Electrocardiographic R-wave changes during cardiac surgery.

Journal Article (Journal Article)

The diagnostic accuracy of exercise electrocardiography has been improved by incorporation of R-wave gain factor to correct the measured ST-segment changes. If marked changes in R-wave amplitude occur in individual patients during cardiac operations, a similar gain factor correction may improve the intraoperative diagnosis of myocardial ischemia. This investigation was designed to determine the frequency and magnitude of intraoperative V5 R-wave amplitude changes during cardiac operations. Electrocardiograms were recorded from 83 patients while patients were awake, anesthetized (baseline), after placement of the Favaloro and Canadian sternal retractors, and at end-operation. Compared with baseline values, placement of the Canadian sternal retractor was associated with a reduction in V5 R-wave amplitude from 15 +/- 1 to 10 +/- 1 mm (mean +/- SEM), in V5 S-wave amplitude from 3.5 +/- 0.4 to 1.7 +/- 0.3 mm, and in absolute ST-segment deviation from 0.50 +/- 0.04 to 0.39 +/- 0.05 mm. Changes in V5 R-wave amplitude were correlated with changes in ST-segment deviation in patients with baseline ST-segment deviations greater than or equal to 0.5 mm (r = 0.55, P = 0.0004, n = 37). Changes associated with the Favaloro retractor and the respiratory cycle were less marked. However, the V5 R-wave amplitude was decreased from 15 +/- 1 to 9 +/- 1 mm at end-operation. In conclusion, sternal spreading with the Canadian retractor was associated with marked reductions in V5 R- and S-wave amplitudes and ST-segment deviations. Marked changes in V5 R-wave amplitude persisted after sternal closure.(ABSTRACT TRUNCATED AT 250 WORDS)

Full Text

Duke Authors

Cited Authors

  • Mark, JB; Chien, GL; Steinbrook, RA; Fenton, T

Published Date

  • January 1992

Published In

Volume / Issue

  • 74 / 1

Start / End Page

  • 26 - 31

PubMed ID

  • 1734793

International Standard Serial Number (ISSN)

  • 0003-2999

Digital Object Identifier (DOI)

  • 10.1213/00000539-199201000-00005


  • eng

Conference Location

  • United States