ABSTRACT
Background: COVID-19 has documented multisystem effects. Whether clinically significant cardiac involvement is related to severity of disease in a working age military population remains unknown, but has implications for occupational grading and ability to deploy. Aims: To determine in the military population 1) whether prior SARS-CoV-2 infection causes clinically significant cardiac disease and 2) whether changes are related to disease severity. Methods: 105 military personnel were recruited, 85 with prior SARS-CoV-2 infection (39±10 years, 87% male;50 mild (community), 35 severe (hospitalized) and 20 healthy volunteers (mean age 39 ±8.4 years, 90% male) underwent comprehensive cardiopulmonary investigations including;cardiopulmonary exercise test, exercise echocardiography, cardiac31MRI and P-MR spectroscopy (rest and dobutamine stress). Results: Prior SARS-CoV-2 infection was related to lower VO2max (110±18.2 vs 133±6.7% predicted, p<0.05), anaerobic threshold (45±10 vs 56±14% of peak VO2, p<0.05), VO2/HR (102±21 vs 128±24% predicted, p<0.05) and VE/VCO2 slope (28.3±5.0 vs 25.8±2.7, p<0.05) and an increase in average E/e' change from rest to exercise stress (+1.49±2.4 vs-0.16±3.6, p<0.05). Whilst resting myocardial energetics were similar, prior SARS-CoV-2 infection was associated with a fall in PCr/ATP during stress (by 8%, p=<0.01) which was not seen in healthy controls. When groups were ordered normal> mild> severe disease, RVEDVi, RV stroke volume, VO2peak, VO2pulse and VE/VCO slope were reduced (Jonckheere-Terpstra, all p<0.05). Conclusion: In a young military population, prior SARS-CoV-2 infection is associated with subclinical cardiovascular changes including;lower right ventricular volumes, reduced markers of exercise capacity and reduced myocardial energetics during stress.