Cardiothoracic patient photos with Dr. Mark Morales and Dr. Mark Bielefeld

Hello. We are Dr. J. Mark Morales and Dr. Mark R. Bielefeld. We are cardiothoracic surgeons certified by the American Board of Surgery, the American Board of Thoracic Surgery and the American Academy of Pediatrics.

Our practice deals with the care of patients, both adult and pediatric, with congenital heart, lung, chest, and vascular defects, as well as adult cardiovascular disease.

Our goal is not only to perform the surgery, but to be available to answer your questions and to help minimize any stress you may have in regards to your child’s condition. We aim to make your experience as hassle free as possible. We serve patients from all over South Texas, Laredo, Eagle Pass, McAllen, Harlingen, Brownsville, Victoria, and Corpus Christi, in addition to the Northern region of Mexico and other states.

We perform open and closed heart surgery, as well as procedures directed towards alleviating problems in the chest, lung, diaphragm, esophagus, mediastinum, and vascular system.

We work in conjunction with pediatric cardiologists who support us with state of the art diagnostic modalities and interventional cardiac catheterizations. We make a special effort to provide you with the most updated information on both new and well-established surgical procedures.


Mark Morales
Mark Bielefeld