More than one third of patients will have chest pain associated with SVT causing providers to order troponins and other cardiac enzymes. Elevated troponins are not pathognomonic for CAD/ACS and could represent other etiologies such as sepsis, subarachnoid hemorrhage, and pulmonary embolism. Also, subsequent coronary angiography is not necessary for risk stratification in all cases. SVT causes a rapid heart rate, which is well documented as a cause for modest troponin elevation secondary to cardiac stretch, poor diastolic perfusion, and/or coronary artery vasospasm.
Posterior myocardial infarction (MI) represents 3.3 – 21% of all acute MIs and can be difficult to diagnose by the standard precordial leads. Typically, leads V7 – V9 are needed to diagnose this entity. Luckily, leads V1 – V3, directly face the posterior wall of the left ventricle and are the “mirror image” of the posterior wall of the left ventricle.
Last week, the Patwari Academy videos covered ECG basics on rate, rhythm, and axis. Here is another set of three videos discussing ECG intervals and segments — specifically the PR interval, QRS interval, and ST segments. Again, this is a nice review on ECG concepts.
Acute coronary syndrome (ACS) is the number one cause of mortality in patients older than 65 years old. 1 To complicate this fact further, they also present atypically with weakness, nausea/vomiting, fatigue, and shortness of breath. It has been shown that older adults who present to the emergency department (ED) with ACS and a chief complaint other than chest pain have worse outcomes:
Differentiating between SVT with aberrancy and VT can be very difficult. It is crucial to be able to make this distinction as therapeutic decisions are anchored to this differentiation. Brugada et al prospectively analyzed 384 patients with VT and 170 patients with SVT with aberrant conduction to see if it was possible to come up with a simple criteria to help differentiate between the two with high sensitivity and specificity.
Dr. Rahul Patwari reviews the basics on how to determine an ECG’s rate, rhythm, and axis. It’s always nice to review these concepts. Do you remember how many seconds a traditional ECG typically spans on a single page? What’s the significance of the numbers: 300, 150, 100, 75, 60, 50? Spend a few minutes on these 2 refresher videos.
EKGs are a simple, cheap modality that can give an emergency physician quite a bit of information. Sometimes, in a busy ER, this information can be very subtle and almost overlooked without a second thought. A perfect example of this is a New Tall T-wave in lead V1 (NTTV1). This finding can be a normal variant, but can also be a precursor to badness.