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Elevated temporal lability of myocardial repolarization after coronary artery bypass grafting

Anna Myredal1, Ann-Kristin Karlsson, Mats Johansson

  • 1Department of Internal Medicine, Varberg Hospital, Varberg, Sweden. anna.myredal@lthalland.se

Journal of Electrocardiology
|July 22, 2008
PubMed

Insights

Myocardial repolarization lability is elevated early after coronary artery bypass grafting (CABG), potentially increasing ventricular arrhythmia risk. This variability improves over time but remains higher in CABG patients long-term.

Area of Science:

  • Cardiology
  • Cardiac Electrophysiology

Background:

  • Ventricular arrhythmias post-coronary artery bypass grafting (CABG) carry high mortality.
  • Elevated temporal lability of myocardial repolarization is linked to sudden cardiac death.

Purpose of the Study:

  • To investigate temporal variability of myocardial repolarization in patients undergoing CABG.
  • To assess repolarization variability during early and long-term recovery phases post-CABG.

Main Methods:

  • Compared 61 CABG patients with 33 healthy subjects (HS).
  • Recorded electrocardiogram and blood pressure at 5 weeks and 5 months post-surgery.
  • Calculated QT variability index (QTVI) as the log ratio of QT and RR interval variabilities.

Main Results:

  • QTVI and QT variances were significantly elevated at 5 weeks post-CABG compared to HS.
  • RR variances were reduced at 5 weeks post-CABG.
  • QTVI and QT variances decreased, while RR variances increased between 5 weeks and 5 months.
  • QTVI remained elevated in CABG patients at 5 months compared to HS.

Conclusions:

  • Elevated temporal lability of myocardial repolarization is prominent in the early recovery phase after CABG.
  • This heightened variability may indicate an increased susceptibility to ventricular arrhythmias.
  • Repolarization lability shows improvement over time but persists long-term post-CABG.
Abstract

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