title: Left ventricular torsion and untwisting during exercise in heart transplant recipients.
abstract: Left ventricular (LV) rotation is the dominant deformation during relaxation and links systole with early diastolic recoil. LV torsion and untwisting rates during submaximal exercise were compared between heart transplant recipients (HTRs), young adults and healthy older individuals to better understand impaired diastolic function in HTRs. Two dimensional and colour M-mode echocardiography with speckle-tracking analysis were completed in eight HTRs (age: 61 +/- 9 years), six recipient age-matched (RM, age: 60 +/- 11 years), and five donor age-matched (DM, age: 35 +/- 8 years) individuals (all males) at rest and during submaximal cycle exercise. LV peak torsion, peak rate of untwisting and peak intraventricular pressure gradients (IVPGs) were examined. LV torsion increased with exercise in DMs (6.5 +/- 5.6 deg, P < 0.05), but not in RMs (-2.6 +/- 7.0 deg) or HTRs (-0.9 +/- 4.4 deg). The change from rest to exercise in the peak rate of untwisting was significantly greater for DMs (-2.1 +/- 0.5 rads s(-1), P < 0.05) compared to RMs (-0.7 +/- 1.3 rads s(-1)) and HTRs (-0.2 +/- 0.9 rads s(-1)). The amount of untwisting occurring prior to mitral valve opening substantially declined with exercise in RMs and HTRs only. The change in IVPGs was 1.3-fold greater in DMs versus HTRs or RMs (P > 0.05). Peak LV torsion and untwisting are blunted during exercise in HTRs and RMs compared to DMs. These factors may contribute to the impaired diastolic filling found in HTRs during exercise. Similarities between HTRs and RMs during exercise suggest functional accelerated ageing of the cardiac allograft.
authors.affiliation: University of British Columbia, Vancouver, Canada.
authors.forename: Ben T
authors.initials: BT
authors.lastname: Esch
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Scott
authors.forename: Darren E R
authors.initials: DE
authors.lastname: Warburton
authors.forename: Richard
authors.initials: R
authors.lastname: Thompson
authors.forename: Dylan
authors.initials: D
authors.lastname: Taylor
authors.forename: June
authors.initials: J
authors.lastname: Cheng Baron
authors.forename: Ian
authors.initials: I
authors.lastname: Paterson
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Haykowsky