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Global and regional left ventricular circumferential strain during incremental cycling and isometric knee extension exercise
Author(s) -
Beaumont Alexander,
Sculthorpe Nicholas,
Hough John,
Unnithan Viswanath,
Richards Joanna
Publication year - 2018
Publication title -
echocardiography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 62
eISSN - 1540-8175
pISSN - 0742-2822
DOI - 10.1111/echo.13894
Subject(s) - isometric exercise , cardiology , medicine , cycling , rest (music) , archaeology , history
Background The objective of this study was to investigate left ventricular (LV) circumferential strain responses to incremental cycling and isometric knee extension exercises. Methods Twenty‐six healthy male participants (age = 30 ± 6 years) were used to study LV global (GCS) and regional circumferential strain at the apex (ACS) and base (BCS) during incremental cycling at 30% and 60% work rate maximum ( W max ) and short‐duration (15 seconds contractions) isometric knee extensions at 40% and 75% maximum voluntary contraction (MVC) using two‐dimensional speckle tracking echocardiography. Results During cycling (n = 22), GCS increased progressively from rest to 60% W max (−22.85 ± 3.26% to −29.87 ± 2.59%, P < .01). ACS increased from rest to 30% W max (−26.29 ± 4.84% to −36.84 ± 6.94%, P < .01) and then remained unchanged to 60% W max (−40.72 ± 4.06%, P = .068). BCS decreased from rest to 30% W max (−19.41 ± 2.79 to −17.51 ± 4.66%, P = .05) and then remained unchanged to 60% W max . During isometric knee extension (n = 23), GCS decreased from rest to 40% MVC (−22.63 ± 3.46 to −20.10 ± 2.78%, P < .05) and then remained unchanged to 75% MVC. Similarly, BCS decreased from rest to 40% MVC (−19.21 ± 2.58% to −13.55 ± 3.45%, P < .01) and then remained unchanged, whereas ACS did not change with exercise intensity (rest, −26.05 ± 5.34%; 40% MVC, −26.64 ± 4.53% and 75% MVC −27.22 ± 5.34%, all P > .05). Conclusion Global circumferential strain increased stepwise during incremental cycling, mediated by the apex with trivial changes at the base. In contrast, GCS decreased during the isometric knee extension to 40% MVC and then plateaued, due to decreased BCS as ACS was maintained. A novel finding is that the GCS response appears to be exercise modality dependant and is the consequence of region‐specific changes.