Cardiac memory in cardiac resynchronization therapy: A vectorcardiographic comparison of biventricular and left ventricular pacing

Laura Perrotta, Giuseppe Ricciardi, Paolo Pieragnoli, Martina Nesti, Giulia Pontecorboli, Fabio Fantini, Luigi Padeletti

Research output: Contribution to journalArticlepeer-review


Abstract Introduction "Cardiac memory" (CM) refers to a change in repolarization induced by an altered pathway of activation, manifested after resumption of spontaneous ventricular activation (SVA). Aims To investigate for the first time in humans the effects of left ventricular (LV) pacing on CM development through vectorcardiography (VCG). Methods We studied 28 patients with heart failure (HF) and left bundle branch block (LBBB) treated with cardiac resynchronization therapy (CRT). Fourteen patients underwent biventricular (BIV) stimulation; the other 14 underwent LV stimulation only. VCG was acquired during SVA at baseline and during AAI and DDD pacing immediately after and 7 and 90 days after the implant. Results At baseline, in both groups, the QRS and T vectors angles were those specific of LBBB pattern. During DDD pacing, QRS vector angle changed to the right and upward in BIV patients while no significant differences were observed in LV patients. During AAI pacing, T vector angle changed significantly in BIV patients, following the direction of the paced QRS and amplitude significantly increased. In LV patients no significant differences in T vector angles were observed. Only T vector amplitude significantly increased at 7 days (p = 0.03) and at 90 days (p = 0.008 vs baseline). Conclusion In patients with LBBB, BIV pacing induces cardiac memory development as a significant change in T vector magnitude and angle, while LV pacing doesn't induce significant modifications in QRS and T vector angles and CM is manifested only as a significant T vector amplitude change.

Original languageEnglish
Article number52058
Pages (from-to)571-577
Number of pages7
JournalJournal of Electrocardiology
Issue number4
Publication statusPublished - Jul 1 2015


  • Abbreviations CM cardiac memory
  • BIV biventricular pacing
  • CRT cardiac resynchronization therapy
  • HF heart failure
  • LBBB left bundle branch block
  • LV left ventricular
  • SVA spontaneous ventricular activation
  • VCG vectorcardiography

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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