Is it true that overweight person is more likely to get irregular heartbeats?

Yes: Being extremely overweight has been identified in some studies as a risk factor for the development of abnormal heart rhythms like atrial fibrillation. However more important to cardiovasvular health seems not to be total mass, often measured as body mass index (bmi), but fat distribution. Those with a lot of belly fat, or visceral adipose tissue (vat) are at higher risk based on the amount of vat.

Overweight : Depends on how you define overweight if you are obese you may have sleep apnea which may cause rapid heart beats.