CME ECG 68/Answers: Gender Specificities in Heart Rhythm Disorders Abstract. Sex differences in heart rhythm disorders have been described, especially due to differences of hormone status in women and men. In general, women do have a higher baseline heart rate than men and shorter refractory periods of most structures in the conduction system, except the ventricles. This is particularly apparent in paroxysmal supraventricular tachycardias. The incidence of a dual AV nodal physiology is the same in both sexes. However, an AV-nodal reentry tachycardia is much more frequent in women than in men. The embryonal disposition for an accessory pathway, as well as the resultant AV reentry tachycardia is more common in men than in women. Focal atrial tachycardias do not reveal a clear dominance between the sexes. Knowledge about sex-related differences in heart rhythm disorders are relevant for its diagnostics. Therefore, important aspects will be discussed in this article.