A six-year-old girl was found with her two younger siblings and her mother, unconscious, in a room filled with carbon monoxide. The mother had been using a charcoal grill inside the house. She managed to call 911 before losing consciousness, and the fire rescue paramedics broke into their house, saving them. This six-year-old required treatment in the pediatric intensive care unit, but recovered completely. The lesson for our students is to judge rate in the setting in which it is found. The heart rate here is 136/min. Normal for a child of six is usually between 80 and 100 at rest. This child is severely hypoxic, and she has sinus tachycardia. It would be a mistake to assume her rate is normal because "all children have fast heart rates". Also, children with sinus tachycardia can be so fast, they appear to have PSVT. The onset and offset can be excellent clues to the origin of the rhythm. Sinus rhythms can be expected to speed up and slow down gradually, unlike PSVTs, which have sudden onset and offset. The most important consideration is that sinus tachycardia usually has an APPARENT CAUSE: exercise, anxiety, hypoxia, hypovolemia, fear ,,,, the list is a long one. Once it is determined that the patient has sinus tachycardia, efforts usually focus on the elimation of the cause.
We welcome any comments on this ECG, perhaps taking the discussion to a more advanced level.
Here is a nice example of sinus tachycardia taken from a 2-year-old in the post-anesthesia care unit after a short GI endoscopic procedure. Would you call this NSR, since it is from a child? The pre-op heart rate in this child was 120/min.
For your more advanced students, remind them that, in adults especially, a heart rate close to 150/min. should cause them to examine the ECG in several leads, looking for the presence of atrial flutter with 2:1 conduction. Another important teaching point, most ADULTS with sinus tach at 150/min. would manifest an obvious reason for the rapid heart rate (dehydration, pain, anxiety, shock, etc.) Challenge your basic students to come up with as many causes for sinus tach as they can.