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Classification (Functional + Anatomical)
Dilated Cardiomyopathy (DCM)
- Dilated LV + reduced contractility (HFrEF)
- Most common cardiomyopathy
- Etiologies:
- Idiopathic (~ 50%)
- Familial / genetic (30-50% â titin TTN, lamin LMNA, myh7, others)
- Inflammatory (viral myocarditis, autoimmune)
- Toxic (alcohol, cocaine, anthracycline, trastuzumab, immune checkpoint inhibitor)
- Tachycardia-induced
- Peripartum (pregnancy / postpartum 6 months)
- Stress-induced (takotsubo) â reversible
Hypertrophic Cardiomyopathy (HCM)
- Asymmetric septal hypertrophy (septum/free wall ratio > 1.3)
- LVOT obstruction in some (HOCM)
- Autosomal dominant â sarcomere mutations (MYH7, MYBPC3, TNNT2 most common)
- 1 in 500 prevalence
- Risk of SCD
- Mavacamten (myosin inhibitor, FDA 2022) â game changer
Restrictive Cardiomyopathy (RCM)
- Stiff ventricles with preserved EF + impaired filling
- HFpEF phenotype
- Etiologies:
- Infiltrative: amyloidosis (AL, ATTR), sarcoidosis, hemochromatosis
- Storage: Fabry, glycogen storage
- Idiopathic
- Endomyocardial fibrosis (tropical)
- Loeffler endocarditis (eosinophilic infiltration)
- Treatment depends on etiology
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)
- Fibrofatty replacement of RV myocardium
- Autosomal dominant (plakophilin-2, desmoplakin, others)
- Risk of VT + sudden cardiac death
- Athletes + young
- ICD + exercise restriction
Stress-Induced Cardiomyopathy (Takotsubo)
- âApical ballooning syndromeâ
- âBroken heart syndromeâ
- Triggered by emotional / physical stress
- Reversible LV dysfunction
- Apical wall motion abnormality with basal sparing
- Mostly postmenopausal women
- Resolves over weeks-months
Peripartum Cardiomyopathy
- Pregnancy / postpartum 6 months
- Diagnosis of exclusion
- ~ 30-50% recover EF
- BRCA-related in some
- Treatment: standard HFrEF (avoid ACEi/ARB in pregnancy, post-partum OK)
Myocarditis
Etiologies
- Viral (most common): Coxsackie B (#1 historically), adenovirus, parvovirus B19, HHV-6, influenza, COVID-19, HIV
- Bacterial: Lyme (Borrelia), diphtheria, Trypanosoma cruzi (Chagas â chronic)
- Autoimmune / immune-mediated:
- Systemic lupus erythematosus
- Polymyositis
- Sarcoidosis (granulomatous)
- Eosinophilic
- Giant cell myocarditis (aggressive, often fatal without immunosuppression)
- Drug-induced:
- Immune checkpoint inhibitors (ICI) â newer entity; 1-2% incidence; can be fatal
- Cocaine
- Anthracyclines (cumulative dose)
- Trastuzumab
- Clozapine
- Hypersensitivity
- Heart transplant rejection
Clinical
- Acute: chest pain (often mimics ACS), dyspnea, palpitations, ARDS, cardiogenic shock
- Fulminant: severe acute LV dysfunction with hemodynamic compromise
- Sub-acute / chronic: gradual onset HF symptoms
Diagnosis
- ECG: ST-T changes, T inversion, low voltage, conduction abnormalities, arrhythmias
- Cardiac biomarkers: elevated troponin, BNP/NT-proBNP
- Echo: LV dysfunction (focal or diffuse), wall motion abnormalities, pericardial effusion
- Cardiac MRI (Lake Louise criteria):
- T1 / T2 mapping abnormal
- Late gadolinium enhancement (LGE) â patchy / epicardial / subepicardial
- Pericardial effusion
- Endomyocardial biopsy (rare; specific scenarios)
- Viral PCR (sometimes)
- Autoimmune workup (suspected immune cause)
Treatment
- Supportive: oxygen, diuretics, inotropes, mechanical support
- Standard HFrEF therapy (ACEi/ARB, β-blocker, MRA, SGLT2i)
- Immunosuppression for specific etiologies:
- Giant cell myocarditis: cyclosporine + steroid
- Eosinophilic myocarditis: steroid + treat underlying
- Sarcoidosis: steroid + methotrexate
- ICI myocarditis: high-dose steroid + stop ICI + sometimes additional immunosuppression
- Mechanical support for severe (Impella, ECMO)
- Heart transplant for refractory severe
