Cardiomyopathy

Question 1

What is cardiomyopathy?

Answer 1

A myocardial disorder in which the heart muscle is structurally or functionally abnormal.
With exclusion of:
- Hypertension
- structural or valvular disease
- coronary disease

Question 2

What are the causes of cardiomyopathy?

Answer 2

1. Dilated:
   - systolic dysfunction
   - dilated ventricles
   - reduced stroke volume
   - familial
   - non-familial (idiopathic, post viral, IHD, HTN, alcohol, takotsubo)
2. Obstructive:
   - HOCM (AD inheritance)
   - LV diastolic impairment
   - obstructive at rest, labile or non-obstructive
3. Restrictive:
   - Diastolic dysfunction
   - Primary (idiopathic)
   - Secondary (amyloid, sarcoid, HTN, haemochromatosis)
4. Arrhythmogenic right ventricle:
   - associated with increased circulating catecholamines and calcium release of sarcoplasmic reticulum
   - may involve ryanodine receptor
   - genetic cause
5. Peripartum:
   - risk factors: tocolytic therapy, pre-eclampsia, obesity, advanced age, African origin.

Question 3

How would you manage a patient with cardiomyopathy?

Answer 3

Resuscitate them using an ABCDE approach correcting abnormalities as they are found.

Specific measures can be divided into pharmacological and non-pharmacological/mechanical

Pharmacological:

i) Reduce LV work
- reduce afterload (ACEi, ARBs, CCBs, spiro, inodilators, nitrates)
- control heart rate (beta blockers, CCBs)
ii) optimise contractility
- beta blockers
- inotropes, inodilators
iii) optimise preload
iv) reduce thrombotic complications
- anticoagulation if EF <30%

Mechanical:

• LVAD
• IABP temporary
• CRT
• ICD
• transplant
• partial left ventriculectomy