Mohammed Alghamdi, MD, FRCPC, FAAP, FACC Assistant Professor and Consultant Pediatric Cardiology, King Saud University Consultant Pediatric Cardiology National Guard Hospital, Riyadh
• RV is described as the “forgotten ventricle” • RV is difficult to image due to: 1. Complex morphology 2. Thin wall with coarse trabeculations 3. Anterior retro-sternal posotion within the chest
• Accurate quantification of RV volume and function is needed • Progressive RV dilatation and dysfunction can be irreversible if intervention is delayed
• Normal RV is accustomed to a low PVR • RV is sensitive to changes in afterload – Changes in RV size and function
• Elevations in RV afterload are manifested by: – Acute: RV dilatation – Chronic: RV hypertrophy
• CMR is currently the referrence imaging modality to quantify RV volume and function – Time consuming – More expensive – Not readily available
• ECHO remains the most widely available modality for the initial screening and serial follow up
Qualitative “eyeballing” Assessment •Often used in many laboratories •Roughly can determine RV enlargement by experience readers •Poor inter-observer variability
Lang et al, JASE. 2005; 18(12)
Quantitative “linear” Assessment: •RV dimension by current ASE guidelines • Relay on linear measurements of the RV body from apical 4 chamber view and the RV outflow tract from parasternal short axis view • Weak correlation with RV size measured by CMR in children with CHD and dilated RV Lai et al, Int J Cardiovasc Imaging. 2008;24(7)
Alghamdi MH et al, JASE. 2012; 25(5)
Quantitative “area” Assessment: • RV area from “apical 4 chamber view”: –Correlate with RV size measured by CMR
• Kempny et al, Int J Cardiol.2010 –(r=0.63; p=0.006)
• Alghamdi et al, JASE. 2012 –(r=0.60; p<0.0001)
Alghamdi MH et al, JASE. 2012; 25(5)
Punn et al, JASE. 2010;23(12)
Punn et al, JASE. 2010;23(12)
Punn et al, JASE. 2010;23(12)
RV AREA •
Incorporates RV area at base, mid and apical regions thus may be more reliable than the annular tilt method alone
20% were excluded because of inadequate RV imaging. – More difficult to incorporate the entire “dilated” RV. – Prominent trabeculations can leads to measurement variability
RV ANNULAR TILT •
Underestimates RV volumes when RV enlargement involves mid or apical regions of RV and TV annulus plane is not tilted
•
No need to image the entire RV to calculate the annular tilt
•
• Correlations between 3D ECHO and CMR measurements of RVEDVi are still suboptimal in the CHD population – Time consuming – Not yet widely used in routine clinical practice. – RVEDVi is often underestimated by 3D ECHO, particularly when the RV is enlarged
• RV ejection is determined by longitudinal shortening – In case of RVH, circumferential and radial shortening contribute more to RV ejection
• RV pressure–volume loops are more triangular compared with the rectangular LV loops
• RV is more sensitive to both acute and chronic pressure loading – ? different embryologic origin of RV and LV myocardial cell
• Importance of Inter-ventricular inter-action – RV hypertrophy and/or dilatation affect LV function an vice versa
No single parameter is generally accepted in clinical practice
• Children older than 5: Normal value > 16 mm – Normal value “z-score” available for children
• Influenced by: – Direction of motion (alignment) – Global cardiac translation – Loading condition – Tricuspid valve Disease (TR, TS, surgery, calcification)
• No imaging of the outflow tract
640 healthy children
Koestenberger et al, JASE. 2009; 22(6)
• TAPSE and RVEF by CMR – (r= 0.81; P < 0.001) in 49 PAH patients – (r= 0.65; P < 0.001) in 156 TOF patients Koestenberger et al, Congenit Heart Dis. 2012; 7(3)
– (r = 0.50, P < 0.05) in 14 TOF patient Morcos et al, Int J Cardiovasc Imaging. 2009; 25(3)
% FAC= {(RVEDA-RVESA)/RVEDA} X 100
36 adults
Anavekar et al, Echocardiography. 2007; 24(5)
51 TOF Children
R = 0.57 , p < 0.0001
Alghamdi MH et al; Eur Heart J Cardiovasc Imaging. 2012 Jul
• Normal value > 35 % • TAPSE and RV %FAC by ECHO – (r = 0.91, P < 0.001) in 52 PAH patients Sexena et al, Echocardiography. 2006; 23(9)
• Limitation: – Definition of endocardial border can be difficult – Load-dependent indices – No imaging of the outflow tract
• (IVRT+ ICCT)/ ejection time • Normal value: 0.28 ± 0.04 • Normal RV : absent or very short isovolumic periods – With increases RV pressure and volume, the isovolumic periods become longer • Progressive RV systolic dysfunction: increase IVCT • Progressive RV diastolic function: increase IVRT
• Limitation: – Very loading dependent. – RV inflow and outflow Doppler can NOT be measured Simultaneously • Needs to be performed using two separate Doppler traces of TV inflow & RVOT Doppler at identical heart rates
• Most lab do not routinely use RV MPI
- Aligned angle - Nyquist limit of 10 - 30 cm/s - Minimal wall filter settings - Minimal optimal gain - PW sample volume of 5 mm - Sweep speed of 100 mm/s
Eidem et al, JASE. 2004 Jul; 17(3)
• Peak systolic wave S’ > 10 cm/sec • Normal pediatric value available • Limitation: – Influenced by alignment with the motion – Influenced by loading conditions – Only one single segment used for global function
51 PAH children
Takatsuki et al, J Pediatr. 2012 Dec;161(6)
Alghamdi MH et al; Eur Heart J Cardiovasc Imaging. 2012 Jul
Alghamdi MH et al; Eur Heart J Cardiovasc Imaging. 2012 Jul
R = 0.57 , p = 0.0005
51 TOF Children
Alghamdi MH et al; Eur Heart J Cardiovasc Imaging. 2012 Jul
• Limitation: – TDI derived Strain: • Angle and load dependency
– Speckle derived Strain • Load dependency
• Solid data on its reliability & reproducibility are still lacking • Growing interest of its use is increasing
• IVC/Hepatic vein reversal flow • SVC is less sensitive
• RA size (in absence of TV disease) • TV Doppler and TDI pattern – Limitation: • load and angle dependent • Respiratory variation
• Pulmonary artery ante-grade flow
Pulmonary artery ante-grade flow
â&#x20AC;˘ Though challenging, quantitative assessment of RV size and function is feasible by echo. â&#x20AC;˘ Echocardiography is the investigation of choice for screening and serial follow up of RV size and function
• RV has been ignored enough! • Each pediatric echo lab should have a systematic approach to investigate RV esp. in selected cases with RV pathology • More researches are needed to validate new RV echo measure before routine clinical use
â&#x20AC;˘ Till now, CMR remains the investigation of choice for RV size and function when echo fails to provide the needed information