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Relation of right ventricular pacing site to left ventricular mechanical synchrony

Amit J Verma1, Matthew S Lemler, Ilana J Zeltser

  • 1Department of Pediatrics, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.

The American Journal of Cardiology
|September 7, 2010
PubMed

Insights

Right ventricular apical pacing can cause left ventricular dyssynchrony in pediatric patients. Tissue Doppler imaging (TDI) identified that pacing the RV outflow tract or apex, but not the atrium or septum, acutely impairs LV synchrony.

Area of Science:

  • Cardiology
  • Pediatric Electrophysiology
  • Echocardiography

Background:

  • Transvenous pacing leads are commonly placed in the right ventricular (RV) apex.
  • Long-term RV apical pacing in pediatric patients is associated with myopathic changes.
  • Left ventricular (LV) mechanical dyssynchrony may contribute to decreased LV function and histopathologic changes.

Purpose of the Study:

  • To determine if tissue Doppler imaging (TDI) can detect acute changes in LV synchrony during pacing from various RV sites.
  • To evaluate the impact of different pacing locations on LV mechanical synchrony.

Main Methods:

  • Prospective study involving 19 subjects undergoing catheter ablation.
  • Measured Ts-4w (LV synchrony) and Doppler-derived cardiac output during pacing at four sites: high right atrium, high RV septum, RV outflow tract, and RV apex.
  • Compared Ts-4w values during sinus rhythm and each pacing protocol; >65 ms defined mechanical dyssynchrony.

Main Results:

  • Pacing from the RV apex (85.7 +/- 18.4 ms) and RV outflow tract (84.2 +/- 20.4 ms) significantly induced LV mechanical dyssynchrony (p <0.0001).
  • Pacing from the high right atrium (32.6 +/- 17.6 ms) and high RV septum (28.9 +/- 10.9 ms) did not differ from sinus rhythm (39.5 +/- 15.5 ms).
  • TDI demonstrated significant differences in LV synchrony based on pacing site.

Conclusions:

  • TDI effectively identifies acute changes in LV synchrony related to pacing site.
  • Ts-4w measurement may aid in selecting optimal transvenous pacing lead placement.
  • Pacing site significantly influences LV mechanical synchrony, with apical and outflow tract pacing being detrimental.

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