Right Ventricular Enlargement



Right Ventricular Enlargement


Gregory Kicska, MD, PhD



DIFFERENTIAL DIAGNOSIS


Common



  • Left Heart Failure


  • Secondary Pulmonary Hypertension


  • Right Heart Failure


Less Common



  • Left to Right Shunt


  • Right Heart Valvular Disease


  • Primary Pulmonary Arterial Hypertension


Rare but Important



  • Arrhythmogenic Right Ventricular Dysplasia


  • Congenital Heart Disease



    • D-transposition of Great Vessels with Atrial Switch


    • Tetralogy of Fallot (TOF) with Pulmonic Regurgitation or Stenosis


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Quantitative determination of right ventricle dilation



    • Normal end diastolic volume = 75 ± 13 mL/m2 for adolescent to adult


    • Volumes best measured with bright-blood cine MR in axial or short axis plane or retrospectively gated CT


  • Radiographic signs of RV dilation



    • Leftward displacement and flattening of left heart contour on frontal view


    • Filling of retrosternal clear space and posterior displacement of left ventricle on lateral view


    • Flattening of interventricular septum only during diastole suggests volume overload


    • Flattening of interventricular septum during systole and diastole suggests pressure overload with or without volume overload


  • Quantitative determination of right ventricular hypertrophy



    • Wall thickness > 5 mm suggests hypertrophy


    • Normal right ventricular free wall mass = 26 ± 5 g/m2


Helpful Clues for Common Diagnoses



  • Left Heart Failure



    • Ischemic cardiomyopathy and diabetes mellitus most common


    • Multi-vessel coronary artery calcifications/disease


    • LV and LA enlargement


    • Pulmonary edema


    • Prior myocardial infarction, LV delayed enhancement, or LV endomyocardial fat


    • Diastolic heart failure more commonly associated with elevated LA pressure


  • Secondary Pulmonary Hypertension



    • Main pulmonary artery > 2.8 cm if < 50 years, main pulmonary artery:ascending aorta ratio > 1 if > 50 years


    • RV mass/(LV + septum mass) > 0.6 suggests pulmonary hypertension


    • MR delayed contrast enhancement at RV wall insertion into interventricular septum


    • Suspect if interstitial lung disease, chronic obstructive pulmonary disease, or chronic pulmonary embolism


    • Suspect if mitral valve stenosis present



      • Calcified mitral valve leaflets


      • High flow jet on MR vertical long axis cine


      • Left atrial dilation


      • MR short axis mitral valve area < 2.5 cm on cine and elevated peak velocity on through plane phase contrast


      • Cardiac masses, such as atrial myxoma, can cause valve occlusion


  • Right Heart Failure



    • Markedly enlarged RV with relatively normal LV


    • Right atrial enlargement


    • Enlarged IVC/SVC and ascites


    • Ischemic cardiomyopathy suggested by proximal right coronary artery occlusive disease or left circumflex disease when left-dominant coronary anatomy present


Helpful Clues for Less Common Diagnoses



  • Left to Right Shunt



    • Atrial septal defect (ASD)



      • 2nd most common left to right shunt but most likely to cause dilated RV


      • Coexistent RA enlargement


      • MR bright-blood cine short axis or 4-chamber stack without skip throughout interatrial septum may show flow jet


      • Large ASD may not show flow jet on bright-blood cine



      • MR phase contrast determines main pulmonary artery:aorta flow > 1


      • In cases of sinus venous ASD, look for partial anomalous pulmonary venous return


    • Ventricular septal defect (VSD)



      • Most common left to right shunt but often not hemodynamically significant or spontaneously closes by adulthood


      • Best investigated with methods similar to ASD


  • Right Heart Valvular Disease



    • Valvular calcifications indicate stenosis or regurgitation


    • Phase contrast MR to determine pressure gradients and regurgitant fractions most helpful


    • Isolated enlargement of left pulmonary artery suggests pulmonary stenosis


  • Primary Pulmonary Arterial Hypertension



    • Pulmonary artery > 25 mmHg, pulmonary capillary wedge pressure < 15 mmHg, pulmonary vascular resistance > 2.4 mN x s/cm5


    • Absence of secondary cause of pulmonary hypertension


    • Distinction between primary and secondary causes is critical because therapeutic pulmonary vasodilators are deleterious in secondary causes


    • Imaging findings suggesting primary pulmonary hypertension



      • Normal lung volumes and parenchyma


      • Normal left heart size and absence of valvular calcifications


Helpful Clues for Rare Diagnoses

Tags:
Aug 8, 2016 | Posted by in CARDIOLOGY | Comments Off on Right Ventricular Enlargement

Full access? Get Clinical Tree
Get Clinical Tree app for offline access