Left Ventricular Systolic and Diastolic Function in Obstructive Sleep Apnea

Abstract

Background-Previous studies in obstructive sleep apnea (OSA) were limited by study cohorts with comorbidities that confound assessment of left ventricular (LV) systolic and diastolic function. We comprehensively evaluated LV function using 2-dimensional echocardiography (2DE), tissue Doppler imaging (TDI), and 3-dimensional echocardiography (3DE) in subjects moderate-severe OSA, who were compared with disease (patients with hypertension, no OSA) and healthy control subjects. Methods and Results-A total of 120 subjects (nϭ40 each of matched OSA, hypertension and healthy cohorts) underwent echocardiographic examination for the assessment of septal and posterior wall thickness, LV mass index, LV volumes and ejection fraction, mitral valve inflow indices (E, A), mitral annular velocity (S, EЈ), and left atrial volume index (LAVI). OSA subjects were treated with continuous positive airway pressure (mean duration of 26 weeks), after which the echocardiographic parameters were reassessed. Posterior wall thickness and LV mass index were significantly higher in OSA and hypertensive groups compared with healthy. Systolic S velocity was reduced in OSA and hypertensive compared with healthy control subjects (PϽ0.05). Diastolic function (E/A, IVRT, and E/EЈ) was impaired in both OSA and hypertensive groups. On 3DE, mean LAVI was significantly greater in OSA and hypertensive compared with healthy. In OSA patients, continuous positive airway pressure therapy resulted in reduction of the posterior wall thickness (Pϭ0.02) and improvement in LV ejection fraction (PϽ0.05), systolic S velocity (PϽ0.05), and diastolic LV impairment parameters. Conclusions-Moderate to severe OSA causes structural and functional changes in LV function and are comparable to that seen in hypertension. These abnormalities significantly improve after CPAP therapy. (Circ Heart Fail. 2012;5:226-233.)

Influence and Predicting Variables of Obstructive Sleep Apnea on Cardiac Function and Remodeling in Patients without Congestive Heart Failure

“…[24][25][26][27][28][29][30] In spite of the fact that these tools are widely available and frequently introduced in clinical settings, the cardiac structural and functional remodeling studied by utilizing TDI and RT3D has rarely been conducted in patients with OSAS to evaluate their cardiac function. [31][32][33][34][35][36][37] In addition, the frequent coexistence of OSAS and congestive heart failure in clinical scenarios make it difficult to clearly define the exact impact of OSAS on cardiac remodeling and function, and vice versa. In order to answer these unresolved issues regarding the impact of OSAS itself on cardiac structure and function, it is crucial to conduct a study enrolling subjects exclusively without clinical symptoms of heart failure.…”

A Novel Method for Sensitive Determination of Subclinical Left-Ventricular Systolic Dysfunction in Subjects With Obstructive Sleep Apnea

“…On the other hand, diastolic function is often impaired in OSA. [4][5][6] Myocardial oxidative stress and ischemia are the main explanations for these disturbances. 7,8 The LV wall is not homogenous and is composed of 3 layers of fibers.…”

Effect of CPAP on Cardiac Function in Minimally Symptomatic Patients with OSA: Results from a Subset of the MOSAIC Randomized Trial

“…20,21 However, the treatment groups in these studies were small (37 and 28, respectively), not randomized, and consequently potentially affected by confounding factors in these high cardiovascular risk populations, such as changes in drug compliance during the trial.…”