Effects of the Mueller Maneuver on Functional Mitral Regurgitation and Implications for Obstructive Sleep XXXX .

@entity1 @entity712 @entity339 @entity27 @entity955 @entity4032 @entity65 @entity386
UNASSIGNED: Obstructive sleep @entity386 is prevalent and adversely affects @entity65 . However, little is known of the acute effects of an obstructive @entity386 on cardiovascular physiology. We hypothesized that pre-existing functional @entity339 ( @entity339 ) would worsen during performance of a Mueller maneuver (MM) used to simulate an obstructive @entity386 ; 15 subjects with an ejection fraction  <=35% and pre-existing functional @entity339 were studied with Doppler echocardiography. The radius of the proximal flow convergence was used as a measure of mitral regurgitant flow. Measurements were made at baseline, during the MM, and post-MM. Areas of all 4 chambers were also measured at these time points, both in systole and diastole. Mean flow convergence radius for the group decreased significantly during the transition from the late-MM to post-MM (0.65  >  0.57  mm, p  = 0.001), implying increased @entity339 during the MM. In addition, in 3 subjects, duration of @entity339 increased during the MM. @entity4032 ( @entity4032 ) areas, both systolic and diastolic, increased during the maneuver, whereas @entity4032 fractional area change decreased, indicating reduced @entity4032 emptying. Left ventricular emptying decreased early in the maneuver, probably because of the increased afterload burden, and then recovered. In conclusion, high negative intrathoracic pressure produces changes that, repeated hundreds of times per night in @entity1 with @entity27 , have the potential to worsen @entity712 and predispose affected subjects to @entity955 .
