Determination of the Longest Intrapatient Left Ventricular Electrical Delay May Predict Acute Hemodynamic Improvement in Patients After Cardiac Resynchronization Therapy

Francesco Zanon*, Enrico Baracca, Gianni Pastore, Chiara Fraccaro, Loris Roncon, Silvio Aggio, Franco Noventa, Alberto Mazza, Frits Prinzen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Background One of the reasons for patient nonresponse to cardiac resynchronization therapy is a suboptimal left ventricular (LV) pacing site. LV electric delay (Q-LV interval) has been indicated as a prognostic parameter of cardiac resynchronization therapy response. This study evaluates the LV delay for the optimization of the LV pacing site. Methods and Results Thirty-two consecutive patients (23 men; mean age, 7111 years; LV ejection fraction, 30 +/- 6%; 18 with ischemic cardiomyopathy; QRS, 181 +/- 25 ms; all mean +/- SD) underwent cardiac resynchronization therapy device implantation. All available tributary veins of the coronary sinus were tested, and the Q-LV interval was measured at each pacing site. The hemodynamic effects of pacing at different sites were evaluated by invasive measurement of LV dP/dt(max) at baseline and during pacing. Overall, 2.9 +/- 0.8 different veins and 6.4 +/- 2.3 pacing sites were tested. In 31 of 32 (96.8%) patients, the highest LV dP/dt(max) coincided with the maximum Q-LV interval. Q-LV interval correlated with the increase in LV dP/dt(max) in all patients at each site (AR1 =0.98; P95 ms corresponded to a >10% in LV dP/dt(max). An inverse correlation between paced QRS duration and improvement in LV dP/dt(max) was seen in 24 patients (75%). Conclusions Pacing the LV at the latest activated site is highly predictive of the maximum increase in contractility, expressed as LV dP/dt(max). A positive correlation between Q-LV interval and hemodynamic improvement was found in all patients at every pacing site, a value of 95 ms corresponding to an increase in LV dP/dt(max) of 10%.
Original languageEnglish
Pages (from-to)377-383
JournalCirculation-Arrhythmia and Electrophysiology
Issue number3
Publication statusPublished - Jun 2014


  • cardiac resynchronization therapy
  • cardiomyopathies
  • heart failure
  • hemodynamics

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