OPERATIONAL DEFINITION OF NORMAL SINUS HEART-RATE

Heart rate (HR) is an accurately measurable descriptor of patients' status immediately available to physicians without special instrumentation. Accepted limits of HR have long been set at 60 and 100 beats/min for normal sinus rhythm. Experience suggests that both these traditional limits are too high, except under undue autonomie activation, an imposed abnormality. In practice, this translates into suspicion of abnormality when a patient has a resting HR between 90 and 100 beats/min, rather than a rigidly classified "tachycardia" at ≥100 beats/min. Furthermore, with the current emphasis on fitness we are not unduly concerned with the asymptomatic patient with a resting HR between 50 and 60 beats/ min. Whereas 1 distinguished investigator reported the traditional limits of 60 and 100 beats/min as "generally agreed" 1 (and they are indeed long-established New York Heart Association recommendations),2 a search of previous publications revealed no investigations that systematically define sinus tachycardia and bradycardia for clinical application. We reexamined the question of operational definitions for sinus bradycardia and tachycardia. Our investigation was designed to determine if a clinically normal population suggested other limits, compare them with the literature and, if comparable, redefine sinus tachycardia and bradycardia. © 1992.