The House voted Thursday to indefinitely extend a 45 percent inheritance tax on estates larger than $3.5 million, canceling a one-year repeal of the tax set to begin next month.

A similar effort is afoot in the Senate, but the health care debate there could preclude action on the estate tax before Congress breaks later this month for holidays. There are also disagreements among senators over the tax rate and the size of estates that should be exempt, further clouding the bill's prospects.