Turandot Saul December 19, 2007. Strengths Can assess morphology and function Cheap No radiation Portable Readily available.

Turandot SaulDecember 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

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 ( πr2 * 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 = 0.86. 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 (<30%), moderate (30%-55%), or normal

(>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, 2007.

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): 973-7

Determination of left ventricular function by emergency physician echocardiography of hypotensive patients.Moore CL - Acad Emerg Med - 01-MAR-2002; 9(3): 186-93

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): 898-902

Superiority of visual versus computerized echocardiographic estimation of radionuclide left ventricular ejection fraction.Amico AF - Am Heart J - 01-DEC-1989; 118(6): 1259-65

Video: Yale Cardiothoracic Imaging www.med.yale.edu