Patent foramen ovale is not associated with hypoxemia in severe chronic obstructive pulmonary disease and does not impair exercise performance.

Rationale: Patent foramen ovale (PFO) may be disadvantageous in chronic obstructive pulmonary disease (COPD). It is unknown whether right-to-left shunting through PFO increases during exercise impairing exercise performance.

Objectives: To determine whether (1) PFO prevalence is greater in hypoxemic versus less hypoxemic patients with COPD, (2) PFO is associated with clinically relevant impairment, and (3) right-to-left shunting increases during exercise and impairs exercise performance.

Patent foramen ovale in severe obstructive sleep apnea: clinical features and effects of closure.

Background: Patent foramen ovale (PFO) may contribute to nocturnal desaturation in patients with obstructive sleep apnea (OSA), and the effect of PFO closure in OSA is unknown. Our study tested the hypotheses that: (1) patients with severe OSA have a higher prevalence of PFO compared with healthy control subjects, (2) patients with severe OSA with clinically significant PFO experience more nocturnal desaturation than those without, and (3) PFO closure reduces nocturnal desaturation.

Methods: Patients with severe OSA and healthy control subjects underwent contrast transthoracic echocardiography and transcranial Doppler to detect PFO and determine shunt size.

Utility of overnight pulse oximetry and heart rate variability analysis to screen for sleep-disordered breathing in chronic heart failure.

Background: Sleep-disordered breathing (SDB) is under diagnosed in chronic heart failure (CHF). Screening with simple monitors may increase detection of SDB in a cardiology setting. This study aimed to evaluate the accuracy of heart rate variability analysis and overnight pulse oximetry for diagnosis of SDB in patients with CHF.