Regression of Left Ventricular Mass in Athletes Undergoing Complete Detraining Is Mediated by Decrease in Intracellular but Not Extracellular Compartments

Abstract

Background: Athletic cardiac remodeling can occasionally be difficult to differentiate from pathological hypertrophy. Detraining is a commonly used diagnostic test to identify physiological hypertrophy, which can be diagnosed if hypertrophy regresses. We aimed to establish whether athletic cardiac remodeling assessed by cardiovascular magnetic resonance is mediated by changes in intracellular or extracellular compartments and whether this occurs by 1 or 3 months of detraining. Methods: Twenty-eight athletes about to embark on a period of forced detraining due to incidental limb bone fracture underwent clinical assessment, ECG, and contrast-enhanced cardiovascular magnetic resonance within a week of their injury and then 1 month and 3 months later. Results: After 1 month of detraining, there was reduction in left ventricular (LV) mass (130±28 to 121±25 g; P <0.0001), increase in native T1 (1225±30 to 1239±30 ms; P =0.02), and extracellular volume fraction (24.5±2.3% to 26.0±2.6%; P =0.0007) with no further changes by 3 months. The decrease in LV mass was mediated by a decrease in intracellular compartment volume (94±22 to 85±19 mL; P <0.0001) with no significant change in the extracellular compartment volume. High LV mass index, low native T1, and low extracellular volume fraction at baseline were all predictive of regression in LV mass in the first month. Conclusions: Regression of athletic LV hypertrophy can be detected after just 1 month of complete detraining and is mediated by a decrease in the intracellular myocardial compartment with no change in the extracellular compartment. Further studies are needed in athletes with overt and pathological hypertrophy to establish whether native T1 and extracellular volume fraction may complement electrocardiography, echocardiography, cardiopulmonary exercise testing, and genetic testing in predicting the outcome of detraining.

Coronary microvascular function and visceral adiposity in patients with normal body weight and type 2 diabetes

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Sex Differences in Cardiac Adaptation to Distinct Modalities of Exercise: A Cardiac Magnetic Resonance Study

“…Participants then underwent a 3-month washout period, during which they were instructed to maintain their usual level of activities and usual diet, before crossing over to complete 3 months of the alternate exercise intervention (RES or END). We chose a 3-month washout based on recent CMR evidence of regression of athletic hypertrophy within 1 month of detraining (19). Both interventions consisted of 3 × 1-h sessions per week, for 12 wk with full details provided in our protocol article (18).…”

Non-ischaemic fibrosis in male veteran endurance athletes: mechanisms and association with premature ventricular beats

“…For global measures apical and out ow tract slices were not included to avoid partial volume effects in thin myocardium. After exclusion of enhancing myocardium intracellular and extracellular compartment volume was calculated using equations previously reported [15].…”

“…Pre and post-contrast myocardial T1 values were measured from the basal and mid-ventricular short axis whole slices using 3-parameter exponential t with Look-Locker correction. ECV was calculated using haematocrit, native and post-contrast T1 times for myocardium and blood pool as previously described [15]. Global T1, T2, ECV and MBF were measured from the basal and mid-ventricular short axis slices excluding areas of brosis.…”