Sinus versus nonsinus tachycardia in the emergency department: Importance of age and heart rate

Background The emergency department diagnosis of sinus versus nonsinus tachycardia is an important clinical challenge. The objective of this study was to identify subjects with a high prevalence of nonsinus tachycardia.Methods Heart rate and cardiac rhythm were prospective reviewed in 500 consecutive patients with heart rate > or = 100 beats/min in a busy emergency department. A predictive model based on age and heart rate was then developed to identify the probability of nonsinus tachycardia.Results As age and heart rate increased, nonsinus tachycardias became more frequent. The probability of nonsinus tachycardia in a subject > or = 71 years with heart rate > or = 141 beats/minute was 93%, compared to only three percent in a subject Conclusion Nonsinus tachycardia is significantly more common than sinus tachycardia in elderly patients in the emergency department. The diagnosis of sinus tachycardia becomes much less likely as age and heart rate increase.