Hypertrophic cardiomyopathy

 

Disease:

Definition

·      Unexplained ventricular hypertrophy

Presentation

·      Forty odd

·      Cardiac symptoms

·      Murmur

·      Collapse

·      Sudden death

Treatment

·      Beta blocker

·      AICD

·      Myomectomy

Complications

·      Dynamic LVOTO (20-30%)

·      Mitral regurgitation

·      Arrhythmias (AF, VT, VF)

·      Ischaemia

·      Hypertrophy -> diastolic dysfunction

·      Remodelling -> systolic dysfunction

 

Investigations:

ECG

·      Left axis deviation

·      P wave abnormalities

·      Deep, narrow Q waves

·      Big amplitude QRS

·      ST-T changes (e.g. giant negative T waves)

Echo

HCM:

·      LV wall thickness >15mm without explanation

·      Most common: basal-anterior septum + anterior wall

LVOTO:

·      Hyperdynamic

·      LV cavity

·      LVOT narrowing

·      LVOT flow acceleration

·      ↑ With Valsalva, ↓ with squatting

·      ±SAM

SAM:

·      i.e. systolic anterior motion of anterior MV leaflet

·      Posteriorly-directed MR

·      Prolonged mitral-septal contact = severe

 

Goals:

Summary

1.         Volume

2.         Pressor

3.         Sympatholysis

No LVOTO

·      ↑↔Preload: crystalloid

·      ↑↔Afterload: metaraminol infusion

·      ↓↔Heart rate: opioid, beta blocker

·      ↓↔Contractility: opioid, beta blocker

No ischaemia

·      ↑↔SVR / ↑AoP: metaraminol infusion

·      ↓↔Heart rate: opioid, beta blocker

No arrhythmias

·      Pacemaker planning

·      Low threshold for cardioversion

·      Normal electrolytes

·      Normal PaCO2

 

Anaesthesia practice:

Access

·      Big IV + pump set

·      Arterial line (low threshold)

Monitoring

·      Standard

·      5 lead ECG

·      Arterial line

·      PPV

Induction drugs

·      CSL 500mL

·      Midazolam 0.025mg/kg

·      Fentanyl 5mcg/kg

·      Propofol 2mg/kg very slowly

·      Rocuronium 0.6mg/kg

·      Metaraminol infusion 5mg/h + boluses 0.5mg

 

 

Feedback welcome at ketaminenightmares@gmail.com