Left Ventricular Outflow Tract Obstruction (LVOTO)

OVERVIEW

• associated with myocardial hypertrophy and systolic anterior motion of the the mitral vale
• important to recognise as can contribute to a low output state that gets worse with inotropic support

ASSESSMENT

History

• hypertension
• post AVR
• known LVH or HCM
• increasing inotropes
• no tamponade

Examination

• late systolic murmur over the praecordium

Investigations

• ECHO:
  • -> small LV cavity
  • -> normal systolic function and no RWMA
  • -> AVR functioning well
  • -> flow acceleration noted in LVOT on colour Doppler
  • -> reduced LVOT area during systole
  • -> systolic anterior motion of valve leaflets (MR)
  • -> high peak gradient across LVOT

MANAGEMENT

• stop adrenaline
• volume load
• beta-blockers to slow heart rate and reduce contractility
• calcium antagonist
• AV sequential pacing
• vasoconstrictor without inotropic effect (ie. phenylephrine/noradrenaline)
• myomectomy or resection of outflow tract

References and Links

• LITFL CCC — Hypertrophic cardiomyopathy
• Scancrit — Systolic anterior motion (SAM)