The Relationship between Nocturnal Hypoxemia and Left Ventricular Ejection Fraction in Congestive Heart Failure Patients

Mohammad Mirzaaghazadeh,Zahra Tavosi,Nasrollah Maleki,Mehrzad Bahtouee,Fariba Mehdiniya

doi:10.1155/2014/978358

Abstract

Congestive heart failure (CHF) is a major cause of mortality and morbidity. Among patients with heart failure, sleep disordered breathing (SDB) is a common problem. Current evidence suggests that SDB, particularly central SDB, is more prevalent in patients with CHF than in the general population, but it is underdiagnosed as SDB symptoms that are less prevalent in CHF. The main aims of this study were to determine the relationship between nocturnal hypoxemia and left ventricular ejection fraction in patients with chronic heart failure. By means of echocardiography, 108 patients with left ventricular ejection fraction ≤45% were divided into mild, moderate, and severe CHF. Hypoxemia was recorded overnight in the hospital and was measured by portable pulse oximetry. In the 108 patients with CHF, 44 (40.7%) were severe, 17 (15.7%) moderate, and 47 (43.6%) mild CHF. 95 (88%) of patients with CHF had abnormal patterns of nocturnal hypoxemia suggestive of Cheyne-Stokes respiration. Ejection fraction correlated negatively with dip frequency. There was no correlation between nocturnal hypoxemia with BMI and snoring. This study confirms strong associations between sleep apnea and heart disease in patients with CHF. Overnight oximetry is a useful screening test for Cheyne-Stokes respiration in patients with known heart failure.

Highlights

Sleep related breathing disorders (SRBD) refer to an abnormal respiratory pattern or an abnormal reduction in gas exchange during sleep
Sleep related breathing disorders are best characterized by polysomnography that has captured one or more periods of rapid eye movement (REM) sleep, as severe perturbations can be common during REM sleep [1, 2]
Two types of sleep disordered breathing are common among patients with heart failure: obstructive sleep apnea (OSA) and Cheyne-Stokes breathing (CSB)

Summary

Introduction

Sleep related breathing disorders (SRBD) refer to an abnormal respiratory pattern (e.g., apneas, hypopneas, or respiratory effort related arousals) or an abnormal reduction in gas exchange (e.g., hypoventilation) during sleep. They tend to repetitively alter sleep duration and architecture, resulting in daytime symptoms, signs, or organ system dysfunction. Sleep apnea is hypothesized to increase the risk of developing cardiovascular disease (CVD) and hypertension. Initial support for this hypothesis came from several population studies of snoring and CVD outcomes, suggesting that those who snore are more likely to develop hypertension, myocardial infarction, and stroke [3,4,5]. Two types of sleep disordered breathing are common among patients with heart failure: obstructive sleep apnea (OSA) and Cheyne-Stokes breathing (CSB)

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