Hello, excellent summary! I was wondering where the information on "the primacy of rate" came from - the idea of a heart rate > 140 being maladaptive and actually decreasing cardiac output. Cardiac Output = HR x SV, but the bodies beat-to-beat fine tuning of autonomic input on the heart makes this a very complex relationship. Reading through all my textbooks (Lilly's pathophysiology of heart disease, Boron and Baulpeeps medical physiology, and Tintinallis Emegency Medicine) and doing a search through some physiology papers online has become very confusing, and much of it has to do with exercise (where there is also a large change in Systemic Vascular Resistance). Nobody seems to directly relate HR at rest (as in arrhythmia) with Cardiac output. Can you please share your sources so I can read more into this? Thanks!
Thats just one of those cool Captain Cortex concepts. He comes up with them from time to time. Us mere mortals can not hope to understand the inner workings of such genius. Did their contemporaries really understand Socrates? Mozart? Shakespeare? Weird Al? Alas...no, like stu they were not fully appreciated in life. In the decades to come EM physicians will look back and truly appreciate the genius that was Stu. Mel, sadly will be remembered for the farting sound effects.
I was hoping someone would comment on the role of electricity in managing the appropriately anti coagulated patient with chronic atrial fib who presents with tachycardia and hypotension. We are taught to cardiovert "unstable" atrial fib but this seems unlikely to be effective in patients with chronic atrial fib who may not have been in sinus rhythm for years. My partners have suggested that the tachycardia may be the result of some AV nodal reentry on top of their chronic atrial Fib and this justifies cardioversion. We generally resort to IV fluid boluses, consider phenylephrine and cautious infusion of cardizem plus digoxin.
Thanks,
Steve C., D.O.
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Stephanie S. - October 11, 2017 11:10 PM
Hello, excellent summary!
I was wondering where the information on "the primacy of rate" came from - the idea of a heart rate > 140 being maladaptive and actually decreasing cardiac output. Cardiac Output = HR x SV, but the bodies beat-to-beat fine tuning of autonomic input on the heart makes this a very complex relationship. Reading through all my textbooks (Lilly's pathophysiology of heart disease, Boron and Baulpeeps medical physiology, and Tintinallis Emegency Medicine) and doing a search through some physiology papers online has become very confusing, and much of it has to do with exercise (where there is also a large change in Systemic Vascular Resistance). Nobody seems to directly relate HR at rest (as in arrhythmia) with Cardiac output. Can you please share your sources so I can read more into this? Thanks!
Sean G., M.D. - November 1, 2017 8:08 AM
Thats just one of those cool Captain Cortex concepts. He comes up with them from time to time. Us mere mortals can not hope to understand the inner workings of such genius. Did their contemporaries really understand Socrates? Mozart? Shakespeare? Weird Al? Alas...no, like stu they were not fully appreciated in life. In the decades to come EM physicians will look back and truly appreciate the genius that was Stu. Mel, sadly will be remembered for the farting sound effects.
Tammy L. - November 8, 2017 5:18 PM
I was hoping someone would comment on the role of electricity in managing the appropriately anti coagulated patient with chronic atrial fib who presents with tachycardia and hypotension. We are taught to cardiovert "unstable" atrial fib but this seems unlikely to be effective in patients with chronic atrial fib who may not have been in sinus rhythm for years. My partners have suggested that the tachycardia may be the result of some AV nodal reentry on top of their chronic atrial Fib and this justifies cardioversion. We generally resort to IV fluid boluses, consider phenylephrine and cautious infusion of cardizem plus digoxin.
Thanks,
Steve C., D.O.