Tachycardia in pregnancy is common and distinguishing between physiological and pathological causes can be a challenge. Plus, until recently, there had not been a well-defined or universally accepted definition of the upper limit of normal for heart rate in pregnancy. But a study published in 2020 from the Green Journal, from the NHS in London has shed light on this issue. The finding of persistent tachycardia beyond a certain rate (and we’ll discuss that rate in this episode), regardless of symptoms, should prompt a search for potential etiologies and at least some basic investigations. Of course, any tachyarrhythmia in pregnancy causing hemodynamic instability requires urgent cardioversion as per adult life support guidelines. In 2023, The Heart Rhythm Society (HRS) developed expert consensus guidelines in collaboration with the American College of Cardiology (ACC), the ACOG, and the AHA to address arrhythmias in pregnancy. In this episode we will focus on and review maternal tachycardia. Does HR really increase by “10-20%” in pregnancy as we all were taught? What heart rate is generally considered evaluable? And what’s the suggested evaluation? Listen in for details.