Specific Cardiomyopathies in Detail
Hypertrophic Cardiomyopathy (HCM)
Genetics
- Autosomal dominant typically
- Sarcomere mutations:
- MYH7 (β-myosin heavy chain)
- MYBPC3 (myosin binding protein C)
- TNNT2 (troponin T)
- Variable penetrance + expression
- 1 in 500 prevalence
Phenotypes
- Asymmetric septal hypertrophy (most common)
- Apical (more common in Asia)
- Mid-cavitary
- Concentric
- Endstage burnt-out (dilated/dysfunctional)
Symptoms
- Often asymptomatic
- Dyspnea
- Chest pain (angina)
- Syncope
- Palpitations
- Sudden cardiac death (especially during exertion)
Diagnosis
- Echo: asymmetric septal hypertrophy, LV wall thickness > 15 mm (or > 13 mm if family history)
- Cardiac MRI: detailed anatomy + LGE
- ECG: LVH + repolarization abnormalities
- Genetic testing
- Family screening (first-degree relatives)
LVOT Obstruction
- Systolic anterior motion (SAM) of mitral valve
- Dynamic with maneuvers:
- Valsalva: increases obstruction + murmur
- Squat: decreases obstruction + murmur
- Severe LVOT obstruction â low cardiac output + symptoms
Treatment
- β-blockers (first-line for symptomatic obstructive)
- Non-dihydropyridine CCB (verapamil) â alternative
- Disopyramide (Class 1a antiarrhythmic with negative inotropic effect) â additional
- Mavacamten (myosin inhibitor, FDA 2022 â EXPLORER-HCM):
- Selective myosin inhibitor
- Reduces LVOT obstruction
- Improves symptoms + exercise capacity
- Less need for septal reduction therapy
- Septal reduction therapy for refractory:
- Septal myectomy (surgical)
- Alcohol septal ablation (catheter-based)
- ICD for high-risk SCD:
- Family history of SCD
- Recent syncope
- NSVT on Holter
- LVH ⥠30 mm
- Abnormal BP response to exercise
- Extensive LGE on CMR
Family Screening
- First-degree relatives
- Echo + ECG + clinical assessment
- Genetic testing
- Cascade screening if mutation identified
HCM SCD Risk Stratification (Multiple Risk Score Calculators)
- ESC HCM Risk-SCD
- HCM Risk Stratification Calculator
- Multiple risk factors integrated
Restrictive Cardiomyopathy + Cardiac Amyloidosis
Cardiac Amyloidosis
- Most common type of RCM
- AL amyloidosis (light chain â plasma cell dyscrasia)
- ATTR amyloidosis (transthyretin â wild-type or hereditary)
AL Amyloidosis
- Plasma cell dyscrasia (MGUS, multiple myeloma)
- Aggressive course
- Free light chains elevated
- Treatment:
- Daratumumab + CyBorD (cyclophosphamide + bortezomib + dexamethasone) â first-line (ANDROMEDA trial)
- Autologous SCT (in select)
- Cardiac involvement = poor prognosis without treatment
ATTR Amyloidosis
- Transthyretin misfolding
- Wild-type (senile) ATTR: elderly, especially men
- Hereditary ATTR: TTR gene mutations
- Cardiac amyloidosis âstiff heartâ + bilateral CTS + spinal stenosis + neuropathy
- Treatment:
- Tafamidis (Vyndaqel/Vyndamax â TTR stabilizer, FDA 2019) â ATTR-ACT trial
- Patisiran (Onpattro), inotersen (Tegsedi), vutrisiran (Amvuttra) â TTR silencer RNA-based
- Diflunisal (off-label, generic)
- Earlier diagnosis + treatment significantly improves outcomes
Imaging for Cardiac Amyloidosis
- Echo: concentric LVH + apical sparing on strain (âcherry-on-topâ)
- CMR: subendocardial circumferential LGE + ECV elevated + T1 elevated
- PYP scan: ATTR-specific (sensitive + specific)
- Bone scintigraphy (alternative): ATTR uptake
Diagnostic Algorithm
- Suspect: HFpEF + LVH + bilateral CTS + low voltage ECG + apical sparing
- Free light chains + SPEP/UPEP: AL screening
- Echo: typical features
- CMR: characteristic LGE pattern
- PYP scan: ATTR
- Biopsy for AL (bone marrow, fat pad, or cardiac)
- Subtype determination: ATTR (tafamidis) vs AL (chemotherapy)
Takotsubo Cardiomyopathy
Background
- âApical ballooning syndromeâ
- âBroken heart syndromeâ
- Triggered by emotional / physical stress
