ECHONOMY
Tools for Echocardiographic Calculations

Muhamed Saric, MD, PhD
New York University

## 1. Diagnosis of Intra-LV Dyssynchrony

 Used in patients being considered for implantation of biventricular (CRT) devices
 Preferred technique: Color tissue Doppler in A4C, A3C and A2C views as described here.
 What to measure: Opposing wall delay (OWD; time difference between S wave peaks of opposing walls). Report the largest OWD value.
 Abnormal cutoff value : OWD >65 msec

## 2. Pacemaker Optimization

 Step 1: AV Optimization
 Step 2: VV Optimization

## 2.1. AV Optimization

 Exclude patients in atrial fibrillation; note that AV optimization in patients with mitral prosthetic valves may be challenging.
 Used in patients with dual-chamber (RA/RV) or biventricular pacemakers. In patients with biventricular systems, the pacemaker is usually set to a monochamber LV pacing mode during AV optimization.
 Preferred technique: Pulsed-wave Doppler of mitral inflow and/or continuous-wave spectral Doppler VTI of aortic outflow described here.
What to measure:
 Mitral inflow - Look for AV delay at which E and A are separate from each other, the A wave is not truncated and there is no diastolic mitral regurgitation. Aortic outflow - Look for AV delay at which the aortic VTI is the largest. Start with AV delay of 200 msec and decrease it in 20-msec steps until AV delay is 60 msec.

## 2.2. VV Optimization

 Used in patients with biventricular pacemakers.
 Preferred technique: Continuous-wave spectral Doppler VTI of aortic outflow described here.
 Note that VV delay can usually be programmed from +80 msec (LV before RV) to -80 msec (RV before LV).
 What to measure: Look for VV delay at which the VTI is the largest. Optimal VTI is often at VV delay = +20 msec (LV before RV).
 When VV delay is used to pre-excite RV (negative VV delay), AV delay obtained in step 1 above (initial AV delay) should be adjusted as follows: : New AV delay = Initial AV delay - VV delay of RV pre-excitation

## 2.3. Intra-LV Optimization

 Once a biventricular pacemaker is implanted, intra-LV optimization is usually unfeasible.
 Measurements of intra-LV delays are primarily used to assess for LV dyssynchrony prior to biventricular pacemaker implantation as described here.

## References

Gorcsan J 3rd, Abraham T, Agler DA, Bax JJ, Derumeaux G, Grimm RA, Martin R, Steinberg JS, Sutton MS, Yu CM; American Society of Echocardiography Dyssynchrony Writing Group. Echocardiography for cardiac resynchronization therapy: recommendations for performance and reporting--a report from the American Society of Echocardiography Dyssynchrony Writing Group endorsed by the Heart Rhythm Society. J Am Soc Echocardiogr. 2008 Mar;21(3):191-213.

Barold SS, Ilercil A, Herweg B. Echocardiographic optimization of the atrioventricular and interventricular intervals during cardiac resynchronization. Europace. 2008 Nov;10 Suppl 3:iii88-95.