Evidence-based cardiac exam, dyspnea triangle

Thanks Josh Liu for a great case! Also thanks to Peter Sullivan, physical diagnosis attending expert for his pearls. This is a patient with a history of heart failure and paroxysmal atrial fibrillation who presented with several weeks of progressive dyspnea with evidence of right sided failure, cardiac tamponade physiology from a likely hemorrhagic cardiac effusion from a supratherapeutic INR.

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Main points:

  1. ) A pulsus paradoxus of >10-12 mmHg has a +LR of ~3.3 and -LR of 0.03 which is the best diagnostic test we have for tamponade physiology (a reflection of a greater than expected drop in stroke volume during inspiration in the setting of high wall pressures and increased bowing of the septum towards the left side). With such a strong negative LR, pulsus is a good maneuver worth learning to make you feel more reassured that a patient does not have tamponade. Here is a great Stanford 25 page to review how to perform a pulsus.
  2. ) Things to do immediately in a patient with tamponade physiology include considering the following: hemodynamic stability (consulting the ICU), IV access, coagulation status (reversal if indicated), fluids to support preload, other consultants (cardiology/ cardiothoracic surgery for definitive treatment)
  3. ) An approach to dyspnea is the dyspnea triangle (below) which is categorized by how often these diagnoses appear: pulmonary, cardiac, anemia and then more rare metabolic/ psych. Check out this great teaching script (especially for your medical student didactics!) by Jeff Wiese at Tulane on the approach to dyspnea. Starts on page 12.
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Want to learn more?

Evidence-based cardiac exam

  • Here is a 2016 BMJ article that is a systematic review of the evidence for performing different aspects of the cardiac exam. Table 1 summarizes the evidence that exists for the various exam maneuvers. It is worth noting some high yield maneuvers include jugular venous waveform, pulsus paradoxus, aortic stenosis exam, and determining if the JVP is elevated or not.
  • Thanks Peter Sullivan for this additional pearl: a falsely elevated pulsus can be from anything that increases pressure around the heart such as asthma or obesity
  • In regards to the jugular venous waveform, check out this great Stanford 25 page on what the normal waveform is and how it changes depending on certain pathologies