Fascicular Blocks:
- Left bundle branch system: sub-divided into an anterior & posterior fascicle.
- Hemi-block does not widen the QRS complex markedly (compared to a RBBB or LBBB)
Left Anterior Fascicular Block (LAFB):
- Diagnosed by finding of a left axis deviation (-45 degrees or more negative)
- Delayed activation of more superior & leftward position of the LV
- Isolated finding is non-specific; can be seen w/ HTN, AV disease, CAD, and aging
LAFB ECG:
- rS complexes in lead II, III, avF, and small R waves and deep S waves
- qR complexes in leads I, aVL, with small Q waves and tall R waves
- (+) deflection in I & avL and (-) deflection in II, III, aVF
Left Posterior Fascicular Block (LPFB):
- Right axis deviation (+ 120 degrees or more positive)
- Delayed activation of more inferior & rightward portion of LV
- Diagnosis of exclusion for right-axis deviation (other more common: RVH, emphysema, lateral wall infarction, PE)
LPFB ECG:
- rS complexes in leads I and avL, with small R waves and deep S waves
- qR complexes in leads II, III, avF with small Q waves and tall R waves
- Right axis deviation: (+) in II, III, aVF and (-) in I & aVL
Bi-fascicular Block
- Block in any of 2/3 fascicles
- RBBB + LAFB = RBBB with left-axis deviation
- RBBB + LPFB = RBBB with right-axis deviation
- Development of a new bi-fascicular block (usually RBBB with LAFB) during acute anterior MI may be warning for complete heart block
Tri-fascicular Block
- With 1:1 AV conduction is rarely present on ECG
- Patients can present with alternating LBBB & RBBB. In these patients, a permanent pacemaker is indicated because of high risk for abrupt complete heart block.
- Image: RBBB + LAFB + 3rd degree
Thanks to this amazing site for the graphics! Stay tuned for the next threads on myocardial ischemia!
Pre-Rounding Tips 3d: How to think about Troponin? (
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Pro-Tip: If you can print out a pre-rounding sheet with the labs auto-populated, that is always helpful.
One of the most common consults from the Emergency Room to Cardiology is 'elevated troponin.'
Yes, elevated troponin can be scary, but here is the framework that I use to analyze / consider troponin.
1. Patient Presentation? 2. Patient's risk factors and prior cardiac history? 3. What is the troponin trend? 4. What does the ECG look like? 5. What are some non-cardiac reasons troponin may be elevated?
1. Patient Presentation?
In Cardiology, the clinical presentation is the most important part of the story when determining the significance of an elevated troponin! In many situations, clinical decisions (whether to pursue a LHC) may be made in the absence of having a troponin available.
Key Questions: 1. If the patient presents with chest pain, how does he/she describe it?
- Some common worrisome symptoms associated with angina. Elevated troponin in the setting of these symptoms should always be taken seriously.
a) Chest pressure, constant, sub-sternal.
b) Radiation of pain to the neck or jaw
c) Diaphoresis
d) Numbness to the left arm
e) New onset dyspnea
f) Worse with exertion, better with rest
2. What makes the pain better?
- If the patient got improvement with nitroglycerin more likely to be consistent with cardiac chest pain.
- If patient's pain improves with muscle relaxers, IV toradol, IV PPI, IV Ativan, less likely to be a cardiac etiology.
3. Has the patient had this type of pain before?
- If similar recent presentation with a negative work-up, this might be reassuring. However, you don't want to have anchor bias and should keep an open perspective.
When I was an intern, pre-rounding was one of the most stressful parts of the day. I would take too long and be inefficient. Part 1.
Now as a PGY7 (long-time, right?), here is 3 parts of my system that I use for new patients.
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On Twitter, I will provide a more condensed version for easier reading. In the email format, I will expand on my thoughts to provide more detailed insights. I will walk you through my thought process and make sure they are concise but helpful.
Future direction will be ECG/Echo/General Cardiology Topics!
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1) Why is the patient here / chief concern?
- This seems like the most basic question that is often overlooked. What made the patient decide to leave his/her house to come to the hospital?
- When reading the overnight H&P, the abundance of clinical documentation can create confusion.
- Simplicity is key. What is the chief concern? Is it chest pain? Is it dyspnea on exertion? Knowing this information will help frame your thoughts.
2) What are the relevant past medical problems?
- Most patients will have chronic medical problems that will contribute to the current presentation.
- It is easy to get lost in the weeds of this presentation. In Cardiology, I typically focus on (but not limited to) coronary artery disease, atrial fibrillation, hypertension, hyperlipidemia, diabetes mellitus, history of CVA. Again, this is not all inclusive but it is a start.
- Although patients may present to the hospital with a new diagnosis, it is more likely that the presentation may be an exacerbation of a previous problem.