memo

Recommendations for Evaluation of Prosthetic Valves With Echocardiography and Doppler Ultrasound 

http://www.ncbi.nlm.nih.gov/pubmed/21429056

http://www.ncbi.nlm.nih.gov/pubmed/17474948

http://www.ncbi.nlm.nih.gov/pubmed/11982834/

http://www.ncbi.nlm.nih.gov/pubmed/16310661/

http://www.nejm.org/doi/full/10.1056/NEJM199902113400606