Cardiomyopathy, Myocarditis and pericarditis – pathophysiology, presentation, investigation and therapy

Question 1

What are the 4 main types of cardiomyopathy?

Answer 1

1️⃣ Hypertrophic Cardiomyopathy (HCM) – Thickened ventricular walls
2️⃣ Dilated Cardiomyopathy (DCM) – Enlarged, weak ventricles
3️⃣ Restrictive Cardiomyopathy (RCM) – Stiff, non-compliant myocardium
4️⃣ Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) – Fatty/fibrotic replacement of RV

Question 2

What are the genetic causes of Hypertrophic Cardiomyopathy (HCM)?

Answer 2

🔹 Autosomal dominant inheritance
🔹 Mutations in sarcomere protein genes (e.g., MYH7, MYBPC3)
🔹 Causes myocyte disarray, fibrosis, left ventricular hypertrophy (LVH)

Question 3

What are the clinical features of Hypertrophic Cardiomyopathy (HCM)?

Answer 3

✅ Dyspnea (due to diastolic dysfunction)
✅ Angina (myocardial oxygen demand ↑)
✅ Syncope & sudden cardiac death (SCD) (risk of arrhythmias)
✅ Harsh systolic murmur (worse with Valsalva)

Question 4

What are the causes of Dilated Cardiomyopathy (DCM)?

Answer 4

🔹 Genetic (TTN, LMNA mutations)
🔹 Infections (viral myocarditis)
🔹 Toxins (alcohol, cocaine, chemotherapy)
🔹 Metabolic (hypothyroidism, thiamine deficiency)

Question 5

What are the clinical features of Dilated Cardiomyopathy (DCM)?

Answer 5

🔹 Heart failure symptoms (dyspnea, fatigue, edema)
🔹 Arrhythmias (A-fib, ventricular tachycardia)
🔹 Murmurs (mitral/tricuspid regurgitation due to dilation)

Question 6

What are the treatment options for Hypertrophic Cardiomyopathy (HCM)?

Answer 6

🩺 Beta-blockers (reduce myocardial oxygen demand)
💊 Calcium channel blockers (e.g., verapamil) – Improve relaxation
⚡ ICD (Implantable Cardioverter-Defibrillator) – Prevent SCD
✂️ Myectomy or alcohol septal ablation – If severe obstruction

Question 7

What are the treatment options for Dilated Cardiomyopathy (DCM)?

Answer 7

🔹 ACE inhibitors, Beta-blockers, Diuretics (treat heart failure)
🔹 Anticoagulation (if A-fib or LV thrombus present)
🔹 Heart transplant (if severe refractory disease)

Question 8

What are the causes of Restrictive Cardiomyopathy (RCM)?

Answer 8

🔹 Amyloidosis (most common)
🔹 Sarcoidosis
🔹 Hemochromatosis
🔹 Endomyocardial fibrosis

Question 9

What are the clinical features of Restrictive Cardiomyopathy (RCM)?

Answer 9

✅ Signs of right heart failure (JVP distension, peripheral edema)
✅ Diastolic dysfunction (stiff ventricle)
✅ Normal ventricular size, thick walls on echo

Question 10

What are the causes of Myocarditis?

Answer 10

🦠 Viral (Coxsackie B, adenovirus, parvovirus B19)
🦠 Bacterial (Diphtheria, Lyme disease)
🦠 Autoimmune (SLE, giant cell myocarditis)
🦠 Toxic (Cocaine, chemotherapy drugs)

Question 11

What are the clinical signs of Myocarditis?

Answer 11

💔 Chest pain (mimics MI but with normal coronary arteries)
💔 Heart failure symptoms (dyspnea, fatigue, edema)
💔 Arrhythmias (palpitations, syncope, sudden death)

Question 12

What is the treatment for Myocarditis?

Answer 12

✅ Supportive care (O2, diuretics, beta-blockers)
✅ Treat underlying cause (e.g., antivirals, immunosuppressants)
✅ Avoid NSAIDs (worsens inflammation)

Question 13

Mnemonic for Cardiomyopathies: “HAR-D”

Answer 13

✅ Hypertrophic – Genetic, thick heart walls
✅ Arrhythmogenic Right Ventricular – Fatty RV replacement
✅ Restrictive – Rigid walls (amyloidosis, sarcoidosis)
✅ Dilated – Large, weak ventricles