The 12 Rhythms of Christmas: Sinus Tachycardia

This article is the first in our latest series, The 12 Rhythms of Christmas, where each day we examine a new rhythm disorder. It is a continuation of the theme behind of last year’s 12 Leads of Christmas. Sinus Tachycardia It’s one of the first arrhythmias we all learn and it seems so simple. Sinus tachycardia is a regular rhythm faster than 100 bpm with a sinus P-wave before each QRS, right? Well, let’s examine some of the finer points of sinus tachycardia. Figure 1. This is not sinus tachycardia. I’m going to tell you that the ECG above does not show sinus tachycardia. It’s from an 85 year old female who presented with shortness of breath and a cough for three weeks who was diagnosed as pneumonia but did not improve on antibiotics. She appeared very healthy for her age and while her BP was 115/55 mmHg, her respiratory rate at rest was 32 /min (surprisingly unlabored) and SpO2 93% on 2 Lpm (no pulmonary Hx). Her temperature was 36.9 C (98.4 F). Unsurprisingly, CT angiography show a large PE in her right main pulmonary artery. So why doesn’t her ECG show sinus tachycardia? Let’s start by talking about her heart rate. The upper rate You may think I’m trying to trick you because her heart rate is above 150 bpm. Nope. There is this misguided notion that a narrow-complex tachycardia in an adult > 150 bpm constitutes “SVT,” implying a re-entrant mechanism involving the AV-node that can be remedied with adenosine. As we...
Source: EMS 12-Lead - Category: Cardiology Authors: Tags: 12 Rhythms of Christmas Vince DiGiulio Source Type: research