- Postmenopausal women (90%)
- Often during natural disasters, deaths, severe illness
Pathophysiology
- Catecholamine surge â myocardial stunning
- Apical hypoplasia with basal hyperkinesis (LV looks like Japanese octopus pot â âtakotsuboâ)
- Some atypical (mid-cavitary, basal)
Clinical
- Chest pain (often mimics MI)
- Dyspnea
- Cardiogenic shock (occasionally)
- ECG: ST elevation often
- Elevated troponin (modest)
- Coronary angiography normal
Diagnosis
- Coronary angiography normal (most reliable)
- LV gram: characteristic apical ballooning
- Echo: same
- CMR: no LGE typically (vs MI)
Treatment
- Supportive: HFrEF therapy temporarily (β-blocker, ACEi, MRA)
- Mechanical support if cardiogenic shock
- Avoid catecholamines (worsens)
- Resolves over weeks-months
- Recurrence ~ 1-5%
- Stress management + counseling
1ïžâ£ Hypertrophic Cardiomyopathy Detailed Management
Asymptomatic HCM
- Risk stratification for SCD
- ICD for high-risk
- Family screening
- Avoid competitive exercise
- Annual follow-up
Symptomatic Non-Obstructive HCM
- β-blocker / CCB (verapamil)
- Diuretics for HF symptoms
- Consider mavacamten
Symptomatic Obstructive HCM
- β-blocker (first-line)
- Verapamil alternative
- Disopyramide (Class 1a with negative inotropic effect)
- Mavacamten â newer, EXPLORER-HCM trial
- Septal reduction therapy for refractory:
- Septal myectomy (surgical, definitive)
- Alcohol septal ablation (catheter-based, alternative)
Avoid in HCM (Especially Obstructive)
- Vasodilators (worsens LVOT obstruction)
- Inotropes (worsens)
- Digoxin (worsens contractility)
- Diuretics (caution â can worsen preload)
Sudden Cardiac Death Prevention
- Risk factors:
- Family history SCD (< 50 yr)
- Recent syncope
- NSVT on Holter
- LV wall thickness ⥠30 mm
- Abnormal BP response to exercise (failure to rise > 25 mmHg)
- Extensive LGE on CMR
- ICD for high-risk
- Avoid competitive exercise
2ïžâ£ Myocarditis Detail
Clinical Presentations
Acute Lymphocytic
- Most common form
- Viral often
- LV dysfunction â HF
- Often improves with supportive care
Fulminant
- Severe acute LV dysfunction
- Cardiogenic shock
- Need mechanical support (Impella, ECMO)
- High mortality without aggressive support
- Many recover function
Sub-Acute / Chronic
- Gradual onset HF
- Often diagnosed as DCM later
- Some viral myocarditis â chronic DCM
Lake Louise Criteria (CMR for Myocarditis)
- T1 mapping abnormal (edema)
- T2 mapping abnormal
- Late gadolinium enhancement (LGE) (often epicardial / patchy)
- Pericardial effusion (often present)
- Increased extracellular volume (ECV)
Treatment
- Supportive HFrEF therapy
- Mechanical support if severe (Impella, ECMO)
- Specific immunosuppression for select forms:
- Giant cell, eosinophilic, sarcoid, ICI
- Endomyocardial biopsy rarely needed (specific scenarios â giant cell suspicion, etc.)
- Avoid competitive exercise during recovery
- Outpatient cardiology follow-up + repeat imaging
3ïžâ£ ARVC (Arrhythmogenic RV Cardiomyopathy)
Genetics
- Autosomal dominant
- Desmosome mutations (plakophilin-2, desmoplakin, plakoglobin)
- Variable penetrance
Pathology
- Fibrofatty replacement of RV myocardium
- Triangle of dysplasia: RVOT + apex + diaphragmatic
Clinical
- Often present with palpitations, syncope, SCD
- VT with LBBB morphology (RV origin)
- Family history of SCD
- Athletes + young
Diagnosis (Modified Task Force Criteria)
- ECG: epsilon wave (small upstroke after QRS in V1)
- T-wave inversion V1-V3
- VT with LBBB morphology
- Family history
- Cardiac MRI: RV dilation, dysfunction, fat infiltration
Treatment
- ICD for high-risk features
- Exercise restriction (especially competitive)
- Antiarrhythmic drugs: sotalol, amiodarone, flecainide
- β-blockers
Family Screening
- First-degree relatives
- ECG, echo, MRI
- Genetic testing