Borderline left ventricle

Abstract

The first problem to solve when dealing with the topic 'borderline left ventricle' is to find the appropriate definition. Several parameters have been taken into consideration, either morphometric (diameter of the mitral valve, indexed mitral valve area, left ventricular inflow dimension, left ventricular cross-sectional area, ratio between the apex-to-base left ventricular dimension and right ventricular dimension, left ventricular long axis to heart long axis ratio, left ventricular end diastolic volume, left ventricular mass index, ratio of the right/left ventricular wall thickness, presence of endocardial fibroelastosis, cardiac apex not formed by the left ventricle, diameter of the ventriculo-aortic junction, diameter of the aortic valve annulus and indexed aortic root diameter) as well as functional (left ventricular ejection fraction, left ventricular end diastolic pressure, mean pulmonary artery pressure, direction of the blood flow in the ascending aorta and at the level of the patent ductus arteriosus). Pre-operative determination whether the left ventricle is adequate to sustain the systemic circulation, or it may became adequate with the available surgical approaches, and therefore a bi-ventricular type of repair is feasible, can be extremely difficult, particularly in the presence of a 'borderline left ventricle'. In the clinical practice pediatric cardiologists and cardiac surgeons are faced with the problem of the 'borderline left ventricle' in four different groups of congenital heart defects: (a) aortic valve stenosis, (b) aortic coarctation, with or without hypoplastic aortic arch, (c) hypoplastic left heart complex, (d) right ventricular pressure and/or volume overload. In all the above situations in the presence of a left ventricle smaller than normal a very exhaustive approach has been reviewed in the decision making process, taking in account the literature reports as well as the personal experience. In each patient with 'borderline left ventricle' the elements to be considered for the decision making process between uni- and bi-ventricular type of repair, or for less ideal options of management, are the following: morphometric and functional parameters, hemodynamic data, available surgical options, results of the personal and institutional experience.

Operations for improving left ventricular diastolic function

“…Patients with severe hypoplasia of left heart structures typically undergo SVP or transplantation, whereas patients with mild hypoplasia and diastolic dysfunction undergo primary left ventricular recruitment or 'biventricular repair'. Within the spectrum are many variants of left heart hypoplasia for which management is not so clear, but usually SVP is most commonly applied [3,4]. These patients may be amenable to eventual biventricular circulation, but are at higher risk if such a strategy is pursued, particularly in the newborn period [1,[5][6][7].…”

“…Interventions to promote initial biventricular circulation may consist of relief of inflow and outflow tract obstructions, either by catheter-based balloon dilation of the aortic valve or by surgical repair of coarctation of the aorta [3,7]. However, EFE, which impedes both systolic and diastolic myocardial function, may lead to persistent left atrial hypertension, pulmonary edema, and pulmonary hypertension, despite relief of anatomic obstructions.…”

Age-Specific Reference Intervals for Indexed Left Ventricular Mass in Children

“…Although the majority of physicians are concerned with LVH and its consequences relative to coronary artery disease risk, the assessment of LVM is equally and critically important for patients with small and, specifically, borderline left ventricles caused by aortic valve stenosis, aortic coarctation, or hypoplastic left-heart syndrome, relative to suitability of a univentricular or biventricular surgical approach. 24 In these latter situations, LVM is one of the most important echocardiographic indices used to determine surgical approach.…”

Palliative stent implantation for coarctation in neonates and young infants

“…In addition, one infant had a borderline left ventricle as defined by the following criteria: indexed mitral valve area <4.75 cm 2 /m 2 , ratio between the apex-to-base left ventricular dimension and right ventricular dimension <0.8, and aortic valve annulus <6 mm. [9]…”