McHugh C; Cardiology Division, Massachusetts General Hospital, Boston,  USA.
Gustus SK; Petek BJ; Schoenike MW; Boyd KS; Kennett JB; VanAtta
C; Tower-Rader AF; Fifer MA; DiCarli MF; Wasfy MM

European Journal of Preventive Cardiology. 32(12):1112-1119, 2025 Sep 08. VI 1

AIMS: Cardiopulmonary exercise testing (CPET) is often used when athletes
present with suspected hypertrophic cardiomyopathy (HCM). While low peak
oxygen consumption (pVO2) augments concern for HCM, athletes with HCM
frequently display supranormal pVO2, which limits this parameter’s
diagnostic utility. We aimed to compare other CPET parameters in healthy
athletes and equally fit individuals with HCM.

METHODS AND RESULTS: Using cycle ergometer CPETs from a single centre, we
compared ventilatory efficiency and recovery kinetics between individuals
with HCM [percent predicted pVO2(ppVO2) > 80%, non-obstructive, no nodal
agents] and healthy athletes, matched (2:1 ratio) for age, sex, height,
weight and ppVO2. Consistent with matching, HCM (n = 30, 43.6 +/- 14.2
years) and athlete (n = 60, 43.8 +/- 14.9 years) groups had similar,
supranormal pVO2 (39.5 +/- 9.1 vs. 41.1 +/- 9.1 mL/kg/min, 125 +/- 26 vs.
124 +/- 25% predicted). Recovery kinetics were also similar. However, HCM
participants had worse ventilatory efficiency, including higher early
VE/VCO2 slope (25.4 +/- 4.7 vs. 23.4 +/- 3.1, P = 0.02), higher VE/VCO2
nadir (27.3 +/- 4.0 vs. 25.2 +/- 2.6, P = 0.004) and lower end-tidal CO2
at the ventilatory threshold (42.9 +/- 6.4 vs. 45.7 +/- 4.8 mmHg, P =
0.02). HCM participants were more likely to have abnormally high VE/VCO2
nadir (>30) than athletes (20 vs. 3%, P = 0.02).

CONCLUSION: Even in the setting of similar and supranormal pVO2,
ventilatory efficiency is worse in HCM participants vs. healthy athletes.
Our results demonstrate the utility of CPET beyond pVO2 assessment in
‘grey zone’ athlete cases in which the diagnosis of HCM is being debated.
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Other Abstract
plain-language-summary
We sought to examine exercise test findings in healthy athletes and
equally fit individuals with a form of heart enlargement that commonly
gets confused with ‘athlete’s heart’ called hypertrophic cardiomyopathy
(HCM) to see if elements of the exercise test could distinguish between
these two groups. This is relevant as fit individuals often present for
exercise testing as part of the work up to see if they have HCM or not,
and getting the answer right is important because HCM is amongst the most
common causes of sudden cardiac death in athletes.By design, individuals
with HCM in this study were equally fit as the athletes, with both groups
having fitness levels (‘VO2 max’ levels) around 25% higher than expected
for individuals of similar age and sex.Despite this similar and
supranormal fitness, individuals with HCM had worse ventilatory efficiency
than athletes. This is a metric that reflects how well the heart and lungs
work together to get rid of the waste gas carbon dioxide during exercise.
This finding should focus more attention on this parameter when exercise
tests are being performed to evaluate for HCM in clinical practice.