Objective The objective of this research was to develop a core traditional Chinese medicine (TCM) syndromes set for non-valvular atrial fibrillation (NVAF). MethodsA dataset of TCM syndrome names via systematic review and medical records was developed, and common TCM syndromes classification for NVAF via cross-sectional study were identified. A questionnaire was then developed according to the results of cross-sectional study and the TCM syndrome names dataset. Two rounds of the Delphi survey were carried; clinicians, researchers of TCM/integrated medicine, and nurses were included in the Delphi survey. After a face to face consensus meeting, a core TCM syndromes set for NVAF was developed. ResultsThe core TCM syndromes set for NVAF included four core TCM syndromes, which involved qi stagnation and blood stasis syndrome (core symptoms/signs: palpitations, chest distress or pain, dark purple tongue, or tongue with ecchymosis or petechial, irregular pulse or uneven pulse), heart-kidney yang deficiency syndrome (core symptoms/signs: palpitation, chest distress, fatigue, weakness, chills, pale complexion, frequent urination, wheezing, edema on the face or both lower extremities, oliguria, slippery pulse or slender pulse or deep pulse), qi and yin deficiency (core symptoms/signs: palpitation, chest distress, fatigue, shortness of breath, fine pulse, spontaneous perspiration, night sweats, forgetfulness, lassitude, red tongue, little or no moss on the tongue, and fine pulse), heart and spleen deficiency (core symptoms/signs: palpitation, chest tightness, spontaneous perspiration, abdominal distension after eating, loose stools, pale tongue, weak pulse). ConclusionsThe core TCM syndromes set of NVAF may improve the consistency of TCM syndromes efficacy evaluation in clinical trials of NVAF.