 8 weeks) with congenital hypothyroidism were studied. In addition to routine evaluation including plasma T3, T4 and TSH estimation and the establishment of a clinical index of hypothyroidism on electrocardiogram and an echocardiogram were performed. The following variables were analysed: heart rate, QRS axis in the frontal plane, PR interval in Lead II, corrected QT interval in V5, amplitude of the P waves in Lead II, R waves in V3R, V1, V5 and V6; S waves in V1, V2 and V4 and T wave in V6. The ventricular activation time in V5 and QRS duration in V3R, V1 and V6 were also measured. The presence of pericardial effusion, left ventricular posterior wall and septal thickness, and left ventricular internal diastolic and systolic dimensions were determined by echocardiography. The following conclusions were drawn: 1. The ECG of hypothyroidism in the neonatal period is characterised by the low amplitude of the left ventricular potentials while increased conduction times were much less evident; 2. Only the sum of R + S in V2, the amplitude of the T wave in V6 and increase in QRS duration in V3R were influenced by severity of hypothyroidism; 3. Left ventricular microvoltage is not due to pericardial effusion which was absent in all our cases.