Basic Echocardiography Wendy Blount, DVM Nacogdoches TX Wendy Blount, DVM Nacogdoches TX
Echo Technique - Anatomy Tricuspid valve Septal leaflet Parietal leaflet Pulmonic Valve Right cusp Left cusp Intermediate cusp Mitral valve Leaflets are less distinct Aortic Valve Right cusp Left cusp Septal cusp
Echo Technique - Anatomy RV Conus arteriosus 3 papillary muscles LV 2 papillary muscles
Echocardiography Equipment Transducer – small footprint Fan-shaped beam or sector High frequency for small animals Low frequency for large animals Machines range from Mhz 5-7 MHz will work fine for most dogs and cats for echo
Echocardiography Equipment Double window with simultaneous B and M modes (video)video Can do measurements on B-mode or M-mode Need a cursor which can measure mm, or cm marks on the images Ability to capture images is important
Echocardiography Preparation Thin coated animals – alcohol, part the hairs, gel Thick coated animals – shave the window – at the sternum, just behind the elbow Sedation only if needed –Acepromazine – mg/lb (max 1 mg) –Buprenex – mg/kg –Mix together and give IV (handout)handout
Echocardiography Positioning for 8 standard views Right lateral recumbency Cardiac table is nice but not necessary Sonographer needs a stool or chair Placement of probe: –Feel the apical beat, and put your probe there (probe marker cranial) –Imagine the longitudinal axis of the heart, probe at 90 o (short axis views) –Adjust 1 intercostal space Cr or Cd PRN –Rarely move the probe head – just fan and twist(video)video
1. Short Axis – Left Ventricle Fan from base to apex, until you have just passed the mitral valve, and the LV papillary muscles appear (mushroom view) Rotate until PM are the same size If you are getting a rib shadow, try one intercostal space cranial or caudal Fan cranial and caudal to center the heart on the screen
1. Short Axis – Left Ventricle Abbreviations - Structures P – pericardium RV – right ventricle IVS – intraventricular septum LV – left ventricle PPM – posterior papillary muscle APM – anterior papillary muscle
1. Short Axis – Left Ventricle Measurements IVSTdIVSTd - IntraVentricular Septum Diastole LVIDd - LV Inner Diameter Diastole LVPWd – LV Posterior Wall Diastole IVSTsIVSTs - IntraVentricular Septum Systole LVIDs - LV Inner Diameter Systole LVPWs – LV Posterior Wall Systole
1. Short Axis – Left Ventricle Measurements IVSTdIVSd VSdIVSTd = IVSd = VSd LVIDd = LVd = LVLd LVPWd = LVFWd = LVWd IVSTsIVSs VSsIVSTs = IVSs = VSs LVIDs = LVs = LVLs LVPWs = LVFWs = LVWs
1. Short Axis – Left Ventricle Measurements - Calculated FS – fractional shortening (LVIDd – LVIDs) LVIDd –Assumes perpendicular to myocardium –Assumes contractility is uniform in the LV –Extremes in preload and afterload can affect FS, as well as myocardial function
1. Short Axis – Left Ventricle Measurements - Calculated FS – fractional shortening AKA shortening fraction (SF) –>30% in the dog –>40% in the cat –>45% if MR is compensated
1. Short Axis – Left Ventricle Measurements - Tips Make sure you don’t include PM in the LVPW measurement –If you do, your LVPW will be artifactually thicker –Clue – check for this if LVPW is much thicker than IVS Make sure you are not too far apical –If you are, your LVID will be artifactually small –And LVPW will be artifactually thick
1. Short Axis – Left Ventricle Measurements - Tips Measure three times –Take the average –Throw out any outliers Several sets of normals published –1-2mm outside normal may not always be significant
2. Short Axis – Apex Structures Pericardium May or may not see RV LV apical lumen No measurements here
3. Short Axis – Chordae Tendinae Structures Pericardium RV LV CH - Chordae Tendinae (posterior & anterior) No measurements here
4. Short Axis – Mitral Valve Structures Pericardium RV RV Papillary Muscles LV MV - Mitral Valve (Posterior & Anterior)
4. Short Axis – Mitral Valve Measurement EPSS – E-Point to Septal Separation –Can denote decreased LV systolic function –Less than 6 mm in large dogs –Less than 3-5 mm in small dogs and cats
5. Short Axis – Aortic Valve Structures RVOT – Right Ventricular Outflow Tract TV – Tricuspid Valve PV – Pulmonic Valve Ao – Aortic Valve LA – Left Atrium
5. Short Axis – Aortic Valve Measurements Ao – at largest dimension (systole) LA – at largest dimension (diastole) LA:Ao – –0.8 to 1.3 in dogs –0.8 to 1.4 in cats
6. Short Axis – Pulmonary Artery Structures RA – Right Atrium Ao – Aorta (ascending) PA– Pulmonary Artery –LPA – left pulmonary artery –RPA – right pulmonary artery CaVC – Caudal Vena Cava
7. Long Axis – 4 Chamber Technique Get short axis “mushroom” view Rotate 90 degrees counterclockwise
7. Long Axis – 4 Chamber Structures RV – Right Ventricle RA – Right Atrium – difficult to view completely TV – Tricuspid Valve LV – Left Ventricle LA – Left Atrium MV – Mitral Valve, PM – papillary muscle
7. Long Axis – 4 Chamber Video
8. Long Axis – LVOT Technique Find 4 Chamber view Angle the “dot” toward the shoulders Elevate the cord end of the probe
8. Long Axis – LVOT Structures RV, TV, RA LV, PM, MV Very edge of the LA LVOT – AV (LC, SC), ascending Ao RPA – Right Pulmonary Artery
8. Long Axis – LVOT Video Normal Dog Video
Dog RV Measurement Values RVWd – less than LVWd RVIDd – 1/3 or less of LVIDd (handout)handout
Cat Echo Normal Values IVSTd – 3-6 mm LVIDd – mm LVPWd – 3-6 mm IVSTs LVIDs – 4-11 mm LVPWs – 4-10 mm Aos – 6-12 mm LAd – 7-15 mm FS - >40% EPSS mm EF - >70% LA:Ao – RVIDd mm RVWd - <3 mm (form)form
Ferret Echo Normal Values (Mean) LVIDD – 11.0 mm LVIDS mm LVPW mm FS - 42% EPSS - 0