Background and Aims
There is evidence that left ventricular global longitudinal strain (LV GLS) is reduced in subjects with persistent symptoms (PCS) compared to recovered subjects (CON) as a sign of possible long-term left myocardial involvement after SARS-CoV-2 infection, as we were able to show in the EPILOC study. The further investigations aimed to determine whether a reduction in LV GLS is associated with the occurrence of cardiopulmonary symptoms and with reduced exercise capacity.
Methods
Transthoracic echocardiogram was performed in 1,154 individuals (mean age 49±12 years, 760 women (66%)) who had a positive SARS-CoV-2 PCR test between October 1, 2020, and April 1, 2021 (mean 73±13 weeks after acute infection). LV GLS was determined in apical four-, two-, three-chamber views in 679 PCS and 475 CON and assessed offline by two blinded investigators using post-processing software. Cardiopulmonary exercise testing (CPET) was performed on a cycle ergometer with a linear ramp protocol and maximal respiratory oxygen uptake (VO2max/kg) was measured. The presence of persistent cardiopulmonary symptoms as well as chronic or rapid physical exhaustion was recorded using questionnaires.
Results
PCS showed significantly lower LV GLS compared to CON (-20.25% [95%CI, 0.36-3.68] vs. -20.73% [95%CI, 0.37-4.23], p=0.003). There was a significant positive association between LV GLS and the occurrence of rapid physical exhaustion (b=0.51, t (398) =1.97, p = 0.050) but no association between LV GLS and cardiopulmonary symptoms. Overall individuals (PCS and CON), a negative association was found for LV GLS (b=-0.38, t(712)=-2.93, p=0.004) and relative VO2max, indicating a higher VO2max in individuals with better LV GLS values.
Conclusions
Significantly reduced LV GLS in PCS compared to CON 1.5 years after SARS-CoV-2 infection may indicate long-term left myocardial involvement. Although cardiopulmonary symptoms are not associated with a reduction in LV GLS, physical performance and the subjective feeling of rapid physical exhaustion is associated with a myocardial component. Possible pathomechanisms should be investigated in further studies, while intervention studies should additionally examine whether cardiac function can be improved by training.
