What is the best approach to the evaluation of resting tachycardia for an adult?

Heart rate varies by age; however, tachycardia in adults is usually defined as a rate exceeding 100 beats/minute. Tachycardia at rest requires a diagnostic evaluation. However, our search found no systematic reviews, randomized trials, or prospective cohort studies relevant to this question. The highest level of evidence we located was an international practice guideline developed by the American College of Cardiology, the American Heart Association Task Force on Practice Guidelines, and the European Society of Cardiology Committee for Practice Guidelines. This joint guideline recommends that the diagnostic evaluation of a hemodynamically stable patient should begin with tachycardia. The FIGURE shows an algorithm of one common diagnostic strategy for evaluation of tachycardia.