I agree, be sure you're getting an accurate pulse count before you question the pacemaker. I don't have one, but I believe they are very accurate.
What do you mean under 70, 68? I'd not worry about that, just rounding "error". If you get 60, say, then you do have a real difference. Again, try to get the pulse count accurately.
I have a great deal of trouble feeling my pulse, yes I know I'm lucky, and I use a sport watch, a Pulsar brand, with a chest strap when I really what to know my pulse. Also effective is a stethoscope, and it lets me clearly hear any "strange" rhythm/sounds. I got my stethoscope at Walmart, must have been under $30.
Hmm, can your pacemaker be interrogated to see if you're having any arrhythmias? If the pacer is set for 70, I can't see how the heart rate should drop below that for any length of time. If you have a BP cuff at home, you could use that when you feel odd to check your BP as well as get a pulse rate. Trying to take the pulse yourself using your fingertips may not be as accurate.