Turandot Saul December 19, 2007

Strengths  Can assess morphology and function  Cheap  No radiation  Portable  Readily available

Limitations  Finding an acoustic window - narrow inter-costal spaces - all regions of LV not visualized in all patients - obesity - intervening lung tissue in pt with COPD - musculoskeletal deformities e.g. kyposis, pectus excavatum

Left Ventricular Function  Fills at low enough pressures to not cause pulmonary congestion  Deliver enough blood to periphery at high enough pressure to perfuse tissues No one quantity measures these assessments of performance - ejection fraction

Ejection Fraction  Depends on contractility, preload and afterload, heart rate, synchronicity of contractions  Global parameter, regional differences in contractility averaged

Ejection Fraction Qualitative - visual inspection - severity: mild, moderate, severe - focality - global: reported as a range in intervals of 5-10% - regional: 17 segments

Global Function - PSLA Normal Cardiomyopathy

Global Function - PSSA Normal Cardiomyopathy

17 Cardiac Segments

Inferior Wall - PSLA

Inferior Wall - PSSA

Anterior Wall - PSLA

Anterior Wall - PSSA

Ejection Fraction Quantitative - accuracy, reproducibility limited - assumes shape of LV cavity - best in symmetric ventricles

Simpson’s Rule – the biplane method of disks  Volume left ventricle - manual tracings in systole and diastole - area divided into series of disks - volume of each disk ( πr 2 * h ) summed = ventricular volume LV-ED LV-ES A4C A2C

Simpson’s Rule – the biplane method of disks  Once volumes determined, EF is calculated : LV diastolic volume - LV systolic volume x 100% LV diastolic volume  Normal > 50%, 35 to 50% moderately depressed, <35% severely depressed  Edge detection software can identify borders

Limitations  Operator dependence - inter/intra observer variability is 10-30%  Limited utility - MR high EF but little forward flow - AS low EF but possibly reversible

Superiority of Visual Versus Computerized Echo Estimation of Radionuclide LVEF - Amico, A. American Heart Journal, 1989  Blinded study, 44 patients  Gold Standard - equilibrium radionuclide angiography (ERNA)  Echocardiographic methods included: 1. Cubed M-mode formula 2. Teichholz M-mode formula 3. Subjective estimation of LVEF from two-dimensional videotape 4. Area-length method in one four-chamber view 5. Average of area-length method in three four-chamber views 6. Average of area-length method in four-chamber and two-chamber views (one beat each) 7. Subjective estimation from stored videoloop of four-chamber and two-chamber view  Best correlation method 3 - subjective estimation by experienced cardiologist  More time-consuming and costly computer techniques yielded worse estimates

Determination of LV Function by EP Echocardiography of Hypotensive Patients - Moore, C. Academic Emergency Medicine, 2002  Prospective, observational study, convenience sample  Four EPs, focused echo training  51 patients with symptomatic hypotension  Blinded cardiologist reviewed studies  Pearson's correlation coefficient R =  Echo quality rated as good 33%, moderate 43%, poor 22%.

Accuracy of Emergency Physician Assessment of Left Ventricular Ejection Fraction – Randazzo, M. Academic Emergency Medicine, 2003  Cross-sectional observational study, convenience sample  115 patients, chest pain (45.1%), congestive heart failure (38.1%), dyspnea (5.7%), and endocarditis (10.6%)  Three-hour training session  LVEF poor ( 55%)  Formal echo within four hours interpreted by cardiologist.  LVEF correlation 86.1% overall agreement  Highest (91%) in normal LVEF category, 70.4% poor LVEF, 47.8% moderate LVEF

Clinical utility  Patients with active chest pain - regional wall motion abnormality - high sensitivity for ischemia or infarction; absence excludes it - moderately specific  Prognostic information short and long term  Other diagnosis: PE, dissection, tamponade

Diastolic function  Impaired diastolic relaxation  LV wall thickness usually increased  Increase LA size

Sources  UptoDate: Noninvasive methods for measurement of left ventricular systolic function  Zipes: Braunwald’s Heart Disease: A Textbook of Cardiovascular Diseases. Elsevier Inc,  Directed bedside transthoracic echocardiography: preferred cardiac window for left ventricular ejection fraction estimation in critically ill patients. American Journal of Emergency Medicine - Volume 25, Issue 8 (October 2007) - Copyright © 2007 W. B. Saunders Company  Accuracy of emergency physician assessment of left ventricular ejection fraction and central venous pressure using echocardiography. Randazzo MR - Acad Emerg Med - 01-SEP-2003; 10(9):  Determination of left ventricular function by emergency physician echocardiography of hypotensive patients. Moore CL - Acad Emerg Med - 01-MAR-2002; 9(3):  Subjective visual echocardiographic estimate of left ventricular ejection fraction as an alternative to conventional echocardiographic methods: comparison with contrast angiography. Mueller X - Clin Cardiol - 01-NOV-1991; 14(11):  Superiority of visual versus computerized echocardiographic estimation of radionuclide left ventricular ejection fraction. Amico AF - Am Heart J - 01-DEC-1989; 118(6):  Video: Yale Cardiothoracic Imaging