A balloon catheter includes a shaft, a balloon including an expandable membrane, one or more ablation elements, and one or more passages via the expandable membrane. The shaft is configured for insertion into an organ of a patient. The balloon is fitted at a distal end of the shaft. The one or more ablation elements are disposed over the expandable membrane and are configured for tissue ablation. The one or more passages via the expandable membrane are configured to allow blood to flow between a distal end and a proximal end of the balloon, while the balloon is in an expanded configuration.