PMC5818722_01
ECG and pressure waveform at 50 bpm VVI pacing. Each VVI pacing spike captures a QRS wave
40981_2016_29_Fig1_HTML.jpg
PMC5818722_01_40981_2016_29_Fig1_HTML.jpg
Fig1
We then attempted to withdraw from CPB and began VVI pacing at 50 bpm (Fig. 1).
ECG and pressure waveform showing Mobitz type AV block. Each AOO pacing spike captures a P wave, but every third P wave does not induce a QRS wave
40981_2016_29_Fig2_HTML.jpg
PMC5818722_01_40981_2016_29_Fig2_HTML.jpg
Fig2
After 30 min, we attempted atrial asynchronous (AOO) pacing, but the patient's atrioventricular (AV) node did not completely conduct supraventricular electrical activity and the ECG showed Mobitz type AV block (Fig. 2); therefore, we elected to maintain VVI pacing.
ECG and pressure waveform during the first episode of ventricular fibrillation. This ECG shows the R-on-T phenomenon resulting from undersensing of a PVC. A pacing spike hit the T wave (large arrow) following a PVC (small arrow)
40981_2016_29_Fig3_HTML.jpg
PMC5818722_01_40981_2016_29_Fig3_HTML.jpg
Fig3
ECG showed Vf (Fig. 3). External defibrillation with 270 J was administered immediately, which resulted in recovery of the electrical rhythm; ventricular pacing was then able to capture ventricular contraction.
ECG and pressure waveform during the second episode of ventricular fibrillation. This ECG also shows the R-on-T phenomenon resulting from undersensing of a PVC. A pacing spike hit the T wave (large arrow) following a PVC (small arrow) in this episode, as well
40981_2016_29_Fig4_HTML.jpg
PMC5818722_01_40981_2016_29_Fig4_HTML.jpg
Fig4
However, within only two minutes of the first Vf, the ECG again showed a Vf waveform (Fig. 4).