We see lots of arrhythmias in the ICU, but one that often comes up that isn’t really an arrhythmia is sinus tachycardia. Sinus tach often makes us nervous, and not without good reason, as this echo from Dr Obiajulu Anozie demonstrates. As the heart rate goes up, stroke volume may decrease. Likewise, tachycardia may often be in response to decreased stroke volume as the body attempts to compensate and maintain adequate cardiac output. Sinus tach can often be in response to pain or agitation as well. What do we do about sinus tach? Well, start off by treating potential causes. Pain. Agitation. Hypovolemia. But we very rarely need to treat tachycardia itself. There are cases (as with patients on VV ECMO) where beta blockade is indicated to reduce heart rate, but typically once the potential causes are addressed, nothing else needs to be done. In some cases (as demonstrated below), the tachycardia may in fact be compensatory and by slowing it down, we actually cause harm.