what kind of amplifier and filters would be better?
you may need an instrumentation amplifier stage to ensure low voltage signal is amplified providing minimum attenuation to actual signal.
heart rate is usually upto around 200 bps-250 max right? so any thing above the frequency could be removed
for signal amplification you may employ a high gain stage using opamps (i assume you observe the waveform on a CRO to get an idea of the range of amplification needed) regards