Cardiomyopathy Flashcards
What are the types of primary cardiomyopathies issued by the AHA?
Genetic, mixed, and acquired
What are the genetic causes of primary cardiomyopathies?
HCM, ARVC/D, LVNC, glycogen storage disorders (PRKAG2, Danon), Conduction defects, mitochondrial myopathies, Ion channel disorders (LQTS, Brugada, SQTS, CVPT, Asian SUNDS)
What are the acquired causes of primary cardiomyopathies?
Inflammatory (myocarditis), stress-induced (Takotsubos), peripartum, tachycardia-induced, infants of insulin-dependent diabetic mothers
What are the mixed causes of primary cardiomyopathies?
Dilated CM, restrictive (non-hypertrophied and non-dilated)
What are the causes of secondary cardiomyopathies?
Infiltrative (amyloidosis, Gaucher disease, Hurler’s disease, Hunter’s disease), Storage (hemochromatosis, Fabry’s disease, Glycogen storage disease - type II, Pompe, Niemann-Pick disease), Toxicity, Endomyocardial (fibrosis or hypereosinophilic syndrom), Inflammatory/granulomatous (Sarcoidosis), Endocrine (DM, hyper/hypothyroidism, pheo, acromegaly), Cardiofacial (Noonan syndrome, Lentiginosis), Neuromuscular (Friedrich’s ataxia, Duchenne-Becker, Emery-Dreifuss, NF1/2, tuberous sclerosis), Nutritional deficiencies (Beriberi -thiamine, pellagra, scurvy, selenium, carnitine, kwashiorkor), Autoimmune/collagen (SLE, dermatomyositis, RA, scleroderma, polyarteritis nodosa), electrolyte imbalances, cancer therapy (anthracyclines like doxorubicin, adriamycin, danorubicin, cyclophosphamide, radiation)
How does the European Society of Cardiology (ESC) classify cardiomyopathies?
Based on ventricular morphological and functional phenotypes; HCM, dilated CM, ARVC, restrictive, or unclassified
What is the most common type of CM as classified by the ESC?
Dilated cardiomyopathy
What is familial dilated cardiomyopathy?
20-48% of all cases + genetics involved (autosomal dominant with incomplete penetrance and variable extression) + 4th to 5th decade of life
What are secondary causes of dilated CM?
Infection, toxins, autoimmune disease, pregnancy
What is the 5-year mortality rate of dilated CM once you develop symptoms?
50%; 25% of patients who develop symptoms will recover sponaneously though
What do you see in the heart with patients with dilated CM?
4 chamber dilation (ventricles > atria) + thinning of ventricular walls + hypertrophy of heart + regurgitant valves
What are the general characteristics of a restrictive cardiomyopathy?
Normal or decreased volume of both ventricles associated with biatrial enlargement + normal LV wall thickness + normal AV valves + impaired ventricular filling with restrictive physiology + normal/near normal systolic function
What are myocardial causes of restrictive CM?
Noninfiltrative (idiopathic, familial, hypertrophic, scleroderma, pseudoxanthoma elasticum, diabetic CM) + infiltrative (amyloidosis, sarcoidosis, Gaucher disease, Hurler disease, fatty infiltration) + storage diseases (hemochromatosis, Fabry disease, glycogen storage disease)
What are endomyocardial causes of restrictive CM?
Endomyocardial fibrosis + hypereosinophilic syndrome + carcinoid heart disease + metastatic cancers + radiation + toxic effects of anthracycline + drugs causing fibrois endocarditis (serotonin, methysergide, erotamine, mercurial agents, busulfan)
Difference between restrictive CM and constrictive pericarditis
RCM: LVEDP > RVEDP (by at least 5 mmHg) + inspiration in spontaneous ventilation leads to drops in both right and left ventricular pressures due to decreased intrathoracic pressure; CP: ventricular diastolic pressures are equal and elevated + inspiration causes increased right-sided filling and subsequent decreased left-sided filling from ventricular interdependence
What signs are associated with a worse prognosis in restrictive CM?
Age > 70yo + increasing NYHA functional class + LA diameter > 60mm
What is arrhythmogenic RV cardiomyopathy (ARVC)?
Progressive fibrofatty replacement of myocardiaum predominantly along the RV free wall –> leads to ventricular wall thinning and aneurysmal dilation (increased risk of re-entry arrhthmias)
What is the pathophysiology of ARVC?
Mutations of desmosomes (cellular adhesion proteins) which can disrupt intercellular junctions and cause myocyte detachment and cell death
What is considered a disease modifier in ARVC?
Sports activity; promotes the progression of disease by aggravating the mechanical uncoupling of myocytes and triggers malignant ventricular arrhythmias through catecholamine release
What age and gender do you normally see ARVC in?
Between adolescence and 4th decade of life, men > women + 50% have a family history of sudden cardiac death
What is the concealed phase of ARVC?
The phase before clinically significant disease; no overt structural damage
What is a common first presenting symptom of ARVC?
Sudden cardiac death (accounts for up to 20% of sudden cardiac death in young people)
What finding is pathognomonic for ARVC?
RV aneurysms
Can the left side be affected by ARVC?
Yes, sometimes this is confused with dilated CM because of biventricular involvement
What is the classic EKG finding for ARVC?
T-wave inversions in the right-sided precordial leads (V1-V3) + Epsilon wave (V1-V2) + QRS > 120ms + extrasystoles with LBBB
What is an epsilon wave on EKG?
Common finding in ARVC; small-amplitude distinct potentials between the end of the QRS complex and the beginning of the T-waves
What is the most common cause of myocarditis?
Viral infections (Parvovirus B19 and human herpes virus 6)
What are the 3 phases of pathogenesis for viral cardiomyopathies?
- Acute viral: virus proliferates in host tissue, often missed
- Subacute immune: activation of acquired immunity leads to chronic inflammation that promotes myocyte necrosis, fibrosis and remodeling
- Chronic myopathic: persistent inflammatory response leads to structural changes, heart failure, and dilated CM
What is the gold standard for diagnosing viral CM?
Endomyocardial biopsy
What are risk factors for peripartum cardiomyopathy?
African-American ethnicity + hypertensive disorders of pregnancy + multiparity + advanced maternal age + multifetal pregnancy + prolonged tocolysis + family history
Why do we think peripartum cardiomyopathy occurs?
It is a vascular disease triggered by hormonal changes of pregnancy
What is the clinical course of peripartum CM?
Highly variable; sometimes it can lead to rapid progression of heart failure or completely recovery; usually seen 3-6 months after diagnosis but can take up to 48 months
What are some risk factors that lead to lower likelihood of recovery from peripartum CM?
African-American ethnicity + LVEF < 30% + LV dilation + LV thrombus + RV systolic dysfunction + obesity
