Sleep-disordered breathing and echocardiographic measures of function and dyssynchrony: a complex approach to cardiac...

We investigated the relationship between sleep-disordered breathing (SDB), cardiac function, and cardiac resynchronization therapy (CRT).

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.

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.

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.