The sex differences in ventricular structure and electrophysiological characteristics under normal / physiological conditions are well-described. These differences are more pronounced in cardiac pathology associated with structural changes of myocardium that can consequently create a substrate for initiating and maintaining ventricular arrhythmias. This chapter reviews structural changes of myocardium in the most common cardiac pathologies leading to ventricular arrhythmias with the focus on the sex difference. The prevalence of ventricular arrhythmias is lower in women; on the other hand, women have a higher risk of drug-induced torsade de pointes. Women have a lower prevalence of obstructive coronary artery disease and more often preserved left ventricular function compared to men, on the other hand, they have a higher prevalence of symptoms, a higher rate of functional microvascular disability, and more adverse outcomes. Women have lower prevalence of LVH compared to men with comparable blood pressure. They have more serious obesity, more visceral fat, more associated pathologies (diabetes mellitus, hypertension, sleep apnea, metabolic syndrome), i.e. conditions affecting the myocardial structure, however, they have less arrhythmia in premenopausal period. Some of the differences decrease after menopause, suggesting a possible effect of sexual hormones. Current imaging methods provide a deeper insight into the structural changes of the heart in cardiac pathology, and thus provide a solid basis for understanding links between structural changes, ventricular activation and repolarization processes, QRS patterns and ventricular arrhythmias.