title: Left atrial phasic function interacts to support left ventricular filling during exercise in healthy athletes.
abstract: We studied the contribution of phasic left atrial (LA) function to left ventricular (LV) filling during exercise. We hypothesized that reduced LV filling time at moderate-intensity exercise limits LA passive emptying and increases LA active emptying. Twenty endurance-trained males (55 ± 6 yr) were studied at rest and during light- (∼100 beats/min) and moderate-intensity (∼130 beats/min) exercise. Two-dimensional and Doppler echocardiography were used to assess phasic volumes and diastolic function. LV end-diastolic volume increased from rest to light exercise (54 ± 6 to 58 ± 5 ml/m(2), P < 0.01) and from light to moderate exercise (58 ± 5 to 62 ± 6 ml/m(2), P < 0.01). LA maximal volume increased from rest to light exercise (26 ± 4 to 30 ± 5 ml/m(2), P < 0.01) related to atrioventricular plane displacement (r = 0.55, P < 0.005), without further change at moderate exercise. LA passive emptying increased at light exercise (9 ± 2 to 13 ± 3 ml/m(2), P < 0.01) and then returned to baseline at moderate exercise, whereas LA active emptying increased appreciably only at moderate exercise (6 ± 2 to 14 ± 3 ml/m(2), P < 0.01). Thus, the total atrial emptying volume did not increase beyond light exercise, and the increase in LV filling at moderate exercise could be attributed primarily to an increase in the conduit flow volume (19 ± 3 to 25 ± 5 ml/m(2), P < 0.01). LA filling increases during exercise in relation to augmented LV longitudinal contraction. Conduit flow increases progressively with exercise in athletes, although this is driven by LV properties rather than intrinsic LA function. The pump function of the LA augments only at moderate exercise due to a reduced diastolic filling time and the Frank-Starling mechanism.
authors.affiliation: Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada; Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada; and.
authors.forename: Steve
authors.initials: S
authors.lastname: Wright
authors.affiliation: Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada; and.
authors.forename: Zion
authors.initials: Z
authors.lastname: Sasson
authors.affiliation: Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada;
authors.forename: Taylor
authors.initials: T
authors.lastname: Gray
authors.affiliation: Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada; and.
authors.forename: Anjala
authors.initials: A
authors.lastname: Chelvanathan
authors.affiliation: Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada; and Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Sam
authors.initials: S
authors.lastname: Esfandiari
authors.affiliation: Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada; and.
authors.forename: John
authors.initials: J
authors.lastname: Dimitry
authors.affiliation: Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada; and.
authors.forename: Sarah
authors.initials: S
authors.lastname: Armstrong
authors.affiliation: Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada; and Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Susanna
authors.initials: S
authors.lastname: Mak
authors.affiliation: Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada; Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada; and Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada jack.goodman@utoronto.ca.
authors.forename: Jack M
authors.initials: JM
authors.lastname: Goodman
mesh_terms: D000368:Aged; D056352:Athletes; D016279:Atrial Function, Left; D003971:Diastole; D015150:Echocardiography, Doppler; D015444:Exercise / Q000502:physiology*; D064368:Healthy Volunteers; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D010807:Physical Endurance; D012420:Running; D013997:Time Factors; D016277:Ventricular Function, Left
keywords: atrial function; diastolic function; echocardiography; exercise physiology