Genetic Cardiomyopathies

Question 1

Hypertrophic CM

Answer 1

NOTE: Young athlete performing an intense sport or athletic event associated with a sudden collapse think hypertrophic cardiomyopathy.

(1. ) Mutation causes ventricle and septum hypertrophy, this increased thickness of causes heart to become stiff and develops DIASTOLIC-HF
(2. ) Can cause LV outflow obstruction (Obstructive CM) and mitral regurgitation.
(4. ) Clinical features = angina, breathlessness, arrhythmia, sudden death
(5. ) Investigations = ECHO, ECG (large voltage, tachycardia), Genetic testing

(6. ) Management:
(a. ) Restrict high intensity exercise & athletic/sporting events
(b. ) AF = ablation or rate control e.g. amiodarone
(c. ) Prevent syncopal attacks = B-blockers, rate-limiting Ca antagonists
(d. ) Implantable cardioverter defibrillator
(e. ) Myectomy

Question 2

Dilated CM - What is it? Clinical features? Investigations? Management?

Answer 2

(1. ) Mutation that causes dilation + impaired contraction of LV and RV. Cavities are enlarged.
(2. ) Dilation can lead to dysfunctional mitral and tricuspid valves. HF is seen due to impairment of contractility of heart
(3. ) Clinical features = Pts present with HF, sporadic chest pains. DDx of ventricular dysfunction and CAD must be ruled out for diagnosis.
(4. ) Investigations = ECHO, MRI, Genetic testing

(5. ) Management - control HF
(a. ) B-blockers, ACEi, ARBs
(b. ) Implantation of cardiac defibrillator pr cardiac resynchronisation therapy
(c. ) transplantation may be indicated

Question 3

Arrhythmogenic CM

Answer 3

(1. ) Predominantly affects myocardium of RV
(2. ) Genetic defects in desmosal protein genes
(3. ) Replacement of myocardium with fibrous and fatty tissues
(4. ) Clinical features = ventricular arrhythmias, sudden death, right sides HF
(5. ) Investigations = MRI, ECG (broad QRS, inverted T wave), Genetic testing

(6. ) Management
- Diuretics = right sided HF
- b-blockers = arrhythmias
- implantable defibrillator = hi risk of sudden deathh