What heart problems palpitations come secondary to pregnancy? when should we worry?

Faster heart rate: Your baseline heart rate should gradually increase somewhat, throughout your pregnancy. However, you should seek assistance for fast heart rates that start or stop suddenly, or persistently stay faster than expected (e.g. > 100 BPM at rest). Also symptoms of chest pain, dizzy, breathlessness. Getting checked out is always safer. Speak with your doctor and possibly heart rhythm specialist.