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Dobutamine - predominant beta-1 adrenergic receptor effect, results in increased inotropy and chronotropy (and can cause tachycardia); minimal alpha and beta-1 adrenergic receptor effect can result in vasodilation, but this tends to happen at higher doses (e.g. >10mcg/kg)
Posted 12/08/16 10:52:14 AM by Anna Krigel
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Causes of Acute Mitral Regurgitation:
- Ruptured mitral chordae tendineae (flail leaflet) - can be due to mitral valve prolapse, infective endocarditis, or trauma
- Papillary muscle rupture - due to acute MI
- Induction of MR in the setting of dynamic LVOT obstruction
Loudness of the MR murmur is not associated with severity of the MR because there is no turbulent flow with wide open MR
Posted 12/08/16 10:58:27 AM by Anna Krigel
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Pathophysiology of acute MR
- sudden marked increase of LA volume -> abrupt elevation of pressure in the LA -> immediately reflected back in the pulmonary circulation -> pulmonary edema
- non dilated LV -> large fraction of blood going back across the MV -> limited effective forward flow -> decreased cardiac output -> hypotension
Posted 12/08/16 11:53:49 AM by Anna Krigel
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Management of Acute MR
- Stabilization with short term mechanical circulatory support - VA ECMO or Impella for increased forward flow and cardiac ouput
- IABP + ECMO - fem-fem VA ECMO can lead to increase in afterload but returning oxygenated blood to the femoral artery, thus IABP can be used in combination to help decrease afterload
- Mitral valve surgery - prompt surgery is recommended for symptomatic acute severe mitral regurgitation
Posted 12/08/16 04:00:33 PM by Anna Krigel
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For further reading...
Posted 12/08/16 04:01:25 PM by Anna Krigel