In an isochoric process the volume is kept constant (i.e. $$\Delta V=0$$). This implies that the work done by the gas is zero (i.e. $$W=0$$).
The change in internal energy during an isochoric process is equal to the heat supplied to the system (i.e. $$\Delta U=Q$$).
The p-V graph of an isochoric process is a vertical line.
$$p=$$pressure; $$Q=$$heat supplied; $$T=$$temperature; $$\Delta U=$$change in internal energy; $$V=$$volume; $$W=$$work done