Would thunder and lightning affect a pacemaker?

Generally no. No. However it is still a bad idea to stand outside during a lightning storm.
Pacemaker. If you get hit by lightning you're in trouble pacer or no. The electric fields during a thunder storm will not interfere with a pacer.....As long as you're not hit or near miss by lightning. Thunder is just sound and won't affect the device.
No because . These devices are shielded...Ok to use microwave & cell phones as well.