Can a catalyctic converter cause no heat?

It's more likely to cause too much heat. What causes no heat is either the heater valve not opening, air in the heater core, or a bad heater core - arranged in descending order of probability and ascending order of suckiness.

A car's cabin heater is a simple system: there is a little radiator under the dashboard, called the heater core. Hot engine coolant flows through it when you open the heater valve. When you have the heat on you usually also have the fan on; the fan pulls air past the heater core, blows it into the cabin, and keeps you warm. (Helpful hint: if your car starts to overheat, turn the heat on all the way and set the fan to high speed.)

The first thing to check if you have no heat, is to open the hood and look at the firewall. On it, somewhere roughly in the middle of the car, is a valve with a little arm to move it, and three coolant hoses coming out of it. If coolant isn't leaking out of anywhere, check to be sure there's a control cable attached to the valve arm. If it's kinda hanging out in midair, or if the end's broken off, the valve can't open - it's spring-loaded to stay closed when the cable isn't hooked up - and you'll get no heat. Reattaching the cable should fix the problem.

If that didn't do it, turn the heat on all the way. Once it is, find the thermostat housing on the engine. There's a bleeder valve on it that opens with a 10mm wrench. With a COOL!!!! engine, first open the valve, then the radiator cap, then pour Honda Genuine antifreeze into the radiator until a good stream of coolant comes out the bleeder valve. This will force the air out of the heater core.

If that didn't work you're looking for leaks in the system. You do NOT want to be hit with a leaky heater core; you have to remove the whole dash to get to it.