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Toronto Notes 2019 Myocardial Disease Cardiology and Cardiac Surgery C39 Myocardial Disease
Definition of Cardiomyopathy
• intrinsicorprimarymyocardialdiseasenotsecondarytocongenital,hypertensive,coronary,valvular,or pericardial disease
• functionalclassification:dilated,hypertrophic,orrestrictive
• LVdysfunction2otoMIoftentermed“ischemiccardiomyopathy”,isnotatruecardiomyopathy(i.e.
primary myocardial disorder) since the primary pathology is obstructive CAD
Table 14. Summary Table for CHF and Myocardial Disease
Cardiomyopathy HARD
Hypertrophic cardiomyopathy Arrhythmogenic right ventricular cardiomyopathy
Restrictive cardiomyopathy Dilated cardiomyopathy
Heart Failure Reduced Ejection Fraction
Heart Failure Preserved Ejection Fraction
Dilated Cardiomyopathy
Idiopathic, infectious (e.g. myocarditis), alcohol, familial, collagen vascular disease, etc
Secondary Causes
CAD, MI, DM, valvular (e.g. AR, MR)
Hypertrophic Cardiomyopathy
Genetic disorder affecting cardiac sarcomeres (most common cause of sudden cardiac death in young athletes)
Restrictive Cardiomyopathy
Amyloidosis, sarcoidosis, scleroderma, hemochromatosis, Fabry’s, Pompe’s Disease, Loeffler’s, etc.
Secondary Causes
HTN, DM, valvular (e.g. AS), post-MI, transiently by ischemia, etc.
Myocarditis
Definition
• inflammatoryprocessinvolvingthemyocardiumrangingfromacutetochronic;animportantcauseof dilated cardiomyopathy
Etiology
• idiopathic • infectious
■ viral (most common): parvovirus B19, influenza, coxsackie B, echovirus, poliovirus, HIV, mumps ■ bacterial: S. aureus, C. perfringens, C. diphtheriae, Mycoplasma, Rickettsia
■ fungi
■ spirochetal (Lyme disease – Borrelia burgdorferi)
■ Chagas disease (Trypanosoma cruzi), toxoplasmosis
• toxic: catecholamines, chemotherapy, cocaine
• hypersensitivity/eosinophilic:drugs(antibiotics,diuretics,lithium,clozapine),insect/snakebites
• systemicdiseases:collagenvasculardiseases(SLE,rheumatoidarthritis,others),sarcoidosis,autoimmune • other:giantcellmyocarditis,acuterheumaticfever
Signs and Symptoms
• constitutionalsymptoms
• acuteCHF-dyspnea,tachycardia,elevatedJVP
• chestpain–duetopericarditisorcardiacischemia • arrhythmias
• systemicorpulmonaryemboli
• pre-syncope/syncope/suddendeath
Investigations
• ECG:non-specificST-Tchanges±conductiondefects
• bloodwork
■ increased CK, troponin, LDH, and AST with acute myocardial necrosis ± increased WBC, ESR, ANA, rheumatoid factor, complement levels
■ blood culture, viral titres, and cold agglutinins for Mycoplasma
• CXR:enlargedcardiacsilhouette
• echo:dilated,hypokineticchambers,segmentalwallmotionabnormalities
• cardiovascularmagneticresonance:functionalandmorphologicalabnormalitiesaswellastissue
pathology (gadolinium enhancement)
• myocardialbiopsy
Management
• supportivecare
• restrictphysicalactivity
• treatCHF
• treatarrhythmias
• anticoagulation
• treatunderlyingcauseifpossible
Prognosis
• oftenunrecognized,andmaybeself-limited
• myocarditistreatmenttrialshowed5yrmortalitybetween25-50%
• giantcellmyocarditis,althoughrarecanpresentwithfulminantCHFandberapidlyfatal,with5yr
mortality >80%
• suddendeathinyoungadults
• mayprogresstodilatedcardiomyopathy