case_images: PMC2729473_01
case_images: 25 seconds snap shot from
  stage 2 non-REM study in patient number 1. Black arrow shows the onset of sinus
  arrest lasting 4.5 seconds. After the pause, junctional rhythm is observed. Upper channels (C4-A1) (C3-A2)
  (O2-A1): electroencephalogram; fourth and fifth channel (ROC-A1) (LOC-A2):
  oculogram; sixth channel: chin electromyogram; seventh channel: oxygen
  saturation; eigth channel: electrocardiogram; ninth channel: airflow; tenth
  channel: chest movement; eleventh channel: abdomen movement.
case_images: CRM2009-675078.001.jpg
case_images: PMC2729473_01_CRM2009-675078.001.jpg
case_images: fig1
case_images: The sleep study showed no evidence of SA but several pauses due to sinus arrest were observed (Figure 1, black arrow).
case_images: PMC2729473_02
case_images: (a) 25 seconds snap shot from sleep
  study in patient number 2 during wakefulness. White arrows show the beats that were
  initially reported as non-conducted P-waves. Upper channels (C3-A1) (01-A1):
  electroencephalogram; third and fourth channel (L-EOG-A1) (R-EOG-A1):
  oculogram; fifth channel (EMG1) (EMG2): electromyogram; sixth channel (EKG1) (EKG2): electrocardiogram; seventh channel (SaO2): oxygen saturation;
  eighth channel (LEG1) (LEG2): leg movement; ninth channel: airflow; tenth
  channel: chest movement; eleventh channel: abdomen movement. (Panel (b)) Amplification of the area
  under the highlighted rectangle in panel (a). White arrows show the PVCs followed
  by a post-extrasystolic pause. (Panel (c)) 12-lead ECG shows right bundle
  branch block. White arrows show PVCs arising probably from the left outflow
  tract.
case_images: CRM2009-675078.002.jpg
case_images: PMC2729473_02_CRM2009-675078.002.jpg
case_images: fig2
case_images: The ECG of the polysomnography was reported as second degree AV block Mobitz II (Figure 2(a)). A closer look to the ECG recording suggests the presence of ectopic beats followed by a postextrasystolic pause rather than what were considered to be nonconducted P-waves (Figure 2(b), white arrows). A 12-lead ECG was obtained showing right bundle branch block and frequent premature ventricular contractions (PVC) with a possible left ventricular outflow tract origin (Figure 2(c), white arrows).