Isolated Apical Hypoplasia of the Left and Right Ventricle

Isolated apical ventricular hypoplasia is an extremely rare congenital heart disease. We describe 2 cases, each affecting a different side, presenting with unique clinical and imaging characteristics not hitherto delineated in the literature.

Natural genetic variation quantitatively regulates heart rate and dimension

The polygenic contribution to heart development and function along the health-disease continuum remains unresolved. To gain insight into the genetic basis of quantitative cardiac phenotypes, we utilize highly inbred Japanese rice fish models, Oryzias latipes, and Oryzias sakaizumii. Employing automated quantification of embryonic heart rates as core metric, we profiled phenotype variability across five inbred strains. We observed maximal phenotypic contrast between individuals of the HO5 and the HdrR strain. HO5 showed elevated heart rates associated with embryonic ventricular hypoplasia and impaired adult cardiac function. This contrast served as the basis for genome-wide mapping. In a segregation population of 1192 HO5 x HdrR F2 embryos, we mapped 59 loci (173 genes) associated with heart rate. Experimental validation of the top 12 candidate genes in loss-of-function models revealed their causal and distinct impact on heart rate, development, ventricle size, and arrhythmia. Our study uncovers new diagnostic and therapeutic targets for developmental and electrophysiological cardiac diseases and provides a novel scalable approach to investigate the intricate genetic architecture of the vertebrate heart.

Hybrid Palliation for Hypoplastic Left Heart Syndrome: Role of Echocardiography

Hypoplastic left heart syndrome is a spectrum of complex congenital cardiac defects. Although in borderline cases, biventricular repair is a viable option, in the majority of cases, univentricular palliation is the treatment of choice. Hybrid palliation can be a valid alternative to classic Norwood operation in the neonatal period, especially in selected cases such as high-risk patients or borderline left ventricles. Echocardiography is the main diagnostic modality in this pediatric population, from the fetal diagnosis to the subsequent surgical steps of palliative treatment. Hybrid palliation is performed after birth and is characterized by surgical banding of the pulmonary arteries along with transcatheter stenting of the ductus arteriosus. There are some peculiar aspects of cardiac imaging that characterize this type of palliation, and that should be considered in the different phases before and after the procedure. We aimed to review the current literature about the role of echocardiography in the management of patients with hypoplastic left heart undergoing hybrid palliation.

Hybrid Palliation for Hypoplastic Borderline Left Ventricle: One More Chance to Biventricular Repair

Treatment options for hypoplastic borderline left ventricle (LV) are critically dependent on the development of the LV itself and include different types of univentricular palliation or biventricular repair performed at birth. Since hybrid palliation allows deferring major surgery to 4-6 months, in borderline cases, the decision can be postponed until the LV has expressed its growth potential. We aimed to evaluate anatomic modifications of borderline LV after hybrid palliation. We retrospectively reviewed data from 45 consecutive patients with hypoplastic LV who underwent hybrid palliation at birth between 2011 and 2015. Sixteen patients (mean weight 3.15 Kg) exhibited borderline LV and were considered for potential LV growth. After 5 months, five patients underwent univentricular palliation (Group 1), eight biventricular repairs (Group 2) and three died before surgery. Echocardiograms of Groups 1 and 2 were reviewed, comparing LV structures at birth and after 5 months. Although, at birth, all LV measurements were far below the normal limits, after 5 months, LV mass in Group 2 was almost normal, while in Group 1, no growth was evident. However, aortic root diameter and long axis ratio were significantly higher in Group 2 already at birth. Hybrid palliation can be positively considered as a "bridge-to-decision" for borderline LV. Echocardiography plays a key role in monitoring the growth of borderline LV.

The Left Ventricular Myocardium in Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome (HLHS) is a collective term applied to severe congenital cardiac malformations, characterised by a combination of abnormalities mainly affecting the left ventricle, associated valves, and ascending aorta. Although in clinical practice HLHS is usually sub-categorised based on the patency of the mitral and aortic (left-sided) valves, it is also possible to comprehensively categorise HLHS into defined sub-groups based on the left ventricular morphology. Here, we discuss the published human-based studies of the ventricular myocardium in HLHS, evaluating whether the available evidence is in keeping with this ventricular morphology concept. Specifically, we highlight results from histological studies, indicating that the appearance of cardiomyocytes can be different based on the sub-group of HLHS. In addition, we discuss the histological appearances of endocardial fibroelastosis (EFE), which is a common feature of one specific sub-group of HLHS. Lastly, we suggest investigations that should ideally be undertaken using HLHS myocardial tissues at early stages of HLHS development to identify biological pathways and aid the understanding of HLHS aetiology.

Development of an echocardiographic scoring system to predict biventricular repair in neonatal hypoplastic left heart complex

Neonates born with borderline left heart hypoplasia, or hypoplastic left heart complex, can undergo biventricular repair while those with severe left heart hypoplasia require single ventricle palliation. Deciding which patients are candidates for biventricular repair may be very difficult since there are no scoring systems to predict biventricular repair in these patients. The purpose of this study is to develop an echocardiographic scoring system capable of predicting successful biventricular repair in neonatal hypoplastic left heart complex. The study cohort consisted of twenty consecutive neonates with hypoplastic left heart complex presenting between 9/2008 and 5/2013. Multiple retrospective echocardiographic measurements of the right and left heart were performed. Six patients with significant LH hypoplasia (patent mitral and aortic valves, small left ventricle) who had undergone single ventricle repair were used to validate the scoring system. Seventeen patients underwent biventricular repair and three underwent single ventricle repair. A scoring system (2V-Score) was developed using the equation {[(MV4C/AVPSLA) ÷ (LV4C/RV4C)] + MPA}/BSA. Using a cutoff value of ≤ 16.2, a biventricular repair would have been predicted with a sensitivity of 1.0, specificity 1.0, positive predictive value 1.0, negative predictive value 1.0, area under the ROC curve 1.0, and the p value was 0.0004. The 2V-Score was more accurate than the Rhodes, CHSS, or Discriminant scores in retrospectively predicting biventricular repair in this cohort. The 2V-Score shows promise in being able to predict a successful biventricular repair in patients with hypoplastic left heart complex but requires prospective validation prior to widespread clinical application.

Classic form of hypoplastic left heart syndrome diagnosed post-natally: an autopsy report

Hypoplastic left heart syndrome (HLHS) is a congenital heart disease, which, despite the current improved knowledge about its management and surgical treatment, is still associated with high mortality, especially in the early neonatal period and before the second stage of reconstruction surgery. The low rate of prenatal diagnosis and delayed diagnostic suspicion results in unsuccessful therapeutic intervention, even though the real impact of early diagnosis and intervention on mortality and quality of life of patients is still uncertain. Fortunately, this syndrome of challenging treatment is not that frequent. It involves a spectrum of obstructions to the blood flow within the left heart and is characterized by an inappropriate size of the left ventricle associated with a wide variety of valvular dysfunctions. Treatment ranges from heart transplantation to palliative surgical procedures. The authors describe a case of a newborn with HLHS, whose diagnosis was made after birth because of early respiratory failure. Despite the use of prostaglandin the newborn died. An autopsy was performed and the anatomical findings were described.