Bundle Branch Blocks (BBBs) 101

722px-Electrical_conduction_system_of_the_heartRecently, I have been asked by several students at my home institution (UTHSC at San Antonio) to help them understand bundle branch blocks.  This is different than some of my usual posts because it is meant to be more educational than evidence based.  So here we go.  The normal conduction system of the healthy heart is shown to the right.  If there is a delay or block in the left or right bundle, depolarization will take longer to occur. Therefore we get a widened QRS (>0.12 sec or >3 small boxes).



PV Card: Brugada Criteria for SVT with Aberrancy vs Ventricular Tachycardia

2011_04_22AwmExpertPeerReviewStamp2x200Due to the overwhelming popularity of Dr. Salim Rezaie‘s recent post discussing the Brugada criteria for  SVT with aberrancy vs VT, Dr. Jason West (@JWestEM, an EM resident from Jacobi/Montefiore) kindly helped to co-author and package this information into a PV card for quick reference. To use this sequential, four-question approach, if at any time you answer YES to the question, it is ventricular tachycardia.



Choosing the right vasopressor agent in hypotension

HypotensionExpertPeerReviewStamp2x200The incidence of critical illness in the ED is rising, with greater than 1 million ED patients requiring emergent resuscitation each year. In addition to definitive airway management, hemodynamic support is among the most important life-saving interventions implemented by emergency physicians. When a patient develops persistent hypotension, what is your approach to choosing the right medication for hemodynamic support?


A time-based approach to elderly patients with altered mental status

clockIt’s 7 am on a Monday. Your first patient is an 82 year-old woman who was brought in by EMS from an assisted living facility. All EMS can tell you is that she was not acting herself. You enter her room and introduce yourself. “Hello Mrs. Jones. How are you today?” The woman startles, “Well, you see, I went to put my dog out, and then I was just walking, and couldn’t remember. So it’s all coming full circle, and then I ate a sandwich.” Just then EMS rolls in with another patient, a 75 year-old male coming from home, who was found by his wife in his recliner minimally responsive, with a GCS of 6.  He is followed by a 76 year-old female who had a fall from standing three days ago, and has been increasingly confused today, and is currently oriented only to person.


Alarms from the ventilator: Troubleshooting high peak pressures

VentilatorAirway management is one of the defining skills of an emergency physician, but our role in the care of intubated patients may continue long after endotracheal tube placement is confirmed. In mechanically ventilated patients, acute elevations in airways pressures can be triggered by both benign and life-threatening causes. When the ventilator alarms, do you know how to tell the difference? What is your approach in troubleshooting the potential problems?


Supraventricular Tachycardia (SVT) With Aberrancy Versus Ventricular Tachycardia (VT)

2011_04_22AwmEPRDifferentiating 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.



EKG Subtlety: Tall T-Wave in Lead V1


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.