Sleep-disordered breathing and echocardiographic measures of function and dyssynchrony

INTRODUCTION: We investigated the relationship between sleep-disordered breathing (SDB), cardiac function, and cardiac resynchronization therapy (CRT). METHODS: Fifty-five CRT patients with SDB diagnosed by Holter ECG (apnea/hypopnea index - AHI) were included in the study. We sought to determine right ventricle (RV) predictors of short-term SDB improvement and long-term outcome in patients with (AHI dippers) and without (AHI nondippers) 25% AHI improvement, markers of CRT response, and SDB influence on survival. RESULTS: Baseline tricuspid E-wave (AUC - 0.925, cut-off value > 0.336 m/s; sensitivity - 90%, specificity - 100%) and RV E/E' - 0.864, ≤16.25; 73%, 100%, respectively) were found as predictors of 25% AHI reduction. Spiroergometric tests, mitral regurgitation, and LVEF results improved significantly in AHI dippers. Regression analysis identified the absence of 25% AHI reduction (OR-7.67, 95% CI 1.52-38.6 and OR-9.92, 95%CI 6.02-15.3) and septal-lateral atrial velocities delay (OR-1.09, 95% CI 0.99-1.2 and 1.07, 95% CI 0.99-1.16) as independent predictors of both clinical and echocardiographic nonresponse. During median follow-up of 6.8 years, mortality was significantly reduced in patients with both AHI 25% reduction and 10% absolute LVEF increase in the first 3 months of CRT, compared with the subjects with only one or none of those criteria. CONCLUSION: The baseline RV diastolic indices were found as independent predictors of SDB improvement during CRT. Both clinical and echocardiographic long-term response can be independently predicted by SDB and intraatrial dyssynchrony. The best survival rate was observed in patients with SDB and LVEF improvement noted in the first 3 months of CRT.