Related Experiment Video
Updated: Jul 16, 2025
Author Spotlight: Effect of Left Atrial Ligation on Avian Embryonic Hearts and HLHS Implications
Published on: June 16, 2023
Which Phenotypes Should We Include in the Hypoplastic Left Heart Syndrome?
Robert H Anderson1, Diane E Spicer2, Adrian Crucean3
1Biosciences Division, Newcastle University, Newcastle-upon-Tyne, UK.
Insights
The integrity of the ventricular septum is key to distinguishing hypoplastic left heart syndrome (HLHS) from related anomalies. This criterion helps classify HLHS phenotypes based on acquired fetal conditions and the timing of left ventricular growth cessation.
Area of Science:
- Pediatric Cardiology
- Congenital Heart Surgery
- Developmental Biology
Background:
- A recent special issue on hypoplastic left heart syndrome (HLHS) lacked focus on ventricular septal integrity for phenotype distinction.
- Differentiating HLHS from related anomalies requires clear criteria for classifying specific cardiac malformations.
Purpose of the Study:
- To propose the integrity of the ventricular septum as a primary criterion for distinguishing HLHS phenotypes.
- To re-evaluate the classification of HLHS and related anomalies based on developmental timing.
Main Methods:
- Review of existing evidence on HLHS and related congenital heart defects.
- Analysis of the role of ventricular septal integrity in cardiac development.
- Comparative evaluation of different HLHS phenotypes based on proposed criteria.
Main Results:
- The integrity of the ventricular septum serves as a crucial distinguishing feature between HLHS and related anomalies.
- Phenotypes within HLHS can be categorized by the timing of left ventricular growth arrest relative to cardiac development, post-septum closure.
- Specific recognized combinations include aortic/mitral atresia, mitral stenosis with aortic atresia, and combined mitral/aortic stenosis.
Conclusions:
- Classifying HLHS based on ventricular septal integrity and developmental timing offers a refined understanding of these complex congenital heart defects.
- This approach aids in recognizing the spectrum of lesions, including the hypoplastic left heart complex, and their origins as acquired fetal conditions.
Abstract:
The recent special issue of the World Journal for Pediatric and Congenital Heart Surgery devoted to hypoplastic left heart syndrome, and its related anomalies, contained significant information of great clinical relevance. Very little attention, however, was devoted to the integrity of ventricular septum as providing a criterion to distinguish between the phenotypes to be included within the syndrome, as opposed to the related anomalies. In this commentary, we summarize the evidence in support of the notion that the phenotypes to be included within the syndrome can be interpreted on the basis of an acquired disease of fetal life. We suggest that it is the integrity of the ventricular septum that provided the major criterion for the distinction between the lesions making up the syndrome and the related anomalies. The subsets of lesions to be included within the syndrome can then be recognized in terms of the time, subsequent to the closure of the embryonic interventricular communication, at which the left ventricle ceased its growth relative to the remainder of the cardiac components. On this basis, it is possible to recognize the combinations of aortic and mitral atresia, mitral stenosis with aortic atresia, combined mitral and aortic stenosis, and hypoplasia of the left ventricle with commensurate hypoplasia of the aortic and mitral valves; the latter combination now recognized as the hypoplastic left heart complex.
Related Concept Videos
01:29Cardiomyopathy III: Hypertrophic Cardiomyopathy
01:26Heart Failure III: Clinical Manifestations
01:17Pathophysiology of Heart Failure
01:30Pulmonary Hypertension: Classification and Pathogenesis
There are various classifications for PH, each relating to different underlying causes and also...
01:22Mitral Stenosis I: Introduction
01:23Mitral Stenosis II: Clinical features and Diagnostic Tests