HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:
Guest Access | Sign In via User Name/Password

This Article Full Text (PDF) All Versions of this Article: chest.07-2595v1 133/4/934    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to My Personal Article Archive Download to citation manager Google Scholar Articles by Ryan, C. M. Articles by Bradley, T. D. PubMed PubMed Citation Articles by Ryan, C. M. Articles by Bradley, T. D.

Timing of Nocturnal Ventricular Ectopy in Heart Failure Patients with Sleep Apnea

¹, the Department of Medicine, Toronto General Hospital of the University Health Network ², the Sleep Research Laboratory of St. Michael's Hospital ³, and the Centre for Sleep Medicine and Circadian Biology University of Toronto ⁴, Toronto, Ontario, Canada, Clodagh.ryan@uhn.on.ca, stephen.juvet@utoronto.ca, richard.leung@utoronto.ca douglas.bradley@utoronto.ca

douglas.bradley{at}utoronto.ca

Abstract

Background: Ventricular ectopy is frequent in heart failure (HF) patients with sleep apnea. A previous report indicated that in HF patients, ventricular premature beats (VPB) occurred more frequently during episodes of recurrent central sleep apnea (CSA) than during normal breathing, and their frequency was greater during hyperpnea than apnea. We hypothesized that because respiratory stimuli that might provoke ventricular ectopy are stronger during obstructive than during central apneas, that in contrast to CSA, VPBs would be more frequent during apnea than hyperpnea in HF patients with obstructive sleep apnea (OSA).

Methods: HF patients in sinus rhythm with OSA or CSA (apnea-hypopnea index 15/hr) and with more than 30 VPBs/hr were matched for severity of cardiac dysfunction and sleep apnea. The frequency of VPBs was then assessed during Stage 2 sleep during the apneic and the hyperpneic phases of recurrent obstructive or central apneas.

Results: VPBs occurred more frequently during the apneic than the hyperpneic phase in patients with OSA. In contrast, VPBs occurred more frequently during the hyperpneic than apneic phase in patients with CSA. There was no difference in the degree of apnea-related oxygen desaturation between central and obstructive apneas.

Conclusions: In patients with HF, nocturnal ventricular ectopy oscillates in time with oscillations in ventilation; with VPBs occurring predominantly during apneas in patients with OSA, but during hyperpneas in patients with CSA. This difference in VPB timing between OSA and CSA may be attributable to the differences in timing of arrhythmic stresses in these patients.

Key Words: Sleep-disordered breathing • congestive heart failure • ventricular arrhythmias