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Increased ventricular premature contraction frequency during rem sleep in patients with coronary artery disease and obstructive sleep apnea.

Watanabe MA, Bhalodia R, Lundequam EJ, Domitrovich PP, Steinmeyer BC, Stein PK, Freedland KE, Duntley SP, Carney RM - Indian Pacing Electrophysiol J (2008)

Bottom Line: VPC frequency was affected significantly by sleep stage (Wake, S2 and REM, F=5.8, p<.005) and by AHI (F=8.7, p<.005).Oxygen desaturation duration per apnea episode correlated positively with AHI (r(2)=.71, p<.0001), and was longer in REM than in non-REM (p<.0001).The heart rate turbulence parameter TS correlated negatively with oxygen desaturation duration in REM (r(2)=.06, p=.014).

View Article: PubMed Central - PubMed

Affiliation: Internal Medicine Department, St. Louis University, USA. watanabe@slu.edu

ABSTRACT

Background: Patients with obstructive sleep apnea are reported to have a peak of sudden cardiac death at night, in contrast to patients without apnea whose peak is in the morning. We hypothesized that ventricular premature contraction (VPC) frequency would correlate with measures of apnea and sympathetic activity.

Methods: Electrocardiograms from a sleep study of 125 patients with coronary artery disease were evaluated. Patients were categorized by apnea-hypopnea index (AHI) into Moderate (AHI <15) or Severe (AHI>15) apnea groups. Sleep stages studied were Wake, S1, S2, S34, and rapid eye movement (REM). Parameters of a potent autonomically-based risk predictor for sudden cardiac death called heart rate turbulence were calculated.

Results: There were 74 Moderate and 51 Severe obstructive sleep apnea patients. VPC frequency was affected significantly by sleep stage (Wake, S2 and REM, F=5.8, p<.005) and by AHI (F=8.7, p<.005). In Severe apnea patients, VPC frequency was higher in REM than in Wake (p=.011). In contrast, patients with Moderate apnea had fewer VPCs and exhibited no sleep stage dependence (p=.19). Oxygen desaturation duration per apnea episode correlated positively with AHI (r(2)=.71, p<.0001), and was longer in REM than in non-REM (p<.0001). The heart rate turbulence parameter TS correlated negatively with oxygen desaturation duration in REM (r(2)=.06, p=.014).

Conclusions: Higher VPC frequency coupled with higher sympathetic activity caused by longer apnea episodes in REM sleep may be one reason for increased nocturnal death in apneic patients.

No MeSH data available.


Related in: MedlinePlus

Histogram of sleep stage distribution of VPC frequency in patients with AHI <15 (left panel) and AHI>15 obstructive sleep apnea (right panel). In each patient, an ordered list of sleep stages was constructed from sleep stage with maximum VPC frequency to minimum VPC frequency. The ordering was tallied over all patients. The vertical axis shows number of patients. For example, the left panel shows Wake was the stage with the highest VPC frequency in 16 patients, whereas REM was the stage with the highest VPC frequency in 14 patients.
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Figure 2: Histogram of sleep stage distribution of VPC frequency in patients with AHI <15 (left panel) and AHI>15 obstructive sleep apnea (right panel). In each patient, an ordered list of sleep stages was constructed from sleep stage with maximum VPC frequency to minimum VPC frequency. The ordering was tallied over all patients. The vertical axis shows number of patients. For example, the left panel shows Wake was the stage with the highest VPC frequency in 16 patients, whereas REM was the stage with the highest VPC frequency in 14 patients.

Mentions: We next focused on possible differences in VPC frequency between sleep stages. To control for patients with high VPC frequency values who could be biasing VPC frequency results (bottom panel, Figure 1), we used VPC frequency to construct an ordered sleep stage list for each patient. For example, a patient whose highest VPC frequency was in REM, followed by S2, Wake, S1, and spent no time in S34, was represented by the ordered list: REM, S2, Wake, S1, blank. After creating this list for all patients, the number of each of the sleep stages in the first to last position in the list was tallied to construct a histogram (Figure 2). In patients with AHI<15 (n=58, left panel), the highest VPC frequency was found most often in Wake followed by REM, S2, S34 and S1, while conversely, the lowest VPC frequency was found most often in S1, followed by S34, Wake, S2, and REM. REM was never the sleep category with the lowest frequency of VPCs. The 3-dimensional graph shows a general reciprocal relationship: a smooth decrease in Wake and a smooth increase in S1 as VPC frequency decreases. The orderly appearance of this chart suggests VPC frequency dependence on sleep stage. Patients with AHI>15 (n=42, right panel) differed from patients with AHI<15 in that REM dominated the highest VPC frequency position.


