Athlete's Heart Lecture Notes

10/2012 Lecture on Athlete's Heart - T Seery, TCH

Athlete’s Heart

-Increased VO2 – volume load

-Increased Static force – pressure load

CV Response to exercise

-incr HR, incr SV, SVR decreases,

-small rise in BP, but more so w isometrics

Volume ld fr dynamic exerciseà incr internal diameter and a proportional incr in wall thickenss = eccentric LVH

Pressure ld -à thirckening of ventric wall w unchanged internal dimension = concentric LVH

Wall stress = P*r/h

Types of exercise & effect on heart:

Runners- def an incr in LV mass

-HR is decr, LV end dias diam incr, septal wall/post wall larger, diameter and wall thickness went up

Cyclist- similar but wall thickness increases more than diameter,

Weight lifters have wall thickness incr more than diameter…

Why it matters:

2% of trained adult male athletes have LVH

15% have incr diameter of LV cavity

Athlete’s heart = “reversible LVH that is 133-15mm”

-reversible- if you have them sit out for a few weeks, the LVH resolves…

à wall thickness decr by 15%, LV mass decr by 28%, LV cavity dimension decr by 25%, and wall thickness returned to Nl; the cavity dilation was still present in some pts. Though, this study looked at pts p 5yrs of deconditioning

RV has similar findings, but less studied

Cardiac Function:

-No impairment of fx w athletes heart vs w CM

-Nl E/A w athlete’s heart, vs w CM see abNl E/A

ECG:

-lower HR, incr parasymp & vagal tone, decr symp tone, non-hemogenous repolarization of ventricles

-many will have abNl ECG, brady, wandering atrial pacer, higher voltages,, ST-T abNlies, ………,

-concerning findings: high grade AV block

Exercise stress testing- in all athletes that are otherwise well, if you stress them, the wandering atrial pacemaker/jctl rhythm etc will resolveà reassuring

HCM vs. Athlete’s Heart

-hard to DDx by echo

-in study of >900 Olympians, only 16 had LV wall thickness >12mm, and the max was 16mm. So, if you see 13-15mm, c/s something may be pathological, and if 16mm or more then def c/s pathology.

-major diff is the internal diameter will also increase in an athlete heart, and fx remains Nl

When to be concerned:

-worse w activity

-FHx

-arrhythmias

-diastolic dysfx

-LV end diastolic cavity dimension is <45mm (should be >55mm)

Be reassured if LV cavity vol is >55, or if regression of sx after 4-8weeks of deconditioning