Hypertrophic Obstructive Cardiomyopathy (HOCM)
Considerations
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Dynamic LVOT obstruction (20-30% of patients) & need to avoid precipitants
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Perioperative hemodynamic complications:
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Arrhythmia
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Ischemia & diastolic dysfunction
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Secondary hypertrophy
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MR
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End stage: dilated cardiomyopathy
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Medication management:
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Beta blockers & calcium channel blockers
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Antiarrhythmics
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Anticoagulants
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Diuretics
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Pacemaker/ AICD
Goals
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Preload: maintain preload
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Rate & rhythm: slow-normal rate; maintain sinus rhythm
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Contractility: ↓ contractility
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Afterload: maintain or ↑ afterload
Pregnancy
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Usually tolerated well
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Continue beta blockers in pregnancy
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Goals:
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Maintenance of intravascular volume & venous return
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Avoidance of aortocaval compression
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Maintenance of adequate SVR
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Maintenance of a slow heart rate in sinus rhythm
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Aggressive treatment of acute atrial fibrillation & other tachyarrhythmias
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Prevention of increases in myocardial contractility
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Anesthetic technique:
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Likely need extra monitoring: arterial line, 5 lead ECG, possible CVC, tertiary/cardiac centre
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Spinal relatively contraindicated because of the rapid onset of a sympathectomy
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Epidural for elective cesarean section well tolerated
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GA also well tolerated
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They tolerate 2nd stage of labor well as ↑SVR helps HOCM, could consider assisted 2nd stage if needed
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Postpartum hemorrhage: oxytocin OK if given slowly; ergot a great agent
Atrial Fibrillation in HOCM Patient
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Acute in OR, best measure is cardioversion
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Beta blockers also very good choice (e.g. esmolol infusion)