Signal-Averaged Recording of his Bundle Activity in Cardiac Postoperative Patients by Temporary Stimulation of Epicardial Wires

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Abstract

Background and objectives

The atrioventricular conduction disturbances occur frequently in valve replacement surgery. However, anticoagulant therapy makes invasive recording difficult.In this study the end-point was to record the His bundle activity from the temporary epicardial pacing wires left during cardiac surgery.

Methods and results

Fifty-eight patients were enrolled, ten of whom underwent the classic invasive procedure as well. A signal averaging computer was used, connecting the Z leads, from Frank's orthogonal system, to temporary epicardial wires. The study ended when noise level reached 0.2 uV. Gain was optimized for data analysis, and filters between 100 and 250Hz were used for noise reduction. It was required that His bundle activity be recorded in at least two of three leads. H-V intervals of 28 to 155 msecs were recorded. When both methods were used (invasive versus non-invasive), the correlation coefficient was 0.96.

Conclusions

1) His bundle activity was easily recorded from temporary epicardial pacing wires left during cardiac surgery. 2) Excellent correlation was observed between invasive and non-invasive methods. 3) This method allows a safe evaluation of conduction disturbances that frequently occur in valve replacement surgery. 4) Patients with long H-V intervals were easily detected and indications for pacemaker placement were clearly determined.