Received: 13 November 2019
Accepted: 27 January 2020
First Online: 31 January 2020
Ethics approval and consent to participate
: This study was approved by the institutional review board of The Affiliated Hospital of Qingdao University, and all patients underwent echocardiographic examination because of clinical indications and gave written informed consent.
: The authors of this study agreed with this manuscript and its submission to Cardiovascular ultrasound.
: The authors declare that they have no competing interests.