Increased ventricular premature contraction frequency during rem sleep in patients with coronary artery disease and obstructive sleep apnea.

Watanabe MA, Bhalodia R, Lundequam EJ, Domitrovich PP, Steinmeyer BC, Stein PK, Freedland KE, Duntley SP, Carney RM - Indian Pacing Electrophysiol J (2008)

Histogram of sleep stage distribution of VPC frequency in patients with AHI <15 (left panel) and AHI>15 obstructive sleep apnea (right panel). In each patient, an ordered list of sleep stages was constructed from sleep stage with maximum VPC frequency to minimum VPC frequency. The ordering was tallied over all patients. The vertical axis shows number of patients. For example, the left panel shows Wake was the stage with the highest VPC frequency in 16 patients, whereas REM was the stage with the highest VPC frequency in 14 patients.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2572026&req=5

Figure 2: Histogram of sleep stage distribution of VPC frequency in patients with AHI <15 (left panel) and AHI>15 obstructive sleep apnea (right panel). In each patient, an ordered list of sleep stages was constructed from sleep stage with maximum VPC frequency to minimum VPC frequency. The ordering was tallied over all patients. The vertical axis shows number of patients. For example, the left panel shows Wake was the stage with the highest VPC frequency in 16 patients, whereas REM was the stage with the highest VPC frequency in 14 patients.
Mentions: We next focused on possible differences in VPC frequency between sleep stages. To control for patients with high VPC frequency values who could be biasing VPC frequency results (bottom panel, Figure 1), we used VPC frequency to construct an ordered sleep stage list for each patient. For example, a patient whose highest VPC frequency was in REM, followed by S2, Wake, S1, and spent no time in S34, was represented by the ordered list: REM, S2, Wake, S1, blank. After creating this list for all patients, the number of each of the sleep stages in the first to last position in the list was tallied to construct a histogram (Figure 2). In patients with AHI<15 (n=58, left panel), the highest VPC frequency was found most often in Wake followed by REM, S2, S34 and S1, while conversely, the lowest VPC frequency was found most often in S1, followed by S34, Wake, S2, and REM. REM was never the sleep category with the lowest frequency of VPCs. The 3-dimensional graph shows a general reciprocal relationship: a smooth decrease in Wake and a smooth increase in S1 as VPC frequency decreases. The orderly appearance of this chart suggests VPC frequency dependence on sleep stage. Patients with AHI>15 (n=42, right panel) differed from patients with AHI<15 in that REM dominated the highest VPC frequency position.

Bottom Line: VPC frequency was affected significantly by sleep stage (Wake, S2 and REM, F=5.8, p<.005) and by AHI (F=8.7, p<.005).Oxygen desaturation duration per apnea episode correlated positively with AHI (r(2)=.71, p<.0001), and was longer in REM than in non-REM (p<.0001).The heart rate turbulence parameter TS correlated negatively with oxygen desaturation duration in REM (r(2)=.06, p=.014).

View Article: PubMed Central - PubMed

Affiliation: Internal Medicine Department, St. Louis University, USA. watanabe@slu.edu

ABSTRACT

Background: Patients with obstructive sleep apnea are reported to have a peak of sudden cardiac death at night, in contrast to patients without apnea whose peak is in the morning. We hypothesized that ventricular premature contraction (VPC) frequency would correlate with measures of apnea and sympathetic activity.

Methods: Electrocardiograms from a sleep study of 125 patients with coronary artery disease were evaluated. Patients were categorized by apnea-hypopnea index (AHI) into Moderate (AHI <15) or Severe (AHI>15) apnea groups. Sleep stages studied were Wake, S1, S2, S34, and rapid eye movement (REM). Parameters of a potent autonomically-based risk predictor for sudden cardiac death called heart rate turbulence were calculated.

Results: There were 74 Moderate and 51 Severe obstructive sleep apnea patients. VPC frequency was affected significantly by sleep stage (Wake, S2 and REM, F=5.8, p<.005) and by AHI (F=8.7, p<.005). In Severe apnea patients, VPC frequency was higher in REM than in Wake (p=.011). In contrast, patients with Moderate apnea had fewer VPCs and exhibited no sleep stage dependence (p=.19). Oxygen desaturation duration per apnea episode correlated positively with AHI (r(2)=.71, p<.0001), and was longer in REM than in non-REM (p<.0001). The heart rate turbulence parameter TS correlated negatively with oxygen desaturation duration in REM (r(2)=.06, p=.014).

Conclusions: Higher VPC frequency coupled with higher sympathetic activity caused by longer apnea episodes in REM sleep may be one reason for increased nocturnal death in apneic patients.

No MeSH data available.


Related in: MedlinePlus