Home
Up

ECHONOMY
Tools for Echocardiographic Calculations
Muhamed Saric, MD, PhD
New York University
 

Intra LV Delay

Diagnosis of Intra-LV Delay (LV Dyssynchrony)

Normal Intra-LV Delay:
Normally, LV contraction starts in the interventricular septum and spreads throughout the LV within 40 msec.

Mechanical Intra-LV Delay:
Mechanical dyssynchrony is usually associated with prolonged QRS on surface EKG and is typically seen with left bundle branch block (LBBB). LV contraction starts in the region of interventricular septum and the anterior wall. It then progresses in a delayed fashion toward the infero-postero-lateral LV segments.

Diagnosis of Intra-LV Delay by Echocardiography:
Multiple echocardiographic techniques are used; most data exist for color tissue Doppler-based techniques.
 

Intra-LV Delay: Color Tissue Doppler Method
Among all methods, this is the preferred method.
 
  1. Obtain color tissue Doppler curves in apical views (A4C, A2C and A3C) during a breath hold.
     
  2. Measure the opposing wall delay using the peak-to-peak time distance between S waves:
    : A4C - inferior septum to lateral wall
    : A2C - anterior wall to inferior wall
    : A3C - anterior wall to inferolateral (posterior) wall.
  3. Report the largest opposing wall delay.
    : Abnormal opposing wall delay by color tissue Doppler >65 msec.
     

Caveat: No guidelines exist for the use of opposing wall technique in atrial fibrillation.

Source: J Am Soc Echocardiogr. 2008 Mar;21(3):191-213.
 

Intra-LV Delay: LV Strain Methods
Of all strain methods, speckle tracking radial strain is the preferred method at present.
 
  1. Obtain radial strain curves in the short axis view at the level of papillary muscles.
  2. Measure the time difference between peak stain values in opposing walls (septum vs. posterior walls)
    : Abnormal opposing wall delay by radial strain >130 msec

Source: J Am Soc Echocardiogr. 2008 Mar;21(3):191-213.
 

Intra-LV Delay: M Mode Methods
Of all the methods, M mode techniques are least reliable and should be used only to supplement other techniques.
 
  1. Obtain the parasternal long-axis or short-axis view of the left ventricle in standard or color M mode.
  2. Measure the opposing wall (septum to posterior wall) delay:
    : Abnormal opposing wall delay by M mode >130 msec

Source: J Am Soc Echocardiogr. 2008 Mar;21(3):191-213.
 

Intra-LV Delay: Spectral Doppler Methods
Compared to color Doppler methods:
bulletThere are much less data for spectral Doppler techniques
bulletIn spectral Doppler techniques time to onset of S wave rather than time to peak S wave is used.
: Abnormal opposing wall delay of spectral Doppler - Not well defined.

Source: J Am Soc Echocardiogr. 2008 Mar;21(3):191-213.
 

Intra-LV Delay: 3D Echo Method
Compared to color Doppler methods:
bullet3D echo methods for intra-LV are less established
 
  1. Obtained a full 3D volume of LV
  2. Use 3DQ Advanced in QLab package
  3. Display time-LV volume curves
  4. Obtain the systolic dyssynchrony index (SDI) defined as the SD of time to minimum systolic volume of the 16 LV segments, expressed in percent RR duration.
    : Abnormal SDI of 3D echo > 8%

3D echo data from a patient without LV dyssynchrony

 

Pacemaker Optimization of Intra-LV Delay
bullet

Once the biventricular pacemaker is implanted, no intra-LV optimization is feasible.

bullet

All intra-LV optimization should occur prior to biventricular pacemaker implantation.

bullet

Echocadiography may be used to guide the optimal placement of the LV pacing lead.

 

Reference
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.

Soliman OI, Geleijnse ML, Theuns DA, van Dalen BM, Vletter WB, Jordaens LJ, Metawei AK, Al-Amin AM, ten Cate FJ. Usefulness of left ventricular systolic dyssynchrony by real-time three-dimensional echocardiography to predict long-term response to cardiac resynchronization therapy. Am J Cardiol. 2009 Jun 1;103(11):1586-91. Epub 2009 Apr 8.