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Regions of latest mechanical contraction correspond to regions of latest electrical activation: an electro-mechanical coupling study in patients undergoing cardiac resynchronization therapy

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Numerous studies have shown that placing the left ventricular (LV) pacing lead in the latest contracting region (mechanically dyssynchronous) or the latest activated region (electrically dyssynchronous) of the LV improves patient response to Cardiac Resynchronization Therapy (CRT)... Electrical dyssynchrony: Regional electrical delay times were determined from local electrograms (EGMs) acquired during CRT device implantation... EGMs were acquired simultaneously from the RV lead (placed in the apex of the RV) and LV lead (placed at several sites in the free wall of the LV). 35 EGM recordings were obtained at several potential pacing sites in the 10 patients... The electrical delay was defined as the peak-to-peak difference between the EGMs from the RV and LV leads... Mechanical delay times within a region the size of an AHA segment centered at the LV pacing location were averaged to obtain a corresponding mechanical delay time... There was a strong linear relationship between electrical and mechanical delay times over all patients (R=0.85 ± 0.21)... The linear best fit in each patient yielded a positive slope (1.7 ± 1.3) and the slope varied greatly between patients (Range: 0.06-4.11)... The site that exhibited the largest electrical delay always corresponded to the site of latest mechanical delay... The location of this latest activated/contracting site varied significantly between patients (Posterolateral: 3, Anterolateral: 3, Anterior: 1)... The latest electrically activated site always corresponded to the latest mechanically contracting site; therefore either mechanical or electrically dyssynchronous regions can be targeted in an attempt to improve patient response to CRT.

No MeSH data available.


Determination of Electrical and Mechanical Delay Times: Electrical delay times were measured using peak-to-peak differences in the RV and LV EGMs (A). The measurement locations were mapped to the bullseye of mechanical delay times (B) to be compared (C).
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Figure 1: Determination of Electrical and Mechanical Delay Times: Electrical delay times were measured using peak-to-peak differences in the RV and LV EGMs (A). The measurement locations were mapped to the bullseye of mechanical delay times (B) to be compared (C).


Regions of latest mechanical contraction correspond to regions of latest electrical activation: an electro-mechanical coupling study in patients undergoing cardiac resynchronization therapy
Determination of Electrical and Mechanical Delay Times: Electrical delay times were measured using peak-to-peak differences in the RV and LV EGMs (A). The measurement locations were mapped to the bullseye of mechanical delay times (B) to be compared (C).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4043851&req=5

Figure 1: Determination of Electrical and Mechanical Delay Times: Electrical delay times were measured using peak-to-peak differences in the RV and LV EGMs (A). The measurement locations were mapped to the bullseye of mechanical delay times (B) to be compared (C).

View Article: PubMed Central - HTML

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

Numerous studies have shown that placing the left ventricular (LV) pacing lead in the latest contracting region (mechanically dyssynchronous) or the latest activated region (electrically dyssynchronous) of the LV improves patient response to Cardiac Resynchronization Therapy (CRT)... Electrical dyssynchrony: Regional electrical delay times were determined from local electrograms (EGMs) acquired during CRT device implantation... EGMs were acquired simultaneously from the RV lead (placed in the apex of the RV) and LV lead (placed at several sites in the free wall of the LV). 35 EGM recordings were obtained at several potential pacing sites in the 10 patients... The electrical delay was defined as the peak-to-peak difference between the EGMs from the RV and LV leads... Mechanical delay times within a region the size of an AHA segment centered at the LV pacing location were averaged to obtain a corresponding mechanical delay time... There was a strong linear relationship between electrical and mechanical delay times over all patients (R=0.85 ± 0.21)... The linear best fit in each patient yielded a positive slope (1.7 ± 1.3) and the slope varied greatly between patients (Range: 0.06-4.11)... The site that exhibited the largest electrical delay always corresponded to the site of latest mechanical delay... The location of this latest activated/contracting site varied significantly between patients (Posterolateral: 3, Anterolateral: 3, Anterior: 1)... The latest electrically activated site always corresponded to the latest mechanically contracting site; therefore either mechanical or electrically dyssynchronous regions can be targeted in an attempt to improve patient response to CRT.

No MeSH data available.