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The Journal of Sports Medicine and Physical Fitness 2001 March;41(1):108-13

Copyright © 2009 EDIZIONI MINERVA MEDICA

lingua: Inglese

The Tei index and exercise capacity

Libonati J. R. *, Ciccolo J. **, Glassberg H. ***

From the * Biokinetics Research Laboratory Temple University, Phyladelphia, PA ** Department of Cardiopulmonary and Exercise Sciences Boston, MA *** Section of Cardiology, Temple University Hospital Philadelphia, PA


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Background. Cardiac func­tion ­time inter­vals are ­known to ­change ­with aero­bic fit­ness. Recently, the Tei ­index of car­diac func­tion [­defined as the sum of the iso­vol­u­met­ric con­trac­tion (ICI) and iso­vol­u­met­ric relax­a­tion inter­vals (IRI) divid­ed by the ­left ven­tric­u­lar ejec­tion ­time (­LVET)] has ­been pro­posed to be a ­very sen­si­tive deter­mi­nant of car­diac func­tion in ­patients ­with car­di­om­yo­pa­thy, i.e. the ­index is great­er in ­patients ­with car­di­om­yo­pa­thy than it is in nor­mal sub­jects. The pur­pose of ­this ­study was to deter­mine the rela­tion­ship ­between the Tei ­index and aero­bic endu­rance in ­healthy vol­un­teers.
Methods. The rel­a­tive­ly new non­in­va­sive meth­od of seis­mo­car­di­og­ra­phy was ­used to meas­ure fol­low­ing rest­ing ­left ven­tric­u­lar (LV) car­diac func­tion ­time inter­vals in 51 sub­jects (18 ­males and 33 ­females); Tei ­index, R-R inter­val, LV ICI, LV IRI, ­LVET, LV sys­tole and LV dias­to­le. Designated on the ­basis of ­peak tread­mill ­time (Bruce pro­to­col), the fol­low­ing ­three ­groups ­were ­assigned: Group 1; tread­mill ­time ≥900 sec­onds; Group 2: tread­mill ­time rang­ing ­from 721 to 899 sec­onds; and Group 3; tread­mill ­time <720 sec­onds.
Results. The Tei ­index val­ue was low­e­r as exer­cise capac­ity ­increased (p<0.05) pri­mar­i­ly due to a reduc­tion in LV IRI (p<0.05). ­LVET tend­ed to be long­er ­with ­increased tread­mill ­time (p<0.05) but ­this ­effect ­appeared to be sec­on­dary to a great­er R-R inter­val in ­more fit sub­jects. When adjust­ed for the R-R inter­val, a ­reduced Tei ­index and LV IRI ­were ­still ­observed in ­more fit sub­jects, ­despite a sim­i­lar ­LVET ­between ­groups.
Conclusions. Peak tread­mill ­time is inverse­ly relat­ed to the Tei ­index. A reduc­tion of LV IRI ­appears to be the pri­mary fac­tor in estab­lish­ing ­these dif­fer­enc­es. These ­data sup­port the impor­tant ­role of LV dia­stol­ic func­tion in aero­bic fitness.

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