Pacemaker insertion may be required for individuals with cardiac conduction abnormalities. Electrical insulation is the absence of electrical conduction. Conventional personal cooling is typically achieved through heat conduction and convection. Voltage-gated sodium channels are responsible for the fast action potentials involved in nerve conduction. Convection may be described as the combined effects of conduction and fluid flow. Arrhythmias are due to problems with the electrical conduction system of the heart. The drug impairs AV node conduction and decreases sinus rate. Conduction band electrons are similarly delocalized. Heat is transferred either by conduction or convection. Also possible is transfer of heat by a combination of conduction and thermal radiation. It is a measure which determines the relative strength of conduction and convection. It is possibly due to the effect of increased temperature on nerve conduction. Semiconductors rely on free electrons knocked out of the crystal by thermal vibration for conduction. The heat can be transferred by convection, conduction, or radiation. This hot added material cools down by conduction and convection of heat.