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

Pinto DS, Ho KK, Zimetbaum PJ, Pedan A, Goldberger AL.

Cardiovascular Division, Beth Israel Deaconess Medical Center, Boston,
Massachusetts; Harvard Medical School, Boston, Massachusetts,
USA. agoldber@caregroup.harvard.edu

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 GreaterEqual; 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
GreaterEqual; 71 years with heart rate GreaterEqual; 141 beats/minute
was 93%, compared to only three percent in a subject leq; 50 years
with heart rate 100-120 beats/minute. A simple point score system
based on age and heart rate helps predict the probability of sinus
tachycardia versus nonsinus tachycardia. 

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.