MORPHOLOGICAL DETERMINANTS VI TRAN EuroEcho, Budapest, 7 th December 2011 DECLARATION OF CONFLICT OF INTEREST: I have nothing to declare
What is the functionally single ventricle? The heart that is incapable of supporting both the pulmonary and systemic circulations Why should this be? Only one ventricle within ventricular mass Two ventricles, but one is incapable of supporting the entirety of either the systemic or the pulmonary circulation
Ventricles unable to support circulations Normally formed, but too small Hypoplastic and rudimentary Obstructions to flows through inlet or outlet
Anatomic substrates Tricuspid atresia Double inlet left ventricle Hypoplastic left heart Pulmonary atresia with intact ventricular septum
Understanding and describing the anatomy Analysis of atrioventricular junctions Do atrial chambers connect to both ventricles or to only one? Description of ventricular morphology What is the morphologic nature of the pumping ventricle, and is there a second ventricle? Describe arrangement in logical fashion
Logical analysis Analyse ventricles in tripartite fashion Use the Morphological method Van Praagh et al, 1980 Use most constant feature of any structure for definition Do not define any structure that is itself variable on the basis of another variable feature
Morphologically Right Ventricle Outlet Inlet Apical trabecular component
Morphologically Left Ventricle Outlet Apical trabecular component Inlet
Tripartite ventricular description Normal ventricles each have three parts Morphology determined by apical component Abnormal ventricles have inlets and outlet components shared between apical parts One ventricle is dominant Other ventricle is rudimentary & incomplete Rudimentary RV is always antero-superior Rudimentary LV is always postero-inferior Hearts with one big and one small ventricle are functionally univentricular
Double Inlet Left Ventricle Dominant Left Ventricle Rudimentary Right Ventricle
Classical Tricuspid Atresia
Are these entities single ventricles? Both have one big and one small chamber Big chamber is morphologically left ventricle Small chamber is the incomplete and hypoplastic morphologically right ventricle Univentricular only if we deny ventricular status to small chamber!
Logical description Tricuspid atresia & DILV both have big left ventricle and small, incomplete, RV Neither is an example of univentricular heart or single ventricle We were wrong, in the past, to deny ventricular status to small RV It is the ATRIOVENTRICULAR CONNECTION which is truly univentricular! Hole between chambers is VSD
UNIVENTRICULAR AV CONNECTION
Double Inlet Right Ventricle Dominant Right Ventricle Rudimentary Left Ventricle Rudimentary LV rarely can be right-sided
Double Inlet Solitary Ventricle Solitary and Indeterminate Ventricle
Hearts with Biventricular AV Connection can also be functionally univentricular! Unbalanced atrioventricular septal defect Imperforate atrioventricular valve Hypoplastic left heart Hypoplastic right heart (pulmonary atresia with intact ventricular septum)
Unbalanced AV Septal Defect
Imperforate Tricuspid Valve Biventricular AV connections Right atrium Left atrium Hypoplastic RV Left ventricle Functionally Univentricular Heart
Hypoplastic left heart Mitral atresia or stenosis Aortic atresia or stenosis Left ventricle not capable of supporting systemic circulation Irrespective of morphology, all examples are functionally univentricular
Hypoplastic left heart Univentricular AV Connection
Hypoplastic Left Heart Biventricular AV Connections
Pulmonary atresia with intact vent. septum Spectrum of malformation Overgrowth of RV cavity All ventricles have three components Cavity can be tripartite, bipartite, or unipartite
Pulmonary Atresia with Intact VS Minimal overgrowth of apical component Functionally biventricular
Pulmonary Atresia with Intact VS Bipartite, suitable for 1 ½ ventricle repair?
Pulmonary Atresia with Intact VS Functionally univentricular
Conclusions Many hearts can be functionally univentricular Anatomically univentricular hearts are exceedingly rare Functionally single ventricles can have biventricular or univentricular AV connections Analyse separately ventricular morphology and AV junctional morphology Tripartite approach to ventricular morphology