Here's what rhymes with heartbeats.

Consider these alternatives

fibrillation / relation irregular / regular palpitations / relations chirps / words defibrillator / later implanted / advantage abnormal / normal rhythms / conditions bradycardia / tachycardia misjudgment / judgment compressions / presence atrial / trial utero / deutero hemorrhages / haemorrhages malformations / relations fetal / people ischaemia / uraemia