A-Fib Physicians

John Johnkoski, MD

Dr. John A. Johnkoski Dr. John A. Johnkoski has been a cardiothoracic surgeon with Aspirus Heart & Lung Surgery since 1999. Dr. Johnkoski received his medical degree from the University of Michigan Medical School. He performed a residency in General Surgery at State University of New York in Buffalo and completed his Cardiothoracic Surgery Residency in 1997 at the University of Washington Medical Center in Seattle, Washington.

Dr. Johnkoski is board certified by the American Board of Surgery and the American Board of Thoracic Surgery. Dr. Johnkoski has a particular interest in treatment of atrial fibrillation and started the Atrial Fibrillation Surgical Program at Aspirus Wausau Hospital in 2006.


Andrew Mykystey, MD                     

Dr. Andrew Mykytsey's specialties are electrophysiology and cardiology at
Aspirus Cardiology. Dr. Mykytsey received his medical degree from Ivano-Frankivsk State Medical Academy, Ivano-Frankivsk, Ukraine. He performed a residency in Internal Medicine at Advocate Illinois Masonic Medical Center, Chicago, IL and completed his Cardiovascular Medicine Fellowship at Michael Reese Hospital and Rush University Medical Center and his Cardiovascular Electrophysiology Fellowship at Rush University Medical Center in Chicago, IL.

Dr. Mykytsey holds board certifications by the American Board of Internal Medicine and in Clinical Cardiac Electrophysiology and Cardiovascular Disease.

Dr. Mykytsey enjoys spending time with his family, studying world history and culture, and skiing.

Kevin Rist, MD, PhD

Dr. Kevin Rist's specialties are electrophysiology  and cardiovascular disease.
He has been with Aspirus Cardiology since 2010. Dr. Kevin Rist received his Doctor of Medicine from Dartmouth Medical School, Hanover, NH and his Doctor of Philosophy (PhD), Respiratory Physiology, Dartmouth Medical School, Hanover, NH. He performed his Cardiology Fellowship a the University of Minnesota, Minneapolis, MN and his Electrophysiology Fellowship at the University of Pittsburgh, Pittsburgh, PA.

Dr. Rist holds board certifications by the American Board of Internal Medicine and in Cardiovascular Disease and Clinical Cardiac Electrophysiology.

Dr. Rist enjoys his family's activities including playing soccer, ice hockey and track.  He participates in alpine racing, cross country skiing and hiking.


Our physicians are committed to providing thorough patient education on the latest atrial fibrillation treatment options. For information on AF treatment or questions about your atrial fibrillation diagnosis, request a consultation at afibclinic@aspirus.org or call the A-Fib Clinic at 715-847-2040.